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Re: [webrtc-pc] setCodecPreferences contradicts JSEP wrt answer codec list being a subset?

From: Taylor Brandstetter via GitHub <sysbot+gh@w3.org>
Date: Fri, 20 Apr 2018 22:04:30 +0000
To: public-webrtc-logs@w3.org
Message-ID: <issue_comment.created-383234588-1524261869-sysbot+gh@w3.org>
The paragraph you quoted is just saying "IF you add new formats, they must be added at the end, so as to not cause codecs to switch unintentionally." For example:

Offer: A B C
Answer: B C (A wasn't available for whatever reason)
New offer: A B C
New answer: B C A (so other side will continue to send using codec B by default, but MAY switch to A)

The contradiction is actually here:

> In either case, the media formats in the answer MUST include at least one format that is present in the offer, but MAY include formats that are locally supported but not present in the offer, as mentioned in [RFC3264], Section 6.1.

It's a MAY, not a MUST. I suggest clarifying the note but not removing it completely, since I believe most people do plan to enforce the "subset" restriction, which is a SHOULD in RFC3264.

GitHub Notification of comment by taylor-b
Please view or discuss this issue at https://github.com/w3c/webrtc-pc/issues/1838#issuecomment-383234588 using your GitHub account
Received on Friday, 20 April 2018 22:04:36 UTC

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