FFmpeg, Cut to frame, different audio

Get audio cuts with Audacity

ffmpeg -ss 0:3:55.570 -t 0:2:36.7 -i in.mp3 -c copy trim.mp3

Encode to FFVhuff

ffmpeg -ss 1:31:0 -t 0:4:0 -i in.mkv -c ffvhuff -an -sn FFVhuff.mkv

Get cut values with Avidemux

ffmpeg -ss 26.818 -t 0:2:33.111 -i FFVhuff.mkv -c copy trim.mkv

ffmpeg -i trim.mkv -i trim.mp3 -vf scale=638:-1,fade=out:3658:14 -c:a copy -threads 6 out.mkv

ffmpeg -ss 26.818 -i FFVhuff.mkv -c copy trim.mkv

Scale, fade, mux audio

ffmpeg -i trim.mkv -i trim.mp3 -vf scale=638:-1,fade=out:3658:14 -c:a copy -shortest -threads 6 out.mkv

Notes

The correct way is to put -ss first, then -i. If you put -i first it will cause sync issues.

Links

stackoverflow.com/questions/4839303/convert-image-sequence-to-lossless-movie