OptionalMaxOptionalMimeDefaults to 'image/jpeg'.
Receives each frame.
OptionalQualityJPEG quality from 0 to 1. Defaults to 0.8. Ignored for PNG.
Frames per second. Pass the rate the inbound video track negotiated; there is no ceiling. An absent, zero, negative or non-finite rate means one frame per second.
Caps the longer side of each frame, in pixels, keeping the aspect ratio. A smaller frame is never enlarged. Defaults to no cap: frames are encoded at the stream's own size.