Merge pull request #3194 from OancaAndrei/syncplay-enhanced

SyncPlay for TV series (and Music)

40 files changed, 3239 insertions, 272 deletions

diff --git a/MediaBrowser.Controller/Net/BasePeriodicWebSocketListener.cs b/MediaBrowser.Controller/Net/BasePeriodicWebSocketListener.cs
index 28227603b..163a9c8f8 100644
--- a/MediaBrowser.Controller/Net/BasePeriodicWebSocketListener.cs
+++ b/MediaBrowser.Controller/Net/BasePeriodicWebSocketListener.cs
@@ -92,6 +92,9 @@ namespace MediaBrowser.Controller.Net
             return Task.CompletedTask;
         }
 
+        /// <inheritdoc />
+        public Task ProcessWebSocketConnectedAsync(IWebSocketConnection connection) => Task.CompletedTask;
+
         /// <summary>
         /// Starts sending messages over a web socket.
         /// </summary>
diff --git a/MediaBrowser.Controller/Net/IWebSocketListener.cs b/MediaBrowser.Controller/Net/IWebSocketListener.cs
index 7250a57b0..f1a75d518 100644
--- a/MediaBrowser.Controller/Net/IWebSocketListener.cs
+++ b/MediaBrowser.Controller/Net/IWebSocketListener.cs
@@ -3,7 +3,7 @@ using System.Threading.Tasks;
 namespace MediaBrowser.Controller.Net
 {
     /// <summary>
-    ///This is an interface for listening to messages coming through a web socket connection.
+    /// Interface for listening to messages coming through a web socket connection.
     /// </summary>
     public interface IWebSocketListener
     {
@@ -13,5 +13,12 @@ namespace MediaBrowser.Controller.Net
         /// <param name="message">The message.</param>
         /// <returns>Task.</returns>
         Task ProcessMessageAsync(WebSocketMessageInfo message);
+
+        /// <summary>
+        /// Processes a new web socket connection.
+        /// </summary>
+        /// <param name="connection">An instance of the <see cref="IWebSocketConnection"/> interface.</param>
+        /// <returns>Task.</returns>
+        Task ProcessWebSocketConnectedAsync(IWebSocketConnection connection);
     }
 }
diff --git a/MediaBrowser.Controller/Net/IWebSocketManager.cs b/MediaBrowser.Controller/Net/IWebSocketManager.cs
index ce74173e7..bb0ae83be 100644
--- a/MediaBrowser.Controller/Net/IWebSocketManager.cs
+++ b/MediaBrowser.Controller/Net/IWebSocketManager.cs
@@ -1,7 +1,4 @@
-using System;
-using System.Collections.Generic;
 using System.Threading.Tasks;
-using Jellyfin.Data.Events;
 using Microsoft.AspNetCore.Http;
 
 namespace MediaBrowser.Controller.Net
@@ -12,11 +9,6 @@ namespace MediaBrowser.Controller.Net
     public interface IWebSocketManager
     {
         /// <summary>
-        /// Occurs when [web socket connected].
-        /// </summary>
-        event EventHandler<GenericEventArgs<IWebSocketConnection>> WebSocketConnected;
-
-        /// <summary>
         /// The HTTP request handler.
         /// </summary>
         /// <param name="context">The current HTTP context.</param>
diff --git a/MediaBrowser.Controller/Session/ISessionManager.cs b/MediaBrowser.Controller/Session/ISessionManager.cs
index 04c3004ee..9ad8557ce 100644
--- a/MediaBrowser.Controller/Session/ISessionManager.cs
+++ b/MediaBrowser.Controller/Session/ISessionManager.cs
@@ -143,22 +143,22 @@ namespace MediaBrowser.Controller.Session
         Task SendPlayCommand(string controllingSessionId, string sessionId, PlayRequest command, CancellationToken cancellationToken);
 
         /// <summary>
-        /// Sends the SyncPlayCommand.
+        /// Sends a SyncPlayCommand to a session.
         /// </summary>
-        /// <param name="sessionId">The session id.</param>
+        /// <param name="session">The session.</param>
         /// <param name="command">The command.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
         /// <returns>Task.</returns>
-        Task SendSyncPlayCommand(string sessionId, SendCommand command, CancellationToken cancellationToken);
+        Task SendSyncPlayCommand(SessionInfo session, SendCommand command, CancellationToken cancellationToken);
 
         /// <summary>
-        /// Sends the SyncPlayGroupUpdate.
+        /// Sends a SyncPlayGroupUpdate to a session.
         /// </summary>
-        /// <param name="sessionId">The session id.</param>
+        /// <param name="session">The session.</param>
         /// <param name="command">The group update.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
         /// <returns>Task.</returns>
-        Task SendSyncPlayGroupUpdate<T>(string sessionId, GroupUpdate<T> command, CancellationToken cancellationToken);
+        Task SendSyncPlayGroupUpdate<T>(SessionInfo session, GroupUpdate<T> command, CancellationToken cancellationToken);
 
         /// <summary>
         /// Sends the browse command.
diff --git a/MediaBrowser.Controller/SyncPlay/GroupInfo.cs b/MediaBrowser.Controller/SyncPlay/GroupInfo.cs
deleted file mode 100644
index a1cada25c..000000000
--- a/MediaBrowser.Controller/SyncPlay/GroupInfo.cs
+++ /dev/null
@@ -1,160 +0,0 @@
-using System;
-using System.Collections.Generic;
-using MediaBrowser.Controller.Entities;
-using MediaBrowser.Controller.Session;
-
-namespace MediaBrowser.Controller.SyncPlay
-{
-    /// <summary>
-    /// Class GroupInfo.
-    /// </summary>
-    /// <remarks>
-    /// Class is not thread-safe, external locking is required when accessing methods.
-    /// </remarks>
-    public class GroupInfo
-    {
-        /// <summary>
-        /// The default ping value used for sessions.
-        /// </summary>
-        public const long DefaultPing = 500;
-
-        /// <summary>
-        /// Gets the group identifier.
-        /// </summary>
-        /// <value>The group identifier.</value>
-        public Guid GroupId { get; } = Guid.NewGuid();
-
-        /// <summary>
-        /// Gets or sets the playing item.
-        /// </summary>
-        /// <value>The playing item.</value>
-        public BaseItem PlayingItem { get; set; }
-
-        /// <summary>
-        /// Gets or sets a value indicating whether playback is paused.
-        /// </summary>
-        /// <value>Playback is paused.</value>
-        public bool IsPaused { get; set; }
-
-        /// <summary>
-        /// Gets or sets a value indicating whether there are position ticks.
-        /// </summary>
-        /// <value>The position ticks.</value>
-        public long PositionTicks { get; set; }
-
-        /// <summary>
-        /// Gets or sets the last activity.
-        /// </summary>
-        /// <value>The last activity.</value>
-        public DateTime LastActivity { get; set; }
-
-        /// <summary>
-        /// Gets the participants.
-        /// </summary>
-        /// <value>The participants, or members of the group.</value>
-        public Dictionary<string, GroupMember> Participants { get; } =
-            new Dictionary<string, GroupMember>(StringComparer.OrdinalIgnoreCase);
-
-        /// <summary>
-        /// Checks if a session is in this group.
-        /// </summary>
-        /// <param name="sessionId">The session id to check.</param>
-        /// <returns><c>true</c> if the session is in this group; <c>false</c> otherwise.</returns>
-        public bool ContainsSession(string sessionId)
-        {
-            return Participants.ContainsKey(sessionId);
-        }
-
-        /// <summary>
-        /// Adds the session to the group.
-        /// </summary>
-        /// <param name="session">The session.</param>
-        public void AddSession(SessionInfo session)
-        {
-            Participants.TryAdd(
-                session.Id,
-                new GroupMember
-                {
-                    Session = session,
-                    Ping = DefaultPing,
-                    IsBuffering = false
-                });
-        }
-
-        /// <summary>
-        /// Removes the session from the group.
-        /// </summary>
-        /// <param name="session">The session.</param>
-        public void RemoveSession(SessionInfo session)
-        {
-            Participants.Remove(session.Id);
-        }
-
-        /// <summary>
-        /// Updates the ping of a session.
-        /// </summary>
-        /// <param name="session">The session.</param>
-        /// <param name="ping">The ping.</param>
-        public void UpdatePing(SessionInfo session, long ping)
-        {
-            if (Participants.TryGetValue(session.Id, out GroupMember value))
-            {
-                value.Ping = ping;
-            }
-        }
-
-        /// <summary>
-        /// Gets the highest ping in the group.
-        /// </summary>
-        /// <returns>The highest ping in the group.</returns>
-        public long GetHighestPing()
-        {
-            long max = long.MinValue;
-            foreach (var session in Participants.Values)
-            {
-                max = Math.Max(max, session.Ping);
-            }
-
-            return max;
-        }
-
-        /// <summary>
-        /// Sets the session's buffering state.
-        /// </summary>
-        /// <param name="session">The session.</param>
-        /// <param name="isBuffering">The state.</param>
-        public void SetBuffering(SessionInfo session, bool isBuffering)
-        {
-            if (Participants.TryGetValue(session.Id, out GroupMember value))
-            {
-                value.IsBuffering = isBuffering;
-            }
-        }
-
-        /// <summary>
-        /// Gets the group buffering state.
-        /// </summary>
-        /// <returns><c>true</c> if there is a session buffering in the group; <c>false</c> otherwise.</returns>
-        public bool IsBuffering()
-        {
-            foreach (var session in Participants.Values)
-            {
-                if (session.IsBuffering)
-                {
-                    return true;
-                }
-            }
-
-            return false;
-        }
-
-        /// <summary>
-        /// Checks if the group is empty.
-        /// </summary>
-        /// <returns><c>true</c> if the group is empty; <c>false</c> otherwise.</returns>
-        public bool IsEmpty()
-        {
-            return Participants.Count == 0;
-        }
-    }
-}
diff --git a/MediaBrowser.Controller/SyncPlay/GroupMember.cs b/MediaBrowser.Controller/SyncPlay/GroupMember.cs
index cde6f8e8c..5fb982e85 100644
--- a/MediaBrowser.Controller/SyncPlay/GroupMember.cs
+++ b/MediaBrowser.Controller/SyncPlay/GroupMember.cs
@@ -8,21 +8,36 @@ namespace MediaBrowser.Controller.SyncPlay
     public class GroupMember
     {
         /// <summary>
-        /// Gets or sets a value indicating whether this member is buffering.
+        /// Initializes a new instance of the <see cref="GroupMember"/> class.
         /// </summary>
-        /// <value><c>true</c> if member is buffering; <c>false</c> otherwise.</value>
-        public bool IsBuffering { get; set; }
+        /// <param name="session">The session.</param>
+        public GroupMember(SessionInfo session)
+        {
+            Session = session;
+        }
 
         /// <summary>
-        /// Gets or sets the session.
+        /// Gets the session.
         /// </summary>
         /// <value>The session.</value>
-        public SessionInfo Session { get; set; }
+        public SessionInfo Session { get; }
 
         /// <summary>
-        /// Gets or sets the ping.
+        /// Gets or sets the ping, in milliseconds.
         /// </summary>
         /// <value>The ping.</value>
         public long Ping { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether this member is buffering.
+        /// </summary>
+        /// <value><c>true</c> if member is buffering; <c>false</c> otherwise.</value>
+        public bool IsBuffering { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether this member is following group playback.
+        /// </summary>
+        /// <value><c>true</c> to ignore member on group wait; <c>false</c> if they're following group playback.</value>
+        public bool IgnoreGroupWait { get; set; }
     }
 }
diff --git a/MediaBrowser.Controller/SyncPlay/GroupStates/AbstractGroupState.cs b/MediaBrowser.Controller/SyncPlay/GroupStates/AbstractGroupState.cs
new file mode 100644
index 000000000..e3de22db3
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/GroupStates/AbstractGroupState.cs
@@ -0,0 +1,222 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Controller.SyncPlay.PlaybackRequests;
+using MediaBrowser.Model.SyncPlay;
+using Microsoft.Extensions.Logging;
+
+namespace MediaBrowser.Controller.SyncPlay.GroupStates
+{
+    /// <summary>
+    /// Class AbstractGroupState.
+    /// </summary>
+    /// <remarks>
+    /// Class is not thread-safe, external locking is required when accessing methods.
+    /// </remarks>
+    public abstract class AbstractGroupState : IGroupState
+    {
+        /// <summary>
+        /// The logger.
+        /// </summary>
+        private readonly ILogger<AbstractGroupState> _logger;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="AbstractGroupState"/> class.
+        /// </summary>
+        /// <param name="loggerFactory">Instance of the <see cref="ILoggerFactory"/> interface.</param>
+        protected AbstractGroupState(ILoggerFactory loggerFactory)
+        {
+            LoggerFactory = loggerFactory;
+            _logger = loggerFactory.CreateLogger<AbstractGroupState>();
+        }
+
+        /// <inheritdoc />
+        public abstract GroupStateType Type { get; }
+
+        /// <summary>
+        /// Gets the logger factory.
+        /// </summary>
+        protected ILoggerFactory LoggerFactory { get; }
+
+        /// <inheritdoc />
+        public abstract void SessionJoined(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <inheritdoc />
+        public abstract void SessionLeaving(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(IGroupPlaybackRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            UnhandledRequest(request);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(PlayGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            UnhandledRequest(request);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(SetPlaylistItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(RemoveFromPlaylistGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            var playingItemRemoved = context.RemoveFromPlayQueue(request.PlaylistItemIds);
+
+            var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.RemoveItems);
+            var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+            context.SendGroupUpdate(session, SyncPlayBroadcastType.AllGroup, update, cancellationToken);
+
+            if (playingItemRemoved && !context.PlayQueue.IsItemPlaying())
+            {
+                _logger.LogDebug("Play queue in group {GroupId} is now empty.", context.GroupId.ToString());
+
+                IGroupState idleState = new IdleGroupState(LoggerFactory);
+                context.SetState(idleState);
+                var stopRequest = new StopGroupRequest();
+                idleState.HandleRequest(stopRequest, context, Type, session, cancellationToken);
+            }
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(MovePlaylistItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            var result = context.MoveItemInPlayQueue(request.PlaylistItemId, request.NewIndex);
+
+            if (!result)
+            {
+                _logger.LogError("Unable to move item in group {GroupId}.", context.GroupId.ToString());
+                return;
+            }
+
+            var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.MoveItem);
+            var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+            context.SendGroupUpdate(session, SyncPlayBroadcastType.AllGroup, update, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(QueueGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            var result = context.AddToPlayQueue(request.ItemIds, request.Mode);
+
+            if (!result)
+            {
+                _logger.LogError("Unable to add items to play queue in group {GroupId}.", context.GroupId.ToString());
+                return;
+            }
+
+            var reason = request.Mode switch
+            {
+                GroupQueueMode.QueueNext => PlayQueueUpdateReason.QueueNext,
+                _ => PlayQueueUpdateReason.Queue
+            };
+            var playQueueUpdate = context.GetPlayQueueUpdate(reason);
+            var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+            context.SendGroupUpdate(session, SyncPlayBroadcastType.AllGroup, update, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(UnpauseGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            UnhandledRequest(request);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(PauseGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            UnhandledRequest(request);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(StopGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            UnhandledRequest(request);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(SeekGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            UnhandledRequest(request);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(BufferGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            UnhandledRequest(request);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(ReadyGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            UnhandledRequest(request);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(NextItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            UnhandledRequest(request);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(PreviousItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            UnhandledRequest(request);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(SetRepeatModeGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            context.SetRepeatMode(request.Mode);
+            var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.RepeatMode);
+            var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+            context.SendGroupUpdate(session, SyncPlayBroadcastType.AllGroup, update, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(SetShuffleModeGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            context.SetShuffleMode(request.Mode);
+            var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.ShuffleMode);
+            var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+            context.SendGroupUpdate(session, SyncPlayBroadcastType.AllGroup, update, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(PingGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Collected pings are used to account for network latency when unpausing playback.
+            context.UpdatePing(session, request.Ping);
+        }
+
+        /// <inheritdoc />
+        public virtual void HandleRequest(IgnoreWaitGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            context.SetIgnoreGroupWait(session, request.IgnoreWait);
+        }
+
+        /// <summary>
+        /// Sends a group state update to all group.
+        /// </summary>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="reason">The reason of the state change.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        protected void SendGroupStateUpdate(IGroupStateContext context, IGroupPlaybackRequest reason, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Notify relevant state change event.
+            var stateUpdate = new GroupStateUpdate(Type, reason.Action);
+            var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.StateUpdate, stateUpdate);
+            context.SendGroupUpdate(session, SyncPlayBroadcastType.AllGroup, update, cancellationToken);
+        }
+
+        private void UnhandledRequest(IGroupPlaybackRequest request)
+        {
+            _logger.LogWarning("Unhandled request of type {RequestType} in {StateType} state.", request.Action, Type);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/GroupStates/IdleGroupState.cs b/MediaBrowser.Controller/SyncPlay/GroupStates/IdleGroupState.cs
new file mode 100644
index 000000000..12ce6c8f8
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/GroupStates/IdleGroupState.cs
@@ -0,0 +1,126 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Controller.SyncPlay.PlaybackRequests;
+using MediaBrowser.Model.SyncPlay;
+using Microsoft.Extensions.Logging;
+
+namespace MediaBrowser.Controller.SyncPlay.GroupStates
+{
+    /// <summary>
+    /// Class IdleGroupState.
+    /// </summary>
+    /// <remarks>
+    /// Class is not thread-safe, external locking is required when accessing methods.
+    /// </remarks>
+    public class IdleGroupState : AbstractGroupState
+    {
+        /// <summary>
+        /// The logger.
+        /// </summary>
+        private readonly ILogger<IdleGroupState> _logger;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="IdleGroupState"/> class.
+        /// </summary>
+        /// <param name="loggerFactory">Instance of the <see cref="ILoggerFactory"/> interface.</param>
+        public IdleGroupState(ILoggerFactory loggerFactory)
+            : base(loggerFactory)
+        {
+            _logger = LoggerFactory.CreateLogger<IdleGroupState>();
+        }
+
+        /// <inheritdoc />
+        public override GroupStateType Type { get; } = GroupStateType.Idle;
+
+        /// <inheritdoc />
+        public override void SessionJoined(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            SendStopCommand(context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void SessionLeaving(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Do nothing.
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(PlayGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(UnpauseGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(PauseGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            SendStopCommand(context, prevState, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(StopGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            SendStopCommand(context, prevState, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(SeekGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            SendStopCommand(context, prevState, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(BufferGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            SendStopCommand(context, prevState, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(ReadyGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            SendStopCommand(context, prevState, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(NextItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(PreviousItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        private void SendStopCommand(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            var command = context.NewSyncPlayCommand(SendCommandType.Stop);
+            if (!prevState.Equals(Type))
+            {
+                context.SendCommand(session, SyncPlayBroadcastType.AllGroup, command, cancellationToken);
+            }
+            else
+            {
+                context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
+            }
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/GroupStates/PausedGroupState.cs b/MediaBrowser.Controller/SyncPlay/GroupStates/PausedGroupState.cs
new file mode 100644
index 000000000..fba8ba9e2
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/GroupStates/PausedGroupState.cs
@@ -0,0 +1,165 @@
+using System;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Controller.SyncPlay.PlaybackRequests;
+using MediaBrowser.Model.SyncPlay;
+using Microsoft.Extensions.Logging;
+
+namespace MediaBrowser.Controller.SyncPlay.GroupStates
+{
+    /// <summary>
+    /// Class PausedGroupState.
+    /// </summary>
+    /// <remarks>
+    /// Class is not thread-safe, external locking is required when accessing methods.
+    /// </remarks>
+    public class PausedGroupState : AbstractGroupState
+    {
+        /// <summary>
+        /// The logger.
+        /// </summary>
+        private readonly ILogger<PausedGroupState> _logger;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PausedGroupState"/> class.
+        /// </summary>
+        /// <param name="loggerFactory">Instance of the <see cref="ILoggerFactory"/> interface.</param>
+        public PausedGroupState(ILoggerFactory loggerFactory)
+            : base(loggerFactory)
+        {
+            _logger = LoggerFactory.CreateLogger<PausedGroupState>();
+        }
+
+        /// <inheritdoc />
+        public override GroupStateType Type { get; } = GroupStateType.Paused;
+
+        /// <inheritdoc />
+        public override void SessionJoined(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Wait for session to be ready.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.SessionJoined(context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void SessionLeaving(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Do nothing.
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(PlayGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(UnpauseGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var playingState = new PlayingGroupState(LoggerFactory);
+            context.SetState(playingState);
+            playingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(PauseGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            if (!prevState.Equals(Type))
+            {
+                // Pause group and compute the media playback position.
+                var currentTime = DateTime.UtcNow;
+                var elapsedTime = currentTime - context.LastActivity;
+                context.LastActivity = currentTime;
+                // Elapsed time is negative if event happens
+                // during the delay added to account for latency.
+                // In this phase clients haven't started the playback yet.
+                // In other words, LastActivity is in the future,
+                // when playback unpause is supposed to happen.
+                // Seek only if playback actually started.
+                context.PositionTicks += Math.Max(elapsedTime.Ticks, 0);
+
+                var command = context.NewSyncPlayCommand(SendCommandType.Pause);
+                context.SendCommand(session, SyncPlayBroadcastType.AllGroup, command, cancellationToken);
+
+                // Notify relevant state change event.
+                SendGroupStateUpdate(context, request, session, cancellationToken);
+            }
+            else
+            {
+                // Client got lost, sending current state.
+                var command = context.NewSyncPlayCommand(SendCommandType.Pause);
+                context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
+            }
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(StopGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var idleState = new IdleGroupState(LoggerFactory);
+            context.SetState(idleState);
+            idleState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(SeekGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(BufferGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(ReadyGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            if (prevState.Equals(Type))
+            {
+                // Client got lost, sending current state.
+                var command = context.NewSyncPlayCommand(SendCommandType.Pause);
+                context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
+            }
+            else if (prevState.Equals(GroupStateType.Waiting))
+            {
+                // Sending current state to all clients.
+                var command = context.NewSyncPlayCommand(SendCommandType.Pause);
+                context.SendCommand(session, SyncPlayBroadcastType.AllGroup, command, cancellationToken);
+
+                // Notify relevant state change event.
+                SendGroupStateUpdate(context, request, session, cancellationToken);
+            }
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(NextItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(PreviousItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/GroupStates/PlayingGroupState.cs b/MediaBrowser.Controller/SyncPlay/GroupStates/PlayingGroupState.cs
new file mode 100644
index 000000000..9797b247c
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/GroupStates/PlayingGroupState.cs
@@ -0,0 +1,168 @@
+using System;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Controller.SyncPlay.PlaybackRequests;
+using MediaBrowser.Model.SyncPlay;
+using Microsoft.Extensions.Logging;
+
+namespace MediaBrowser.Controller.SyncPlay.GroupStates
+{
+    /// <summary>
+    /// Class PlayingGroupState.
+    /// </summary>
+    /// <remarks>
+    /// Class is not thread-safe, external locking is required when accessing methods.
+    /// </remarks>
+    public class PlayingGroupState : AbstractGroupState
+    {
+        /// <summary>
+        /// The logger.
+        /// </summary>
+        private readonly ILogger<PlayingGroupState> _logger;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PlayingGroupState"/> class.
+        /// </summary>
+        /// <param name="loggerFactory">Instance of the <see cref="ILoggerFactory"/> interface.</param>
+        public PlayingGroupState(ILoggerFactory loggerFactory)
+            : base(loggerFactory)
+        {
+            _logger = LoggerFactory.CreateLogger<PlayingGroupState>();
+        }
+
+        /// <inheritdoc />
+        public override GroupStateType Type { get; } = GroupStateType.Playing;
+
+        /// <summary>
+        /// Gets or sets a value indicating whether requests for buffering should be ignored.
+        /// </summary>
+        public bool IgnoreBuffering { get; set; }
+
+        /// <inheritdoc />
+        public override void SessionJoined(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Wait for session to be ready.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.SessionJoined(context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void SessionLeaving(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Do nothing.
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(PlayGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(UnpauseGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            if (!prevState.Equals(Type))
+            {
+                // Pick a suitable time that accounts for latency.
+                var delayMillis = Math.Max(context.GetHighestPing() * 2, context.DefaultPing);
+
+                // Unpause group and set starting point in future.
+                // Clients will start playback at LastActivity (datetime) from PositionTicks (playback position).
+                // The added delay does not guarantee, of course, that the command will be received in time.
+                // Playback synchronization will mainly happen client side.
+                context.LastActivity = DateTime.UtcNow.AddMilliseconds(delayMillis);
+
+                var command = context.NewSyncPlayCommand(SendCommandType.Unpause);
+                context.SendCommand(session, SyncPlayBroadcastType.AllGroup, command, cancellationToken);
+
+                // Notify relevant state change event.
+                SendGroupStateUpdate(context, request, session, cancellationToken);
+            }
+            else
+            {
+                // Client got lost, sending current state.
+                var command = context.NewSyncPlayCommand(SendCommandType.Unpause);
+                context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
+            }
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(PauseGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var pausedState = new PausedGroupState(LoggerFactory);
+            context.SetState(pausedState);
+            pausedState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(StopGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var idleState = new IdleGroupState(LoggerFactory);
+            context.SetState(idleState);
+            idleState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(SeekGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(BufferGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            if (IgnoreBuffering)
+            {
+                return;
+            }
+
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(ReadyGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            if (prevState.Equals(Type))
+            {
+                // Group was not waiting, make sure client has latest state.
+                var command = context.NewSyncPlayCommand(SendCommandType.Unpause);
+                context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
+            }
+            else if (prevState.Equals(GroupStateType.Waiting))
+            {
+                // Notify relevant state change event.
+                SendGroupStateUpdate(context, request, session, cancellationToken);
+            }
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(NextItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(PreviousItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Change state.
+            var waitingState = new WaitingGroupState(LoggerFactory);
+            context.SetState(waitingState);
+            waitingState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/GroupStates/WaitingGroupState.cs b/MediaBrowser.Controller/SyncPlay/GroupStates/WaitingGroupState.cs
new file mode 100644
index 000000000..507573653
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/GroupStates/WaitingGroupState.cs
@@ -0,0 +1,680 @@
+using System;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Controller.SyncPlay.PlaybackRequests;
+using MediaBrowser.Model.SyncPlay;
+using Microsoft.Extensions.Logging;
+
+namespace MediaBrowser.Controller.SyncPlay.GroupStates
+{
+    /// <summary>
+    /// Class WaitingGroupState.
+    /// </summary>
+    /// <remarks>
+    /// Class is not thread-safe, external locking is required when accessing methods.
+    /// </remarks>
+    public class WaitingGroupState : AbstractGroupState
+    {
+        /// <summary>
+        /// The logger.
+        /// </summary>
+        private readonly ILogger<WaitingGroupState> _logger;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="WaitingGroupState"/> class.
+        /// </summary>
+        /// <param name="loggerFactory">Instance of the <see cref="ILoggerFactory"/> interface.</param>
+        public WaitingGroupState(ILoggerFactory loggerFactory)
+            : base(loggerFactory)
+        {
+            _logger = LoggerFactory.CreateLogger<WaitingGroupState>();
+        }
+
+        /// <inheritdoc />
+        public override GroupStateType Type { get; } = GroupStateType.Waiting;
+
+        /// <summary>
+        /// Gets or sets a value indicating whether playback should resume when group is ready.
+        /// </summary>
+        public bool ResumePlaying { get; set; } = false;
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the initial state has been set.
+        /// </summary>
+        private bool InitialStateSet { get; set; } = false;
+
+        /// <summary>
+        /// Gets or sets the group state before the first ever event.
+        /// </summary>
+        private GroupStateType InitialState { get; set; }
+
+        /// <inheritdoc />
+        public override void SessionJoined(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Save state if first event.
+            if (!InitialStateSet)
+            {
+                InitialState = prevState;
+                InitialStateSet = true;
+            }
+
+            if (prevState.Equals(GroupStateType.Playing))
+            {
+                ResumePlaying = true;
+                // Pause group and compute the media playback position.
+                var currentTime = DateTime.UtcNow;
+                var elapsedTime = currentTime - context.LastActivity;
+                context.LastActivity = currentTime;
+                // Elapsed time is negative if event happens
+                // during the delay added to account for latency.
+                // In this phase clients haven't started the playback yet.
+                // In other words, LastActivity is in the future,
+                // when playback unpause is supposed to happen.
+                // Seek only if playback actually started.
+                context.PositionTicks += Math.Max(elapsedTime.Ticks, 0);
+            }
+
+            // Prepare new session.
+            var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.NewPlaylist);
+            var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+            context.SendGroupUpdate(session, SyncPlayBroadcastType.CurrentSession, update, cancellationToken);
+
+            context.SetBuffering(session, true);
+
+            // Send pause command to all non-buffering sessions.
+            var command = context.NewSyncPlayCommand(SendCommandType.Pause);
+            context.SendCommand(session, SyncPlayBroadcastType.AllReady, command, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void SessionLeaving(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Save state if first event.
+            if (!InitialStateSet)
+            {
+                InitialState = prevState;
+                InitialStateSet = true;
+            }
+
+            context.SetBuffering(session, false);
+
+            if (!context.IsBuffering())
+            {
+                if (ResumePlaying)
+                {
+                    _logger.LogDebug("Session {SessionId} left group {GroupId}, notifying others to resume.", session.Id, context.GroupId.ToString());
+
+                    // Client, that was buffering, left the group.
+                    var playingState = new PlayingGroupState(LoggerFactory);
+                    context.SetState(playingState);
+                    var unpauseRequest = new UnpauseGroupRequest();
+                    playingState.HandleRequest(unpauseRequest, context, Type, session, cancellationToken);
+                }
+                else
+                {
+                    _logger.LogDebug("Session {SessionId} left group {GroupId}, returning to previous state.", session.Id, context.GroupId.ToString());
+
+                    // Group is ready, returning to previous state.
+                    var pausedState = new PausedGroupState(LoggerFactory);
+                    context.SetState(pausedState);
+                }
+            }
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(PlayGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Save state if first event.
+            if (!InitialStateSet)
+            {
+                InitialState = prevState;
+                InitialStateSet = true;
+            }
+
+            ResumePlaying = true;
+
+            var setQueueStatus = context.SetPlayQueue(request.PlayingQueue, request.PlayingItemPosition, request.StartPositionTicks);
+            if (!setQueueStatus)
+            {
+                _logger.LogError("Unable to set playing queue in group {GroupId}.", context.GroupId.ToString());
+
+                // Ignore request and return to previous state.
+                IGroupState newState = prevState switch {
+                    GroupStateType.Playing => new PlayingGroupState(LoggerFactory),
+                    GroupStateType.Paused => new PausedGroupState(LoggerFactory),
+                    _ => new IdleGroupState(LoggerFactory)
+                };
+
+                context.SetState(newState);
+                return;
+            }
+
+            var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.NewPlaylist);
+            var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+            context.SendGroupUpdate(session, SyncPlayBroadcastType.AllGroup, update, cancellationToken);
+
+            // Reset status of sessions and await for all Ready events.
+            context.SetAllBuffering(true);
+
+            _logger.LogDebug("Session {SessionId} set a new play queue in group {GroupId}.", session.Id, context.GroupId.ToString());
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(SetPlaylistItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Save state if first event.
+            if (!InitialStateSet)
+            {
+                InitialState = prevState;
+                InitialStateSet = true;
+            }
+
+            ResumePlaying = true;
+
+            var result = context.SetPlayingItem(request.PlaylistItemId);
+            if (result)
+            {
+                var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.SetCurrentItem);
+                var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+                context.SendGroupUpdate(session, SyncPlayBroadcastType.AllGroup, update, cancellationToken);
+
+                // Reset status of sessions and await for all Ready events.
+                context.SetAllBuffering(true);
+            }
+            else
+            {
+                // Return to old state.
+                IGroupState newState = prevState switch
+                {
+                    GroupStateType.Playing => new PlayingGroupState(LoggerFactory),
+                    GroupStateType.Paused => new PausedGroupState(LoggerFactory),
+                    _ => new IdleGroupState(LoggerFactory)
+                };
+
+                context.SetState(newState);
+
+                _logger.LogDebug("Unable to change current playing item in group {GroupId}.", context.GroupId.ToString());
+            }
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(UnpauseGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Save state if first event.
+            if (!InitialStateSet)
+            {
+                InitialState = prevState;
+                InitialStateSet = true;
+            }
+
+            if (prevState.Equals(GroupStateType.Idle))
+            {
+                ResumePlaying = true;
+                context.RestartCurrentItem();
+
+                var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.NewPlaylist);
+                var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+                context.SendGroupUpdate(session, SyncPlayBroadcastType.AllGroup, update, cancellationToken);
+
+                // Reset status of sessions and await for all Ready events.
+                context.SetAllBuffering(true);
+
+                _logger.LogDebug("Group {GroupId} is waiting for all ready events.", context.GroupId.ToString());
+            }
+            else
+            {
+                if (ResumePlaying)
+                {
+                    _logger.LogDebug("Forcing the playback to start in group {GroupId}. Group-wait is disabled until next state change.", context.GroupId.ToString());
+
+                    // An Unpause request is forcing the playback to start, ignoring sessions that are not ready.
+                    context.SetAllBuffering(false);
+
+                    // Change state.
+                    var playingState = new PlayingGroupState(LoggerFactory)
+                    {
+                        IgnoreBuffering = true
+                    };
+                    context.SetState(playingState);
+                    playingState.HandleRequest(request, context, Type, session, cancellationToken);
+                }
+                else
+                {
+                    // Group would have gone to paused state, now will go to playing state when ready.
+                    ResumePlaying = true;
+
+                    // Notify relevant state change event.
+                    SendGroupStateUpdate(context, request, session, cancellationToken);
+                }
+            }
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(PauseGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Save state if first event.
+            if (!InitialStateSet)
+            {
+                InitialState = prevState;
+                InitialStateSet = true;
+            }
+
+            // Wait for sessions to be ready, then switch to paused state.
+            ResumePlaying = false;
+
+            // Notify relevant state change event.
+            SendGroupStateUpdate(context, request, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(StopGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Save state if first event.
+            if (!InitialStateSet)
+            {
+                InitialState = prevState;
+                InitialStateSet = true;
+            }
+
+            // Change state.
+            var idleState = new IdleGroupState(LoggerFactory);
+            context.SetState(idleState);
+            idleState.HandleRequest(request, context, Type, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(SeekGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Save state if first event.
+            if (!InitialStateSet)
+            {
+                InitialState = prevState;
+                InitialStateSet = true;
+            }
+
+            if (prevState.Equals(GroupStateType.Playing))
+            {
+                ResumePlaying = true;
+            }
+            else if (prevState.Equals(GroupStateType.Paused))
+            {
+                ResumePlaying = false;
+            }
+
+            // Sanitize PositionTicks.
+            var ticks = context.SanitizePositionTicks(request.PositionTicks);
+
+            // Seek.
+            context.PositionTicks = ticks;
+            context.LastActivity = DateTime.UtcNow;
+
+            var command = context.NewSyncPlayCommand(SendCommandType.Seek);
+            context.SendCommand(session, SyncPlayBroadcastType.AllGroup, command, cancellationToken);
+
+            // Reset status of sessions and await for all Ready events.
+            context.SetAllBuffering(true);
+
+            // Notify relevant state change event.
+            SendGroupStateUpdate(context, request, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(BufferGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Save state if first event.
+            if (!InitialStateSet)
+            {
+                InitialState = prevState;
+                InitialStateSet = true;
+            }
+
+            // Make sure the client is playing the correct item.
+            if (!request.PlaylistItemId.Equals(context.PlayQueue.GetPlayingItemPlaylistId()))
+            {
+                _logger.LogDebug("Session {SessionId} reported wrong playlist item in group {GroupId}.", session.Id, context.GroupId.ToString());
+
+                var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.SetCurrentItem);
+                var updateSession = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+                context.SendGroupUpdate(session, SyncPlayBroadcastType.CurrentSession, updateSession, cancellationToken);
+                context.SetBuffering(session, true);
+
+                return;
+            }
+
+            if (prevState.Equals(GroupStateType.Playing))
+            {
+                // Resume playback when all ready.
+                ResumePlaying = true;
+
+                context.SetBuffering(session, true);
+
+                // Pause group and compute the media playback position.
+                var currentTime = DateTime.UtcNow;
+                var elapsedTime = currentTime - context.LastActivity;
+                context.LastActivity = currentTime;
+                // Elapsed time is negative if event happens
+                // during the delay added to account for latency.
+                // In this phase clients haven't started the playback yet.
+                // In other words, LastActivity is in the future,
+                // when playback unpause is supposed to happen.
+                // Seek only if playback actually started.
+                context.PositionTicks += Math.Max(elapsedTime.Ticks, 0);
+
+                // Send pause command to all non-buffering sessions.
+                var command = context.NewSyncPlayCommand(SendCommandType.Pause);
+                context.SendCommand(session, SyncPlayBroadcastType.AllReady, command, cancellationToken);
+            }
+            else if (prevState.Equals(GroupStateType.Paused))
+            {
+                // Don't resume playback when all ready.
+                ResumePlaying = false;
+
+                context.SetBuffering(session, true);
+
+                // Send pause command to buffering session.
+                var command = context.NewSyncPlayCommand(SendCommandType.Pause);
+                context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
+            }
+            else if (prevState.Equals(GroupStateType.Waiting))
+            {
+                // Another session is now buffering.
+                context.SetBuffering(session, true);
+
+                if (!ResumePlaying)
+                {
+                    // Force update for this session that should be paused.
+                    var command = context.NewSyncPlayCommand(SendCommandType.Pause);
+                    context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
+                }
+            }
+
+            // Notify relevant state change event.
+            SendGroupStateUpdate(context, request, session, cancellationToken);
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(ReadyGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Save state if first event.
+            if (!InitialStateSet)
+            {
+                InitialState = prevState;
+                InitialStateSet = true;
+            }
+
+            // Make sure the client is playing the correct item.
+            if (!request.PlaylistItemId.Equals(context.PlayQueue.GetPlayingItemPlaylistId()))
+            {
+                _logger.LogDebug("Session {SessionId} reported wrong playlist item in group {GroupId}.", session.Id, context.GroupId.ToString());
+
+                var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.SetCurrentItem);
+                var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+                context.SendGroupUpdate(session, SyncPlayBroadcastType.CurrentSession, update, cancellationToken);
+                context.SetBuffering(session, true);
+
+                return;
+            }
+
+            // Compute elapsed time between the client reported time and now.
+            // Elapsed time is used to estimate the client position when playback is unpaused.
+            // Ideally, the request is received and handled without major delays.
+            // However, to avoid waiting indefinitely when a client is not reporting a correct time,
+            // the elapsed time is ignored after a certain threshold.
+            var currentTime = DateTime.UtcNow;
+            var elapsedTime = currentTime.Subtract(request.When);
+            var timeSyncThresholdTicks = TimeSpan.FromMilliseconds(context.TimeSyncOffset).Ticks;
+            if (Math.Abs(elapsedTime.Ticks) > timeSyncThresholdTicks)
+            {
+                _logger.LogWarning("Session {SessionId} is not time syncing properly. Ignoring elapsed time.", session.Id);
+
+                elapsedTime = TimeSpan.Zero;
+            }
+
+            // Ignore elapsed time if client is paused.
+            if (!request.IsPlaying)
+            {
+                elapsedTime = TimeSpan.Zero;
+            }
+
+            var requestTicks = context.SanitizePositionTicks(request.PositionTicks);
+            var clientPosition = TimeSpan.FromTicks(requestTicks) + elapsedTime;
+            var delayTicks = context.PositionTicks - clientPosition.Ticks;
+            var maxPlaybackOffsetTicks = TimeSpan.FromMilliseconds(context.MaxPlaybackOffset).Ticks;
+
+            _logger.LogDebug("Session {SessionId} is at {PositionTicks} (delay of {Delay} seconds) in group {GroupId}.", session.Id, clientPosition, TimeSpan.FromTicks(delayTicks).TotalSeconds, context.GroupId.ToString());
+
+            if (ResumePlaying)
+            {
+                // Handle case where session reported as ready but in reality
+                // it has no clue of the real position nor the playback state.
+                if (!request.IsPlaying && Math.Abs(delayTicks) > maxPlaybackOffsetTicks)
+                {
+                    // Session not ready at all.
+                    context.SetBuffering(session, true);
+
+                    // Correcting session's position.
+                    var command = context.NewSyncPlayCommand(SendCommandType.Seek);
+                    context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
+
+                    // Notify relevant state change event.
+                    SendGroupStateUpdate(context, request, session, cancellationToken);
+
+                    _logger.LogWarning("Session {SessionId} got lost in time, correcting.", session.Id);
+                    return;
+                }
+
+                // Session is ready.
+                context.SetBuffering(session, false);
+
+                if (context.IsBuffering())
+                {
+                    // Others are still buffering, tell this client to pause when ready.
+                    var command = context.NewSyncPlayCommand(SendCommandType.Pause);
+                    command.When = currentTime.AddTicks(delayTicks);
+                    context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
+
+                    _logger.LogInformation("Session {SessionId} will pause when ready in {Delay} seconds. Group {GroupId} is waiting for all ready events.", session.Id, TimeSpan.FromTicks(delayTicks).TotalSeconds, context.GroupId.ToString());
+                }
+                else
+                {
+                    // If all ready, then start playback.
+                    // Let other clients resume as soon as the buffering client catches up.
+                    if (delayTicks > context.GetHighestPing() * 2 * TimeSpan.TicksPerMillisecond)
+                    {
+                        // Client that was buffering is recovering, notifying others to resume.
+                        context.LastActivity = currentTime.AddTicks(delayTicks);
+                        var command = context.NewSyncPlayCommand(SendCommandType.Unpause);
+                        var filter = SyncPlayBroadcastType.AllExceptCurrentSession;
+                        if (!request.IsPlaying)
+                        {
+                            filter = SyncPlayBroadcastType.AllGroup;
+                        }
+
+                        context.SendCommand(session, filter, command, cancellationToken);
+
+                        _logger.LogInformation("Session {SessionId} is recovering, group {GroupId} will resume in {Delay} seconds.", session.Id, context.GroupId.ToString(), TimeSpan.FromTicks(delayTicks).TotalSeconds);
+                    }
+                    else
+                    {
+                        // Client, that was buffering, resumed playback but did not update others in time.
+                        delayTicks = context.GetHighestPing() * 2 * TimeSpan.TicksPerMillisecond;
+                        delayTicks = Math.Max(delayTicks, context.DefaultPing);
+
+                        context.LastActivity = currentTime.AddTicks(delayTicks);
+
+                        var command = context.NewSyncPlayCommand(SendCommandType.Unpause);
+                        context.SendCommand(session, SyncPlayBroadcastType.AllGroup, command, cancellationToken);
+
+                        _logger.LogWarning("Session {SessionId} resumed playback, group {GroupId} has {Delay} seconds to recover.", session.Id, context.GroupId.ToString(), TimeSpan.FromTicks(delayTicks).TotalSeconds);
+                    }
+
+                    // Change state.
+                    var playingState = new PlayingGroupState(LoggerFactory);
+                    context.SetState(playingState);
+                    playingState.HandleRequest(request, context, Type, session, cancellationToken);
+                }
+            }
+            else
+            {
+                // Check that session is really ready, tolerate player imperfections under a certain threshold.
+                if (Math.Abs(context.PositionTicks - requestTicks) > maxPlaybackOffsetTicks)
+                {
+                    // Session still not ready.
+                    context.SetBuffering(session, true);
+                    // Session is seeking to wrong position, correcting.
+                    var command = context.NewSyncPlayCommand(SendCommandType.Seek);
+                    context.SendCommand(session, SyncPlayBroadcastType.CurrentSession, command, cancellationToken);
+
+                    // Notify relevant state change event.
+                    SendGroupStateUpdate(context, request, session, cancellationToken);
+
+                    _logger.LogWarning("Session {SessionId} is seeking to wrong position, correcting.", session.Id);
+                    return;
+                }
+                else
+                {
+                    // Session is ready.
+                    context.SetBuffering(session, false);
+                }
+
+                if (!context.IsBuffering())
+                {
+                    _logger.LogDebug("Session {SessionId} is ready, group {GroupId} is ready.", session.Id, context.GroupId.ToString());
+
+                    // Group is ready, returning to previous state.
+                    var pausedState = new PausedGroupState(LoggerFactory);
+                    context.SetState(pausedState);
+
+                    if (InitialState.Equals(GroupStateType.Playing))
+                    {
+                        // Group went from playing to waiting state and a pause request occured while waiting.
+                        var pauseRequest = new PauseGroupRequest();
+                        pausedState.HandleRequest(pauseRequest, context, Type, session, cancellationToken);
+                    }
+                    else if (InitialState.Equals(GroupStateType.Paused))
+                    {
+                        pausedState.HandleRequest(request, context, Type, session, cancellationToken);
+                    }
+                }
+            }
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(NextItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Save state if first event.
+            if (!InitialStateSet)
+            {
+                InitialState = prevState;
+                InitialStateSet = true;
+            }
+
+            ResumePlaying = true;
+
+            // Make sure the client knows the playing item, to avoid duplicate requests.
+            if (!request.PlaylistItemId.Equals(context.PlayQueue.GetPlayingItemPlaylistId()))
+            {
+                _logger.LogDebug("Session {SessionId} provided the wrong playlist item for group {GroupId}.", session.Id, context.GroupId.ToString());
+                return;
+            }
+
+            var newItem = context.NextItemInQueue();
+            if (newItem)
+            {
+                // Send playing-queue update.
+                var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.NextItem);
+                var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+                context.SendGroupUpdate(session, SyncPlayBroadcastType.AllGroup, update, cancellationToken);
+
+                // Reset status of sessions and await for all Ready events.
+                context.SetAllBuffering(true);
+            }
+            else
+            {
+                // Return to old state.
+                IGroupState newState = prevState switch
+                {
+                    GroupStateType.Playing => new PlayingGroupState(LoggerFactory),
+                    GroupStateType.Paused => new PausedGroupState(LoggerFactory),
+                    _ => new IdleGroupState(LoggerFactory)
+                };
+
+                context.SetState(newState);
+
+                _logger.LogDebug("No next item available in group {GroupId}.", context.GroupId.ToString());
+            }
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(PreviousItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            // Save state if first event.
+            if (!InitialStateSet)
+            {
+                InitialState = prevState;
+                InitialStateSet = true;
+            }
+
+            ResumePlaying = true;
+
+            // Make sure the client knows the playing item, to avoid duplicate requests.
+            if (!request.PlaylistItemId.Equals(context.PlayQueue.GetPlayingItemPlaylistId()))
+            {
+                _logger.LogDebug("Session {SessionId} provided the wrong playlist item for group {GroupId}.", session.Id, context.GroupId.ToString());
+                return;
+            }
+
+            var newItem = context.PreviousItemInQueue();
+            if (newItem)
+            {
+                // Send playing-queue update.
+                var playQueueUpdate = context.GetPlayQueueUpdate(PlayQueueUpdateReason.PreviousItem);
+                var update = context.NewSyncPlayGroupUpdate(GroupUpdateType.PlayQueue, playQueueUpdate);
+                context.SendGroupUpdate(session, SyncPlayBroadcastType.AllGroup, update, cancellationToken);
+
+                // Reset status of sessions and await for all Ready events.
+                context.SetAllBuffering(true);
+            }
+            else
+            {
+                // Return to old state.
+                IGroupState newState = prevState switch
+                {
+                    GroupStateType.Playing => new PlayingGroupState(LoggerFactory),
+                    GroupStateType.Paused => new PausedGroupState(LoggerFactory),
+                    _ => new IdleGroupState(LoggerFactory)
+                };
+
+                context.SetState(newState);
+
+                _logger.LogDebug("No previous item available in group {GroupId}.", context.GroupId.ToString());
+            }
+        }
+
+        /// <inheritdoc />
+        public override void HandleRequest(IgnoreWaitGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken)
+        {
+            context.SetIgnoreGroupWait(session, request.IgnoreWait);
+
+            if (!context.IsBuffering())
+            {
+                _logger.LogDebug("Ignoring session {SessionId}, group {GroupId} is ready.", session.Id, context.GroupId.ToString());
+
+                if (ResumePlaying)
+                {
+                    // Client, that was buffering, stopped following playback.
+                    var playingState = new PlayingGroupState(LoggerFactory);
+                    context.SetState(playingState);
+                    var unpauseRequest = new UnpauseGroupRequest();
+                    playingState.HandleRequest(unpauseRequest, context, Type, session, cancellationToken);
+                }
+                else
+                {
+                    // Group is ready, returning to previous state.
+                    var pausedState = new PausedGroupState(LoggerFactory);
+                    context.SetState(pausedState);
+                }
+            }
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/IGroupPlaybackRequest.cs b/MediaBrowser.Controller/SyncPlay/IGroupPlaybackRequest.cs
new file mode 100644
index 000000000..201f29952
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/IGroupPlaybackRequest.cs
@@ -0,0 +1,27 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay
+{
+    /// <summary>
+    /// Interface IGroupPlaybackRequest.
+    /// </summary>
+    public interface IGroupPlaybackRequest : ISyncPlayRequest
+    {
+        /// <summary>
+        /// Gets the playback request type.
+        /// </summary>
+        /// <returns>The playback request type.</returns>
+        PlaybackRequestType Action { get; }
+
+        /// <summary>
+        /// Applies the request to a group.
+        /// </summary>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="state">The current state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken);
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/IGroupState.cs b/MediaBrowser.Controller/SyncPlay/IGroupState.cs
new file mode 100644
index 000000000..95ee09985
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/IGroupState.cs
@@ -0,0 +1,217 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Controller.SyncPlay.PlaybackRequests;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay
+{
+    /// <summary>
+    /// Interface IGroupState.
+    /// </summary>
+    public interface IGroupState
+    {
+        /// <summary>
+        /// Gets the group state type.
+        /// </summary>
+        /// <value>The group state type.</value>
+        GroupStateType Type { get; }
+
+        /// <summary>
+        /// Handles a session that joined the group.
+        /// </summary>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void SessionJoined(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a session that is leaving the group.
+        /// </summary>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void SessionLeaving(IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Generic handler. Context's state can change.
+        /// </summary>
+        /// <param name="request">The generic request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(IGroupPlaybackRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a play request from a session. Context's state can change.
+        /// </summary>
+        /// <param name="request">The play request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(PlayGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a set-playlist-item request from a session. Context's state can change.
+        /// </summary>
+        /// <param name="request">The set-playlist-item request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(SetPlaylistItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a remove-items request from a session. Context's state can change.
+        /// </summary>
+        /// <param name="request">The remove-items request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(RemoveFromPlaylistGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a move-playlist-item request from a session. Context's state should not change.
+        /// </summary>
+        /// <param name="request">The move-playlist-item request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(MovePlaylistItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a queue request from a session. Context's state should not change.
+        /// </summary>
+        /// <param name="request">The queue request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(QueueGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles an unpause request from a session. Context's state can change.
+        /// </summary>
+        /// <param name="request">The unpause request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(UnpauseGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a pause request from a session. Context's state can change.
+        /// </summary>
+        /// <param name="request">The pause request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(PauseGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a stop request from a session. Context's state can change.
+        /// </summary>
+        /// <param name="request">The stop request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(StopGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a seek request from a session. Context's state can change.
+        /// </summary>
+        /// <param name="request">The seek request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(SeekGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a buffer request from a session. Context's state can change.
+        /// </summary>
+        /// <param name="request">The buffer request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(BufferGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a ready request from a session. Context's state can change.
+        /// </summary>
+        /// <param name="request">The ready request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(ReadyGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a next-item request from a session. Context's state can change.
+        /// </summary>
+        /// <param name="request">The next-item request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(NextItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a previous-item request from a session. Context's state can change.
+        /// </summary>
+        /// <param name="request">The previous-item request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(PreviousItemGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a set-repeat-mode request from a session. Context's state should not change.
+        /// </summary>
+        /// <param name="request">The repeat-mode request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(SetRepeatModeGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a set-shuffle-mode request from a session. Context's state should not change.
+        /// </summary>
+        /// <param name="request">The shuffle-mode request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(SetShuffleModeGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Updates the ping of a session. Context's state should not change.
+        /// </summary>
+        /// <param name="request">The ping request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(PingGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Handles a ignore-wait request from a session. Context's state can change.
+        /// </summary>
+        /// <param name="request">The ignore-wait request.</param>
+        /// <param name="context">The context of the state.</param>
+        /// <param name="prevState">The previous state.</param>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void HandleRequest(IgnoreWaitGroupRequest request, IGroupStateContext context, GroupStateType prevState, SessionInfo session, CancellationToken cancellationToken);
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/IGroupStateContext.cs b/MediaBrowser.Controller/SyncPlay/IGroupStateContext.cs
new file mode 100644
index 000000000..aa263638a
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/IGroupStateContext.cs
@@ -0,0 +1,222 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Controller.SyncPlay.Queue;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay
+{
+    /// <summary>
+    /// Interface IGroupStateContext.
+    /// </summary>
+    public interface IGroupStateContext
+    {
+        /// <summary>
+        /// Gets the default ping value used for sessions, in milliseconds.
+        /// </summary>
+        /// <value>The default ping value used for sessions, in milliseconds.</value>
+        long DefaultPing { get; }
+
+        /// <summary>
+        /// Gets the maximum time offset error accepted for dates reported by clients, in milliseconds.
+        /// </summary>
+        /// <value>The maximum offset error accepted, in milliseconds.</value>
+        long TimeSyncOffset { get; }
+
+        /// <summary>
+        /// Gets the maximum offset error accepted for position reported by clients, in milliseconds.
+        /// </summary>
+        /// <value>The maximum offset error accepted, in milliseconds.</value>
+        long MaxPlaybackOffset { get; }
+
+        /// <summary>
+        /// Gets the group identifier.
+        /// </summary>
+        /// <value>The group identifier.</value>
+        Guid GroupId { get; }
+
+        /// <summary>
+        /// Gets or sets the position ticks.
+        /// </summary>
+        /// <value>The position ticks.</value>
+        long PositionTicks { get; set; }
+
+        /// <summary>
+        /// Gets or sets the last activity.
+        /// </summary>
+        /// <value>The last activity.</value>
+        DateTime LastActivity { get; set; }
+
+        /// <summary>
+        /// Gets the play queue.
+        /// </summary>
+        /// <value>The play queue.</value>
+        PlayQueueManager PlayQueue { get; }
+
+        /// <summary>
+        /// Sets a new state.
+        /// </summary>
+        /// <param name="state">The new state.</param>
+        void SetState(IGroupState state);
+
+        /// <summary>
+        /// Sends a GroupUpdate message to the interested sessions.
+        /// </summary>
+        /// <typeparam name="T">The type of the data of the message.</typeparam>
+        /// <param name="from">The current session.</param>
+        /// <param name="type">The filtering type.</param>
+        /// <param name="message">The message to send.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>The task.</returns>
+        Task SendGroupUpdate<T>(SessionInfo from, SyncPlayBroadcastType type, GroupUpdate<T> message, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Sends a playback command to the interested sessions.
+        /// </summary>
+        /// <param name="from">The current session.</param>
+        /// <param name="type">The filtering type.</param>
+        /// <param name="message">The message to send.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>The task.</returns>
+        Task SendCommand(SessionInfo from, SyncPlayBroadcastType type, SendCommand message, CancellationToken cancellationToken);
+
+        /// <summary>
+        /// Builds a new playback command with some default values.
+        /// </summary>
+        /// <param name="type">The command type.</param>
+        /// <returns>The command.</returns>
+        SendCommand NewSyncPlayCommand(SendCommandType type);
+
+        /// <summary>
+        /// Builds a new group update message.
+        /// </summary>
+        /// <typeparam name="T">The type of the data of the message.</typeparam>
+        /// <param name="type">The update type.</param>
+        /// <param name="data">The data to send.</param>
+        /// <returns>The group update.</returns>
+        GroupUpdate<T> NewSyncPlayGroupUpdate<T>(GroupUpdateType type, T data);
+
+        /// <summary>
+        /// Sanitizes the PositionTicks, considers the current playing item when available.
+        /// </summary>
+        /// <param name="positionTicks">The PositionTicks.</param>
+        /// <returns>The sanitized position ticks.</returns>
+        long SanitizePositionTicks(long? positionTicks);
+
+        /// <summary>
+        /// Updates the ping of a session, in milliseconds.
+        /// </summary>
+        /// <param name="session">The session.</param>
+        /// <param name="ping">The ping, in milliseconds.</param>
+        void UpdatePing(SessionInfo session, long ping);
+
+        /// <summary>
+        /// Gets the highest ping in the group, in milliseconds.
+        /// </summary>
+        /// <returns>The highest ping in the group.</returns>
+        long GetHighestPing();
+
+        /// <summary>
+        /// Sets the session's buffering state.
+        /// </summary>
+        /// <param name="session">The session.</param>
+        /// <param name="isBuffering">The state.</param>
+        void SetBuffering(SessionInfo session, bool isBuffering);
+
+        /// <summary>
+        /// Sets the buffering state of all the sessions.
+        /// </summary>
+        /// <param name="isBuffering">The state.</param>
+        void SetAllBuffering(bool isBuffering);
+
+        /// <summary>
+        /// Gets the group buffering state.
+        /// </summary>
+        /// <returns><c>true</c> if there is a session buffering in the group; <c>false</c> otherwise.</returns>
+        bool IsBuffering();
+
+        /// <summary>
+        /// Sets the session's group wait state.
+        /// </summary>
+        /// <param name="session">The session.</param>
+        /// <param name="ignoreGroupWait">The state.</param>
+        void SetIgnoreGroupWait(SessionInfo session, bool ignoreGroupWait);
+
+        /// <summary>
+        /// Sets a new play queue.
+        /// </summary>
+        /// <param name="playQueue">The new play queue.</param>
+        /// <param name="playingItemPosition">The playing item position in the play queue.</param>
+        /// <param name="startPositionTicks">The start position ticks.</param>
+        /// <returns><c>true</c> if the play queue has been changed; <c>false</c> if something went wrong.</returns>
+        bool SetPlayQueue(IReadOnlyList<Guid> playQueue, int playingItemPosition, long startPositionTicks);
+
+        /// <summary>
+        /// Sets the playing item.
+        /// </summary>
+        /// <param name="playlistItemId">The new playing item identifier.</param>
+        /// <returns><c>true</c> if the play queue has been changed; <c>false</c> if something went wrong.</returns>
+        bool SetPlayingItem(Guid playlistItemId);
+
+        /// <summary>
+        /// Removes items from the play queue.
+        /// </summary>
+        /// <param name="playlistItemIds">The items to remove.</param>
+        /// <returns><c>true</c> if playing item got removed; <c>false</c> otherwise.</returns>
+        bool RemoveFromPlayQueue(IReadOnlyList<Guid> playlistItemIds);
+
+        /// <summary>
+        /// Moves an item in the play queue.
+        /// </summary>
+        /// <param name="playlistItemId">The playlist identifier of the item to move.</param>
+        /// <param name="newIndex">The new position.</param>
+        /// <returns><c>true</c> if item has been moved; <c>false</c> if something went wrong.</returns>
+        bool MoveItemInPlayQueue(Guid playlistItemId, int newIndex);
+
+        /// <summary>
+        /// Updates the play queue.
+        /// </summary>
+        /// <param name="newItems">The new items to add to the play queue.</param>
+        /// <param name="mode">The mode with which the items will be added.</param>
+        /// <returns><c>true</c> if the play queue has been changed; <c>false</c> if something went wrong.</returns>
+        bool AddToPlayQueue(IReadOnlyList<Guid> newItems, GroupQueueMode mode);
+
+        /// <summary>
+        /// Restarts current item in play queue.
+        /// </summary>
+        void RestartCurrentItem();
+
+        /// <summary>
+        /// Picks next item in play queue.
+        /// </summary>
+        /// <returns><c>true</c> if the item changed; <c>false</c> otherwise.</returns>
+        bool NextItemInQueue();
+
+        /// <summary>
+        /// Picks previous item in play queue.
+        /// </summary>
+        /// <returns><c>true</c> if the item changed; <c>false</c> otherwise.</returns>
+        bool PreviousItemInQueue();
+
+        /// <summary>
+        /// Sets the repeat mode.
+        /// </summary>
+        /// <param name="mode">The new mode.</param>
+        void SetRepeatMode(GroupRepeatMode mode);
+
+        /// <summary>
+        /// Sets the shuffle mode.
+        /// </summary>
+        /// <param name="mode">The new mode.</param>
+        void SetShuffleMode(GroupShuffleMode mode);
+
+        /// <summary>
+        /// Creates a play queue update.
+        /// </summary>
+        /// <param name="reason">The reason for the update.</param>
+        /// <returns>The play queue update.</returns>
+        PlayQueueUpdate GetPlayQueueUpdate(PlayQueueUpdateReason reason);
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/ISyncPlayController.cs b/MediaBrowser.Controller/SyncPlay/ISyncPlayController.cs
deleted file mode 100644
index 60d17fe36..000000000
--- a/MediaBrowser.Controller/SyncPlay/ISyncPlayController.cs
+++ /dev/null
@@ -1,67 +0,0 @@
-using System;
-using System.Threading;
-using MediaBrowser.Controller.Session;
-using MediaBrowser.Model.SyncPlay;
-
-namespace MediaBrowser.Controller.SyncPlay
-{
-    /// <summary>
-    /// Interface ISyncPlayController.
-    /// </summary>
-    public interface ISyncPlayController
-    {
-        /// <summary>
-        /// Gets the group id.
-        /// </summary>
-        /// <value>The group id.</value>
-        Guid GetGroupId();
-
-        /// <summary>
-        /// Gets the playing item id.
-        /// </summary>
-        /// <value>The playing item id.</value>
-        Guid GetPlayingItemId();
-
-        /// <summary>
-        /// Checks if the group is empty.
-        /// </summary>
-        /// <value>If the group is empty.</value>
-        bool IsGroupEmpty();
-
-        /// <summary>
-        /// Initializes the group with the session's info.
-        /// </summary>
-        /// <param name="session">The session.</param>
-        /// <param name="cancellationToken">The cancellation token.</param>
-        void CreateGroup(SessionInfo session, CancellationToken cancellationToken);
-
-        /// <summary>
-        /// Adds the session to the group.
-        /// </summary>
-        /// <param name="session">The session.</param>
-        /// <param name="request">The request.</param>
-        /// <param name="cancellationToken">The cancellation token.</param>
-        void SessionJoin(SessionInfo session, JoinGroupRequest request, CancellationToken cancellationToken);
-
-        /// <summary>
-        /// Removes the session from the group.
-        /// </summary>
-        /// <param name="session">The session.</param>
-        /// <param name="cancellationToken">The cancellation token.</param>
-        void SessionLeave(SessionInfo session, CancellationToken cancellationToken);
-
-        /// <summary>
-        /// Handles the requested action by the session.
-        /// </summary>
-        /// <param name="session">The session.</param>
-        /// <param name="request">The requested action.</param>
-        /// <param name="cancellationToken">The cancellation token.</param>
-        void HandleRequest(SessionInfo session, PlaybackRequest request, CancellationToken cancellationToken);
-
-        /// <summary>
-        /// Gets the info about the group for the clients.
-        /// </summary>
-        /// <value>The group info for the clients.</value>
-        GroupInfoView GetInfo();
-    }
-}
diff --git a/MediaBrowser.Controller/SyncPlay/ISyncPlayManager.cs b/MediaBrowser.Controller/SyncPlay/ISyncPlayManager.cs
index 006fb687b..d0244563a 100644
--- a/MediaBrowser.Controller/SyncPlay/ISyncPlayManager.cs
+++ b/MediaBrowser.Controller/SyncPlay/ISyncPlayManager.cs
@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Threading;
 using MediaBrowser.Controller.Session;
+using MediaBrowser.Controller.SyncPlay.Requests;
 using MediaBrowser.Model.SyncPlay;
 
 namespace MediaBrowser.Controller.SyncPlay
@@ -15,32 +16,33 @@ namespace MediaBrowser.Controller.SyncPlay
         /// Creates a new group.
         /// </summary>
         /// <param name="session">The session that's creating the group.</param>
+        /// <param name="request">The request.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
-        void NewGroup(SessionInfo session, CancellationToken cancellationToken);
+        void NewGroup(SessionInfo session, NewGroupRequest request, CancellationToken cancellationToken);
 
         /// <summary>
         /// Adds the session to a group.
         /// </summary>
         /// <param name="session">The session.</param>
-        /// <param name="groupId">The group id.</param>
         /// <param name="request">The request.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
-        void JoinGroup(SessionInfo session, Guid groupId, JoinGroupRequest request, CancellationToken cancellationToken);
+        void JoinGroup(SessionInfo session, JoinGroupRequest request, CancellationToken cancellationToken);
 
         /// <summary>
         /// Removes the session from a group.
         /// </summary>
         /// <param name="session">The session.</param>
+        /// <param name="request">The request.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
-        void LeaveGroup(SessionInfo session, CancellationToken cancellationToken);
+        void LeaveGroup(SessionInfo session, LeaveGroupRequest request, CancellationToken cancellationToken);
 
         /// <summary>
         /// Gets list of available groups for a session.
         /// </summary>
         /// <param name="session">The session.</param>
-        /// <param name="filterItemId">The item id to filter by.</param>
-        /// <value>The list of available groups.</value>
-        List<GroupInfoView> ListGroups(SessionInfo session, Guid filterItemId);
+        /// <param name="request">The request.</param>
+        /// <returns>The list of available groups.</returns>
+        List<GroupInfoDto> ListGroups(SessionInfo session, ListGroupsRequest request);
 
         /// <summary>
         /// Handle a request by a session in a group.
@@ -48,22 +50,6 @@ namespace MediaBrowser.Controller.SyncPlay
         /// <param name="session">The session.</param>
         /// <param name="request">The request.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
-        void HandleRequest(SessionInfo session, PlaybackRequest request, CancellationToken cancellationToken);
-
-        /// <summary>
-        /// Maps a session to a group.
-        /// </summary>
-        /// <param name="session">The session.</param>
-        /// <param name="group">The group.</param>
-        /// <exception cref="InvalidOperationException"></exception>
-        void AddSessionToGroup(SessionInfo session, ISyncPlayController group);
-
-        /// <summary>
-        /// Unmaps a session from a group.
-        /// </summary>
-        /// <param name="session">The session.</param>
-        /// <param name="group">The group.</param>
-        /// <exception cref="InvalidOperationException"></exception>
-        void RemoveSessionFromGroup(SessionInfo session, ISyncPlayController group);
+        void HandleRequest(SessionInfo session, IGroupPlaybackRequest request, CancellationToken cancellationToken);
     }
 }
diff --git a/MediaBrowser.Controller/SyncPlay/ISyncPlayRequest.cs b/MediaBrowser.Controller/SyncPlay/ISyncPlayRequest.cs
new file mode 100644
index 000000000..bf1981773
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/ISyncPlayRequest.cs
@@ -0,0 +1,16 @@
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay
+{
+    /// <summary>
+    /// Interface ISyncPlayRequest.
+    /// </summary>
+    public interface ISyncPlayRequest
+    {
+        /// <summary>
+        /// Gets the request type.
+        /// </summary>
+        /// <returns>The request type.</returns>
+        RequestType Type { get; }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/AbstractPlaybackRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/AbstractPlaybackRequest.cs
new file mode 100644
index 000000000..4090f65b9
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/AbstractPlaybackRequest.cs
@@ -0,0 +1,29 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class AbstractPlaybackRequest.
+    /// </summary>
+    public abstract class AbstractPlaybackRequest : IGroupPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="AbstractPlaybackRequest"/> class.
+        /// </summary>
+        protected AbstractPlaybackRequest()
+        {
+            // Do nothing.
+        }
+
+        /// <inheritdoc />
+        public RequestType Type { get; } = RequestType.Playback;
+
+        /// <inheritdoc />
+        public abstract PlaybackRequestType Action { get; }
+
+        /// <inheritdoc />
+        public abstract void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken);
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/BufferGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/BufferGroupRequest.cs
new file mode 100644
index 000000000..11cc99fcd
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/BufferGroupRequest.cs
@@ -0,0 +1,61 @@
+using System;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class BufferGroupRequest.
+    /// </summary>
+    public class BufferGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="BufferGroupRequest"/> class.
+        /// </summary>
+        /// <param name="when">When the request has been made, as reported by the client.</param>
+        /// <param name="positionTicks">The position ticks.</param>
+        /// <param name="isPlaying">Whether the client playback is unpaused.</param>
+        /// <param name="playlistItemId">The playlist item identifier of the playing item.</param>
+        public BufferGroupRequest(DateTime when, long positionTicks, bool isPlaying, Guid playlistItemId)
+        {
+            When = when;
+            PositionTicks = positionTicks;
+            IsPlaying = isPlaying;
+            PlaylistItemId = playlistItemId;
+        }
+
+        /// <summary>
+        /// Gets when the request has been made by the client.
+        /// </summary>
+        /// <value>The date of the request.</value>
+        public DateTime When { get; }
+
+        /// <summary>
+        /// Gets the position ticks.
+        /// </summary>
+        /// <value>The position ticks.</value>
+        public long PositionTicks { get; }
+
+        /// <summary>
+        /// Gets a value indicating whether the client playback is unpaused.
+        /// </summary>
+        /// <value>The client playback status.</value>
+        public bool IsPlaying { get; }
+
+        /// <summary>
+        /// Gets the playlist item identifier of the playing item.
+        /// </summary>
+        /// <value>The playlist item identifier.</value>
+        public Guid PlaylistItemId { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.Buffer;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/IgnoreWaitGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/IgnoreWaitGroupRequest.cs
new file mode 100644
index 000000000..64ef791ed
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/IgnoreWaitGroupRequest.cs
@@ -0,0 +1,36 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class IgnoreWaitGroupRequest.
+    /// </summary>
+    public class IgnoreWaitGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="IgnoreWaitGroupRequest"/> class.
+        /// </summary>
+        /// <param name="ignoreWait">Whether the client should be ignored.</param>
+        public IgnoreWaitGroupRequest(bool ignoreWait)
+        {
+            IgnoreWait = ignoreWait;
+        }
+
+        /// <summary>
+        /// Gets a value indicating whether the client should be ignored.
+        /// </summary>
+        /// <value>The client group-wait status.</value>
+        public bool IgnoreWait { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.IgnoreWait;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/MovePlaylistItemGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/MovePlaylistItemGroupRequest.cs
new file mode 100644
index 000000000..9cd8da566
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/MovePlaylistItemGroupRequest.cs
@@ -0,0 +1,45 @@
+using System;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class MovePlaylistItemGroupRequest.
+    /// </summary>
+    public class MovePlaylistItemGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="MovePlaylistItemGroupRequest"/> class.
+        /// </summary>
+        /// <param name="playlistItemId">The playlist identifier of the item.</param>
+        /// <param name="newIndex">The new position.</param>
+        public MovePlaylistItemGroupRequest(Guid playlistItemId, int newIndex)
+        {
+            PlaylistItemId = playlistItemId;
+            NewIndex = newIndex;
+        }
+
+        /// <summary>
+        /// Gets the playlist identifier of the item.
+        /// </summary>
+        /// <value>The playlist identifier of the item.</value>
+        public Guid PlaylistItemId { get; }
+
+        /// <summary>
+        /// Gets the new position.
+        /// </summary>
+        /// <value>The new position.</value>
+        public int NewIndex { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.MovePlaylistItem;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/NextItemGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/NextItemGroupRequest.cs
new file mode 100644
index 000000000..e0ae0deb7
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/NextItemGroupRequest.cs
@@ -0,0 +1,37 @@
+using System;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class NextItemGroupRequest.
+    /// </summary>
+    public class NextItemGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="NextItemGroupRequest"/> class.
+        /// </summary>
+        /// <param name="playlistItemId">The playing item identifier.</param>
+        public NextItemGroupRequest(Guid playlistItemId)
+        {
+            PlaylistItemId = playlistItemId;
+        }
+
+        /// <summary>
+        /// Gets the playing item identifier.
+        /// </summary>
+        /// <value>The playing item identifier.</value>
+        public Guid PlaylistItemId { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.NextItem;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/PauseGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/PauseGroupRequest.cs
new file mode 100644
index 000000000..2869b35f7
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/PauseGroupRequest.cs
@@ -0,0 +1,21 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class PauseGroupRequest.
+    /// </summary>
+    public class PauseGroupRequest : AbstractPlaybackRequest
+    {
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.Pause;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/PingGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/PingGroupRequest.cs
new file mode 100644
index 000000000..8ef3b2030
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/PingGroupRequest.cs
@@ -0,0 +1,36 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class PingGroupRequest.
+    /// </summary>
+    public class PingGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PingGroupRequest"/> class.
+        /// </summary>
+        /// <param name="ping">The ping time.</param>
+        public PingGroupRequest(long ping)
+        {
+            Ping = ping;
+        }
+
+        /// <summary>
+        /// Gets the ping time.
+        /// </summary>
+        /// <value>The ping time.</value>
+        public long Ping { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.Ping;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/PlayGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/PlayGroupRequest.cs
new file mode 100644
index 000000000..16f9b4087
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/PlayGroupRequest.cs
@@ -0,0 +1,54 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class PlayGroupRequest.
+    /// </summary>
+    public class PlayGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PlayGroupRequest"/> class.
+        /// </summary>
+        /// <param name="playingQueue">The playing queue.</param>
+        /// <param name="playingItemPosition">The playing item position.</param>
+        /// <param name="startPositionTicks">The start position ticks.</param>
+        public PlayGroupRequest(IReadOnlyList<Guid> playingQueue, int playingItemPosition, long startPositionTicks)
+        {
+            PlayingQueue = playingQueue ?? Array.Empty<Guid>();
+            PlayingItemPosition = playingItemPosition;
+            StartPositionTicks = startPositionTicks;
+        }
+
+        /// <summary>
+        /// Gets the playing queue.
+        /// </summary>
+        /// <value>The playing queue.</value>
+        public IReadOnlyList<Guid> PlayingQueue { get; }
+
+        /// <summary>
+        /// Gets the position of the playing item in the queue.
+        /// </summary>
+        /// <value>The playing item position.</value>
+        public int PlayingItemPosition { get; }
+
+        /// <summary>
+        /// Gets the start position ticks.
+        /// </summary>
+        /// <value>The start position ticks.</value>
+        public long StartPositionTicks { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.Play;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/PreviousItemGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/PreviousItemGroupRequest.cs
new file mode 100644
index 000000000..166ee0800
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/PreviousItemGroupRequest.cs
@@ -0,0 +1,37 @@
+using System;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class PreviousItemGroupRequest.
+    /// </summary>
+    public class PreviousItemGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PreviousItemGroupRequest"/> class.
+        /// </summary>
+        /// <param name="playlistItemId">The playing item identifier.</param>
+        public PreviousItemGroupRequest(Guid playlistItemId)
+        {
+            PlaylistItemId = playlistItemId;
+        }
+
+        /// <summary>
+        /// Gets the playing item identifier.
+        /// </summary>
+        /// <value>The playing item identifier.</value>
+        public Guid PlaylistItemId { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.PreviousItem;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/QueueGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/QueueGroupRequest.cs
new file mode 100644
index 000000000..d4af63b6d
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/QueueGroupRequest.cs
@@ -0,0 +1,46 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class QueueGroupRequest.
+    /// </summary>
+    public class QueueGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="QueueGroupRequest"/> class.
+        /// </summary>
+        /// <param name="items">The items to add to the queue.</param>
+        /// <param name="mode">The enqueue mode.</param>
+        public QueueGroupRequest(IReadOnlyList<Guid> items, GroupQueueMode mode)
+        {
+            ItemIds = items ?? Array.Empty<Guid>();
+            Mode = mode;
+        }
+
+        /// <summary>
+        /// Gets the items to enqueue.
+        /// </summary>
+        /// <value>The items to enqueue.</value>
+        public IReadOnlyList<Guid> ItemIds { get; }
+
+        /// <summary>
+        /// Gets the mode in which to add the new items.
+        /// </summary>
+        /// <value>The enqueue mode.</value>
+        public GroupQueueMode Mode { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.Queue;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/ReadyGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/ReadyGroupRequest.cs
new file mode 100644
index 000000000..74f01cbea
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/ReadyGroupRequest.cs
@@ -0,0 +1,61 @@
+using System;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class ReadyGroupRequest.
+    /// </summary>
+    public class ReadyGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ReadyGroupRequest"/> class.
+        /// </summary>
+        /// <param name="when">When the request has been made, as reported by the client.</param>
+        /// <param name="positionTicks">The position ticks.</param>
+        /// <param name="isPlaying">Whether the client playback is unpaused.</param>
+        /// <param name="playlistItemId">The playlist item identifier of the playing item.</param>
+        public ReadyGroupRequest(DateTime when, long positionTicks, bool isPlaying, Guid playlistItemId)
+        {
+            When = when;
+            PositionTicks = positionTicks;
+            IsPlaying = isPlaying;
+            PlaylistItemId = playlistItemId;
+        }
+
+        /// <summary>
+        /// Gets when the request has been made by the client.
+        /// </summary>
+        /// <value>The date of the request.</value>
+        public DateTime When { get; }
+
+        /// <summary>
+        /// Gets the position ticks.
+        /// </summary>
+        /// <value>The position ticks.</value>
+        public long PositionTicks { get; }
+
+        /// <summary>
+        /// Gets a value indicating whether the client playback is unpaused.
+        /// </summary>
+        /// <value>The client playback status.</value>
+        public bool IsPlaying { get; }
+
+        /// <summary>
+        /// Gets the playlist item identifier of the playing item.
+        /// </summary>
+        /// <value>The playlist item identifier.</value>
+        public Guid PlaylistItemId { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.Ready;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/RemoveFromPlaylistGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/RemoveFromPlaylistGroupRequest.cs
new file mode 100644
index 000000000..47c06c222
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/RemoveFromPlaylistGroupRequest.cs
@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class RemoveFromPlaylistGroupRequest.
+    /// </summary>
+    public class RemoveFromPlaylistGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="RemoveFromPlaylistGroupRequest"/> class.
+        /// </summary>
+        /// <param name="items">The playlist ids of the items to remove.</param>
+        public RemoveFromPlaylistGroupRequest(IReadOnlyList<Guid> items)
+        {
+            PlaylistItemIds = items ?? Array.Empty<Guid>();
+        }
+
+        /// <summary>
+        /// Gets the playlist identifiers ot the items.
+        /// </summary>
+        /// <value>The playlist identifiers ot the items.</value>
+        public IReadOnlyList<Guid> PlaylistItemIds { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.RemoveFromPlaylist;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/SeekGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/SeekGroupRequest.cs
new file mode 100644
index 000000000..ecaa689ae
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/SeekGroupRequest.cs
@@ -0,0 +1,36 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class SeekGroupRequest.
+    /// </summary>
+    public class SeekGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SeekGroupRequest"/> class.
+        /// </summary>
+        /// <param name="positionTicks">The position ticks.</param>
+        public SeekGroupRequest(long positionTicks)
+        {
+            PositionTicks = positionTicks;
+        }
+
+        /// <summary>
+        /// Gets the position ticks.
+        /// </summary>
+        /// <value>The position ticks.</value>
+        public long PositionTicks { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.Seek;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/SetPlaylistItemGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/SetPlaylistItemGroupRequest.cs
new file mode 100644
index 000000000..c3451703e
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/SetPlaylistItemGroupRequest.cs
@@ -0,0 +1,37 @@
+using System;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class SetPlaylistItemGroupRequest.
+    /// </summary>
+    public class SetPlaylistItemGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SetPlaylistItemGroupRequest"/> class.
+        /// </summary>
+        /// <param name="playlistItemId">The playlist identifier of the item.</param>
+        public SetPlaylistItemGroupRequest(Guid playlistItemId)
+        {
+            PlaylistItemId = playlistItemId;
+        }
+
+        /// <summary>
+        /// Gets the playlist identifier of the playing item.
+        /// </summary>
+        /// <value>The playlist identifier of the playing item.</value>
+        public Guid PlaylistItemId { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.SetPlaylistItem;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/SetRepeatModeGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/SetRepeatModeGroupRequest.cs
new file mode 100644
index 000000000..51011672e
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/SetRepeatModeGroupRequest.cs
@@ -0,0 +1,36 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class SetRepeatModeGroupRequest.
+    /// </summary>
+    public class SetRepeatModeGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SetRepeatModeGroupRequest"/> class.
+        /// </summary>
+        /// <param name="mode">The repeat mode.</param>
+        public SetRepeatModeGroupRequest(GroupRepeatMode mode)
+        {
+            Mode = mode;
+        }
+
+        /// <summary>
+        /// Gets the repeat mode.
+        /// </summary>
+        /// <value>The repeat mode.</value>
+        public GroupRepeatMode Mode { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.SetRepeatMode;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/SetShuffleModeGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/SetShuffleModeGroupRequest.cs
new file mode 100644
index 000000000..d7b2504b4
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/SetShuffleModeGroupRequest.cs
@@ -0,0 +1,36 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class SetShuffleModeGroupRequest.
+    /// </summary>
+    public class SetShuffleModeGroupRequest : AbstractPlaybackRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SetShuffleModeGroupRequest"/> class.
+        /// </summary>
+        /// <param name="mode">The shuffle mode.</param>
+        public SetShuffleModeGroupRequest(GroupShuffleMode mode)
+        {
+            Mode = mode;
+        }
+
+        /// <summary>
+        /// Gets the shuffle mode.
+        /// </summary>
+        /// <value>The shuffle mode.</value>
+        public GroupShuffleMode Mode { get; }
+
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.SetShuffleMode;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/StopGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/StopGroupRequest.cs
new file mode 100644
index 000000000..ad739213c
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/StopGroupRequest.cs
@@ -0,0 +1,21 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class StopGroupRequest.
+    /// </summary>
+    public class StopGroupRequest : AbstractPlaybackRequest
+    {
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.Stop;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/PlaybackRequests/UnpauseGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/UnpauseGroupRequest.cs
new file mode 100644
index 000000000..aaf3d65a8
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/PlaybackRequests/UnpauseGroupRequest.cs
@@ -0,0 +1,21 @@
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.PlaybackRequests
+{
+    /// <summary>
+    /// Class UnpauseGroupRequest.
+    /// </summary>
+    public class UnpauseGroupRequest : AbstractPlaybackRequest
+    {
+        /// <inheritdoc />
+        public override PlaybackRequestType Action { get; } = PlaybackRequestType.Unpause;
+
+        /// <inheritdoc />
+        public override void Apply(IGroupStateContext context, IGroupState state, SessionInfo session, CancellationToken cancellationToken)
+        {
+            state.HandleRequest(this, context, state.Type, session, cancellationToken);
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/Queue/PlayQueueManager.cs b/MediaBrowser.Controller/SyncPlay/Queue/PlayQueueManager.cs
new file mode 100644
index 000000000..fdec29417
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/Queue/PlayQueueManager.cs
@@ -0,0 +1,577 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.Queue
+{
+    /// <summary>
+    /// Class PlayQueueManager.
+    /// </summary>
+    public class PlayQueueManager
+    {
+        /// <summary>
+        /// Placeholder index for when no item is playing.
+        /// </summary>
+        /// <value>The no-playing item index.</value>
+        private const int NoPlayingItemIndex = -1;
+
+        /// <summary>
+        /// Random number generator used to shuffle lists.
+        /// </summary>
+        /// <value>The random number generator.</value>
+        private readonly Random _randomNumberGenerator = new Random();
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PlayQueueManager" /> class.
+        /// </summary>
+        public PlayQueueManager()
+        {
+            Reset();
+        }
+
+        /// <summary>
+        /// Gets the playing item index.
+        /// </summary>
+        /// <value>The playing item index.</value>
+        public int PlayingItemIndex { get; private set; }
+
+        /// <summary>
+        /// Gets the last time the queue has been changed.
+        /// </summary>
+        /// <value>The last time the queue has been changed.</value>
+        public DateTime LastChange { get; private set; }
+
+        /// <summary>
+        /// Gets the shuffle mode.
+        /// </summary>
+        /// <value>The shuffle mode.</value>
+        public GroupShuffleMode ShuffleMode { get; private set; } = GroupShuffleMode.Sorted;
+
+        /// <summary>
+        /// Gets the repeat mode.
+        /// </summary>
+        /// <value>The repeat mode.</value>
+        public GroupRepeatMode RepeatMode { get; private set; } = GroupRepeatMode.RepeatNone;
+
+        /// <summary>
+        /// Gets or sets the sorted playlist.
+        /// </summary>
+        /// <value>The sorted playlist, or play queue of the group.</value>
+        private List<QueueItem> SortedPlaylist { get; set; } = new List<QueueItem>();
+
+        /// <summary>
+        /// Gets or sets the shuffled playlist.
+        /// </summary>
+        /// <value>The shuffled playlist, or play queue of the group.</value>
+        private List<QueueItem> ShuffledPlaylist { get; set; } = new List<QueueItem>();
+
+        /// <summary>
+        /// Checks if an item is playing.
+        /// </summary>
+        /// <returns><c>true</c> if an item is playing; <c>false</c> otherwise.</returns>
+        public bool IsItemPlaying()
+        {
+            return PlayingItemIndex != NoPlayingItemIndex;
+        }
+
+        /// <summary>
+        /// Gets the current playlist considering the shuffle mode.
+        /// </summary>
+        /// <returns>The playlist.</returns>
+        public IReadOnlyList<QueueItem> GetPlaylist()
+        {
+            return GetPlaylistInternal();
+        }
+
+        /// <summary>
+        /// Sets a new playlist. Playing item is reset.
+        /// </summary>
+        /// <param name="items">The new items of the playlist.</param>
+        public void SetPlaylist(IReadOnlyList<Guid> items)
+        {
+            SortedPlaylist.Clear();
+            ShuffledPlaylist.Clear();
+
+            SortedPlaylist = CreateQueueItemsFromArray(items);
+            if (ShuffleMode.Equals(GroupShuffleMode.Shuffle))
+            {
+                ShuffledPlaylist = new List<QueueItem>(SortedPlaylist);
+                Shuffle(ShuffledPlaylist);
+            }
+
+            PlayingItemIndex = NoPlayingItemIndex;
+            LastChange = DateTime.UtcNow;
+        }
+
+        /// <summary>
+        /// Appends new items to the playlist. The specified order is mantained.
+        /// </summary>
+        /// <param name="items">The items to add to the playlist.</param>
+        public void Queue(IReadOnlyList<Guid> items)
+        {
+            var newItems = CreateQueueItemsFromArray(items);
+
+            SortedPlaylist.AddRange(newItems);
+            if (ShuffleMode.Equals(GroupShuffleMode.Shuffle))
+            {
+                ShuffledPlaylist.AddRange(newItems);
+            }
+
+            LastChange = DateTime.UtcNow;
+        }
+
+        /// <summary>
+        /// Shuffles the playlist. Shuffle mode is changed. The playlist gets re-shuffled if already shuffled.
+        /// </summary>
+        public void ShufflePlaylist()
+        {
+            if (PlayingItemIndex == NoPlayingItemIndex)
+            {
+                ShuffledPlaylist = new List<QueueItem>(SortedPlaylist);
+                Shuffle(ShuffledPlaylist);
+            }
+            else if (ShuffleMode.Equals(GroupShuffleMode.Sorted))
+            {
+                // First time shuffle.
+                var playingItem = SortedPlaylist[PlayingItemIndex];
+                ShuffledPlaylist = new List<QueueItem>(SortedPlaylist);
+                ShuffledPlaylist.RemoveAt(PlayingItemIndex);
+                Shuffle(ShuffledPlaylist);
+                ShuffledPlaylist.Insert(0, playingItem);
+                PlayingItemIndex = 0;
+            }
+            else
+            {
+                // Re-shuffle playlist.
+                var playingItem = ShuffledPlaylist[PlayingItemIndex];
+                ShuffledPlaylist.RemoveAt(PlayingItemIndex);
+                Shuffle(ShuffledPlaylist);
+                ShuffledPlaylist.Insert(0, playingItem);
+                PlayingItemIndex = 0;
+            }
+
+            ShuffleMode = GroupShuffleMode.Shuffle;
+            LastChange = DateTime.UtcNow;
+        }
+
+        /// <summary>
+        /// Resets the playlist to sorted mode. Shuffle mode is changed.
+        /// </summary>
+        public void RestoreSortedPlaylist()
+        {
+            if (PlayingItemIndex != NoPlayingItemIndex)
+            {
+                var playingItem = ShuffledPlaylist[PlayingItemIndex];
+                PlayingItemIndex = SortedPlaylist.IndexOf(playingItem);
+            }
+
+            ShuffledPlaylist.Clear();
+
+            ShuffleMode = GroupShuffleMode.Sorted;
+            LastChange = DateTime.UtcNow;
+        }
+
+        /// <summary>
+        /// Clears the playlist. Shuffle mode is preserved.
+        /// </summary>
+        /// <param name="clearPlayingItem">Whether to remove the playing item as well.</param>
+        public void ClearPlaylist(bool clearPlayingItem)
+        {
+            var playingItem = GetPlayingItem();
+            SortedPlaylist.Clear();
+            ShuffledPlaylist.Clear();
+            LastChange = DateTime.UtcNow;
+
+            if (!clearPlayingItem && playingItem != null)
+            {
+                SortedPlaylist.Add(playingItem);
+                if (ShuffleMode.Equals(GroupShuffleMode.Shuffle))
+                {
+                    ShuffledPlaylist.Add(playingItem);
+                }
+
+                PlayingItemIndex = 0;
+            }
+            else
+            {
+                PlayingItemIndex = NoPlayingItemIndex;
+            }
+        }
+
+        /// <summary>
+        /// Adds new items to the playlist right after the playing item. The specified order is mantained.
+        /// </summary>
+        /// <param name="items">The items to add to the playlist.</param>
+        public void QueueNext(IReadOnlyList<Guid> items)
+        {
+            var newItems = CreateQueueItemsFromArray(items);
+
+            if (ShuffleMode.Equals(GroupShuffleMode.Shuffle))
+            {
+                var playingItem = GetPlayingItem();
+                var sortedPlayingItemIndex = SortedPlaylist.IndexOf(playingItem);
+                // Append items to sorted and shuffled playlist as they are.
+                SortedPlaylist.InsertRange(sortedPlayingItemIndex + 1, newItems);
+                ShuffledPlaylist.InsertRange(PlayingItemIndex + 1, newItems);
+            }
+            else
+            {
+                SortedPlaylist.InsertRange(PlayingItemIndex + 1, newItems);
+            }
+
+            LastChange = DateTime.UtcNow;
+        }
+
+        /// <summary>
+        /// Gets playlist identifier of the playing item, if any.
+        /// </summary>
+        /// <returns>The playlist identifier of the playing item.</returns>
+        public Guid GetPlayingItemPlaylistId()
+        {
+            var playingItem = GetPlayingItem();
+            return playingItem?.PlaylistItemId ?? Guid.Empty;
+        }
+
+        /// <summary>
+        /// Gets the playing item identifier, if any.
+        /// </summary>
+        /// <returns>The playing item identifier.</returns>
+        public Guid GetPlayingItemId()
+        {
+            var playingItem = GetPlayingItem();
+            return playingItem?.ItemId ?? Guid.Empty;
+        }
+
+        /// <summary>
+        /// Sets the playing item using its identifier. If not in the playlist, the playing item is reset.
+        /// </summary>
+        /// <param name="itemId">The new playing item identifier.</param>
+        public void SetPlayingItemById(Guid itemId)
+        {
+            var playlist = GetPlaylistInternal();
+            PlayingItemIndex = playlist.FindIndex(item => item.ItemId.Equals(itemId));
+            LastChange = DateTime.UtcNow;
+        }
+
+        /// <summary>
+        /// Sets the playing item using its playlist identifier. If not in the playlist, the playing item is reset.
+        /// </summary>
+        /// <param name="playlistItemId">The new playing item identifier.</param>
+        /// <returns><c>true</c> if playing item has been set; <c>false</c> if item is not in the playlist.</returns>
+        public bool SetPlayingItemByPlaylistId(Guid playlistItemId)
+        {
+            var playlist = GetPlaylistInternal();
+            PlayingItemIndex = playlist.FindIndex(item => item.PlaylistItemId.Equals(playlistItemId));
+            LastChange = DateTime.UtcNow;
+
+            return PlayingItemIndex != NoPlayingItemIndex;
+        }
+
+        /// <summary>
+        /// Sets the playing item using its position. If not in range, the playing item is reset.
+        /// </summary>
+        /// <param name="playlistIndex">The new playing item index.</param>
+        public void SetPlayingItemByIndex(int playlistIndex)
+        {
+            var playlist = GetPlaylistInternal();
+            if (playlistIndex < 0 || playlistIndex > playlist.Count)
+            {
+                PlayingItemIndex = NoPlayingItemIndex;
+            }
+            else
+            {
+                PlayingItemIndex = playlistIndex;
+            }
+
+            LastChange = DateTime.UtcNow;
+        }
+
+        /// <summary>
+        /// Removes items from the playlist. If not removed, the playing item is preserved.
+        /// </summary>
+        /// <param name="playlistItemIds">The items to remove.</param>
+        /// <returns><c>true</c> if playing item got removed; <c>false</c> otherwise.</returns>
+        public bool RemoveFromPlaylist(IReadOnlyList<Guid> playlistItemIds)
+        {
+            var playingItem = GetPlayingItem();
+
+            SortedPlaylist.RemoveAll(item => playlistItemIds.Contains(item.PlaylistItemId));
+            ShuffledPlaylist.RemoveAll(item => playlistItemIds.Contains(item.PlaylistItemId));
+
+            LastChange = DateTime.UtcNow;
+
+            if (playingItem != null)
+            {
+                if (playlistItemIds.Contains(playingItem.PlaylistItemId))
+                {
+                    // Playing item has been removed, picking previous item.
+                    PlayingItemIndex--;
+                    if (PlayingItemIndex < 0)
+                    {
+                        // Was first element, picking next if available.
+                        // Default to no playing item otherwise.
+                        PlayingItemIndex = SortedPlaylist.Count > 0 ? 0 : NoPlayingItemIndex;
+                    }
+
+                    return true;
+                }
+                else
+                {
+                    // Restoring playing item.
+                    SetPlayingItemByPlaylistId(playingItem.PlaylistItemId);
+                    return false;
+                }
+            }
+            else
+            {
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Moves an item in the playlist to another position.
+        /// </summary>
+        /// <param name="playlistItemId">The item to move.</param>
+        /// <param name="newIndex">The new position.</param>
+        /// <returns><c>true</c> if the item has been moved; <c>false</c> otherwise.</returns>
+        public bool MovePlaylistItem(Guid playlistItemId, int newIndex)
+        {
+            var playlist = GetPlaylistInternal();
+            var playingItem = GetPlayingItem();
+
+            var oldIndex = playlist.FindIndex(item => item.PlaylistItemId.Equals(playlistItemId));
+            if (oldIndex < 0)
+            {
+                return false;
+            }
+
+            var queueItem = playlist[oldIndex];
+            playlist.RemoveAt(oldIndex);
+            newIndex = Math.Clamp(newIndex, 0, playlist.Count);
+            playlist.Insert(newIndex, queueItem);
+
+            LastChange = DateTime.UtcNow;
+            PlayingItemIndex = playlist.IndexOf(playingItem);
+            return true;
+        }
+
+        /// <summary>
+        /// Resets the playlist to its initial state.
+        /// </summary>
+        public void Reset()
+        {
+            SortedPlaylist.Clear();
+            ShuffledPlaylist.Clear();
+            PlayingItemIndex = NoPlayingItemIndex;
+            ShuffleMode = GroupShuffleMode.Sorted;
+            RepeatMode = GroupRepeatMode.RepeatNone;
+            LastChange = DateTime.UtcNow;
+        }
+
+        /// <summary>
+        /// Sets the repeat mode.
+        /// </summary>
+        /// <param name="mode">The new mode.</param>
+        public void SetRepeatMode(GroupRepeatMode mode)
+        {
+            RepeatMode = mode;
+            LastChange = DateTime.UtcNow;
+        }
+
+        /// <summary>
+        /// Sets the shuffle mode.
+        /// </summary>
+        /// <param name="mode">The new mode.</param>
+        public void SetShuffleMode(GroupShuffleMode mode)
+        {
+            if (mode.Equals(GroupShuffleMode.Shuffle))
+            {
+                ShufflePlaylist();
+            }
+            else
+            {
+                RestoreSortedPlaylist();
+            }
+        }
+
+        /// <summary>
+        /// Toggles the shuffle mode between sorted and shuffled.
+        /// </summary>
+        public void ToggleShuffleMode()
+        {
+            if (ShuffleMode.Equals(GroupShuffleMode.Sorted))
+            {
+                ShufflePlaylist();
+            }
+            else
+            {
+                RestoreSortedPlaylist();
+            }
+        }
+
+        /// <summary>
+        /// Gets the next item in the playlist considering repeat mode and shuffle mode.
+        /// </summary>
+        /// <returns>The next item in the playlist.</returns>
+        public QueueItem GetNextItemPlaylistId()
+        {
+            int newIndex;
+            var playlist = GetPlaylistInternal();
+
+            switch (RepeatMode)
+            {
+                case GroupRepeatMode.RepeatOne:
+                    newIndex = PlayingItemIndex;
+                    break;
+                case GroupRepeatMode.RepeatAll:
+                    newIndex = PlayingItemIndex + 1;
+                    if (newIndex >= playlist.Count)
+                    {
+                        newIndex = 0;
+                    }
+
+                    break;
+                default:
+                    newIndex = PlayingItemIndex + 1;
+                    break;
+            }
+
+            if (newIndex < 0 || newIndex >= playlist.Count)
+            {
+                return null;
+            }
+
+            return playlist[newIndex];
+        }
+
+        /// <summary>
+        /// Sets the next item in the queue as playing item.
+        /// </summary>
+        /// <returns><c>true</c> if the playing item changed; <c>false</c> otherwise.</returns>
+        public bool Next()
+        {
+            if (RepeatMode.Equals(GroupRepeatMode.RepeatOne))
+            {
+                LastChange = DateTime.UtcNow;
+                return true;
+            }
+
+            PlayingItemIndex++;
+            if (PlayingItemIndex >= SortedPlaylist.Count)
+            {
+                if (RepeatMode.Equals(GroupRepeatMode.RepeatAll))
+                {
+                    PlayingItemIndex = 0;
+                }
+                else
+                {
+                    PlayingItemIndex = SortedPlaylist.Count - 1;
+                    return false;
+                }
+            }
+
+            LastChange = DateTime.UtcNow;
+            return true;
+        }
+
+        /// <summary>
+        /// Sets the previous item in the queue as playing item.
+        /// </summary>
+        /// <returns><c>true</c> if the playing item changed; <c>false</c> otherwise.</returns>
+        public bool Previous()
+        {
+            if (RepeatMode.Equals(GroupRepeatMode.RepeatOne))
+            {
+                LastChange = DateTime.UtcNow;
+                return true;
+            }
+
+            PlayingItemIndex--;
+            if (PlayingItemIndex < 0)
+            {
+                if (RepeatMode.Equals(GroupRepeatMode.RepeatAll))
+                {
+                    PlayingItemIndex = SortedPlaylist.Count - 1;
+                }
+                else
+                {
+                    PlayingItemIndex = 0;
+                    return false;
+                }
+            }
+
+            LastChange = DateTime.UtcNow;
+            return true;
+        }
+
+        /// <summary>
+        /// Shuffles a given list.
+        /// </summary>
+        /// <param name="list">The list to shuffle.</param>
+        private void Shuffle<T>(IList<T> list)
+        {
+            int n = list.Count;
+            while (n > 1)
+            {
+                n--;
+                int k = _randomNumberGenerator.Next(n + 1);
+                T value = list[k];
+                list[k] = list[n];
+                list[n] = value;
+            }
+        }
+
+        /// <summary>
+        /// Creates a list from the array of items. Each item is given an unique playlist identifier.
+        /// </summary>
+        /// <returns>The list of queue items.</returns>
+        private List<QueueItem> CreateQueueItemsFromArray(IReadOnlyList<Guid> items)
+        {
+            var list = new List<QueueItem>();
+            foreach (var item in items)
+            {
+                var queueItem = new QueueItem(item);
+                list.Add(queueItem);
+            }
+
+            return list;
+        }
+
+        /// <summary>
+        /// Gets the current playlist considering the shuffle mode.
+        /// </summary>
+        /// <returns>The playlist.</returns>
+        private List<QueueItem> GetPlaylistInternal()
+        {
+            if (ShuffleMode.Equals(GroupShuffleMode.Shuffle))
+            {
+                return ShuffledPlaylist;
+            }
+            else
+            {
+                return SortedPlaylist;
+            }
+        }
+
+        /// <summary>
+        /// Gets the current playing item, depending on the shuffle mode.
+        /// </summary>
+        /// <returns>The playing item.</returns>
+        private QueueItem GetPlayingItem()
+        {
+            if (PlayingItemIndex == NoPlayingItemIndex)
+            {
+                return null;
+            }
+            else if (ShuffleMode.Equals(GroupShuffleMode.Shuffle))
+            {
+                return ShuffledPlaylist[PlayingItemIndex];
+            }
+            else
+            {
+                return SortedPlaylist[PlayingItemIndex];
+            }
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/Requests/JoinGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/Requests/JoinGroupRequest.cs
new file mode 100644
index 000000000..38c9e8e20
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/Requests/JoinGroupRequest.cs
@@ -0,0 +1,29 @@
+using System;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.Requests
+{
+    /// <summary>
+    /// Class JoinGroupRequest.
+    /// </summary>
+    public class JoinGroupRequest : ISyncPlayRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="JoinGroupRequest"/> class.
+        /// </summary>
+        /// <param name="groupId">The identifier of the group to join.</param>
+        public JoinGroupRequest(Guid groupId)
+        {
+            GroupId = groupId;
+        }
+
+        /// <summary>
+        /// Gets the group identifier.
+        /// </summary>
+        /// <value>The identifier of the group to join.</value>
+        public Guid GroupId { get; }
+
+        /// <inheritdoc />
+        public RequestType Type { get; } = RequestType.JoinGroup;
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/Requests/LeaveGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/Requests/LeaveGroupRequest.cs
new file mode 100644
index 000000000..545778264
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/Requests/LeaveGroupRequest.cs
@@ -0,0 +1,13 @@
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.Requests
+{
+    /// <summary>
+    /// Class LeaveGroupRequest.
+    /// </summary>
+    public class LeaveGroupRequest : ISyncPlayRequest
+    {
+        /// <inheritdoc />
+        public RequestType Type { get; } = RequestType.LeaveGroup;
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/Requests/ListGroupsRequest.cs b/MediaBrowser.Controller/SyncPlay/Requests/ListGroupsRequest.cs
new file mode 100644
index 000000000..4a234fdab
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/Requests/ListGroupsRequest.cs
@@ -0,0 +1,13 @@
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.Requests
+{
+    /// <summary>
+    /// Class ListGroupsRequest.
+    /// </summary>
+    public class ListGroupsRequest : ISyncPlayRequest
+    {
+        /// <inheritdoc />
+        public RequestType Type { get; } = RequestType.ListGroups;
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/Requests/NewGroupRequest.cs b/MediaBrowser.Controller/SyncPlay/Requests/NewGroupRequest.cs
new file mode 100644
index 000000000..1321f0de8
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/Requests/NewGroupRequest.cs
@@ -0,0 +1,28 @@
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay.Requests
+{
+    /// <summary>
+    /// Class NewGroupRequest.
+    /// </summary>
+    public class NewGroupRequest : ISyncPlayRequest
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="NewGroupRequest"/> class.
+        /// </summary>
+        /// <param name="groupName">The name of the new group.</param>
+        public NewGroupRequest(string groupName)
+        {
+            GroupName = groupName;
+        }
+
+        /// <summary>
+        /// Gets the group name.
+        /// </summary>
+        /// <value>The name of the new group.</value>
+        public string GroupName { get; }
+
+        /// <inheritdoc />
+        public RequestType Type { get; } = RequestType.NewGroup;
+    }
+}