Properly handle stream addition and removal for strm use cases

Emby.Server.Implementations/Library/MediaSourceManager.cs

@@ -151,7 +151,9 @@ namespace Emby.Server.Implementations.Library
         {
             var mediaSources = GetStaticMediaSources(item, enablePathSubstitution, user);
 
-            if (allowMediaProbe && mediaSources[0].Type != MediaSourceType.Placeholder && !mediaSources[0].MediaStreams.Any(i => i.Type == MediaStreamType.Audio || i.Type == MediaStreamType.Video))
+            if (allowMediaProbe && mediaSources[0].Type != MediaSourceType.Placeholder
+                && (item.MediaType == MediaType.Video && !mediaSources[0].MediaStreams.Any(i => i.Type == MediaStreamType.Video)
+                || item.MediaType == MediaType.Audio && !mediaSources[0].MediaStreams.Any(i => i.Type == MediaStreamType.Audio)))
             {
                 await item.RefreshMetadata(
                     new MetadataRefreshOptions(_directoryService)

MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs

@@ -2228,13 +2228,14 @@ namespace MediaBrowser.Controller.MediaEncoding
             }
 
             var args = string.Empty;
+            var numberOfExternalStreams = state.MediaSource.MediaStreams.Where(stream => stream.IsExternal == true).Count();
 
             if (state.VideoStream != null)
             {
                 args += string.Format(
                     CultureInfo.InvariantCulture,
                     "-map 0:{0}",
-                    state.VideoStream.Index);
+                    state.VideoStream.Index - numberOfExternalStreams);
             }
             else
             {

MediaBrowser.Providers/MediaInfo/FFProbeVideoInfo.cs

@@ -173,9 +173,22 @@ namespace MediaBrowser.Providers.MediaInfo
             IReadOnlyList<MediaAttachment> mediaAttachments;
             ChapterInfo[] chapters;
 
+            mediaStreams = new List<MediaStream>();
+
+            // Add external streams before adding the streams from the file to preserve stream IDs on remote videos
+            await AddExternalSubtitlesAsync(video, mediaStreams, options, cancellationToken).ConfigureAwait(false);
+
+            await AddExternalAudioAsync(video, mediaStreams, options, cancellationToken).ConfigureAwait(false);
+
             if (mediaInfo != null)
             {
-                mediaStreams = mediaInfo.MediaStreams.ToList();
+                var startIndex = mediaStreams.Count == 0 ? 0 : (mediaStreams.Select(i => i.Index).Max() + 1);
+                foreach (var mediaStream in mediaInfo.MediaStreams)
+                {
+                    mediaStream.Index = startIndex++;
+                    mediaStreams.Add(mediaStream);
+                }
+
                 mediaAttachments = mediaInfo.MediaAttachments;
 
                 video.TotalBitrate = mediaInfo.Bitrate;
@@ -213,15 +226,10 @@ namespace MediaBrowser.Providers.MediaInfo
             }
             else
             {
-                mediaStreams = new List<MediaStream>();
                 mediaAttachments = Array.Empty<MediaAttachment>();
                 chapters = Array.Empty<ChapterInfo>();
             }
 
-            await AddExternalSubtitlesAsync(video, mediaStreams, options, cancellationToken).ConfigureAwait(false);
-
-            await AddExternalAudioAsync(video, mediaStreams, options, cancellationToken).ConfigureAwait(false);
-
             var libraryOptions = _libraryManager.GetLibraryOptions(video);
 
             if (mediaInfo != null)