SOLVED: Transcode/remux problem with x264 MKV content

[PMG]

Dear all,

I have a mediaserver, running Ubuntu Server 22.04, set up with Jellyfin 10.8.9. Mostly, this works like a charm, except for x264 MKV content that does not play via the Android Jellyfin client. It plays via Chrome browser without issues. But not through the official Android Jellyfin app apparently, it simply hangs indefinitely on loading. Other content in x265 MKV plays fine.

The server has an Intel Celeron 3205 cpu/gpu. Hardware acceleration and decoding is set up as supported by this cpu/gpu: acceleration is set to Intel QuickSync (QSV). Decoding enabled for H264, MPEG2, VC1, VP8. Others are disabled because unsupported.

Even to my untrained eye the log shows something suspicious: TransCodeReason: VideoCodecNotSupported, AudioCodecNotSupported.
Jellyfin Media Player on Android should support H.264 8-bit playback according to the codec support: https://jellyfin.org/docs/general/client...c-support/.
The ffmpeg log for these files start with FFmpeg.Remux. Any idea why this is not playing? Also, why is it remuxing instead of direct play, if this codec is supported by the client? If needed, I can also share the ffmpeg log.

I can manually convert to a compatible format, but I don't see it as a long-term solution to manually check and convert every time when receiving new content. Of course, if there is no other way, I will have to find a way of automating this.

Jellyfin log:

Code:

[2025-03-11 16:17:19.928 +01:00] [INF] User policy for "Paul". EnablePlaybackRemuxing: True EnableVideoPlaybackTranscoding: True EnableAudioPlaybackTranscoding: True
[2025-03-11 16:17:19.929 +01:00] [INF] StreamBuilder.BuildVideoItem( Profile="Anonymous Profile", Path="/media/nas-public/Series/Clarkson's Farm/Clarksons.Farm.S03.COMPLETE.720p.AMZN.WEBRip.x264-GalaxyTV[TGx]/Clarksons.Farm.S03E04.720p.AMZN.WEBRip.x264-GalaxyTV.mkv", AudioStreamIndex=1, SubtitleStreamIndex=2 ) => ( PlayMethod=Transcode, TranscodeReason=VideoCodecNotSupported, AudioCodecNotSupported ) "media:/videos/9049cf65-721d-305c-c443-d54d79642d46/master.m3u8?MediaSourceId=9049cf65721d305cc443d54d79642d46&VideoCodec=h264,h264&AudioCodec=aac&AudioStreamIndex=1&VideoBitrate=139360000&AudioBitrate=640000&AudioSampleRate=48000&MaxFramerate=25&api_key=<token>&TranscodingMaxAudioChannels=2&RequireAvc=false&Tag=772bb5c785a514c53dbbdbbd2179bca4&SegmentContainer=ts&MinSegments=1&BreakOnNonKeyFrames=False&h264-level=31&h264-videobitdepth=8&h264-profile=high&h264-audiochannels=2&aac-profile=lc&TranscodeReasons=VideoCodecNotSupported,%20AudioCodecNotSupported"
[2025-03-11 16:17:20.452 +01:00] [INF] "/usr/lib/jellyfin-ffmpeg/ffmpeg" "-analyzeduration 200M -fflags +genpts  -i file:\"/media/nas-public/Series/Clarkson's Farm/Clarksons.Farm.S03.COMPLETE.720p.AMZN.WEBRip.x264-GalaxyTV[TGx]/Clarksons.Farm.S03E04.720p.AMZN.WEBRip.x264-GalaxyTV.mkv\" -map_metadata -1 -map_chapters -1 -threads 0 -map 0:0 -map 0:1 -map -0:s -codec:v:0 copy -bsf:v h264_mp4toannexb -start_at_zero -codec:a:0 copy -copyts -avoid_negative_ts disabled -max_muxing_queue_size 2048 -f hls -max_delay 5000000 -hls_time 6 -hls_segment_type mpegts -start_number 0 -hls_segment_filename \"/var/lib/jellyfin/transcodes/c5b4be96ae64ecee2dc3ce68340f2377%d.ts\" -hls_playlist_type vod -hls_list_size 0 -y \"/var/lib/jellyfin/transcodes/c5b4be96ae64ecee2dc3ce68340f2377.m3u8\""
[2025-03-11 16:17:21.145 +01:00] [INF] "/usr/lib/jellyfin-ffmpeg/ffmpeg" "-i file:\"/media/nas-public/Series/Clarkson's Farm/Clarksons.Farm.S03.COMPLETE.720p.AMZN.WEBRip.x264-GalaxyTV[TGx]/Clarksons.Farm.S03E04.720p.AMZN.WEBRip.x264-GalaxyTV.mkv\" -copyts -map 0:2 -an -vn -c:s copy \"/var/lib/jellyfin/data/subtitles/0/028d8275-8620-e4af-5456-d5410e88a3eb.srt\""
[2025-03-11 16:17:24.145 +01:00] [INF] ffmpeg subtitle extraction completed for "file:\"/media/nas-public/Series/Clarkson's Farm/Clarksons.Farm.S03.COMPLETE.720p.AMZN.WEBRip.x264-GalaxyTV[TGx]/Clarksons.Farm.S03E04.720p.AMZN.WEBRip.x264-GalaxyTV.mkv\"" to "/var/lib/jellyfin/data/subtitles/0/028d8275-8620-e4af-5456-d5410e88a3eb.srt"
[2025-03-11 16:17:24.147 +01:00] [WRN] Slow HTTP Response from "http://192.168.1.100:8096/Videos/9049cf65-721d-305c-c443-d54d79642d46/9049cf65721d305cc443d54d79642d46/Subtitles/2/0/Stream.js?api_key=bedef1a601a74b29881296b5ea651cd1" to "192.168.1.102" in 0:00:03.0049019 with Status Code 200
[2025-03-11 16:17:24.941 +01:00] [INF] FFmpeg exited with code 0

Media info:
Video
Title: GalaxyTV - small excellence! - 720p - H264 - SDR
Codec: H264
AVC: Yes
Profile: High
Level: 31
Resolution: 1280x580
Aspect ratio: 959:436
Interlaced: No
Framerate: 25
Bitrate: 1641 kbps
Bit depth: 8 bit
Video range: SDR
Video range type: SDR
Color space: bt709
Color transfer: bt709
Color primaries: bt709
Pixel format: yuv420p
Ref frames: 1
NAL: 4

[theguymadmax]

I have a mediaserver, running Ubuntu Server 22.04, set up with Jellyfin 10.8.9.

You're using a 2 year outdated version of Jellyfin.

[PMG]

Well what do you know.. I update the system regularly yet failed to notice that Jellyfin was not automatically updating all this time.
An update to the latest version, 10.10.6, seems to have resolved the problem. Thanks!