Ffmpeg incantations
From Infiniwiki
Change container
ffmpeg -i input.mkv -c:v copy -c:a copy output.mp4
Keep resolution, lower bitrate
ffmpeg -i input.mp4 -c:v libx264 -crf 20 -c:a copy output.mp4
CRF value can be changed - note lower CRF equals higher bitrate
Change resolution, lower bitrate
ffmpeg -i input.mp4 -c:v libx264 -crf 20 -vf scale=-1:720 output.mp4
CRF value can be changed as before, scale is w:h, -1 = keep aspect ratio based on the other value
Merge files, no re-encode
ffmpeg -f concat -i files.txt -c copy output.mp4
files.txt format:
file 'input1.mp4'
file 'input2.mp4'
Copy part of video, no re-encode (slow seeking but accurate times)
ffmpeg -i input.mp4 -ss 00:00:30.000 -t 00:00:05.000 -c:v copy -c:a copy output.mp4
Argument order matters!
Copy part of video, no re-encode (time-inaccurate but fast seeking)
ffmpeg -ss 00:00:30.000 -i input.mp4 -t 00:00:05.000 -c:v copy -c:a copy output.mp4
Argument order matters!
Re-encode to a format supported by Vegas Pro
ffmpeg -y -i input.mkv -bf 0 -c:v libx264 -c:a aac -strict experimental -tune fastdecode -pix_fmt yuv420p -b:a 192k -ar 48000 -ac 2 output.mp4
Argument order matters!
Change playback rate
ffmpeg -y -i input.mp4 -c:v copy -an -filter:v "setpts=0.01*PTS" output.mp4
Rate change is 1/N where N is 0.01 in the example. This example thus outputs at 100x speed.
Re-encode to a sensible size/bitrate for YouTube
ffmpeg -i input.mp4 -c:v libx264 -crf 18 -g 30 -bf 2 -profile:v high -pix_fmt yuv420p -movflags faststart -c:a aac -b:a 384k -profile:a aac_low output.mp4
Also enables fast start (moov atom at start).
Merge multiple audio tracks into a single track
ffmpeg -i input.mp4 -c:v copy -c:a aac -filter_complex "[0:a:0][0:a:1]amerge=inputs=2[a]" -map "0:v:0" -map "[a]" output.mp4
