1 files changed, 24 insertions, 2 deletions
diff --git a/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs b/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs
index 10c21ee03c..9952c10c3a 100644
--- a/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs
+++ b/MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs
@@ -695,7 +695,11 @@ namespace MediaBrowser.Controller.MediaEncoding
                 "ogg" or "oga" or "ogv" or "webm" or "webma" => "opus",
                 "m4a" or "m4b" or "mp4" or "mov" or "mkv" or "mka" => "aac",
                 "ts" or "avi" or "flv" or "f4v" or "swf" => "mp3",
-                _ => inferredCodec
+                // Containers that share their name with the codec they carry.
+                "aac" or "ac3" or "alac" or "dts" or "eac3" or "flac" or "mp2" or "mp3" or "opus" or "truehd" or "vorbis" => inferredCodec,
+                // Anything else - manifests such as m3u8/mpd in particular - names a container that
+                // is not an audio codec. Never hand that name to ffmpeg as an encoder.
+                _ => "aac"
             };
         }
 
@@ -6311,7 +6315,7 @@ namespace MediaBrowser.Controller.MediaEncoding
                         string.Join(',', overlayFilters));
 
                 var mapPrefix = Convert.ToInt32(state.SubtitleStream.IsExternal);
-                var subtitleStreamIndex = FindIndex(state.MediaSource.MediaStreams, state.SubtitleStream);
+                var subtitleStreamIndex = GetSubtitleStreamIndexForFfmpeg(state.MediaSource, state.SubtitleStream);
                 var videoStreamIndex = FindIndex(state.MediaSource.MediaStreams, state.VideoStream);
 
                 if (hasSubs)
@@ -7943,6 +7947,24 @@ namespace MediaBrowser.Controller.MediaEncoding
             return -1;
         }
 
+        public static int GetSubtitleStreamIndexForFfmpeg(MediaSourceInfo mediaSource, MediaStream subtitleStream)
+        {
+            var index = FindIndex(mediaSource.MediaStreams, subtitleStream);
+            if (index == -1 || subtitleStream.IsExternal || mediaSource.VideoType != VideoType.BluRay)
+            {
+                return index;
+            }
+
+            var hiddenStreamsBefore = mediaSource.MediaStreams.Count(s =>
+                s.Type == MediaStreamType.Audio
+                && !s.IsExternal
+                && (string.Equals(s.Codec, "truehd", StringComparison.OrdinalIgnoreCase)
+                    || string.Equals(s.Codec, "atmos", StringComparison.OrdinalIgnoreCase))
+                && s.Index < subtitleStream.Index);
+
+            return index + hiddenStreamsBefore;
+        }
+
         public static bool IsCopyCodec(string codec)
         {
             return string.Equals(codec, "copy", StringComparison.OrdinalIgnoreCase);