Adding &meshcastcodec to the publisher's side together with &meshcast gives the option to change the publishing codec for Meshcast.
Example usage: https://vdo.ninja/?meshcast&meshcastcodec=vp9
There's 4 codec options currently, including the default option:
The unspecified default, which is software h264.
There's also h264, which is what the browser then sets. This could include hardware encoding, but that will not work with Firefox or Safari viewers then.
vp8 is pretty compatible, so if the default codec doesn't work, you can try that.
vp9 is also available, which has better compression/quality, but not fully compatible with all devices.
av1 and svc are not yet supported, but that is planned at some point.
