ffmpeg is a multimedia framework used to record, convert, and stream audio and video.

# Convert between filetypes
$ ffmpeg -i input.mp4 output.avi

Useful Options / Examples

$ ffmpeg -i input.mp4 output.avi

A simple command to convert from one encoding format to another.

$ ffmpeg -i input.mp3 output.wav

The same as above, but with audio instead of video.

$ ffmpeg -i input.avi -r 24 output.avi

the -r flag specifies the desired output framerate in fps. This example is converting whatever framerate input.avi is to a 24fps .avi output.

$ ffmpeg -i input.mp4 -vf fps=1/60 screenshot%d.png

This gets stills of a .mp4 every second and call them screenshot[NUM].png. It stores them in the current directory.

$ ffmpeg -f image2 -pattern_type glob -framerate 12 -i 'still-*.jpeg' -s WxH output.avi

Alternatively, you can turn a bunch of images that you have into a video. Here image2 is a required format, a 12 fps video output.avi is being created from all images that follow the file naming pattern still-*.jpeg.

$ ffmpeg -i input.mp4 -ss 00:00:25 -codec copy -t 40 output.mp4

This cuts the video file into a clip. The -ss tells it the starting time, here 25 seconds, and the -t tells it how much of the clip you want, so here 40 seconds.

This can also work to split the whole file into multiple smaller files as shown below.

$ ffmpeg -i input.mp4 -t 00:00:41 -c copy part1.mp4 -ss 00:00:59 -codec copy part2.mp4

In this case -t 00:00:41 shows a part that is created from the start of the video to the 41st second of video. -ss 00:00:59 shows the starting time stamp for the video. It means that the 2nd part will start from the 59th second and will continue up to the end of the original file.

You can also join various video/audio files together.

$ ffmpeg -f concat -i file-list.txt -c copy output.mp4

where file-list.txt is a list of files with the same codec that are to be joined together, eg.

file '/Users/USER_NAME/Documents/movie_parts/part1.mp4'
file '/Users/USER_NAME/Documents/movie_parts/part2.mp4'
file '/Users/USER_NAME/Documents/movie_parts/part3.mp4'
file '/Users/USER_NAME/Documents/movie_parts/part4.mp4'