av1 codec sdp syntax change some case

[ilpyoung]

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Hi

I am trying to use AV1 on m98
AV1 codec of sdp was marked as AV1X.
However, there are cases where it comes in as AV1 depending on the PC.
It might be a change in libwebrtc m98

So janus shows Unsupported codec 'none' and fails to negotiate video

When I change AV1X in sdputils file and utils to AV1, the codec is recognized normally.
Looks like it needs a fix

It may be a problem depending on the version of libwebrtc
It seems that it needs to be modified so that both AV1 and AV1X work.

[fippo]

libwebrtc changed this in M96 as noted in this PSA

[lminiero]

Yeah I read the PSA but forgot to act on it. Supporting both sounds like a pain, so not sure I'll do that. I'll likely end up sticking to the new version, but I'll only decide when I go back to the office after my vacation.

[lminiero]

As anticipated, I just modified the syntax to use the new (and correct) one.