Live Recorder

Using Firefox ESR version 68? or some other old version? Use version 1.6 of this add-on: https://addons.mozilla.org/en-US/firefox/addon/live-recorder/versions/ and disable auto-updates from the about:addons.

Record audio, video, and canvas elements into webm, in real time.

To try it out:

1. Go to a website with video or audio, like youtube, for example.
2. Hit the addon button and you should see bar (see screenshots).
   • Some websites, like Soundcloud, serve media differently, it won't work on those and the status bar will not appear then.
3. Click the button and it'll start recording. You might see the video start stuttering, but the recording should be fine.
4. Once you hit stop, the recording will be offered to you.
5. Wa la.

ffmpeg -i YOUR_FILE.webm -c:v copy -c:a copy output.webm

If you want to change audio and video codecs, then your go-to option is to use an external program. Here is an example, changing audio codec to vorbis with ffmpeg:

ffmpeg -i input.webm -acodec libvorbis -vcodec copy out.webm