Merge branch 'master' into install-plugin

18 files changed, 485 insertions, 52 deletions

diff --git a/MediaBrowser.Controller/Devices/CameraImageUploadInfo.cs b/MediaBrowser.Controller/Devices/CameraImageUploadInfo.cs
deleted file mode 100644
index 89d0be58f..000000000
--- a/MediaBrowser.Controller/Devices/CameraImageUploadInfo.cs
+++ /dev/null
@@ -1,10 +0,0 @@
-using MediaBrowser.Model.Devices;
-
-namespace MediaBrowser.Controller.Devices
-{
-    public class CameraImageUploadInfo
-    {
-        public LocalFileInfo FileInfo { get; set; }
-        public DeviceInfo Device { get; set; }
-    }
-}
diff --git a/MediaBrowser.Controller/Drawing/IImageEncoder.cs b/MediaBrowser.Controller/Drawing/IImageEncoder.cs
index 88e67b648..e09ccd204 100644
--- a/MediaBrowser.Controller/Drawing/IImageEncoder.cs
+++ b/MediaBrowser.Controller/Drawing/IImageEncoder.cs
@@ -44,6 +44,15 @@ namespace MediaBrowser.Controller.Drawing
         ImageDimensions GetImageSize(string path);
 
         /// <summary>
+        /// Gets the blurhash of an image.
+        /// </summary>
+        /// <param name="xComp">Amount of X components of DCT to take.</param>
+        /// <param name="yComp">Amount of Y components of DCT to take.</param>
+        /// <param name="path">The filepath of the image.</param>
+        /// <returns>The blurhash.</returns>
+        string GetImageBlurHash(int xComp, int yComp, string path);
+
+        /// <summary>
         /// Encode an image.
         /// </summary>
         string EncodeImage(string inputPath, DateTime dateModified, string outputPath, bool autoOrient, ImageOrientation? orientation, int quality, ImageProcessingOptions options, ImageFormat outputFormat);
diff --git a/MediaBrowser.Controller/Drawing/IImageProcessor.cs b/MediaBrowser.Controller/Drawing/IImageProcessor.cs
index 36c746624..8800fdf99 100644
--- a/MediaBrowser.Controller/Drawing/IImageProcessor.cs
+++ b/MediaBrowser.Controller/Drawing/IImageProcessor.cs
@@ -41,12 +41,20 @@ namespace MediaBrowser.Controller.Drawing
         ImageDimensions GetImageDimensions(BaseItem item, ItemImageInfo info);
 
         /// <summary>
+        /// Gets the blurhash of the image.
+        /// </summary>
+        /// <param name="path">Path to the image file.</param>
+        /// <returns>BlurHash</returns>
+        string GetImageBlurHash(string path);
+
+        /// <summary>
         /// Gets the image cache tag.
         /// </summary>
         /// <param name="item">The item.</param>
         /// <param name="image">The image.</param>
         /// <returns>Guid.</returns>
         string GetImageCacheTag(BaseItem item, ItemImageInfo image);
+
         string GetImageCacheTag(BaseItem item, ChapterInfo info);
 
         /// <summary>
diff --git a/MediaBrowser.Controller/Entities/BaseItem.cs b/MediaBrowser.Controller/Entities/BaseItem.cs
index 7ed8fa767..f4b71d8bf 100644
--- a/MediaBrowser.Controller/Entities/BaseItem.cs
+++ b/MediaBrowser.Controller/Entities/BaseItem.cs
@@ -1374,6 +1374,7 @@ namespace MediaBrowser.Controller.Entities
                         new List<FileSystemMetadata>();
 
                     var ownedItemsChanged = await RefreshedOwnedItems(options, files, cancellationToken).ConfigureAwait(false);
+                    LibraryManager.UpdateImages(this); // ensure all image properties in DB are fresh
 
                     if (ownedItemsChanged)
                     {
@@ -2222,6 +2223,7 @@ namespace MediaBrowser.Controller.Entities
                 existingImage.DateModified = image.DateModified;
                 existingImage.Width = image.Width;
                 existingImage.Height = image.Height;
+                existingImage.BlurHash = image.BlurHash;
             }
             else
             {
@@ -2373,6 +2375,46 @@ namespace MediaBrowser.Controller.Entities
                 .ElementAtOrDefault(imageIndex);
         }
 
+        /// <summary>
+        /// Computes image index for given image or raises if no matching image found.
+        /// </summary>
+        /// <param name="image">Image to compute index for.</param>
+        /// <exception cref="ArgumentException">Image index cannot be computed as no matching image found.
+        /// </exception>
+        /// <returns>Image index.</returns>
+        public int GetImageIndex(ItemImageInfo image)
+        {
+            if (image == null)
+            {
+                throw new ArgumentNullException(nameof(image));
+            }
+
+            if (image.Type == ImageType.Chapter)
+            {
+                var chapters = ItemRepository.GetChapters(this);
+                for (var i = 0; i < chapters.Count; i++)
+                {
+                    if (chapters[i].ImagePath == image.Path)
+                    {
+                        return i;
+                    }
+                }
+
+                throw new ArgumentException("No chapter index found for image path", image.Path);
+            }
+
+            var images = GetImages(image.Type).ToArray();
+            for (var i = 0; i < images.Length; i++)
+            {
+                if (images[i].Path == image.Path)
+                {
+                    return i;
+                }
+            }
+
+            throw new ArgumentException("No image index found for image path", image.Path);
+        }
+
         public IEnumerable<ItemImageInfo> GetImages(ImageType imageType)
         {
             if (imageType == ImageType.Chapter)
diff --git a/MediaBrowser.Controller/Entities/Folder.cs b/MediaBrowser.Controller/Entities/Folder.cs
index a468e0c35..29040f92e 100644
--- a/MediaBrowser.Controller/Entities/Folder.cs
+++ b/MediaBrowser.Controller/Entities/Folder.cs
@@ -341,6 +341,11 @@ namespace MediaBrowser.Controller.Entities
                         {
                             currentChild.UpdateToRepository(ItemUpdateType.MetadataImport, cancellationToken);
                         }
+                        else
+                        {
+                            // metadata is up-to-date; make sure DB has correct images dimensions and hash
+                            LibraryManager.UpdateImages(currentChild);
+                        }
 
                         continue;
                     }
diff --git a/MediaBrowser.Controller/Entities/ItemImageInfo.cs b/MediaBrowser.Controller/Entities/ItemImageInfo.cs
index fc46dec2e..12f5db2e0 100644
--- a/MediaBrowser.Controller/Entities/ItemImageInfo.cs
+++ b/MediaBrowser.Controller/Entities/ItemImageInfo.cs
@@ -28,6 +28,12 @@ namespace MediaBrowser.Controller.Entities
 
         public int Height { get; set; }
 
+        /// <summary>
+        /// Gets or sets the blurhash.
+        /// </summary>
+        /// <value>The blurhash.</value>
+        public string BlurHash { get; set; }
+
         [JsonIgnore]
         public bool IsLocalFile => Path == null || !Path.StartsWith("http", StringComparison.OrdinalIgnoreCase);
     }
diff --git a/MediaBrowser.Controller/Library/ILibraryManager.cs b/MediaBrowser.Controller/Library/ILibraryManager.cs
index 2e1c97f67..916e4fda7 100644
--- a/MediaBrowser.Controller/Library/ILibraryManager.cs
+++ b/MediaBrowser.Controller/Library/ILibraryManager.cs
@@ -118,7 +118,7 @@ namespace MediaBrowser.Controller.Library
         /// </summary>
         void QueueLibraryScan();
 
-        void UpdateImages(BaseItem item);
+        void UpdateImages(BaseItem item, bool forceUpdate = false);
 
         /// <summary>
         /// Gets the default view.
@@ -195,6 +195,7 @@ namespace MediaBrowser.Controller.Library
         /// Updates the item.
         /// </summary>
         void UpdateItems(IEnumerable<BaseItem> items, BaseItem parent, ItemUpdateType updateReason, CancellationToken cancellationToken);
+
         void UpdateItem(BaseItem item, BaseItem parent, ItemUpdateType updateReason, CancellationToken cancellationToken);
 
         /// <summary>
diff --git a/MediaBrowser.Controller/Library/IUserManager.cs b/MediaBrowser.Controller/Library/IUserManager.cs
index ec6cb35eb..be7b4ce59 100644
--- a/MediaBrowser.Controller/Library/IUserManager.cs
+++ b/MediaBrowser.Controller/Library/IUserManager.cs
@@ -144,14 +144,6 @@ namespace MediaBrowser.Controller.Library
         UserDto GetUserDto(User user, string remoteEndPoint = null);
 
         /// <summary>
-        /// Gets the user public dto.
-        /// </summary>
-        /// <param name="user">Ther user.</param>\
-        /// <param name="remoteEndPoint">The remote end point.</param>
-        /// <returns>A public UserDto, aka a UserDto stripped of personal data.</returns>
-        PublicUserDto GetPublicUserDto(User user, string remoteEndPoint = null);
-
-        /// <summary>
         /// Authenticates the user.
         /// </summary>
         Task<User> AuthenticateUser(string username, string password, string passwordSha1, string remoteEndPoint, bool isUserSession);
diff --git a/MediaBrowser.Controller/LiveTv/TimerEventInfo.cs b/MediaBrowser.Controller/LiveTv/TimerEventInfo.cs
index cfec39b4e..1b8f41db6 100644
--- a/MediaBrowser.Controller/LiveTv/TimerEventInfo.cs
+++ b/MediaBrowser.Controller/LiveTv/TimerEventInfo.cs
@@ -1,10 +1,19 @@
+#nullable enable
+#pragma warning disable CS1591
+
 using System;
 
 namespace MediaBrowser.Controller.LiveTv
 {
     public class TimerEventInfo
     {
-        public string Id { get; set; }
-        public Guid ProgramId { get; set; }
+        public TimerEventInfo(string id)
+        {
+            Id = id;
+        }
+
+        public string Id { get; }
+
+        public Guid? ProgramId { get; set; }
     }
 }
diff --git a/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs b/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs
index 61a330675..2d2f73148 100644
--- a/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs
+++ b/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs
@@ -1338,7 +1338,7 @@ namespace MediaBrowser.Controller.MediaEncoding
                 transcoderChannelLimit = 6;
             }
 
-            var isTranscodingAudio = !string.Equals(codec, "copy", StringComparison.OrdinalIgnoreCase);
+            var isTranscodingAudio = !EncodingHelper.IsCopyCodec(codec);
 
             int? resultChannels = state.GetRequestedAudioChannels(codec);
             if (isTranscodingAudio)
@@ -1734,7 +1734,8 @@ namespace MediaBrowser.Controller.MediaEncoding
 
             var hasTextSubs = state.SubtitleStream != null && state.SubtitleStream.IsTextSubtitleStream && state.SubtitleDeliveryMethod == SubtitleDeliveryMethod.Encode;
 
-            if (string.Equals(videoEncoder, "h264_vaapi", StringComparison.OrdinalIgnoreCase) || (string.Equals(videoEncoder, "h264_qsv", StringComparison.OrdinalIgnoreCase) && !hasTextSubs)
+            if ((string.Equals(videoEncoder, "h264_vaapi", StringComparison.OrdinalIgnoreCase)
+                || (string.Equals(videoEncoder, "h264_qsv", StringComparison.OrdinalIgnoreCase) && !hasTextSubs))
                 && width.HasValue
                 && height.HasValue)
             {
@@ -1991,7 +1992,7 @@ namespace MediaBrowser.Controller.MediaEncoding
                 filters.Add("hwupload");
             }
 
-            // When the input may or may not be hardware QSV decodable            
+            // When the input may or may not be hardware QSV decodable
             else if (string.Equals(outputVideoCodec, "h264_qsv", StringComparison.OrdinalIgnoreCase))
             {
                 if (!hasTextSubs)
@@ -2248,7 +2249,7 @@ namespace MediaBrowser.Controller.MediaEncoding
                 flags.Add("+ignidx");
             }
 
-            if (state.GenPtsInput || string.Equals(state.OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+            if (state.GenPtsInput || EncodingHelper.IsCopyCodec(state.OutputVideoCodec))
             {
                 flags.Add("+genpts");
             }
@@ -2511,7 +2512,7 @@ namespace MediaBrowser.Controller.MediaEncoding
         /// </summary>
         protected string GetHardwareAcceleratedVideoDecoder(EncodingJobInfo state, EncodingOptions encodingOptions)
         {
-            if (string.Equals(state.OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+            if (EncodingHelper.IsCopyCodec(state.OutputVideoCodec))
             {
                 return null;
             }
@@ -2799,7 +2800,7 @@ namespace MediaBrowser.Controller.MediaEncoding
                 args += " -mpegts_m2ts_mode 1";
             }
 
-            if (string.Equals(videoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+            if (EncodingHelper.IsCopyCodec(videoCodec))
             {
                 if (state.VideoStream != null
                     && string.Equals(state.OutputContainer, "ts", StringComparison.OrdinalIgnoreCase)
@@ -2901,7 +2902,7 @@ namespace MediaBrowser.Controller.MediaEncoding
 
             var args = "-codec:a:0 " + codec;
 
-            if (string.Equals(codec, "copy", StringComparison.OrdinalIgnoreCase))
+            if (EncodingHelper.IsCopyCodec(codec))
             {
                 return args;
             }
@@ -2973,5 +2974,10 @@ namespace MediaBrowser.Controller.MediaEncoding
                 string.Empty,
                 string.Empty).Trim();
         }
+
+        public static bool IsCopyCodec(string codec)
+        {
+            return string.Equals(codec, "copy", StringComparison.OrdinalIgnoreCase);
+        }
     }
 }
diff --git a/MediaBrowser.Controller/MediaEncoding/EncodingJobInfo.cs b/MediaBrowser.Controller/MediaEncoding/EncodingJobInfo.cs
index 1127a08de..7cd783595 100644
--- a/MediaBrowser.Controller/MediaEncoding/EncodingJobInfo.cs
+++ b/MediaBrowser.Controller/MediaEncoding/EncodingJobInfo.cs
@@ -302,7 +302,7 @@ namespace MediaBrowser.Controller.MediaEncoding
                     return false;
                 }
 
-                return BaseRequest.BreakOnNonKeyFrames && string.Equals(videoCodec, "copy", StringComparison.OrdinalIgnoreCase);
+                return BaseRequest.BreakOnNonKeyFrames && EncodingHelper.IsCopyCodec(videoCodec);
             }
 
             return false;
@@ -367,7 +367,7 @@ namespace MediaBrowser.Controller.MediaEncoding
             get
             {
                 if (BaseRequest.Static
-                    || string.Equals(OutputAudioCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                    || EncodingHelper.IsCopyCodec(OutputAudioCodec))
                 {
                     if (AudioStream != null)
                     {
@@ -390,7 +390,7 @@ namespace MediaBrowser.Controller.MediaEncoding
             get
             {
                 if (BaseRequest.Static
-                    || string.Equals(OutputAudioCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                    || EncodingHelper.IsCopyCodec(OutputAudioCodec))
                 {
                     if (AudioStream != null)
                     {
@@ -409,7 +409,7 @@ namespace MediaBrowser.Controller.MediaEncoding
         {
             get
             {
-                if (BaseRequest.Static || string.Equals(OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                if (BaseRequest.Static || EncodingHelper.IsCopyCodec(OutputVideoCodec))
                 {
                     return VideoStream?.Level;
                 }
@@ -433,7 +433,7 @@ namespace MediaBrowser.Controller.MediaEncoding
             get
             {
                 if (BaseRequest.Static
-                    || string.Equals(OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                    || EncodingHelper.IsCopyCodec(OutputVideoCodec))
                 {
                     return VideoStream?.BitDepth;
                 }
@@ -451,7 +451,7 @@ namespace MediaBrowser.Controller.MediaEncoding
             get
             {
                 if (BaseRequest.Static
-                    || string.Equals(OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                    || EncodingHelper.IsCopyCodec(OutputVideoCodec))
                 {
                     return VideoStream?.RefFrames;
                 }
@@ -468,7 +468,7 @@ namespace MediaBrowser.Controller.MediaEncoding
             get
             {
                 if (BaseRequest.Static
-                    || string.Equals(OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                    || EncodingHelper.IsCopyCodec(OutputVideoCodec))
                 {
                     return VideoStream == null ? null : (VideoStream.AverageFrameRate ?? VideoStream.RealFrameRate);
                 }
@@ -499,7 +499,7 @@ namespace MediaBrowser.Controller.MediaEncoding
         {
             get
             {
-                if (BaseRequest.Static || string.Equals(OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                if (BaseRequest.Static || EncodingHelper.IsCopyCodec(OutputVideoCodec))
                 {
                     return VideoStream?.PacketLength;
                 }
@@ -515,7 +515,7 @@ namespace MediaBrowser.Controller.MediaEncoding
         {
             get
             {
-                if (BaseRequest.Static || string.Equals(OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                if (BaseRequest.Static || EncodingHelper.IsCopyCodec(OutputVideoCodec))
                 {
                     return VideoStream?.Profile;
                 }
@@ -535,7 +535,7 @@ namespace MediaBrowser.Controller.MediaEncoding
             get
             {
                 if (BaseRequest.Static
-                    || string.Equals(OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                    || EncodingHelper.IsCopyCodec(OutputVideoCodec))
                 {
                     return VideoStream?.CodecTag;
                 }
@@ -549,7 +549,7 @@ namespace MediaBrowser.Controller.MediaEncoding
             get
             {
                 if (BaseRequest.Static
-                    || string.Equals(OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                    || EncodingHelper.IsCopyCodec(OutputVideoCodec))
                 {
                     return VideoStream?.IsAnamorphic;
                 }
@@ -562,7 +562,7 @@ namespace MediaBrowser.Controller.MediaEncoding
         {
             get
             {
-                if (string.Equals(OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                if (EncodingHelper.IsCopyCodec(OutputVideoCodec))
                 {
                     return VideoStream?.Codec;
                 }
@@ -575,7 +575,7 @@ namespace MediaBrowser.Controller.MediaEncoding
         {
             get
             {
-                if (string.Equals(OutputAudioCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                if (EncodingHelper.IsCopyCodec(OutputAudioCodec))
                 {
                     return AudioStream?.Codec;
                 }
@@ -589,7 +589,7 @@ namespace MediaBrowser.Controller.MediaEncoding
             get
             {
                 if (BaseRequest.Static
-                    || string.Equals(OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                    || EncodingHelper.IsCopyCodec(OutputVideoCodec))
                 {
                     return VideoStream?.IsInterlaced;
                 }
@@ -607,7 +607,7 @@ namespace MediaBrowser.Controller.MediaEncoding
         {
             get
             {
-                if (BaseRequest.Static || string.Equals(OutputVideoCodec, "copy", StringComparison.OrdinalIgnoreCase))
+                if (BaseRequest.Static || EncodingHelper.IsCopyCodec(OutputVideoCodec))
                 {
                     return VideoStream?.IsAVC;
                 }
diff --git a/MediaBrowser.Controller/Net/BasePeriodicWebSocketListener.cs b/MediaBrowser.Controller/Net/BasePeriodicWebSocketListener.cs
index 1162bff13..5be656bdb 100644
--- a/MediaBrowser.Controller/Net/BasePeriodicWebSocketListener.cs
+++ b/MediaBrowser.Controller/Net/BasePeriodicWebSocketListener.cs
@@ -104,7 +104,7 @@ namespace MediaBrowser.Controller.Net
             }
         }
 
-        protected void SendData(bool force)
+        protected async Task SendData(bool force)
         {
             Tuple<IWebSocketConnection, CancellationTokenSource, TStateType>[] tuples;
 
@@ -128,13 +128,18 @@ namespace MediaBrowser.Controller.Net
                     .ToArray();
             }
 
-            foreach (var tuple in tuples)
+            IEnumerable<Task> GetTasks()
             {
-                SendData(tuple);
+                foreach (var tuple in tuples)
+                {
+                    yield return SendData(tuple);
+                }
             }
+
+            await Task.WhenAll(GetTasks()).ConfigureAwait(false);
         }
 
-        private async void SendData(Tuple<IWebSocketConnection, CancellationTokenSource, TStateType> tuple)
+        private async Task SendData(Tuple<IWebSocketConnection, CancellationTokenSource, TStateType> tuple)
         {
             var connection = tuple.Item1;
 
@@ -148,11 +153,13 @@ namespace MediaBrowser.Controller.Net
 
                 if (data != null)
                 {
-                    await connection.SendAsync(new WebSocketMessage<TReturnDataType>
-                    {
-                        MessageType = Name,
-                        Data = data
-                    }, cancellationToken).ConfigureAwait(false);
+                    await connection.SendAsync(
+                        new WebSocketMessage<TReturnDataType>
+                        {
+                            MessageType = Name,
+                            Data = data
+                        },
+                        cancellationToken).ConfigureAwait(false);
 
                     state.DateLastSendUtc = DateTime.UtcNow;
                 }
diff --git a/MediaBrowser.Controller/Net/IWebSocketConnection.cs b/MediaBrowser.Controller/Net/IWebSocketConnection.cs
index 09e43c683..3ef8e5f6d 100644
--- a/MediaBrowser.Controller/Net/IWebSocketConnection.cs
+++ b/MediaBrowser.Controller/Net/IWebSocketConnection.cs
@@ -24,6 +24,12 @@ namespace MediaBrowser.Controller.Net
         DateTime LastActivityDate { get; }
 
         /// <summary>
+        /// Gets or sets the date of last Keeplive received.
+        /// </summary>
+        /// <value>The date of last Keeplive received.</value>
+        DateTime LastKeepAliveDate { get; set; }
+
+        /// <summary>
         /// Gets or sets the query string.
         /// </summary>
         /// <value>The query string.</value>
diff --git a/MediaBrowser.Controller/Session/ISessionManager.cs b/MediaBrowser.Controller/Session/ISessionManager.cs
index 771027103..4c2f834cb 100644
--- a/MediaBrowser.Controller/Session/ISessionManager.cs
+++ b/MediaBrowser.Controller/Session/ISessionManager.cs
@@ -9,6 +9,7 @@ using MediaBrowser.Controller.Security;
 using MediaBrowser.Model.Dto;
 using MediaBrowser.Model.Events;
 using MediaBrowser.Model.Session;
+using MediaBrowser.Model.SyncPlay;
 
 namespace MediaBrowser.Controller.Session
 {
@@ -141,6 +142,24 @@ namespace MediaBrowser.Controller.Session
         Task SendPlayCommand(string controllingSessionId, string sessionId, PlayRequest command, CancellationToken cancellationToken);
 
         /// <summary>
+        /// Sends the SyncPlayCommand.
+        /// </summary>
+        /// <param name="sessionId">The session id.</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);
+
+        /// <summary>
+        /// Sends the SyncPlayGroupUpdate.
+        /// </summary>
+        /// <param name="sessionId">The session id.</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);
+
+        /// <summary>
         /// Sends the browse command.
         /// </summary>
         /// <param name="controllingSessionId">The controlling session identifier.</param>
diff --git a/MediaBrowser.Controller/SyncPlay/GroupInfo.cs b/MediaBrowser.Controller/SyncPlay/GroupInfo.cs
new file mode 100644
index 000000000..28a3ac505
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/GroupInfo.cs
@@ -0,0 +1,169 @@
+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>
+        /// Default ping value used for sessions.
+        /// </summary>
+        public long DefaulPing { get; } = 500;
+
+        /// <summary>
+        /// Gets or sets 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 whether playback is paused.
+        /// </summary>
+        /// <value>Playback is paused.</value>
+        public bool IsPaused { get; set; }
+
+        /// <summary>
+        /// Gets or sets the 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>
+        /// <value><c>true</c> if the session is in this group; <c>false</c> otherwise.</value>
+        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)
+        {
+            if (ContainsSession(session.Id.ToString()))
+            {
+                return;
+            }
+
+            var member = new GroupMember();
+            member.Session = session;
+            member.Ping = DefaulPing;
+            member.IsBuffering = false;
+            Participants[session.Id.ToString()] = member;
+        }
+
+        /// <summary>
+        /// Removes the session from the group.
+        /// </summary>
+        /// <param name="session">The session.</param>
+        public void RemoveSession(SessionInfo session)
+        {
+            if (!ContainsSession(session.Id.ToString()))
+            {
+                return;
+            }
+
+            Participants.Remove(session.Id.ToString(), out _);
+        }
+
+        /// <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 (!ContainsSession(session.Id.ToString()))
+            {
+                return;
+            }
+
+            Participants[session.Id.ToString()].Ping = ping;
+        }
+
+        /// <summary>
+        /// Gets the highest ping in the group.
+        /// </summary>
+        /// <value name="session">The highest ping in the group.</value>
+        public long GetHighestPing()
+        {
+            long max = Int64.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 (!ContainsSession(session.Id.ToString()))
+            {
+                return;
+            }
+
+            Participants[session.Id.ToString()].IsBuffering = isBuffering;
+        }
+
+        /// <summary>
+        /// Gets the group buffering state.
+        /// </summary>
+        /// <value><c>true</c> if there is a session buffering in the group; <c>false</c> otherwise.</value>
+        public bool IsBuffering()
+        {
+            foreach (var session in Participants.Values)
+            {
+                if (session.IsBuffering)
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Checks if the group is empty.
+        /// </summary>
+        /// <value><c>true</c> if the group is empty; <c>false</c> otherwise.</value>
+        public bool IsEmpty()
+        {
+            return Participants.Count == 0;
+        }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/GroupMember.cs b/MediaBrowser.Controller/SyncPlay/GroupMember.cs
new file mode 100644
index 000000000..a3975c334
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/GroupMember.cs
@@ -0,0 +1,28 @@
+using MediaBrowser.Controller.Session;
+
+namespace MediaBrowser.Controller.SyncPlay
+{
+    /// <summary>
+    /// Class GroupMember.
+    /// </summary>
+    public class GroupMember
+    {
+        /// <summary>
+        /// Gets or sets 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 the session.
+        /// </summary>
+        /// <value>The session.</value>
+        public SessionInfo Session { get; set; }
+
+        /// <summary>
+        /// Gets or sets the ping.
+        /// </summary>
+        /// <value>The ping.</value>
+        public long Ping { get; set; }
+    }
+}
diff --git a/MediaBrowser.Controller/SyncPlay/ISyncPlayController.cs b/MediaBrowser.Controller/SyncPlay/ISyncPlayController.cs
new file mode 100644
index 000000000..de1fcd259
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/ISyncPlayController.cs
@@ -0,0 +1,67 @@
+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 InitGroup(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();
+    }
+}
\ No newline at end of file
diff --git a/MediaBrowser.Controller/SyncPlay/ISyncPlayManager.cs b/MediaBrowser.Controller/SyncPlay/ISyncPlayManager.cs
new file mode 100644
index 000000000..006fb687b
--- /dev/null
+++ b/MediaBrowser.Controller/SyncPlay/ISyncPlayManager.cs
@@ -0,0 +1,69 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using MediaBrowser.Controller.Session;
+using MediaBrowser.Model.SyncPlay;
+
+namespace MediaBrowser.Controller.SyncPlay
+{
+    /// <summary>
+    /// Interface ISyncPlayManager.
+    /// </summary>
+    public interface ISyncPlayManager
+    {
+        /// <summary>
+        /// Creates a new group.
+        /// </summary>
+        /// <param name="session">The session that's creating the group.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void NewGroup(SessionInfo session, 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);
+
+        /// <summary>
+        /// Removes the session from a group.
+        /// </summary>
+        /// <param name="session">The session.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        void LeaveGroup(SessionInfo session, 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);
+
+        /// <summary>
+        /// Handle a request by a session in a group.
+        /// </summary>
+        /// <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);
+    }
+}