ffmpeg.md (1318B)
1 # ffmpeg 2 3 ### extract audio from video 4 ``` 5 ffmpeg -i input-video.mkv -q:a 0 -map a output-audio.mp3 6 ``` 7 8 ### remove audio from a video 9 ``` 10 ffmpeg -i video.mkv -c copy -an video-nosound.mkv 11 ``` 12 13 ### record a video 14 without audio 15 ``` 16 ffmpeg -f x11grab -r 15 -i :0.0 -acodec libmp3lame -vcodec mpeg4 -ar 48000 -qscale 0 -framerate 24 outputvideo.avi 17 ``` 18 19 with audio 20 ``` 21 ffmpeg -f alsa -ac 2 -i alsa -f x11grab -r 15 -i :0.0 -acodec libmp3lame -vcodec mpeg4 -ar 48000 -qscale 0 -framerate 24 outputvideo.avi 22 ``` 23 24 ### convert video format 25 ``` 26 ffmpeg -i videofile.mp4 videofile.webm 27 ``` 28 29 ### adjust crf 30 adjust constant rate factor to lower bit rate 31 ``` 32 ffmpeg -i input.mp4 -vcodec libx264 -crf 20 output.mp4 33 ``` 34 35 ### remove id3 tag image and metadata from audio file 36 ``` 37 ffmpeg -i input.mp3 -vn -codec:a copy -map_metadata -1 output.mp3 38 ``` 39 40 ### trim start and end of video file 41 ``` 42 ffmpeg -i input.mp4 -ss 00:00:10 -to 01:23:14 -async 1 -c copy output.mp4 43 ``` 44 45 ### rotate video 46 * 90° clockwise - increase transpose number for greater rotation 47 ``` 48 ffmpeg -i input.mp3 -vf "transpose=1" output.mp4 49 ``` 50 51 52 ## firefox corrupt file 53 firefox complains about videos recorded with `ffmpeg`, saying they are corrupt. apparently using the following options fixes this (mentioned by seninha in #nixers irc) 54 ``` 55 -vf format=yuv420p 56 ```