[AVTCORE] Design question about the V3C codec

Jonathan Lennox <jonathan.lennox@8x8.com> Mon, 24 June 2024 19:38 UTC

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From: Jonathan Lennox <jonathan.lennox@8x8.com>
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Date: Mon, 24 Jun 2024 15:38:14 -0400
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Subject: [AVTCORE] Design question about the V3C codec
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Hi all — I’ve read over the latest V3C codec draft, as I promised at the interim.

My biggest question about the draft is a design question, about how backward compatibility in offer/answer should be supported.

As the draft is currently written, when a V3C-capable offerer sends an offer to a V3C-ignorant answerer, the answerer will ignore the V3C atlas codec and V3C-related parameters, but it can (and likely will) negotiate the video streams as 2D streams without any volumetric component, thus establishing a call with 2D video.

Is this what you want?  Or would you rather define the payload such that a V3C-ignorant answerer will completely ignore the volumetric m-lines, and negotiate something with a cleaner fallback (e.g. audio-only, rejecting the call entirely, etc.)

If the latter is what you want, the codec’s signaling will need changes.

Jonathan Lennox
As an individual