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S4-260222 / TSGS4_135_India / 10.4 / Qualcomm Inc. / CR on correction to animation samples transport
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S4-260222

CR on correction to animation samples transport

Source: Qualcomm Inc.
Meeting: TSGS4_135_India
Agenda Item: 10.4

All Metadata
Agenda item description Release 19 and earlier matters
Doc type CR
Secretary remarks Source modified on 2/3/2026. Original source : Qualcomm Atheros, Inc.
Release Rel-19
Specification 26.264
Version 19.1.0
Related WIs AvCall-MED
CR number 17.0
CR category F
Clauses affected 6.2, 6.3.2
download_url Download Original
CN True
CR 17.0
ME True
Spec 26.264
Type CR
Contact Imed Bouazizi
Uploaded 2026-02-03T21:49:01.353000
Contact ID 84417
Revised to S4-260433
TDoc Status revised
Clauses Affected 6.2, 6.3.2
Reservation date 03/02/2026 19:44:24
Secretary Remarks Source modified on 2/3/2026. Original source : Qualcomm Atheros, Inc.
Agenda item sort order 51
Review Comments
manager - 2026-02-09 09:09


  1. [Technical] The new “3gpp-ar-animation” data channel definition lacks a normative mapping to WebRTC/RTCDataChannel payload type expectations (binary vs text) and does not explicitly state that messages are sent as binary (e.g., “binary message” / “application/octet-stream”), which is essential to avoid implementations still treating payloads as UTF-8 text.




  2. [Technical] The CR removes the JSON “message type” and subtype structure (facial/joint/landmark/audio/video) but does not replace it with any in-band or out-of-band mechanism to identify the animation sample type/stream, risking ambiguity when multiple ARF sample kinds exist or when multiple animation streams are used concurrently.




  3. [Technical] “Each message contains exactly one ARF animation sample” is underspecified without defining framing rules relative to ARF (TS 26.565 clause 8): if an ARF sample can exceed SCTP message size/MTU, fragmentation/reassembly behavior and any maximum message size constraints should be specified to ensure interoperability.




  4. [Technical] The reliability guidance is inconsistent/weakly normative (“should be reliable by default” + “may negotiate partial reliability”); the spec should clearly state default ordered/reliability parameters and the required behavior when endpoints do not support partial reliability, otherwise different defaults will break interop.




  5. [Technical] The SDP example uses a=dcmap with ordered max-time=150 but the CR does not specify the full required dcmap parameter set (e.g., whether ordered is mandatory, whether max-time/max-retr are mutually exclusive, and what to do if both are offered), leaving negotiation behavior unclear.




  6. [Technical] The statement that the animation channel “shall only carry avatar animation samples” conflicts with the retained “stopped/resumed” control messages remaining on the metadata channel; if control needs tight synchronization with samples, the CR should justify why control is not on the same channel or define correlation rules across channels.




  7. [Technical] The CR introduces a new subprotocol identifier but does not address backward compatibility/interworking with Rel-19 implementations that followed the previous JSON/base64 approach; at minimum, it should specify how an endpoint detects peer support and what fallback behavior is permitted/forbidden.




  8. [Technical] The new channel purpose references “ARF avatar animation samples (clause 8 of TS 26.565)” but does not normatively constrain codec/profile/versioning of ARF samples or how version mismatches are handled, which was previously partially handled via typed JSON structures.




  9. [Technical] Removing the JSON payload object also removes any explicit timestamping/sequence metadata that may have been present or implied; the CR should confirm whether timing/ordering is entirely derived from ARF sample contents and what happens if ARF does not carry sufficient timing for playout.




  10. [Technical] The CR says “No compression scheme defined for animation samples” but does not clarify whether ARF samples may already be compressed or whether additional compression is prohibited; this can lead to incompatible assumptions about payload processing.




  11. [Editorial] Clause references are potentially inconsistent: the CR claims changes in “Clause 6.3.2” and deletion of “Table 6.3-1” while retaining “Table 6.3-2/6.3-3”; ensure numbering and cross-references in TS 26.264 remain correct after deletions/additions.




  12. [Editorial] The wording “metadata data channel … shall not be used to transport ARF avatar animation samples” should be aligned with existing 3GPP normative language and scope (e.g., “AR-MTSI client shall not…”), otherwise it may read as a general prohibition beyond the spec’s intended applicability.




  13. [Editorial] The CR summary asserts the metadata channel is “defined as text-only UTF-8 JSON”; if TS 26.264 currently defines it that strictly, cite the exact normative text being corrected—otherwise the CR should adjust the rationale to match the actual spec wording to avoid overstating the error.



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