Easily capture a good quality webm of a movie clip with ffmpeg.

This simple one-liner will capture a high-quality webm file from a movie.

4.4 Thu May 07 jason@Yog-Sothoth 0: $ ffmpeg -i inputmovie.avi -ss 51:43.02 -t 7 -c:v libvpx -b:v 3200k -an -sn -copyts -threads 4 guns1.webm

This is high-quality capture and is also able to keep the file size as small as possible. The video below is an example of the conversion quality that can be reached with this useful one-liner.

This is great for sharing captures from movies or certain cool scenes from gaming footage. This is a very good tip. This does not capture with sound though.

This example will allow sound. This encodes it as Vorbis audio, a free format.

ffmpeg -i chernobyl.s01e02.720p.webrip.x264-tbs.mkv -c:a libvorbis  -ss 34:56.9 -t 7 -c:v libvpx -b:v 3000k -copyts -threads 4 eel22.webm

Encoding to webm can be very tricky, but it is good when you find a great solution that actually works. Use the -ss 34:56.9 parameter to start recording at the 34:56.9 timestamp. And record for 7 seconds with the -t parameter.