[webrtc-pc] Confusion over duplicates in setCodecPreferences? Why allow them? (#2955)

jan-ivar has just created a new issue for https://github.com/w3c/webrtc-pc:

== Confusion over duplicates in setCodecPreferences? Why allow them? ==
I spotted a dubious claim in the [setCodecPreferences](https://w3c.github.io/webrtc-pc/#dom-rtcrtptransceiver-setcodecpreferences) algorithm: 
- _"4. Remove any duplicate values in codecs. Start at the back of the list such that the order of the codecs is maintained; the index of the first occurrence of a codec within the list is the same before and after this step."_

The claim about indexes remaining the same seems wrong. E.g. with codecs `[A, A₁, B]` removing `A₁` results in `[A, B]` necessarily altering the index B.*

We should also link "duplicate" to the [codec match](https://w3c.github.io/webrtc-pc/#dfn-codec-match) algorithm.

But why allow duplicates in the first place? This seems to only invite trouble.

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<sub>*) This is implementation language, e.g. c++, operating on infra or WebIDL types, so JS concepts like sparse arrays shouldn't apply.

Please view or discuss this issue at https://github.com/w3c/webrtc-pc/issues/2955 using your GitHub account


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Received on Tuesday, 16 April 2024 22:12:59 UTC