It seems that ffmpeg 4.0 supports av1, but only via the reference encoder. The faster rav1e encoder isn't a bundled option... ( https://github.com/xiph/rav1e h

It seems that ffmpeg 4.0 supports av1, but only via the reference encoder. The faster rav1e encoder isn't a bundled option... ( https://github.com/xiph/rav1e https://github.com/xiph/rav1e ) https://www.ffmpeg.org/index.html#news https://www.ffmpeg.org/index.html#news https://trac.ffmpeg.org/wiki/Encode/AV1 https://trac.ffmpeg.org/wiki/Encode/AV1 However that does make me hopeful that I could annotate the start delay for each track, split off the video track, and re-combine an externally encoded video stream.