2.9 KiB
Basics
ffmpeg -i [input file] output_file.mkv
The input file might be a device, such as a camera.
Play video:
ffplay file.mp4
#Record screen Take the format as 'grab the x11 screen'.
ffmpeg -f x11grab -s [screensize] -i :0.0 out.mkv
Get screensize with
xrandr -q
or maybe just...
ffmpeg -f x11grab -s "$(xdpyinfo | grep dimensions | awk '{print $2}')" -i :1.0 out.mkv
#Add default pulse audio
ffmpeg -f x11grab -s [screensize] -i :0.0 -f alsa -i default out.mkv
For problems, see pavucontrol.
Random online suggestion
ffmpeg -video_size "$(xdpyinfo | grep dimensions | awk '{print $2}')" -f x11grab -i :0.0 -f pulse -ac 2 -i default ~/out.mkv
Rotate
ffmpeg -i in.mov -vf "transpose=1" out.mov
0 = 90 Counterclockwise and verfical flip (default) 1 = 90 Clockwise 2 = 90 CounterClockwise 3 = 90Clockwise and vertical flip
Lower Video Quality
A crf quality of 18 is high, while 24 is low quality.
ffmpeg -i input.mp4 -vcodec libx264 -crf 20 output.mp4
convert
Check for supported formats:
ffmpeg -formats
To convert from mkv to mp4 we can use a codec rather than proper conversion. Both are wrappers around other formats, so this conversion loses less quality than other conversion types.
ffmpeg -i LostInTranslation.mkv -codec copy LostInTranslation.mp4
Opus to mp3
ffmpeg -i song.opus song.mp3
ffmpeg -i video.flv video.mpeg
ffmpeg -i input.webm -qscale 0 output.mp4
Video to Audio
ffmpeg -i input.mp4 -vn output.mp3
Convert all mkv files to mp4
for i in *.mkv; do
> ffmpeg -i "$i" -codec copy "${i%.*}.mp4"
done
Change resolution
ffmpeg -i input.mp4 -filter:v scale=1280:720 -c:a copy output.mp4
Or just crop:
ffmpeg -i input.mp4 -filter:v "crop=w:h:x:y" output.mp4
Or aspect ratio:
ffmpeg -i input.mp4 -aspect 16:9 output.mp4
Or trim to start and stop times:
ffmpeg -i input.mp4 -ss 00:00:50 -codec copy -t 50 output.mp4
Indicate start times with -ss and time with -t in seconds.
Or split a video into parts:
ffmpeg -i input.mp4 -t 00:00:30 -c copy part1.mp4 -ss 00:00:30 -codec copy part2.mp4
Compress Video
ffmpeg -i input.mp4 -vf scale=1280:-1 -c:v libx264 -preset veryslow -crf 24 output.mp4
Extract Images from Video
-r sets the frame rate, and -f selects the format.
ffmpeg -i input.mp4 -r 1 -f image2 image-%2d.png
Add Images to Audio
$ ffmpeg -loop 1 -i inputimage.jpg -i inputaudio.mp3 -c:v libx264 -c:a aac -strict experimental -b:a 192k -shortest output.mp4
Create a Video from Multiple Parts
First make a text file indicating all the parts, e.g.
file /home/sk/myvideos/part1.mp4
file /home/sk/myvideos/part2.mp4
file /home/sk/myvideos/part3.mp4
file /home/sk/myvideos/part4.mp4
Then join with:
ffmpeg -f concat -i join.txt -c copy output.mp4
Add Subtitles
fmpeg -i input.mp4 -i subtitle.srt -map 0 -map 1 -c copy -c:v libx264 -crf 23 -preset veryfast output.mp4