RTMP MultiTrack usage

[urlocalguru]

Question

I am new to MediaMTX as a whole so pardon if I overlooked something

I recently gained access to Twitchs new Dual Format stream functionality which uses RTMP MultiTrack video's. I followed the guide on getting OBS to successfully send multiple video tracks, even updated it to include both formats at multiple encodings (below 'Config Override').. I was able to open the stream in VLC using an RTSP connection and was able to successfully verify each video track.
I have now progressed to the next step which is to select video tracks and forward to various platforms, as well as forward the entire stack to twitch.

I have added the following to the config file
ffmpeg -i rtsp://localhost:8554/mystream -map 0:v:X -map 0:a:0 -c copy -f flv "rtmp://server/live/key"
where the X is the video track i want to use.
0 - 1080p
1 - 720p
3 - 1080p vertical
etc

This seems to work... but I am struggeling to figure out how to output multiple sessions with different mappings

ffmpeg -i rtsp://localhost:8554/mystream -map 0:v:0 -map 0:a:0 -c copy -f flv "rtmp://server1080/live/key"
ffmpeg -i rtsp://localhost:8554/mystream -map 0:v:1 -map 0:a:0 -c copy -f flv "rtmp://server720/live/key"
ffmpeg -i rtsp://localhost:8554/mystream -map 0:v:3 -map 0:a:0 -c copy -f flv "rtmp://serverVert/live/key"

Ideally I would also be able to feed the full stack as is onto twich or any other platform that supports this format in the future, but I assume this would follow the same logic.

Config Override

{ "encoder_configurations": [ { "type": "obs_nvenc_h264_tex", "width": 1920, "height": 1080, "framerate": { "numerator": 60, "denominator": 1 }, "settings": { "rate_control": "CBR", "bitrate": 6000, "keyint_sec": 2, "preset": "veryfast", "profile": "high", "tune": "zerolatency" }, "canvas_index": 0 }, { "type": "obs_nvenc_h264_tex", "width": 1280, "height": 720, "framerate": { "numerator": 60, "denominator": 1 }, "settings": { "rate_control": "CBR", "bitrate": 3000, "keyint_sec": 2, "preset": "veryfast", "profile": "high", "tune": "zerolatency" }, "canvas_index": 0 }, { "type": "obs_nvenc_h264_tex", "width": 640, "height": 360, "framerate": { "numerator": 30, "denominator": 1 }, "settings": { "rate_control": "CBR", "bitrate": 500, "keyint_sec": 2, "preset": "veryfast", "profile": "main", "tune": "zerolatency" }, "canvas_index": 0 }, { "type": "obs_nvenc_h264_tex", "width": 1080, "height": 1920, "framerate": { "numerator": 60, "denominator": 1 }, "settings": { "rate_control": "CBR", "bitrate": 6000, "keyint_sec": 2, "preset": "veryfast", "profile": "main", "tune": "zerolatency" }, "canvas_index": 1 }, { "type": "obs_nvenc_h264_tex", "width": 720, "height": 1280, "framerate": { "numerator": 30, "denominator": 1 }, "settings": { "rate_control": "CBR", "bitrate": 1500, "keyint_sec": 2, "preset": "veryfast", "profile": "main", "tune": "zerolatency" }, "canvas_index": 1 }, { "type": "obs_nvenc_h264_tex", "width": 360, "height": 640, "framerate": { "numerator": 30, "denominator": 1 }, "settings": { "rate_control": "CBR", "bitrate": 500, "keyint_sec": 2, "preset": "veryfast", "profile": "main", "tune": "zerolatency" }, "canvas_index": 1 } ], "audio_configurations": { "live": [ { "codec": "ffmpeg_aac", "track_id": 1, "channels": 2, "settings": { "bitrate": 160 } } ] } }

[urlocalguru]

looks like I was having a formatting issue with my yaml. was able to get it working by wrapping the commands in a sh -c " xxxx " and an & at the end of each line.

runOnReady: >
sh -c "
ffmpeg -i rtsp://localhost:8554/restream -map 0:v:0 -map 0:a:0 -c copy -f flv rtmp://server1080/live/key &
ffmpeg -i rtsp://localhost:8554/restream -map 0:v:1 -map 0:a:0 -c copy -f flv rtmp://server720/live/key &
ffmpeg -i rtsp://localhost:8554/restream -map 0:v:3 -map 0:a:0 -c copy -f flv rtmp://serverVert/live/key
"

I am still struggling with getting a feed to Twitch however.. as it seems they are not doing simple MultiTrack RMTP and instead are doing some fMP4 ingest.. and I am struggeling to figure out how to replicate.

[urlocalguru]

Looks like the issue is the docker build of MediaMTX has an older version of ffmpeg that doesnt support the enhanced codec for sending the multi-track video out contrary to this

https://mediamtx.org/docs/read/ffmpeg

-rtmp_enhanced_codecs is not a parameter ?? was this removed in later builds then 1.11.0?
https://github.com/bluenviron/mediamtx/releases/tag/v1.11.0