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

From: Philipp Hancke via GitHub <sysbot+gh@w3.org>
Date: Mon, 16 Apr 2018 19:57:45 +0000
To: public-webrtc-logs@w3.org
Message-ID: <issues.opened-314795854-1523908664-sysbot+gh@w3.org>
fippo has just created a new issue for https://github.com/w3c/webrtc-pc:

== setCodecPreferences contradicts JSEP wrt answer codec list being a subset? ==
https://w3c.github.io/webrtc-pc/#dom-rtcrtptransceiver-setcodecpreferences says
```
Note that calls to createAnswer will use only the common subset of these codecs and the codecs that appear in the offer.
```
seems to contradict the last sentence of this paragraph from http://rtcweb-wg.github.io/jsep/#rfc.section.5.3.1
```
Otherwise, the media formats on the m= line MUST be generated in the same order as those offered in the current remote description, excluding any currently unsupported formats. Any currently available media formats that are not present in the current remote description MUST be added after all existing formats.
```
However, this paragraph won't apply when setCodecPreferences has been used as the one before it says
```
If codec preferences have been set for the associated transceiver, media formats MUST be generated in the corresponding order, regardless of what was offered, and MUST exclude any codecs not present in the codec preferences.
```

I think removing that informal "Note" is the way to go.

Please view or discuss this issue at https://github.com/w3c/webrtc-pc/issues/1838 using your GitHub account
Received on Monday, 16 April 2018 19:57:52 UTC

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