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[128.59.13.25]) by smtp.gmail.com with ESMTPSA id af79cd13be357-79bce91d8b2sm342724785a.80.2024.06.24.12.38.30 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 24 Jun 2024 12:38:31 -0700 (PDT) From: Jonathan Lennox Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3774.600.62\)) Message-Id: <0386AF45-DDCA-4606-9001-54905E69FAF0@8x8.com> Date: Mon, 24 Jun 2024 15:38:14 -0400 To: avt@ietf.org X-Mailer: Apple Mail (2.3774.600.62) Message-ID-Hash: JSSZGWFPMBZ2GL4SJBWOHGU4BQP6PPQ6 X-Message-ID-Hash: JSSZGWFPMBZ2GL4SJBWOHGU4BQP6PPQ6 X-MailFrom: jonathan.lennox@8x8.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-avt.ietf.org-0; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: draft-ietf-avtcore-rtp-v3c@ietf.org X-Mailman-Version: 3.3.9rc4 Precedence: list Subject: =?utf-8?q?=5BAVTCORE=5D_Design_question_about_the_V3C_codec?= List-Id: Audio/Video Transport Core Maintenance Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Hi all =E2=80=94 I=E2=80=99ve 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=E2=80=99s signaling will need = changes. Jonathan Lennox As an individual=