add recommendation to use good video compression for videos

[shearer12345]

e.g. winFF, handbrake, youTube's tools, etc

• for submission videos

[Jekks]

Screencast-o-matic automatically converts and compresses files to MP4 if the recording is accepted (though is doesn't record audio).
CamStudio allows exporting to AVI, captures the screen with any external input so editing isn't entirely necessary.