Session Date/Time: 24 Oct 2023 19:00

CELLAR

Summary

The CELLAR Working Group meeting focused on the status of documents currently in ISG evaluation, particularly Matroska and FLAC. Key discussions revolved around IANA considerations for FLAC, handling of normative references to external documents like MP4, and addressing specific discuss comments. Updates were also provided on milestones for Matroska's associated documents and a potential errata for FFV1 v0-v3.

Key Discussion Points

Previous Meeting Minutes: The draft minutes from the previous meeting were reviewed. With no objections, they were considered passed.
Document Status (ISG Evaluation):
- The draft-ietf-cellar-tags document has been updated.
- draft-ietf-cellar-matroska has cleared its ISG discuss comments and is ready for submission to the RFC editor.
- draft-ietf-cellar-flac has one remaining discuss comment from Roman.
Milestone Updates:
- A suggestion was made to create a new milestone for "Matroska Associated Documents" to track draft-ietf-cellar-codec, draft-ietf-cellar-tags, and the chapter document (draft-ietf-cellar-chapter).
- Target dates for these new milestones will be revisited once the primary Matroska and FLAC documents are finalized.
Matroska Open Comments: No open comments remain for draft-ietf-cellar-matroska as all previous issues, including those from Elwi, have been addressed. The document is prepared for submission to the RFC Editor.
FLAC IANA Considerations:
- The ISG's preference for an IANA registry over the existing ziv-h.org registry was discussed. The historical lack of maintenance (2009-2016) of the existing registry reinforces the move to IANA.
- The proposed IANA policy is "First Come First Served," aligning with past FLAC practices.
FLAC "Brightly Colored Fish" Entry (Entry 17):
- A discuss comment questioned the meaning of "brightly colored fish" in the FLAC specification's picture types list.
- It was noted that this entry was copied directly from the ID3v2 specification.
- The resolution is to document its origin (ID3v2) and make ID3v2 an informative or normative reference, thereby addressing the comment without needing to explain the specific joke or meaning.
FLAC Normative References and MP4 Encapsulation:
- Roman's discuss comment raised concerns about Section 10 regarding normative behavior on embedding FLAC into other containers.
- Specifically, the document mentions encapsulation into MP4, but the MP4 specification is not freely accessible (costs approximately 98 EUR). This creates a problem for ISG reviewers who may need to read normative references.
- It was suggested to remove the summary text about MP4 encapsulation from the FLAC document to avoid making it a normative reference that relies on a paid external document. Instead, the document would only describe FLAC encapsulation in Matroska and Ogg.
- The existing FLAC-in-MP4 specification would then be an informative reference, acknowledged but not formally specified or reviewed by the IETF in the FLAC document.
- The working group acknowledged that similar issues might have been overlooked in the past (e.g., FFV1 in MP4).
FFV1 v0-v3 Errata:
- Mikel Nida has proposed a patch on the FFMPEG development list addressing a corner case where encoding/decoding is incorrect for odd widths/heights with chroma subsampling in FFV1 v0-v3.
- If accepted, this patch will require an errata for the FFV1 v0-v3 specification.
RFC Publication Order: If FLAC reaches the RFC Editor before Matroska, it will need to wait for Matroska to be published first, as FLAC depends on Matroska. Matroska has already received all necessary ballots for approval.

Decisions and Action Items

Decision: The minutes from the previous meeting were approved with no objections.
Decision: Create a new milestone for "Matroska Associated Documents" to include draft-ietf-cellar-codec, draft-ietf-cellar-tags, and the chapter document. Target dates for this milestone will be set at a later stage.
Action Item: Michael to prepare a GitHub PR for the FLAC document updating the IANA considerations, including the "First Come First Served" policy and referencing Matroska's IANA section as a model. Spencer offered to review.
Action Item: Michael to respond to Roman's discuss comments on FLAC, specifically addressing the "brightly colored fish" entry by documenting its origin in the ID3v2 specification, and addressing the MP4 normative reference issue by removing the MP4 encapsulation summary from the document and making the MP4 specification an informative reference.
Action Item: Spencer to follow up with Murray, the AD, regarding the handling of normative references for FLAC, specifically concerning the MP4 document and the proposed approach of removing its summary text from the FLAC specification.
Note: Michael noted a current personal burnout and house-buying process, which might delay his work on these action items. The chairs acknowledged this and advised against rushing the responses, especially since the documents are in ISG review, where response times can vary.

Next Steps

Michael will proceed with the action items for the FLAC document at his pace.
The working group will await the resolution of ISG discusses and RFC Editor queue processing for Matroska and FLAC.
The next scheduled meeting is December 5th.