[FFmpeg-devel] Stream selection algorithm crossing program boundaries

Devin Heitmueller dheitmueller at ltnglobal.com
Fri May 18 16:20:28 EEST 2018


Hello all,

By default, ffmpeg will pick the "best" audio and video streams if the user doesn’t explicitly indicate such using the “-map” argument.  However it completely ignores which programs streams are a part of, which can lead to cases where the video is picked from one program and the audio is from a completely different program.

Is this something anyone is actively looking into?  If not, I'll dig into it and see about respecting program membership in ffmpeg's selection algorithm.  My larger concern is that with MPEG-TS streams, the commonly accepted heuristic is to play the first audio/video streams in the first PMT entry (this is what VLC does for example), rather than trying to pick the "best quality" streams, and it's not clear whether such a change in the selection algorithm would be accepted upstream (since it would make selection of audio/video in MPEG-TS streams behave differently than other formats).

Thoughts?

Devin

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Devin Heitmueller - LTN Global Communications
dheitmueller at ltnglobal.com






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