Preparing video clips

Rencode the video

It makes it lighter and easier to view with VLC (but not with Totem):

ffmpeg -i [input.ogv] [output.webm]

For example:

ffmpeg -i P1.ogv P1.webm

Cut out a video clip from a longer recording

ffmpeg -i [input] -ss [start] -t [duration] -c copy [output]

For example:

ffmpeg -i P4.ogv -ss 25:20 -t 10 -c copy clip.webm

Amplify the audio in a video clip

ffmpeg -i [input] -af "volume=25dB" [output]

For example:

ffmpeg -i clip.webm -af "volume=25dB" clip-amplified.webm

Remove the sound in a video clip

ffmpeg -i [input] -an [output]

For example:

ffmpeg -i clip.webm -an clip-nosound.webm