Merge remote-tracking branch 'upstream/master' into client-logger

33 files changed, 361 insertions, 325 deletions

diff --git a/Emby.Server.Implementations/Library/CoreResolutionIgnoreRule.cs b/Emby.Server.Implementations/Library/CoreResolutionIgnoreRule.cs
index 3380e29d4..bc5b4499f 100644
--- a/Emby.Server.Implementations/Library/CoreResolutionIgnoreRule.cs
+++ b/Emby.Server.Implementations/Library/CoreResolutionIgnoreRule.cs
@@ -54,7 +54,7 @@ namespace Emby.Server.Implementations.Library
                 if (parent != null)
                 {
                     // Ignore trailer folders but allow it at the collection level
-                    if (string.Equals(filename, BaseItem.TrailerFolderName, StringComparison.OrdinalIgnoreCase)
+                    if (string.Equals(filename, BaseItem.TrailersFolderName, StringComparison.OrdinalIgnoreCase)
                         && !(parent is AggregateFolder)
                         && !(parent is UserRootFolder))
                     {
@@ -77,7 +77,7 @@ namespace Emby.Server.Implementations.Library
                 if (parent != null)
                 {
                     // Don't resolve these into audio files
-                    if (string.Equals(Path.GetFileNameWithoutExtension(filename), BaseItem.ThemeSongFilename, StringComparison.Ordinal)
+                    if (Path.GetFileNameWithoutExtension(filename.AsSpan()).Equals(BaseItem.ThemeSongFileName, StringComparison.Ordinal)
                         && _libraryManager.IsAudioFile(filename))
                     {
                         return true;
diff --git a/Emby.Server.Implementations/Library/ExclusiveLiveStream.cs b/Emby.Server.Implementations/Library/ExclusiveLiveStream.cs
index 236453e80..868071a99 100644
--- a/Emby.Server.Implementations/Library/ExclusiveLiveStream.cs
+++ b/Emby.Server.Implementations/Library/ExclusiveLiveStream.cs
@@ -1,7 +1,10 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
 using System.Globalization;
+using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
 using MediaBrowser.Controller.Library;
@@ -39,6 +42,11 @@ namespace Emby.Server.Implementations.Library
             return _closeFn();
         }
 
+        public Stream GetStream()
+        {
+            throw new NotSupportedException();
+        }
+
         public Task Open(CancellationToken openCancellationToken)
         {
             return Task.CompletedTask;
diff --git a/Emby.Server.Implementations/Library/IgnorePatterns.cs b/Emby.Server.Implementations/Library/IgnorePatterns.cs
index e30a67593..5384c04b3 100644
--- a/Emby.Server.Implementations/Library/IgnorePatterns.cs
+++ b/Emby.Server.Implementations/Library/IgnorePatterns.cs
@@ -1,5 +1,3 @@
-#nullable enable
-
 using System;
 using System.Linq;
 using DotNet.Globbing;
diff --git a/Emby.Server.Implementations/Library/LibraryManager.cs b/Emby.Server.Implementations/Library/LibraryManager.cs
index 7d030418a..1326f60fe 100644
--- a/Emby.Server.Implementations/Library/LibraryManager.cs
+++ b/Emby.Server.Implementations/Library/LibraryManager.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
@@ -19,6 +21,7 @@ using Emby.Server.Implementations.Playlists;
 using Emby.Server.Implementations.ScheduledTasks;
 using Jellyfin.Data.Entities;
 using Jellyfin.Data.Enums;
+using Jellyfin.Extensions;
 using MediaBrowser.Common.Extensions;
 using MediaBrowser.Common.Progress;
 using MediaBrowser.Controller;
@@ -48,6 +51,7 @@ using MediaBrowser.Providers.MediaInfo;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.Logging;
 using Episode = MediaBrowser.Controller.Entities.TV.Episode;
+using EpisodeInfo = Emby.Naming.TV.EpisodeInfo;
 using Genre = MediaBrowser.Controller.Entities.Genre;
 using Person = MediaBrowser.Controller.Entities.Person;
 using VideoResolver = Emby.Naming.Video.VideoResolver;
@@ -175,10 +179,7 @@ namespace Emby.Server.Implementations.Library
                 {
                     lock (_rootFolderSyncLock)
                     {
-                        if (_rootFolder == null)
-                        {
-                            _rootFolder = CreateRootFolder();
-                        }
+                        _rootFolder ??= CreateRootFolder();
                     }
                 }
 
@@ -286,14 +287,14 @@ namespace Emby.Server.Implementations.Library
 
             if (item is IItemByName)
             {
-                if (!(item is MusicArtist))
+                if (item is not MusicArtist)
                 {
                     return;
                 }
             }
             else if (!item.IsFolder)
             {
-                if (!(item is Video) && !(item is LiveTvChannel))
+                if (item is not Video && item is not LiveTvChannel)
                 {
                     return;
                 }
@@ -558,7 +559,6 @@ namespace Emby.Server.Implementations.Library
             var args = new ItemResolveArgs(_configurationManager.ApplicationPaths, directoryService)
             {
                 Parent = parent,
-                Path = fullPath,
                 FileInfo = fileInfo,
                 CollectionType = collectionType,
                 LibraryOptions = libraryOptions
@@ -647,7 +647,7 @@ namespace Emby.Server.Implementations.Library
         /// Determines whether a path should be ignored based on its contents - called after the contents have been read.
         /// </summary>
         /// <param name="args">The args.</param>
-        /// <returns><c>true</c> if XXXX, <c>false</c> otherwise</returns>
+        /// <returns><c>true</c> if XXXX, <c>false</c> otherwise.</returns>
         private static bool ShouldResolvePathContents(ItemResolveArgs args)
         {
             // Ignore any folders containing a file called .ignore
@@ -684,7 +684,7 @@ namespace Emby.Server.Implementations.Library
 
                         foreach (var item in items)
                         {
-                            ResolverHelper.SetInitialItemValues(item, parent, _fileSystem, this, directoryService);
+                            ResolverHelper.SetInitialItemValues(item, parent, this, directoryService);
                         }
 
                         items.AddRange(ResolveFileList(result.ExtraFiles, directoryService, parent, collectionType, resolvers, libraryOptions));
@@ -697,25 +697,32 @@ namespace Emby.Server.Implementations.Library
         }
 
         private IEnumerable<BaseItem> ResolveFileList(
-            IEnumerable<FileSystemMetadata> fileList,
+            IReadOnlyList<FileSystemMetadata> fileList,
             IDirectoryService directoryService,
             Folder parent,
             string collectionType,
             IItemResolver[] resolvers,
             LibraryOptions libraryOptions)
         {
-            return fileList.Select(f =>
+            // Given that fileList is a list we can save enumerator allocations by indexing
+            for (var i = 0; i < fileList.Count; i++)
             {
+                var file = fileList[i];
+                BaseItem result = null;
                 try
                 {
-                    return ResolvePath(f, directoryService, resolvers, parent, collectionType, libraryOptions);
+                    result = ResolvePath(file, directoryService, resolvers, parent, collectionType, libraryOptions);
                 }
                 catch (Exception ex)
                 {
-                    _logger.LogError(ex, "Error resolving path {path}", f.FullName);
-                    return null;
+                    _logger.LogError(ex, "Error resolving path {Path}", file.FullName);
+                }
+
+                if (result != null)
+                {
+                    yield return result;
                 }
-            }).Where(i => i != null);
+            }
         }
 
         /// <summary>
@@ -859,7 +866,7 @@ namespace Emby.Server.Implementations.Library
         {
             var path = Person.GetPath(name);
             var id = GetItemByNameId<Person>(path);
-            if (!(GetItemById(id) is Person item))
+            if (GetItemById(id) is not Person item)
             {
                 item = new Person
                 {
@@ -1066,17 +1073,17 @@ namespace Emby.Server.Implementations.Library
             // Start by just validating the children of the root, but go no further
             await RootFolder.ValidateChildren(
                 new SimpleProgress<double>(),
-                cancellationToken,
                 new MetadataRefreshOptions(new DirectoryService(_fileSystem)),
-                recursive: false).ConfigureAwait(false);
+                recursive: false,
+                cancellationToken).ConfigureAwait(false);
 
             await GetUserRootFolder().RefreshMetadata(cancellationToken).ConfigureAwait(false);
 
             await GetUserRootFolder().ValidateChildren(
                 new SimpleProgress<double>(),
-                cancellationToken,
                 new MetadataRefreshOptions(new DirectoryService(_fileSystem)),
-                recursive: false).ConfigureAwait(false);
+                recursive: false,
+                cancellationToken).ConfigureAwait(false);
 
             // Quickly scan CollectionFolders for changes
             foreach (var folder in GetUserRootFolder().Children.OfType<Folder>())
@@ -1096,7 +1103,7 @@ namespace Emby.Server.Implementations.Library
             innerProgress.RegisterAction(pct => progress.Report(pct * 0.96));
 
             // Validate the entire media library
-            await RootFolder.ValidateChildren(innerProgress, cancellationToken, new MetadataRefreshOptions(new DirectoryService(_fileSystem)), recursive: true).ConfigureAwait(false);
+            await RootFolder.ValidateChildren(innerProgress, new MetadataRefreshOptions(new DirectoryService(_fileSystem)), recursive: true, cancellationToken).ConfigureAwait(false);
 
             progress.Report(96);
 
@@ -1163,7 +1170,7 @@ namespace Emby.Server.Implementations.Library
                 progress.Report(percent * 100);
             }
 
-            _itemRepository.UpdateInheritedValues(cancellationToken);
+            _itemRepository.UpdateInheritedValues();
 
             progress.Report(100);
         }
@@ -1243,10 +1250,8 @@ namespace Emby.Server.Implementations.Library
         private CollectionTypeOptions? GetCollectionType(string path)
         {
             var files = _fileSystem.GetFilePaths(path, new[] { ".collection" }, true, false);
-            foreach (var file in files)
+            foreach (ReadOnlySpan<char> file in files)
             {
-                // TODO: @bond use a ReadOnlySpan<char> here when Enum.TryParse supports it
-                // https://github.com/dotnet/runtime/issues/20008
                 if (Enum.TryParse<CollectionTypeOptions>(Path.GetFileNameWithoutExtension(file), true, out var res))
                 {
                     return res;
@@ -1261,7 +1266,7 @@ namespace Emby.Server.Implementations.Library
         /// </summary>
         /// <param name="id">The id.</param>
         /// <returns>BaseItem.</returns>
-        /// <exception cref="ArgumentNullException">id</exception>
+        /// <exception cref="ArgumentNullException"><paramref name="id"/> is <c>null</c>.</exception>
         public BaseItem GetItemById(Guid id)
         {
             if (id == Guid.Empty)
@@ -1754,22 +1759,20 @@ namespace Emby.Server.Implementations.Library
             return orderedItems ?? items;
         }
 
-        public IEnumerable<BaseItem> Sort(IEnumerable<BaseItem> items, User user, IEnumerable<ValueTuple<string, SortOrder>> orderByList)
+        public IEnumerable<BaseItem> Sort(IEnumerable<BaseItem> items, User user, IEnumerable<ValueTuple<string, SortOrder>> orderBy)
         {
             var isFirst = true;
 
             IOrderedEnumerable<BaseItem> orderedItems = null;
 
-            foreach (var orderBy in orderByList)
+            foreach (var (name, sortOrder) in orderBy)
             {
-                var comparer = GetComparer(orderBy.Item1, user);
+                var comparer = GetComparer(name, user);
                 if (comparer == null)
                 {
                     continue;
                 }
 
-                var sortOrder = orderBy.Item2;
-
                 if (isFirst)
                 {
                     orderedItems = sortOrder == SortOrder.Descending ? items.OrderByDescending(i => i, comparer) : items.OrderBy(i => i, comparer);
@@ -2077,7 +2080,7 @@ namespace Emby.Server.Implementations.Library
                 return new List<Folder>();
             }
 
-            return GetCollectionFoldersInternal(item, GetUserRootFolder().Children.OfType<Folder>().ToList());
+            return GetCollectionFoldersInternal(item, GetUserRootFolder().Children.OfType<Folder>());
         }
 
         public List<Folder> GetCollectionFolders(BaseItem item, List<Folder> allUserRootChildren)
@@ -2102,20 +2105,20 @@ namespace Emby.Server.Implementations.Library
             return GetCollectionFoldersInternal(item, allUserRootChildren);
         }
 
-        private static List<Folder> GetCollectionFoldersInternal(BaseItem item, List<Folder> allUserRootChildren)
+        private static List<Folder> GetCollectionFoldersInternal(BaseItem item, IEnumerable<Folder> allUserRootChildren)
         {
             return allUserRootChildren
-                .Where(i => string.Equals(i.Path, item.Path, StringComparison.OrdinalIgnoreCase) || i.PhysicalLocations.Contains(item.Path, StringComparer.OrdinalIgnoreCase))
+                .Where(i => string.Equals(i.Path, item.Path, StringComparison.OrdinalIgnoreCase) || i.PhysicalLocations.Contains(item.Path.AsSpan(), StringComparison.OrdinalIgnoreCase))
                 .ToList();
         }
 
         public LibraryOptions GetLibraryOptions(BaseItem item)
         {
-            if (!(item is CollectionFolder collectionFolder))
+            if (item is not CollectionFolder collectionFolder)
             {
+                // List.Find is more performant than FirstOrDefault due to enumerator allocation
                 collectionFolder = GetCollectionFolders(item)
-                   .OfType<CollectionFolder>()
-                   .FirstOrDefault();
+                    .Find(folder => folder is CollectionFolder) as CollectionFolder;
             }
 
             return collectionFolder == null ? new LibraryOptions() : collectionFolder.GetLibraryOptions();
@@ -2501,8 +2504,7 @@ namespace Emby.Server.Implementations.Library
         /// <inheritdoc />
         public bool IsVideoFile(string path)
         {
-            var resolver = new VideoResolver(GetNamingOptions());
-            return resolver.IsVideoFile(path);
+            return VideoResolver.IsVideoFile(path, GetNamingOptions());
         }
 
         /// <inheritdoc />
@@ -2517,7 +2519,7 @@ namespace Emby.Server.Implementations.Library
         public bool FillMissingEpisodeNumbersFromPath(Episode episode, bool forceRefresh)
         {
             var series = episode.Series;
-            bool? isAbsoluteNaming = series == null ? false : string.Equals(series.DisplayOrder, "absolute", StringComparison.OrdinalIgnoreCase);
+            bool? isAbsoluteNaming = series != null && string.Equals(series.DisplayOrder, "absolute", StringComparison.OrdinalIgnoreCase);
             if (!isAbsoluteNaming.Value)
             {
                 // In other words, no filter applied
@@ -2529,9 +2531,24 @@ namespace Emby.Server.Implementations.Library
             var isFolder = episode.VideoType == VideoType.BluRay || episode.VideoType == VideoType.Dvd;
 
             // TODO nullable - what are we trying to do there with empty episodeInfo?
-            var episodeInfo = episode.IsFileProtocol
-                ? resolver.Resolve(episode.Path, isFolder, null, null, isAbsoluteNaming) ?? new Naming.TV.EpisodeInfo(episode.Path)
-                : new Naming.TV.EpisodeInfo(episode.Path);
+            EpisodeInfo episodeInfo = null;
+            if (episode.IsFileProtocol)
+            {
+                episodeInfo = resolver.Resolve(episode.Path, isFolder, null, null, isAbsoluteNaming);
+                // Resolve from parent folder if it's not the Season folder
+                var parent = episode.GetParent();
+                if (episodeInfo == null && parent.GetType() == typeof(Folder))
+                {
+                    episodeInfo = resolver.Resolve(parent.Path, true, null, null, isAbsoluteNaming);
+                    if (episodeInfo != null)
+                    {
+                        // add the container
+                        episodeInfo.Container = Path.GetExtension(episode.Path)?.TrimStart('.');
+                    }
+                }
+            }
+
+            episodeInfo ??= new EpisodeInfo(episode.Path);
 
             try
             {
@@ -2666,6 +2683,7 @@ namespace Emby.Server.Implementations.Library
             return changed;
         }
 
+        /// <inheritdoc />
         public NamingOptions GetNamingOptions()
         {
             if (_namingOptions == null)
@@ -2679,13 +2697,12 @@ namespace Emby.Server.Implementations.Library
 
         public ItemLookupInfo ParseName(string name)
         {
-            var resolver = new VideoResolver(GetNamingOptions());
-
-            var result = resolver.CleanDateTime(name);
+            var namingOptions = GetNamingOptions();
+            var result = VideoResolver.CleanDateTime(name, namingOptions);
 
             return new ItemLookupInfo
             {
-                Name = resolver.TryCleanString(result.Name, out var newName) ? newName.ToString() : result.Name,
+                Name = VideoResolver.TryCleanString(result.Name, namingOptions, out var newName) ? newName.ToString() : result.Name,
                 Year = result.Year
             };
         }
@@ -2695,13 +2712,11 @@ namespace Emby.Server.Implementations.Library
             var namingOptions = GetNamingOptions();
 
             var files = owner.IsInMixedFolder ? new List<FileSystemMetadata>() : fileSystemChildren.Where(i => i.IsDirectory)
-                .Where(i => string.Equals(i.Name, BaseItem.TrailerFolderName, StringComparison.OrdinalIgnoreCase))
+                .Where(i => string.Equals(i.Name, BaseItem.TrailersFolderName, StringComparison.OrdinalIgnoreCase))
                 .SelectMany(i => _fileSystem.GetFiles(i.FullName, _videoFileExtensions, false, false))
                 .ToList();
 
-            var videoListResolver = new VideoListResolver(namingOptions);
-
-            var videos = videoListResolver.Resolve(fileSystemChildren);
+            var videos = VideoListResolver.Resolve(fileSystemChildren, namingOptions);
 
             var currentVideo = videos.FirstOrDefault(i => string.Equals(owner.Path, i.Files[0].Path, StringComparison.OrdinalIgnoreCase));
 
@@ -2741,13 +2756,11 @@ namespace Emby.Server.Implementations.Library
             var namingOptions = GetNamingOptions();
 
             var files = owner.IsInMixedFolder ? new List<FileSystemMetadata>() : fileSystemChildren.Where(i => i.IsDirectory)
-                .Where(i => BaseItem.AllExtrasTypesFolderNames.Contains(i.Name ?? string.Empty, StringComparer.OrdinalIgnoreCase))
+                .Where(i => BaseItem.AllExtrasTypesFolderNames.ContainsKey(i.Name ?? string.Empty))
                 .SelectMany(i => _fileSystem.GetFiles(i.FullName, _videoFileExtensions, false, false))
                 .ToList();
 
-            var videoListResolver = new VideoListResolver(namingOptions);
-
-            var videos = videoListResolver.Resolve(fileSystemChildren);
+            var videos = VideoListResolver.Resolve(fileSystemChildren, namingOptions);
 
             var currentVideo = videos.FirstOrDefault(i => string.Equals(owner.Path, i.Files[0].Path, StringComparison.OrdinalIgnoreCase));
 
@@ -3059,9 +3072,9 @@ namespace Emby.Server.Implementations.Library
             });
         }
 
-        public void AddMediaPath(string virtualFolderName, MediaPathInfo pathInfo)
+        public void AddMediaPath(string virtualFolderName, MediaPathInfo mediaPath)
         {
-            AddMediaPathInternal(virtualFolderName, pathInfo, true);
+            AddMediaPathInternal(virtualFolderName, mediaPath, true);
         }
 
         private void AddMediaPathInternal(string virtualFolderName, MediaPathInfo pathInfo, bool saveLibraryOptions)
@@ -3114,11 +3127,11 @@ namespace Emby.Server.Implementations.Library
             }
         }
 
-        public void UpdateMediaPath(string virtualFolderName, MediaPathInfo pathInfo)
+        public void UpdateMediaPath(string virtualFolderName, MediaPathInfo mediaPath)
         {
-            if (pathInfo == null)
+            if (mediaPath == null)
             {
-                throw new ArgumentNullException(nameof(pathInfo));
+                throw new ArgumentNullException(nameof(mediaPath));
             }
 
             var rootFolderPath = _configurationManager.ApplicationPaths.DefaultUserViewsPath;
@@ -3131,9 +3144,9 @@ namespace Emby.Server.Implementations.Library
             var list = libraryOptions.PathInfos.ToList();
             foreach (var originalPathInfo in list)
             {
-                if (string.Equals(pathInfo.Path, originalPathInfo.Path, StringComparison.Ordinal))
+                if (string.Equals(mediaPath.Path, originalPathInfo.Path, StringComparison.Ordinal))
                 {
-                    originalPathInfo.NetworkPath = pathInfo.NetworkPath;
+                    originalPathInfo.NetworkPath = mediaPath.NetworkPath;
                     break;
                 }
             }
@@ -3156,10 +3169,7 @@ namespace Emby.Server.Implementations.Library
                 {
                     if (!list.Any(i => string.Equals(i.Path, location, StringComparison.Ordinal)))
                     {
-                        list.Add(new MediaPathInfo
-                        {
-                            Path = location
-                        });
+                        list.Add(new MediaPathInfo(location));
                     }
                 }
 
diff --git a/Emby.Server.Implementations/Library/LiveStreamHelper.cs b/Emby.Server.Implementations/Library/LiveStreamHelper.cs
index c2951dd15..83acd8e9f 100644
--- a/Emby.Server.Implementations/Library/LiveStreamHelper.cs
+++ b/Emby.Server.Implementations/Library/LiveStreamHelper.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
@@ -8,13 +10,14 @@ using System.Linq;
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
+using Jellyfin.Extensions.Json;
 using MediaBrowser.Common.Configuration;
 using MediaBrowser.Common.Extensions;
-using MediaBrowser.Common.Json;
 using MediaBrowser.Controller.MediaEncoding;
 using MediaBrowser.Model.Dlna;
 using MediaBrowser.Model.Dto;
 using MediaBrowser.Model.Entities;
+using MediaBrowser.Model.IO;
 using MediaBrowser.Model.MediaInfo;
 using Microsoft.Extensions.Logging;
 
@@ -47,7 +50,7 @@ namespace Emby.Server.Implementations.Library
             {
                 try
                 {
-                    await using FileStream jsonStream = File.OpenRead(cacheFilePath);
+                    await using FileStream jsonStream = AsyncFile.OpenRead(cacheFilePath);
                     mediaInfo = await JsonSerializer.DeserializeAsync<MediaInfo>(jsonStream, _jsonOptions, cancellationToken).ConfigureAwait(false);
 
                     // _logger.LogDebug("Found cached media info");
@@ -84,7 +87,7 @@ namespace Emby.Server.Implementations.Library
                 if (cacheFilePath != null)
                 {
                     Directory.CreateDirectory(Path.GetDirectoryName(cacheFilePath));
-                    await using FileStream createStream = File.OpenWrite(cacheFilePath);
+                    await using FileStream createStream = AsyncFile.OpenWrite(cacheFilePath);
                     await JsonSerializer.SerializeAsync(createStream, mediaInfo, _jsonOptions, cancellationToken).ConfigureAwait(false);
 
                     // _logger.LogDebug("Saved media info to {0}", cacheFilePath);
diff --git a/Emby.Server.Implementations/Library/MediaSourceManager.cs b/Emby.Server.Implementations/Library/MediaSourceManager.cs
index d0b85f07d..351fced34 100644
--- a/Emby.Server.Implementations/Library/MediaSourceManager.cs
+++ b/Emby.Server.Implementations/Library/MediaSourceManager.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
@@ -11,9 +13,9 @@ using System.Threading;
 using System.Threading.Tasks;
 using Jellyfin.Data.Entities;
 using Jellyfin.Data.Enums;
+using Jellyfin.Extensions.Json;
 using MediaBrowser.Common.Configuration;
 using MediaBrowser.Common.Extensions;
-using MediaBrowser.Common.Json;
 using MediaBrowser.Controller.Entities;
 using MediaBrowser.Controller.Library;
 using MediaBrowser.Controller.MediaEncoding;
@@ -350,7 +352,7 @@ namespace Emby.Server.Implementations.Library
 
         private string[] NormalizeLanguage(string language)
         {
-            if (language == null)
+            if (string.IsNullOrEmpty(language))
             {
                 return Array.Empty<string>();
             }
@@ -379,8 +381,7 @@ namespace Emby.Server.Implementations.Library
                 }
             }
 
-            var preferredSubs = string.IsNullOrEmpty(user.SubtitleLanguagePreference)
-                ? Array.Empty<string>() : NormalizeLanguage(user.SubtitleLanguagePreference);
+            var preferredSubs = NormalizeLanguage(user.SubtitleLanguagePreference);
 
             var defaultAudioIndex = source.DefaultAudioStreamIndex;
             var audioLangage = defaultAudioIndex == null
@@ -409,9 +410,7 @@ namespace Emby.Server.Implementations.Library
                 }
             }
 
-            var preferredAudio = string.IsNullOrEmpty(user.AudioLanguagePreference)
-                ? Array.Empty<string>()
-                : NormalizeLanguage(user.AudioLanguagePreference);
+            var preferredAudio = NormalizeLanguage(user.AudioLanguagePreference);
 
             source.DefaultAudioStreamIndex = MediaStreamSelector.GetDefaultAudioStreamIndex(source.MediaStreams, preferredAudio, user.PlayDefaultAudioTrack);
         }
@@ -522,7 +521,7 @@ namespace Emby.Server.Implementations.Library
 
             // TODO: @bond Fix
             var json = JsonSerializer.SerializeToUtf8Bytes(mediaSource, _jsonOptions);
-            _logger.LogInformation("Live stream opened: " + json);
+            _logger.LogInformation("Live stream opened: {@MediaSource}", mediaSource);
             var clone = JsonSerializer.Deserialize<MediaSourceInfo>(json, _jsonOptions);
 
             if (!request.UserId.Equals(Guid.Empty))
@@ -588,22 +587,6 @@ namespace Emby.Server.Implementations.Library
             mediaSource.InferTotalBitrate();
         }
 
-        public Task<IDirectStreamProvider> GetDirectStreamProviderByUniqueId(string uniqueId, CancellationToken cancellationToken)
-        {
-            var info = _openStreams.Values.FirstOrDefault(i =>
-            {
-                var liveStream = i as ILiveStream;
-                if (liveStream != null)
-                {
-                    return string.Equals(liveStream.UniqueId, uniqueId, StringComparison.OrdinalIgnoreCase);
-                }
-
-                return false;
-            });
-
-            return Task.FromResult(info as IDirectStreamProvider);
-        }
-
         public async Task<LiveStreamResponse> OpenLiveStream(LiveStreamRequest request, CancellationToken cancellationToken)
         {
             var result = await OpenLiveStreamInternal(request, cancellationToken).ConfigureAwait(false);
@@ -612,7 +595,8 @@ namespace Emby.Server.Implementations.Library
 
         public async Task<MediaSourceInfo> GetLiveStreamMediaInfo(string id, CancellationToken cancellationToken)
         {
-            var liveStreamInfo = await GetLiveStreamInfo(id, cancellationToken).ConfigureAwait(false);
+            // TODO probably shouldn't throw here but it is kept for "backwards compatibility"
+            var liveStreamInfo = GetLiveStreamInfo(id) ?? throw new ResourceNotFoundException();
 
             var mediaSource = liveStreamInfo.MediaSource;
 
@@ -648,7 +632,7 @@ namespace Emby.Server.Implementations.Library
             {
                 try
                 {
-                    await using FileStream jsonStream = File.OpenRead(cacheFilePath);
+                    await using FileStream jsonStream = AsyncFile.OpenRead(cacheFilePath);
                     mediaInfo = await JsonSerializer.DeserializeAsync<MediaInfo>(jsonStream, _jsonOptions, cancellationToken).ConfigureAwait(false);
 
                     // _logger.LogDebug("Found cached media info");
@@ -781,18 +765,19 @@ namespace Emby.Server.Implementations.Library
             mediaSource.InferTotalBitrate(true);
         }
 
-        public async Task<Tuple<MediaSourceInfo, IDirectStreamProvider>> GetLiveStreamWithDirectStreamProvider(string id, CancellationToken cancellationToken)
+        public Task<Tuple<MediaSourceInfo, IDirectStreamProvider>> GetLiveStreamWithDirectStreamProvider(string id, CancellationToken cancellationToken)
         {
             if (string.IsNullOrEmpty(id))
             {
                 throw new ArgumentNullException(nameof(id));
             }
 
-            var info = await GetLiveStreamInfo(id, cancellationToken).ConfigureAwait(false);
-            return new Tuple<MediaSourceInfo, IDirectStreamProvider>(info.MediaSource, info as IDirectStreamProvider);
+            // TODO probably shouldn't throw here but it is kept for "backwards compatibility"
+            var info = GetLiveStreamInfo(id) ?? throw new ResourceNotFoundException();
+            return Task.FromResult(new Tuple<MediaSourceInfo, IDirectStreamProvider>(info.MediaSource, info as IDirectStreamProvider));
         }
 
-        private Task<ILiveStream> GetLiveStreamInfo(string id, CancellationToken cancellationToken)
+        public ILiveStream GetLiveStreamInfo(string id)
         {
             if (string.IsNullOrEmpty(id))
             {
@@ -801,12 +786,16 @@ namespace Emby.Server.Implementations.Library
 
             if (_openStreams.TryGetValue(id, out ILiveStream info))
             {
-                return Task.FromResult(info);
-            }
-            else
-            {
-                return Task.FromException<ILiveStream>(new ResourceNotFoundException());
+                return info;
             }
+
+            return null;
+        }
+
+        /// <inheritdoc />
+        public ILiveStream GetLiveStreamInfoByUniqueId(string uniqueId)
+        {
+            return _openStreams.Values.FirstOrDefault(stream => string.Equals(uniqueId, stream?.UniqueId, StringComparison.OrdinalIgnoreCase));
         }
 
         public async Task<MediaSourceInfo> GetLiveStream(string id, CancellationToken cancellationToken)
diff --git a/Emby.Server.Implementations/Library/MediaStreamSelector.cs b/Emby.Server.Implementations/Library/MediaStreamSelector.cs
index 28fa06239..b833122ea 100644
--- a/Emby.Server.Implementations/Library/MediaStreamSelector.cs
+++ b/Emby.Server.Implementations/Library/MediaStreamSelector.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
diff --git a/Emby.Server.Implementations/Library/MusicManager.cs b/Emby.Server.Implementations/Library/MusicManager.cs
index 658c53f28..e2f1fb0ad 100644
--- a/Emby.Server.Implementations/Library/MusicManager.cs
+++ b/Emby.Server.Implementations/Library/MusicManager.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
@@ -34,9 +36,10 @@ namespace Emby.Server.Implementations.Library
             return list.Concat(GetInstantMixFromGenres(item.Genres, user, dtoOptions)).ToList();
         }
 
-        public List<BaseItem> GetInstantMixFromArtist(MusicArtist item, User user, DtoOptions dtoOptions)
+        /// <inheritdoc />
+        public List<BaseItem> GetInstantMixFromArtist(MusicArtist artist, User user, DtoOptions dtoOptions)
         {
-            return GetInstantMixFromGenres(item.Genres, user, dtoOptions);
+            return GetInstantMixFromGenres(artist.Genres, user, dtoOptions);
         }
 
         public List<BaseItem> GetInstantMixFromAlbum(MusicAlbum item, User user, DtoOptions dtoOptions)
@@ -100,8 +103,7 @@ namespace Emby.Server.Implementations.Library
 
         public List<BaseItem> GetInstantMixFromItem(BaseItem item, User user, DtoOptions dtoOptions)
         {
-            var genre = item as MusicGenre;
-            if (genre != null)
+            if (item is MusicGenre genre)
             {
                 return GetInstantMixFromGenreIds(new[] { item.Id }, user, dtoOptions);
             }
diff --git a/Emby.Server.Implementations/Library/PathExtensions.cs b/Emby.Server.Implementations/Library/PathExtensions.cs
index 770cf6bb0..d5b855cdf 100644
--- a/Emby.Server.Implementations/Library/PathExtensions.cs
+++ b/Emby.Server.Implementations/Library/PathExtensions.cs
@@ -1,5 +1,3 @@
-#nullable enable
-
 using System;
 using System.Diagnostics.CodeAnalysis;
 using MediaBrowser.Common.Providers;
@@ -55,7 +53,7 @@ namespace Emby.Server.Implementations.Library
         /// <param name="path">The original path.</param>
         /// <param name="subPath">The original sub path.</param>
         /// <param name="newSubPath">The new sub path.</param>
-        /// <param name="newPath">The result of the sub path replacement</param>
+        /// <param name="newPath">The result of the sub path replacement.</param>
         /// <returns>The path after replacing the sub path.</returns>
         /// <exception cref="ArgumentNullException"><paramref name="path" />, <paramref name="newSubPath" /> or <paramref name="newSubPath" /> is empty.</exception>
         public static bool TryReplaceSubPath(
@@ -96,8 +94,14 @@ namespace Emby.Server.Implementations.Library
             // We have to ensure that the sub path ends with a directory separator otherwise we'll get weird results
             // when the sub path matches a similar but in-complete subpath
             var oldSubPathEndsWithSeparator = subPath[^1] == newDirectorySeparatorChar;
-            if (!path.StartsWith(subPath, StringComparison.OrdinalIgnoreCase)
-                || (!oldSubPathEndsWithSeparator && path[subPath.Length] != newDirectorySeparatorChar))
+            if (!path.StartsWith(subPath, StringComparison.OrdinalIgnoreCase))
+            {
+                return false;
+            }
+
+            if (path.Length > subPath.Length
+                && !oldSubPathEndsWithSeparator
+                && path[subPath.Length] != newDirectorySeparatorChar)
             {
                 return false;
             }
diff --git a/Emby.Server.Implementations/Library/ResolverHelper.cs b/Emby.Server.Implementations/Library/ResolverHelper.cs
index 4e4cac75b..ac75e5d3a 100644
--- a/Emby.Server.Implementations/Library/ResolverHelper.cs
+++ b/Emby.Server.Implementations/Library/ResolverHelper.cs
@@ -18,11 +18,10 @@ namespace Emby.Server.Implementations.Library
         /// </summary>
         /// <param name="item">The item.</param>
         /// <param name="parent">The parent.</param>
-        /// <param name="fileSystem">The file system.</param>
         /// <param name="libraryManager">The library manager.</param>
         /// <param name="directoryService">The directory service.</param>
-        /// <exception cref="ArgumentException">Item must have a path</exception>
-        public static void SetInitialItemValues(BaseItem item, Folder parent, IFileSystem fileSystem, ILibraryManager libraryManager, IDirectoryService directoryService)
+        /// <exception cref="ArgumentException">Item must have a path.</exception>
+        public static void SetInitialItemValues(BaseItem item, Folder? parent, ILibraryManager libraryManager, IDirectoryService directoryService)
         {
             // This version of the below method has no ItemResolveArgs, so we have to require the path already being set
             if (string.IsNullOrEmpty(item.Path))
@@ -43,9 +42,14 @@ namespace Emby.Server.Implementations.Library
 
             // Make sure DateCreated and DateModified have values
             var fileInfo = directoryService.GetFile(item.Path);
-            SetDateCreated(item, fileSystem, fileInfo);
+            if (fileInfo == null)
+            {
+                throw new FileNotFoundException("Can't find item path.", item.Path);
+            }
 
-            EnsureName(item, item.Path, fileInfo);
+            SetDateCreated(item, fileInfo);
+
+            EnsureName(item, fileInfo);
         }
 
         /// <summary>
@@ -72,9 +76,9 @@ namespace Emby.Server.Implementations.Library
             item.Id = libraryManager.GetNewItemId(item.Path, item.GetType());
 
             // Make sure the item has a name
-            EnsureName(item, item.Path, args.FileInfo);
+            EnsureName(item, args.FileInfo);
 
-            item.IsLocked = item.Path.IndexOf("[dontfetchmeta]", StringComparison.OrdinalIgnoreCase) != -1 ||
+            item.IsLocked = item.Path.Contains("[dontfetchmeta]", StringComparison.OrdinalIgnoreCase) ||
                 item.GetParents().Any(i => i.IsLocked);
 
             // Make sure DateCreated and DateModified have values
@@ -84,29 +88,16 @@ namespace Emby.Server.Implementations.Library
         /// <summary>
         /// Ensures the name.
         /// </summary>
-        private static void EnsureName(BaseItem item, string fullPath, FileSystemMetadata fileInfo)
+        private static void EnsureName(BaseItem item, FileSystemMetadata fileInfo)
         {
             // If the subclass didn't supply a name, add it here
-            if (string.IsNullOrEmpty(item.Name) && !string.IsNullOrEmpty(fullPath))
+            if (string.IsNullOrEmpty(item.Name) && !string.IsNullOrEmpty(item.Path))
             {
-                var fileName = fileInfo == null ? Path.GetFileName(fullPath) : fileInfo.Name;
-
-                item.Name = GetDisplayName(fileName, fileInfo != null && fileInfo.IsDirectory);
+                item.Name = fileInfo.IsDirectory ? fileInfo.Name : Path.GetFileNameWithoutExtension(fileInfo.Name);
             }
         }
 
         /// <summary>
-        /// Gets the display name.
-        /// </summary>
-        /// <param name="path">The path.</param>
-        /// <param name="isDirectory">if set to <c>true</c> [is directory].</param>
-        /// <returns>System.String.</returns>
-        private static string GetDisplayName(string path, bool isDirectory)
-        {
-            return isDirectory ? Path.GetFileName(path) : Path.GetFileNameWithoutExtension(path);
-        }
-
-        /// <summary>
         /// Ensures DateCreated and DateModified have values.
         /// </summary>
         /// <param name="fileSystem">The file system.</param>
@@ -114,21 +105,6 @@ namespace Emby.Server.Implementations.Library
         /// <param name="args">The args.</param>
         private static void EnsureDates(IFileSystem fileSystem, BaseItem item, ItemResolveArgs args)
         {
-            if (fileSystem == null)
-            {
-                throw new ArgumentNullException(nameof(fileSystem));
-            }
-
-            if (item == null)
-            {
-                throw new ArgumentNullException(nameof(item));
-            }
-
-            if (args == null)
-            {
-                throw new ArgumentNullException(nameof(args));
-            }
-
             // See if a different path came out of the resolver than what went in
             if (!fileSystem.AreEqual(args.Path, item.Path))
             {
@@ -136,7 +112,7 @@ namespace Emby.Server.Implementations.Library
 
                 if (childData != null)
                 {
-                    SetDateCreated(item, fileSystem, childData);
+                    SetDateCreated(item, childData);
                 }
                 else
                 {
@@ -144,17 +120,17 @@ namespace Emby.Server.Implementations.Library
 
                     if (fileData.Exists)
                     {
-                        SetDateCreated(item, fileSystem, fileData);
+                        SetDateCreated(item, fileData);
                     }
                 }
             }
             else
             {
-                SetDateCreated(item, fileSystem, args.FileInfo);
+                SetDateCreated(item, args.FileInfo);
             }
         }
 
-        private static void SetDateCreated(BaseItem item, IFileSystem fileSystem, FileSystemMetadata info)
+        private static void SetDateCreated(BaseItem item, FileSystemMetadata? info)
         {
             var config = BaseItem.ConfigurationManager.GetMetadataConfiguration();
 
@@ -163,7 +139,7 @@ namespace Emby.Server.Implementations.Library
                 // directoryService.getFile may return null
                 if (info != null)
                 {
-                    var dateCreated = fileSystem.GetCreationTimeUtc(info);
+                    var dateCreated = info.CreationTimeUtc;
 
                     if (dateCreated.Equals(DateTime.MinValue))
                     {
diff --git a/Emby.Server.Implementations/Library/Resolvers/Audio/AudioResolver.cs b/Emby.Server.Implementations/Library/Resolvers/Audio/AudioResolver.cs
index 4ad84579d..fd9747b4b 100644
--- a/Emby.Server.Implementations/Library/Resolvers/Audio/AudioResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/Audio/AudioResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
@@ -19,11 +21,11 @@ namespace Emby.Server.Implementations.Library.Resolvers.Audio
     /// </summary>
     public class AudioResolver : ItemResolver<MediaBrowser.Controller.Entities.Audio.Audio>, IMultiItemResolver
     {
-        private readonly ILibraryManager LibraryManager;
+        private readonly ILibraryManager _libraryManager;
 
         public AudioResolver(ILibraryManager libraryManager)
         {
-            LibraryManager = libraryManager;
+            _libraryManager = libraryManager;
         }
 
         /// <summary>
@@ -86,13 +88,13 @@ namespace Emby.Server.Implementations.Library.Resolvers.Audio
                 }
 
                 var files = args.FileSystemChildren
-                    .Where(i => !LibraryManager.IgnoreFile(i, args.Parent))
+                    .Where(i => !_libraryManager.IgnoreFile(i, args.Parent))
                     .ToList();
 
                 return FindAudio<AudioBook>(args, args.Path, args.Parent, files, args.DirectoryService, collectionType, false);
             }
 
-            if (LibraryManager.IsAudioFile(args.Path))
+            if (_libraryManager.IsAudioFile(args.Path))
             {
                 var extension = Path.GetExtension(args.Path);
 
@@ -105,7 +107,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.Audio
                 var isMixedCollectionType = string.IsNullOrEmpty(collectionType);
 
                 // For conflicting extensions, give priority to videos
-                if (isMixedCollectionType && LibraryManager.IsVideoFile(args.Path))
+                if (isMixedCollectionType && _libraryManager.IsVideoFile(args.Path))
                 {
                     return null;
                 }
@@ -180,7 +182,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.Audio
                 }
             }
 
-            var namingOptions = ((LibraryManager)LibraryManager).GetNamingOptions();
+            var namingOptions = ((LibraryManager)_libraryManager).GetNamingOptions();
 
             var resolver = new AudioBookListResolver(namingOptions);
             var resolverResult = resolver.Resolve(files).ToList();
diff --git a/Emby.Server.Implementations/Library/Resolvers/Audio/MusicAlbumResolver.cs b/Emby.Server.Implementations/Library/Resolvers/Audio/MusicAlbumResolver.cs
index bf32381eb..60720dd2f 100644
--- a/Emby.Server.Implementations/Library/Resolvers/Audio/MusicAlbumResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/Audio/MusicAlbumResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -80,6 +82,9 @@ namespace Emby.Server.Implementations.Library.Resolvers.Audio
         /// <summary>
         /// Determine if the supplied file data points to a music album.
         /// </summary>
+        /// <param name="path">The path to check.</param>
+        /// <param name="directoryService">The directory service.</param>
+        /// <returns><c>true</c> if the provided path points to a music album, <c>false</c> otherwise.</returns>
         public bool IsMusicAlbum(string path, IDirectoryService directoryService)
         {
             return ContainsMusic(directoryService.GetFileSystemEntries(path), true, directoryService, _logger, _fileSystem, _libraryManager);
diff --git a/Emby.Server.Implementations/Library/Resolvers/Audio/MusicArtistResolver.cs b/Emby.Server.Implementations/Library/Resolvers/Audio/MusicArtistResolver.cs
index 60f82806f..3d2ae95d2 100644
--- a/Emby.Server.Implementations/Library/Resolvers/Audio/MusicArtistResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/Audio/MusicArtistResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 using System;
 using System.Linq;
 using System.Threading.Tasks;
diff --git a/Emby.Server.Implementations/Library/Resolvers/BaseVideoResolver.cs b/Emby.Server.Implementations/Library/Resolvers/BaseVideoResolver.cs
index 6e688693b..9ff99fa43 100644
--- a/Emby.Server.Implementations/Library/Resolvers/BaseVideoResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/BaseVideoResolver.cs
@@ -1,8 +1,11 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
 using System.IO;
 using System.Linq;
+using DiscUtils.Udf;
 using Emby.Naming.Video;
 using MediaBrowser.Controller.Entities;
 using MediaBrowser.Controller.Library;
@@ -14,17 +17,17 @@ namespace Emby.Server.Implementations.Library.Resolvers
     /// <summary>
     /// Resolves a Path into a Video or Video subclass.
     /// </summary>
-    /// <typeparam name="T"></typeparam>
+    /// <typeparam name="T">The type of item to resolve.</typeparam>
     public abstract class BaseVideoResolver<T> : MediaBrowser.Controller.Resolvers.ItemResolver<T>
         where T : Video, new()
     {
-        protected readonly ILibraryManager LibraryManager;
-
         protected BaseVideoResolver(ILibraryManager libraryManager)
         {
             LibraryManager = libraryManager;
         }
 
+        protected ILibraryManager LibraryManager { get; }
+
         /// <summary>
         /// Resolves the specified args.
         /// </summary>
@@ -45,11 +48,9 @@ namespace Emby.Server.Implementations.Library.Resolvers
         protected virtual TVideoType ResolveVideo<TVideoType>(ItemResolveArgs args, bool parseName)
               where TVideoType : Video, new()
         {
-            var namingOptions = ((LibraryManager)LibraryManager).GetNamingOptions();
+            var namingOptions = LibraryManager.GetNamingOptions();
 
             // If the path is a file check for a matching extensions
-            var parser = new VideoResolver(namingOptions);
-
             if (args.IsDirectory)
             {
                 TVideoType video = null;
@@ -64,7 +65,7 @@ namespace Emby.Server.Implementations.Library.Resolvers
                     {
                         if (IsDvdDirectory(child.FullName, filename, args.DirectoryService))
                         {
-                            videoInfo = parser.ResolveDirectory(args.Path);
+                            videoInfo = VideoResolver.ResolveDirectory(args.Path, namingOptions);
 
                             if (videoInfo == null)
                             {
@@ -80,9 +81,9 @@ namespace Emby.Server.Implementations.Library.Resolvers
                             break;
                         }
 
-                        if (IsBluRayDirectory(child.FullName, filename, args.DirectoryService))
+                        if (IsBluRayDirectory(filename))
                         {
-                            videoInfo = parser.ResolveDirectory(args.Path);
+                            videoInfo = VideoResolver.ResolveDirectory(args.Path, namingOptions);
 
                             if (videoInfo == null)
                             {
@@ -100,7 +101,7 @@ namespace Emby.Server.Implementations.Library.Resolvers
                     }
                     else if (IsDvdFile(filename))
                     {
-                        videoInfo = parser.ResolveDirectory(args.Path);
+                        videoInfo = VideoResolver.ResolveDirectory(args.Path, namingOptions);
 
                         if (videoInfo == null)
                         {
@@ -130,7 +131,7 @@ namespace Emby.Server.Implementations.Library.Resolvers
             }
             else
             {
-                var videoInfo = parser.Resolve(args.Path, false, false);
+                var videoInfo = VideoResolver.Resolve(args.Path, false, namingOptions, false);
 
                 if (videoInfo == null)
                 {
@@ -165,13 +166,13 @@ namespace Emby.Server.Implementations.Library.Resolvers
 
         protected void SetVideoType(Video video, VideoFileInfo videoInfo)
         {
-            var extension = Path.GetExtension(video.Path);
-            video.VideoType = string.Equals(extension, ".iso", StringComparison.OrdinalIgnoreCase) ||
-                string.Equals(extension, ".img", StringComparison.OrdinalIgnoreCase) ?
-              VideoType.Iso :
-              VideoType.VideoFile;
+            var extension = Path.GetExtension(video.Path.AsSpan());
+            video.VideoType = extension.Equals(".iso", StringComparison.OrdinalIgnoreCase)
+                              || extension.Equals(".img", StringComparison.OrdinalIgnoreCase)
+                ? VideoType.Iso
+                : VideoType.VideoFile;
 
-            video.IsShortcut = string.Equals(extension, ".strm", StringComparison.OrdinalIgnoreCase);
+            video.IsShortcut = extension.Equals(".strm", StringComparison.OrdinalIgnoreCase);
             video.IsPlaceHolder = videoInfo.IsStub;
 
             if (videoInfo.IsStub)
@@ -193,14 +194,30 @@ namespace Emby.Server.Implementations.Library.Resolvers
         {
             if (video.VideoType == VideoType.Iso)
             {
-                if (video.Path.IndexOf("dvd", StringComparison.OrdinalIgnoreCase) != -1)
+                if (video.Path.Contains("dvd", StringComparison.OrdinalIgnoreCase))
                 {
                     video.IsoType = IsoType.Dvd;
                 }
-                else if (video.Path.IndexOf("bluray", StringComparison.OrdinalIgnoreCase) != -1)
+                else if (video.Path.Contains("bluray", StringComparison.OrdinalIgnoreCase))
                 {
                     video.IsoType = IsoType.BluRay;
                 }
+                else
+                {
+                    // use disc-utils, both DVDs and BDs use UDF filesystem
+                    using (var videoFileStream = File.Open(video.Path, FileMode.Open, FileAccess.Read))
+                    {
+                        UdfReader udfReader = new UdfReader(videoFileStream);
+                        if (udfReader.DirectoryExists("VIDEO_TS"))
+                        {
+                            video.IsoType = IsoType.Dvd;
+                        }
+                        else if (udfReader.DirectoryExists("BDMV"))
+                        {
+                            video.IsoType = IsoType.BluRay;
+                        }
+                    }
+                }
             }
         }
 
@@ -250,10 +267,7 @@ namespace Emby.Server.Implementations.Library.Resolvers
 
         protected void Set3DFormat(Video video)
         {
-            var namingOptions = ((LibraryManager)LibraryManager).GetNamingOptions();
-
-            var resolver = new Format3DParser(namingOptions);
-            var result = resolver.Parse(video.Path);
+            var result = Format3DParser.Parse(video.Path, LibraryManager.GetNamingOptions());
 
             Set3DFormat(video, result.Is3D, result.Format3D);
         }
@@ -261,6 +275,10 @@ namespace Emby.Server.Implementations.Library.Resolvers
         /// <summary>
         /// Determines whether [is DVD directory] [the specified directory name].
         /// </summary>
+        /// <param name="fullPath">The full path of the directory.</param>
+        /// <param name="directoryName">The name of the directory.</param>
+        /// <param name="directoryService">The directory service.</param>
+        /// <returns><c>true</c> if the provided directory is a DVD directory, <c>false</c> otherwise.</returns>
         protected bool IsDvdDirectory(string fullPath, string directoryName, IDirectoryService directoryService)
         {
             if (!string.Equals(directoryName, "video_ts", StringComparison.OrdinalIgnoreCase))
@@ -282,25 +300,13 @@ namespace Emby.Server.Implementations.Library.Resolvers
         }
 
         /// <summary>
-        /// Determines whether [is blu ray directory] [the specified directory name].
+        /// Determines whether [is bluray directory] [the specified directory name].
         /// </summary>
-        protected bool IsBluRayDirectory(string fullPath, string directoryName, IDirectoryService directoryService)
+        /// <param name="directoryName">The directory name.</param>
+        /// <returns>Whether the directory is a bluray directory.</returns>
+        protected bool IsBluRayDirectory(string directoryName)
         {
-            if (!string.Equals(directoryName, "bdmv", StringComparison.OrdinalIgnoreCase))
-            {
-                return false;
-            }
-
-            return true;
-            // var blurayExtensions = new[]
-            //{
-            //    ".mts",
-            //    ".m2ts",
-            //    ".bdmv",
-            //    ".mpls"
-            //};
-
-            // return directoryService.GetFiles(fullPath).Any(i => blurayExtensions.Contains(i.Extension ?? string.Empty, StringComparer.OrdinalIgnoreCase));
+            return string.Equals(directoryName, "bdmv", StringComparison.OrdinalIgnoreCase);
         }
     }
 }
diff --git a/Emby.Server.Implementations/Library/Resolvers/Books/BookResolver.cs b/Emby.Server.Implementations/Library/Resolvers/Books/BookResolver.cs
index 0525c7e30..e685c87f1 100644
--- a/Emby.Server.Implementations/Library/Resolvers/Books/BookResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/Books/BookResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
@@ -47,13 +49,12 @@ namespace Emby.Server.Implementations.Library.Resolvers.Books
         {
             var bookFiles = args.FileSystemChildren.Where(f =>
             {
-                var fileExtension = Path.GetExtension(f.FullName) ??
-                                    string.Empty;
+                var fileExtension = Path.GetExtension(f.FullName)
+                    ?? string.Empty;
 
                 return _validExtensions.Contains(
                     fileExtension,
-                                                StringComparer
-                                                    .OrdinalIgnoreCase);
+                    StringComparer.OrdinalIgnoreCase);
             }).ToList();
 
             // Don't return a Book if there is more (or less) than one document in the directory
diff --git a/Emby.Server.Implementations/Library/Resolvers/FolderResolver.cs b/Emby.Server.Implementations/Library/Resolvers/FolderResolver.cs
index 7dbce7a6e..db7703cd6 100644
--- a/Emby.Server.Implementations/Library/Resolvers/FolderResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/FolderResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 using MediaBrowser.Controller.Entities;
 using MediaBrowser.Controller.Library;
 using MediaBrowser.Controller.Resolvers;
@@ -7,7 +9,7 @@ namespace Emby.Server.Implementations.Library.Resolvers
     /// <summary>
     /// Class FolderResolver.
     /// </summary>
-    public class FolderResolver : FolderResolver<Folder>
+    public class FolderResolver : GenericFolderResolver<Folder>
     {
         /// <summary>
         /// Gets the priority.
@@ -30,24 +32,4 @@ namespace Emby.Server.Implementations.Library.Resolvers
             return null;
         }
     }
-
-    /// <summary>
-    /// Class FolderResolver.
-    /// </summary>
-    /// <typeparam name="TItemType">The type of the T item type.</typeparam>
-    public abstract class FolderResolver<TItemType> : ItemResolver<TItemType>
-        where TItemType : Folder, new()
-    {
-        /// <summary>
-        /// Sets the initial item values.
-        /// </summary>
-        /// <param name="item">The item.</param>
-        /// <param name="args">The args.</param>
-        protected override void SetInitialItemValues(TItemType item, ItemResolveArgs args)
-        {
-            base.SetInitialItemValues(item, args);
-
-            item.IsRoot = args.Parent == null;
-        }
-    }
 }
diff --git a/Emby.Server.Implementations/Library/Resolvers/GenericFolderResolver.cs b/Emby.Server.Implementations/Library/Resolvers/GenericFolderResolver.cs
new file mode 100644
index 000000000..f109a5e9a
--- /dev/null
+++ b/Emby.Server.Implementations/Library/Resolvers/GenericFolderResolver.cs
@@ -0,0 +1,27 @@
+#nullable disable
+
+using MediaBrowser.Controller.Entities;
+using MediaBrowser.Controller.Library;
+
+namespace Emby.Server.Implementations.Library.Resolvers
+{
+    /// <summary>
+    /// Class FolderResolver.
+    /// </summary>
+    /// <typeparam name="TItemType">The type of the T item type.</typeparam>
+    public abstract class GenericFolderResolver<TItemType> : ItemResolver<TItemType>
+        where TItemType : Folder, new()
+    {
+        /// <summary>
+        /// Sets the initial item values.
+        /// </summary>
+        /// <param name="item">The item.</param>
+        /// <param name="args">The args.</param>
+        protected override void SetInitialItemValues(TItemType item, ItemResolveArgs args)
+        {
+            base.SetInitialItemValues(item, args);
+
+            item.IsRoot = args.Parent == null;
+        }
+    }
+}
diff --git a/Emby.Server.Implementations/Library/Resolvers/VideoResolver.cs b/Emby.Server.Implementations/Library/Resolvers/GenericVideoResolver.cs
index 62268fce9..9599faea4 100644
--- a/Emby.Server.Implementations/Library/Resolvers/VideoResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/GenericVideoResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using MediaBrowser.Controller.Entities;
diff --git a/Emby.Server.Implementations/Library/Resolvers/ItemResolver.cs b/Emby.Server.Implementations/Library/Resolvers/ItemResolver.cs
index 9ca76095b..3f29ab191 100644
--- a/Emby.Server.Implementations/Library/Resolvers/ItemResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/ItemResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 using MediaBrowser.Controller.Entities;
 using MediaBrowser.Controller.Library;
 using MediaBrowser.Controller.Resolvers;
@@ -7,11 +9,17 @@ namespace Emby.Server.Implementations.Library.Resolvers
     /// <summary>
     /// Class ItemResolver.
     /// </summary>
-    /// <typeparam name="T"></typeparam>
+    /// <typeparam name="T">The type of BaseItem.</typeparam>
     public abstract class ItemResolver<T> : IItemResolver
         where T : BaseItem, new()
     {
         /// <summary>
+        /// Gets the priority.
+        /// </summary>
+        /// <value>The priority.</value>
+        public virtual ResolverPriority Priority => ResolverPriority.First;
+
+        /// <summary>
         /// Resolves the specified args.
         /// </summary>
         /// <param name="args">The args.</param>
@@ -22,12 +30,6 @@ namespace Emby.Server.Implementations.Library.Resolvers
         }
 
         /// <summary>
-        /// Gets the priority.
-        /// </summary>
-        /// <value>The priority.</value>
-        public virtual ResolverPriority Priority => ResolverPriority.First;
-
-        /// <summary>
         /// Sets initial values on the newly resolved item.
         /// </summary>
         /// <param name="item">The item.</param>
diff --git a/Emby.Server.Implementations/Library/Resolvers/Movies/BoxSetResolver.cs b/Emby.Server.Implementations/Library/Resolvers/Movies/BoxSetResolver.cs
index 295e9e120..e7abe1e6d 100644
--- a/Emby.Server.Implementations/Library/Resolvers/Movies/BoxSetResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/Movies/BoxSetResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 using System;
 using System.IO;
 using MediaBrowser.Controller.Entities;
@@ -10,7 +12,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.Movies
     /// <summary>
     /// Class BoxSetResolver.
     /// </summary>
-    public class BoxSetResolver : FolderResolver<BoxSet>
+    public class BoxSetResolver : GenericFolderResolver<BoxSet>
     {
         /// <summary>
         /// Resolves the specified args.
diff --git a/Emby.Server.Implementations/Library/Resolvers/Movies/MovieResolver.cs b/Emby.Server.Implementations/Library/Resolvers/Movies/MovieResolver.cs
index 714bc3a84..f3b6ef0a2 100644
--- a/Emby.Server.Implementations/Library/Resolvers/Movies/MovieResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/Movies/MovieResolver.cs
@@ -1,9 +1,12 @@
+#nullable disable
+
 using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Text.RegularExpressions;
 using Emby.Naming.Video;
+using Jellyfin.Extensions;
 using MediaBrowser.Controller.Drawing;
 using MediaBrowser.Controller.Entities;
 using MediaBrowser.Controller.Entities.Movies;
@@ -21,6 +24,8 @@ namespace Emby.Server.Implementations.Library.Resolvers.Movies
     /// </summary>
     public class MovieResolver : BaseVideoResolver<Video>, IMultiItemResolver
     {
+        private readonly IImageProcessor _imageProcessor;
+
         private string[] _validCollectionTypes = new[]
         {
                 CollectionType.Movies,
@@ -30,8 +35,6 @@ namespace Emby.Server.Implementations.Library.Resolvers.Movies
                 CollectionType.Photos
         };
 
-        private readonly IImageProcessor _imageProcessor;
-
         /// <summary>
         /// Initializes a new instance of the <see cref="MovieResolver"/> class.
         /// </summary>
@@ -255,10 +258,9 @@ namespace Emby.Server.Implementations.Library.Resolvers.Movies
                 }
             }
 
-            var namingOptions = ((LibraryManager)LibraryManager).GetNamingOptions();
+            var namingOptions = LibraryManager.GetNamingOptions();
 
-            var resolver = new VideoListResolver(namingOptions);
-            var resolverResult = resolver.Resolve(files, suppportMultiEditions).ToList();
+            var resolverResult = VideoListResolver.Resolve(files, namingOptions, suppportMultiEditions).ToList();
 
             var result = new MultiItemResolverResult
             {
@@ -376,7 +378,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.Movies
         {
             var multiDiscFolders = new List<FileSystemMetadata>();
 
-            var libraryOptions = args.GetLibraryOptions();
+            var libraryOptions = args.LibraryOptions;
             var supportPhotos = string.Equals(collectionType, CollectionType.HomeVideos, StringComparison.OrdinalIgnoreCase) && libraryOptions.EnablePhotos;
             var photos = new List<FileSystemMetadata>();
 
@@ -398,7 +400,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.Movies
                         return movie;
                     }
 
-                    if (IsBluRayDirectory(child.FullName, filename, directoryService))
+                    if (IsBluRayDirectory(filename))
                     {
                         var movie = new T
                         {
@@ -479,7 +481,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.Movies
                     return true;
                 }
 
-                if (subfolders.Any(s => IsBluRayDirectory(s.FullName, s.Name, directoryService)))
+                if (subfolders.Any(s => IsBluRayDirectory(s.Name)))
                 {
                     videoTypes.Add(VideoType.BluRay);
                     return true;
@@ -535,7 +537,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.Movies
             return returnVideo;
         }
 
-        private bool IsInvalid(Folder parent, string collectionType)
+        private bool IsInvalid(Folder parent, ReadOnlySpan<char> collectionType)
         {
             if (parent != null)
             {
@@ -545,12 +547,12 @@ namespace Emby.Server.Implementations.Library.Resolvers.Movies
                 }
             }
 
-            if (string.IsNullOrEmpty(collectionType))
+            if (collectionType.IsEmpty)
             {
                 return false;
             }
 
-            return !_validCollectionTypes.Contains(collectionType, StringComparer.OrdinalIgnoreCase);
+            return !_validCollectionTypes.Contains(collectionType, StringComparison.OrdinalIgnoreCase);
         }
     }
 }
diff --git a/Emby.Server.Implementations/Library/Resolvers/PhotoAlbumResolver.cs b/Emby.Server.Implementations/Library/Resolvers/PhotoAlbumResolver.cs
index 3ac837057..1c560e8a6 100644
--- a/Emby.Server.Implementations/Library/Resolvers/PhotoAlbumResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/PhotoAlbumResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 using System;
 using MediaBrowser.Controller.Drawing;
 using MediaBrowser.Controller.Entities;
@@ -10,10 +12,10 @@ namespace Emby.Server.Implementations.Library.Resolvers
     /// <summary>
     /// Class PhotoAlbumResolver.
     /// </summary>
-    public class PhotoAlbumResolver : FolderResolver<PhotoAlbum>
+    public class PhotoAlbumResolver : GenericFolderResolver<PhotoAlbum>
     {
         private readonly IImageProcessor _imageProcessor;
-        private ILibraryManager _libraryManager;
+        private readonly ILibraryManager _libraryManager;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="PhotoAlbumResolver"/> class.
@@ -26,6 +28,9 @@ namespace Emby.Server.Implementations.Library.Resolvers
             _libraryManager = libraryManager;
         }
 
+        /// <inheritdoc />
+        public override ResolverPriority Priority => ResolverPriority.Second;
+
         /// <summary>
         /// Resolves the specified args.
         /// </summary>
@@ -39,8 +44,8 @@ namespace Emby.Server.Implementations.Library.Resolvers
                 // Must be an image file within a photo collection
                 var collectionType = args.GetCollectionType();
 
-                if (string.Equals(collectionType, CollectionType.Photos, StringComparison.OrdinalIgnoreCase) ||
-                    (string.Equals(collectionType, CollectionType.HomeVideos, StringComparison.OrdinalIgnoreCase) && args.GetLibraryOptions().EnablePhotos))
+                if (string.Equals(collectionType, CollectionType.Photos, StringComparison.OrdinalIgnoreCase)
+                    || (string.Equals(collectionType, CollectionType.HomeVideos, StringComparison.OrdinalIgnoreCase) && args.LibraryOptions.EnablePhotos))
                 {
                     if (HasPhotos(args))
                     {
@@ -84,8 +89,5 @@ namespace Emby.Server.Implementations.Library.Resolvers
 
             return false;
         }
-
-        /// <inheritdoc />
-        public override ResolverPriority Priority => ResolverPriority.Second;
     }
 }
diff --git a/Emby.Server.Implementations/Library/Resolvers/PhotoResolver.cs b/Emby.Server.Implementations/Library/Resolvers/PhotoResolver.cs
index bcfcee9c6..57bf40e9e 100644
--- a/Emby.Server.Implementations/Library/Resolvers/PhotoResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/PhotoResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
@@ -47,7 +49,7 @@ namespace Emby.Server.Implementations.Library.Resolvers
                 var collectionType = args.CollectionType;
 
                 if (string.Equals(collectionType, CollectionType.Photos, StringComparison.OrdinalIgnoreCase)
-                    || (string.Equals(collectionType, CollectionType.HomeVideos, StringComparison.OrdinalIgnoreCase) && args.GetLibraryOptions().EnablePhotos))
+                    || (string.Equals(collectionType, CollectionType.HomeVideos, StringComparison.OrdinalIgnoreCase) && args.LibraryOptions.EnablePhotos))
                 {
                     if (IsImageFile(args.Path, _imageProcessor))
                     {
diff --git a/Emby.Server.Implementations/Library/Resolvers/PlaylistResolver.cs b/Emby.Server.Implementations/Library/Resolvers/PlaylistResolver.cs
index 5f051321f..8ce59717d 100644
--- a/Emby.Server.Implementations/Library/Resolvers/PlaylistResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/PlaylistResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
@@ -14,9 +16,10 @@ namespace Emby.Server.Implementations.Library.Resolvers
     /// <summary>
     /// <see cref="IItemResolver"/> for <see cref="Playlist"/> library items.
     /// </summary>
-    public class PlaylistResolver : FolderResolver<Playlist>
+    public class PlaylistResolver : GenericFolderResolver<Playlist>
     {
-        private string[] _musicPlaylistCollectionTypes = new string[] {
+        private string[] _musicPlaylistCollectionTypes =
+        {
             string.Empty,
             CollectionType.Music
         };
diff --git a/Emby.Server.Implementations/Library/Resolvers/SpecialFolderResolver.cs b/Emby.Server.Implementations/Library/Resolvers/SpecialFolderResolver.cs
index 99f304190..6bb999641 100644
--- a/Emby.Server.Implementations/Library/Resolvers/SpecialFolderResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/SpecialFolderResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
@@ -11,7 +13,7 @@ using MediaBrowser.Model.IO;
 
 namespace Emby.Server.Implementations.Library.Resolvers
 {
-    public class SpecialFolderResolver : FolderResolver<Folder>
+    public class SpecialFolderResolver : GenericFolderResolver<Folder>
     {
         private readonly IFileSystem _fileSystem;
         private readonly IServerApplicationPaths _appPaths;
@@ -65,7 +67,6 @@ namespace Emby.Server.Implementations.Library.Resolvers
             return args.FileSystemChildren
                 .Where(i =>
                 {
-
                     try
                     {
                         return !i.IsDirectory &&
diff --git a/Emby.Server.Implementations/Library/Resolvers/TV/EpisodeResolver.cs b/Emby.Server.Implementations/Library/Resolvers/TV/EpisodeResolver.cs
index 9b4cd7a3d..cf2d22f4d 100644
--- a/Emby.Server.Implementations/Library/Resolvers/TV/EpisodeResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/TV/EpisodeResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 using System;
 using System.Linq;
 using MediaBrowser.Controller.Entities;
@@ -35,31 +37,23 @@ namespace Emby.Server.Implementations.Library.Resolvers.TV
                 return null;
             }
 
-            var season = parent as Season;
-
             // Just in case the user decided to nest episodes.
             // Not officially supported but in some cases we can handle it.
-            if (season == null)
-            {
-                season = parent.GetParents().OfType<Season>().FirstOrDefault();
-            }
+
+            var season = parent as Season ?? parent.GetParents().OfType<Season>().FirstOrDefault();
 
             // If the parent is a Season or Series and the parent is not an extras folder, then this is an Episode if the VideoResolver returns something
             // Also handle flat tv folders
             if ((season != null ||
                  string.Equals(args.GetCollectionType(), CollectionType.TvShows, StringComparison.OrdinalIgnoreCase) ||
                  args.HasParent<Series>())
-                && (parent is Series || !BaseItem.AllExtrasTypesFolderNames.Contains(parent.Name, StringComparer.OrdinalIgnoreCase)))
+                && (parent is Series || !BaseItem.AllExtrasTypesFolderNames.ContainsKey(parent.Name)))
             {
                 var episode = ResolveVideo<Episode>(args, false);
 
                 if (episode != null)
                 {
-                    var series = parent as Series;
-                    if (series == null)
-                    {
-                        series = parent.GetParents().OfType<Series>().FirstOrDefault();
-                    }
+                    var series = parent as Series ?? parent.GetParents().OfType<Series>().FirstOrDefault();
 
                     if (series != null)
                     {
diff --git a/Emby.Server.Implementations/Library/Resolvers/TV/SeasonResolver.cs b/Emby.Server.Implementations/Library/Resolvers/TV/SeasonResolver.cs
index 3332e1806..063f67543 100644
--- a/Emby.Server.Implementations/Library/Resolvers/TV/SeasonResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/TV/SeasonResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 using System.Globalization;
 using Emby.Naming.TV;
 using MediaBrowser.Controller.Entities.TV;
@@ -10,7 +12,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.TV
     /// <summary>
     /// Class SeasonResolver.
     /// </summary>
-    public class SeasonResolver : FolderResolver<Season>
+    public class SeasonResolver : GenericFolderResolver<Season>
     {
         private readonly ILibraryManager _libraryManager;
         private readonly ILocalizationManager _localization;
@@ -88,7 +90,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.TV
                             CultureInfo.InvariantCulture,
                             _localization.GetLocalizedString("NameSeasonNumber"),
                             seasonNumber,
-                            args.GetLibraryOptions().PreferredMetadataLanguage);
+                            args.LibraryOptions.PreferredMetadataLanguage);
                 }
 
                 return season;
diff --git a/Emby.Server.Implementations/Library/Resolvers/TV/SeriesResolver.cs b/Emby.Server.Implementations/Library/Resolvers/TV/SeriesResolver.cs
index 4a9d2cf8c..b7fbe01c5 100644
--- a/Emby.Server.Implementations/Library/Resolvers/TV/SeriesResolver.cs
+++ b/Emby.Server.Implementations/Library/Resolvers/TV/SeriesResolver.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
@@ -6,7 +8,6 @@ using System.IO;
 using Emby.Naming.TV;
 using MediaBrowser.Controller.Entities.TV;
 using MediaBrowser.Controller.Library;
-using MediaBrowser.Controller.Providers;
 using MediaBrowser.Controller.Resolvers;
 using MediaBrowser.Model.Entities;
 using MediaBrowser.Model.IO;
@@ -17,21 +18,18 @@ namespace Emby.Server.Implementations.Library.Resolvers.TV
     /// <summary>
     /// Class SeriesResolver.
     /// </summary>
-    public class SeriesResolver : FolderResolver<Series>
+    public class SeriesResolver : GenericFolderResolver<Series>
     {
-        private readonly IFileSystem _fileSystem;
         private readonly ILogger<SeriesResolver> _logger;
         private readonly ILibraryManager _libraryManager;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="SeriesResolver"/> class.
         /// </summary>
-        /// <param name="fileSystem">The file system.</param>
         /// <param name="logger">The logger.</param>
         /// <param name="libraryManager">The library manager.</param>
-        public SeriesResolver(IFileSystem fileSystem, ILogger<SeriesResolver> logger, ILibraryManager libraryManager)
+        public SeriesResolver(ILogger<SeriesResolver> logger, ILibraryManager libraryManager)
         {
-            _fileSystem = fileSystem;
             _logger = logger;
             _libraryManager = libraryManager;
         }
@@ -59,15 +57,6 @@ namespace Emby.Server.Implementations.Library.Resolvers.TV
                 var collectionType = args.GetCollectionType();
                 if (string.Equals(collectionType, CollectionType.TvShows, StringComparison.OrdinalIgnoreCase))
                 {
-                    // if (args.ContainsFileSystemEntryByName("tvshow.nfo"))
-                    //{
-                    //    return new Series
-                    //    {
-                    //        Path = args.Path,
-                    //        Name = Path.GetFileName(args.Path)
-                    //    };
-                    //}
-
                     var configuredContentType = _libraryManager.GetConfiguredContentType(args.Path);
                     if (!string.Equals(configuredContentType, CollectionType.TvShows, StringComparison.OrdinalIgnoreCase))
                     {
@@ -100,7 +89,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.TV
                         return null;
                     }
 
-                    if (IsSeriesFolder(args.Path, args.FileSystemChildren, args.DirectoryService, _fileSystem, _logger, _libraryManager, false))
+                    if (IsSeriesFolder(args.Path, args.FileSystemChildren, _logger, _libraryManager, false))
                     {
                         return new Series
                         {
@@ -117,8 +106,6 @@ namespace Emby.Server.Implementations.Library.Resolvers.TV
         public static bool IsSeriesFolder(
             string path,
             IEnumerable<FileSystemMetadata> fileSystemChildren,
-            IDirectoryService directoryService,
-            IFileSystem fileSystem,
             ILogger<SeriesResolver> logger,
             ILibraryManager libraryManager,
             bool isTvContentType)
diff --git a/Emby.Server.Implementations/Library/SearchEngine.cs b/Emby.Server.Implementations/Library/SearchEngine.cs
index bcdf854ca..bebc25b77 100644
--- a/Emby.Server.Implementations/Library/SearchEngine.cs
+++ b/Emby.Server.Implementations/Library/SearchEngine.cs
@@ -1,14 +1,16 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Diacritics.Extensions;
 using Jellyfin.Data.Entities;
 using Jellyfin.Data.Enums;
 using MediaBrowser.Controller.Dto;
 using MediaBrowser.Controller.Entities;
 using MediaBrowser.Controller.Entities.Audio;
-using MediaBrowser.Controller.Extensions;
 using MediaBrowser.Controller.Library;
 using MediaBrowser.Model.Querying;
 using MediaBrowser.Model.Search;
@@ -71,7 +73,7 @@ namespace Emby.Server.Implementations.Library
         /// <param name="query">The query.</param>
         /// <param name="user">The user.</param>
         /// <returns>IEnumerable{SearchHintResult}.</returns>
-        /// <exception cref="ArgumentNullException">searchTerm</exception>
+        /// <exception cref="ArgumentException"><c>query.SearchTerm</c> is <c>null</c> or empty.</exception>
         private List<SearchHintInfo> GetSearchHints(SearchQuery query, User user)
         {
             var searchTerm = query.SearchTerm;
diff --git a/Emby.Server.Implementations/Library/UserDataManager.cs b/Emby.Server.Implementations/Library/UserDataManager.cs
index 827e3c64b..bb3034142 100644
--- a/Emby.Server.Implementations/Library/UserDataManager.cs
+++ b/Emby.Server.Implementations/Library/UserDataManager.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
@@ -23,8 +25,6 @@ namespace Emby.Server.Implementations.Library
     /// </summary>
     public class UserDataManager : IUserDataManager
     {
-        public event EventHandler<UserDataSaveEventArgs> UserDataSaved;
-
         private readonly ConcurrentDictionary<string, UserItemData> _userData =
             new ConcurrentDictionary<string, UserItemData>(StringComparer.OrdinalIgnoreCase);
 
@@ -42,6 +42,8 @@ namespace Emby.Server.Implementations.Library
             _repository = repository;
         }
 
+        public event EventHandler<UserDataSaveEventArgs> UserDataSaved;
+
         public void SaveUserData(Guid userId, BaseItem item, UserItemData userData, UserDataSaveReason reason, CancellationToken cancellationToken)
         {
             var user = _userManager.GetUserById(userId);
@@ -88,10 +90,9 @@ namespace Emby.Server.Implementations.Library
         /// <summary>
         /// Save the provided user data for the given user.  Batch operation. Does not fire any events or update the cache.
         /// </summary>
-        /// <param name="userId"></param>
-        /// <param name="userData"></param>
-        /// <param name="cancellationToken"></param>
-        /// <returns></returns>
+        /// <param name="userId">The user id.</param>
+        /// <param name="userData">The user item data.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
         public void SaveAllUserData(Guid userId, UserItemData[] userData, CancellationToken cancellationToken)
         {
             var user = _userManager.GetUserById(userId);
@@ -102,8 +103,8 @@ namespace Emby.Server.Implementations.Library
         /// <summary>
         /// Retrieve all user data for the given user.
         /// </summary>
-        /// <param name="userId"></param>
-        /// <returns></returns>
+        /// <param name="userId">The user id.</param>
+        /// <returns>A <see cref="List{UserItemData}"/> containing all of the user's item data.</returns>
         public List<UserItemData> GetAllUserData(Guid userId)
         {
             var user = _userManager.GetUserById(userId);
@@ -175,6 +176,7 @@ namespace Emby.Server.Implementations.Library
             return dto;
         }
 
+        /// <inheritdoc />
         public UserItemDataDto GetUserDataDto(BaseItem item, BaseItemDto itemDto, User user, DtoOptions options)
         {
             var userData = GetUserData(user, item);
@@ -189,7 +191,7 @@ namespace Emby.Server.Implementations.Library
         /// </summary>
         /// <param name="data">The data.</param>
         /// <returns>DtoUserItemData.</returns>
-        /// <exception cref="ArgumentNullException"></exception>
+        /// <exception cref="ArgumentNullException"><paramref name="data"/> is <c>null</c>.</exception>
         private UserItemDataDto GetUserItemDataDto(UserItemData data)
         {
             if (data == null)
@@ -210,6 +212,7 @@ namespace Emby.Server.Implementations.Library
             };
         }
 
+        /// <inheritdoc />
         public bool UpdatePlayState(BaseItem item, UserItemData data, long? reportedPositionTicks)
         {
             var playedToCompletion = false;
@@ -220,7 +223,7 @@ namespace Emby.Server.Implementations.Library
             var hasRuntime = runtimeTicks > 0;
 
             // If a position has been reported, and if we know the duration
-            if (positionTicks > 0 && hasRuntime && !(item is AudioBook))
+            if (positionTicks > 0 && hasRuntime && item is not AudioBook && item is not Book)
             {
                 var pctIn = decimal.Divide(positionTicks, runtimeTicks) * 100;
 
@@ -239,7 +242,7 @@ namespace Emby.Server.Implementations.Library
                 {
                     // Enforce MinResumeDuration
                     var durationSeconds = TimeSpan.FromTicks(runtimeTicks).TotalSeconds;
-                    if (durationSeconds < _config.Configuration.MinResumeDurationSeconds && !(item is Book))
+                    if (durationSeconds < _config.Configuration.MinResumeDurationSeconds)
                     {
                         positionTicks = 0;
                         data.Played = playedToCompletion = true;
diff --git a/Emby.Server.Implementations/Library/UserViewManager.cs b/Emby.Server.Implementations/Library/UserViewManager.cs
index ac041bcf6..711647e7a 100644
--- a/Emby.Server.Implementations/Library/UserViewManager.cs
+++ b/Emby.Server.Implementations/Library/UserViewManager.cs
@@ -1,3 +1,5 @@
+#nullable disable
+
 #pragma warning disable CS1591
 
 using System;
@@ -339,19 +341,26 @@ namespace Emby.Server.Implementations.Library
                 mediaTypes = mediaTypes.Distinct().ToList();
             }
 
-            var excludeItemTypes = includeItemTypes.Length == 0 && mediaTypes.Count == 0 ? new[]
-            {
-                nameof(Person),
-                nameof(Studio),
-                nameof(Year),
-                nameof(MusicGenre),
-                nameof(Genre)
-            } : Array.Empty<string>();
+            var excludeItemTypes = includeItemTypes.Length == 0 && mediaTypes.Count == 0
+                ? new[]
+                {
+                    nameof(Person),
+                    nameof(Studio),
+                    nameof(Year),
+                    nameof(MusicGenre),
+                    nameof(Genre)
+                }
+                : Array.Empty<string>();
 
             var query = new InternalItemsQuery(user)
             {
                 IncludeItemTypes = includeItemTypes,
-                OrderBy = new[] { (ItemSortBy.DateCreated, SortOrder.Descending) },
+                OrderBy = new[]
+                {
+                    (ItemSortBy.DateCreated, SortOrder.Descending),
+                    (ItemSortBy.SortName, SortOrder.Descending),
+                    (ItemSortBy.ProductionYear, SortOrder.Descending)
+                },
                 IsFolder = includeItemTypes.Length == 0 ? false : (bool?)null,
                 ExcludeItemTypes = excludeItemTypes,
                 IsVirtualItem = false,
diff --git a/Emby.Server.Implementations/Library/Validators/ArtistsValidator.cs b/Emby.Server.Implementations/Library/Validators/ArtistsValidator.cs
index f9a3e2c64..40436d9c5 100644
--- a/Emby.Server.Implementations/Library/Validators/ArtistsValidator.cs
+++ b/Emby.Server.Implementations/Library/Validators/ArtistsValidator.cs
@@ -95,10 +95,13 @@ namespace Emby.Server.Implementations.Library.Validators
 
                 _logger.LogInformation("Deleting dead {2} {0} {1}.", item.Id.ToString("N", CultureInfo.InvariantCulture), item.Name, item.GetType().Name);
 
-                _libraryManager.DeleteItem(item, new DeleteOptions
-                {
-                    DeleteFileLocation = false
-                }, false);
+                _libraryManager.DeleteItem(
+                    item,
+                    new DeleteOptions
+                    {
+                        DeleteFileLocation = false
+                    },
+                    false);
             }
 
             progress.Report(100);
diff --git a/Emby.Server.Implementations/Library/Validators/StudiosValidator.cs b/Emby.Server.Implementations/Library/Validators/StudiosValidator.cs
index 9a8c5f39d..8577d722e 100644
--- a/Emby.Server.Implementations/Library/Validators/StudiosValidator.cs
+++ b/Emby.Server.Implementations/Library/Validators/StudiosValidator.cs
@@ -87,12 +87,15 @@ namespace Emby.Server.Implementations.Library.Validators
 
             foreach (var item in deadEntities)
             {
-                _logger.LogInformation("Deleting dead {2} {0} {1}.", item.Id.ToString("N", CultureInfo.InvariantCulture), item.Name, item.GetType().Name);
+                _logger.LogInformation("Deleting dead {ItemType} {ItemId} {ItemName}", item.GetType().Name, item.Id.ToString("N", CultureInfo.InvariantCulture), item.Name);
 
-                _libraryManager.DeleteItem(item, new DeleteOptions
-                {
-                    DeleteFileLocation = false
-                }, false);
+                _libraryManager.DeleteItem(
+                    item,
+                    new DeleteOptions
+                    {
+                        DeleteFileLocation = false
+                    },
+                    false);
             }
 
             progress.Report(100);