ffmpeg

One of my favorite pieces of software. I always enjoy solving problems with ffmpeg, no matter how annoying they could be.

Resources

https://trac.ffmpeg.org/wiki
- This is a good start
https://ffmpeg.org/documentation.html
- Valuable resource once you start to get the basics of how the ffmpeg cli works.

Some ffmpeg options are just aliases, and thus do the same thing. I use the specific aliases in the examples either out of habit or they are easier to type. The aliases don't have to be used. A couple of examples are

-vcodec is an alias for -codec:v. -acodec is an alias for -codec:a
-vf is an alias for -filter:v. -af is an alias for -filter:a

However some aliases are obsolete and should not be used. An example is -vframes, which should not be used and -frames:v should be used instead.

Tricks

Simple way to disable audio

Disable audio with -an. Useful for reducing file size when audio is not needed, like for setting a video wallpaper as a desktop background.

ffmpeg -i in.mp4 -c copy -an out.mp4

Resources:

https://ffmpeg.org/ffmpeg.html#Audio-Options

Scale a Video

ffmpeg -i in.mp4 -vf "scale:-1:1080" -vcodec libx264 -acodec copy out.mp4

The -1 will automatically choose a value such that it preserves the input video aspect ratio.

Alternatively, you can use -s as an output option, which will place the scale filter at the end of the filtergraph. I personally prefer placing the scale filter in manually.

ffmpeg -i in.mp4 -vcodec libx264 -acodec copy -s 1920x1080 out.mp4

References:

Mute sections of a video

# This mutes the audio from 0 seconds to 10 seconds and
# from 20 seconds to 30 seconds
ffmpeg -i in.mp4 \
    -af "volume=0:enable='between(t, 0, 10)', volume=0:enable='between(t, 20, 30)'" \
    -vcodec libx264 \
    -acodec aac \
    out.mp4