Make rendering default value generally useful
By default video are 720 * 576 with Theora codec, and Sound Mono 8kHz Vorbis in an ogv container. I think it would be better and simpler for the users than by default video are 1920 * 1080 with the VP8 codec, and Sound Stereo 48 kHz Opus all in a Matroska container. It would also be nice to see the codec AV1 supported ;)
I agree with the proposed defaults.