brew install ffmpeg
pip install ffmpeg-normalize
ffmpeg-normalize input.mp4 -o output.mp4 -c:a aac -b:a 192k --progress
ffmpeg -i Commentary.m4a -filter:a loudnorm Commentary2.m4a
ffmpeg -i video.mov -map 0:1 -c copy audio.m4a
ffmpeg -i Segment_0001.mp4 -i Commentary2.m4a -c copy -map 0:v:0 -map 1:a:0 meetup.mp4
ffmpeg -i meetup.mp4 -ss 00:00:08 -c copy meetup1.mp4
ffmpeg -i in.mp4 -ss [start] -t [duration] -c copy out.mp4
missing keyframes? use -async 1
in place of -c copy
to reencode the video. Longer but add missing keyframes
alternative for missing keyframes: -c copy -copyinkf
it doesn't reencode but does not work great
cat list.txt
file ./1.mov
file ./2.mov
ffmpeg -safe 0 -f concat -i list.txt -vcodec copy -acodec copy merged.mov