Session Date/Time: 28 Jan 2025 20:00

CELLAR

Summary

The CELLAR Working Group discussed the status of several in-progress drafts (tags-15, codec-14, chapter-codecs-5, control-5), potential errata for the published RFC 9559, and ongoing developments for FFV1 Version 4. Robert Sparks was welcomed as a new co-chair. Key discussions included proceeding with tags-15 to Working Group Last Call, determining the process for registering a historic media type, and addressing unresolved pull requests and referencing issues for other drafts.

Key Discussion Points

Welcome New Co-chair: Robert Sparks joined the CELLAR WG as a co-chair, with Michael St. Johns stepping back due to medical issues.
Previous Meeting Minutes: Minutes from the last meeting were reviewed and approved without comments.
Errata for RFC 9559:
- Discussion around the font/x-otf media type, which is historic and not an official media type. It was agreed that this should be registered with IANA as a historic media type using the standard media type template process, rather than an Errata or new document.
- Two pull requests (PRs 946 and 932) were identified as fixes for RFC 9559. PR 946 addresses underspecified queue time fields, and PR 932 allows more than one attachment link per track. These are considered non-controversial and will be submitted as errata once merged.
draft-ietf-cellar-tags (tags-15):
- The document is largely ready for Working Group Last Call (WGLC).
- A pending item is the potential inclusion of a loudness tag based on ITU EBU R 128. This tag currently lacks definition and input from an expert. It was agreed that tags-15 should proceed to WGLC, and if expert input is received before publication, the tag can be slipped in; otherwise, it can be added in a future document.
draft-ietf-cellar-codec (codec-14):
- Three pull requests were highlighted:
  - PR 937: Addresses an interpretation issue with SMPTE bits. Further review from participants (Steve, Jerome, Dave) is needed.
  - PR 745: Requires rebase due to age.
  - PR 446: Also requires rebase due to age, but the underlying idea remains valid.
- These PRs need to be resolved before codec-14 can proceed to WGLC.
draft-ietf-cellar-chapter-codecs (chapter-codecs-5):
- This document is pending further work, particularly for the Matroska.js JavaScript scripting codec.
- A significant issue is a normative reference to a non-public DVD specification. It was noted that this specification is effectively reverse-engineered in existing implementations, and the DVD Forum is dissolving, potentially releasing the specification. The working group needs to identify a publicly accessible normative reference or explore how reviewers can access the original.
- It was clarified that chapter-codecs-5 is not necessarily tied to the progression of Matroska V5 and can be worked on in parallel.
draft-ietf-cellar-control (control-5):
- This document was taken out of the main Matroska specification due to being underspecified and currently unused. It is not a priority and its future (finalization or dropping) is uncertain.
FFV1 V4 Improvements:
- An update was provided on ongoing work for FFV1 Version 4, including GPU encoder implementation and a work-in-progress GPU decoder.
- Discussions on proposed improvements are taking place on the ffmpeg-devel mailing list. The draft will be updated and published on the IETF datatracker once consensus is reached on these improvements. FFV1 Version 3 is already an RFC.
Matroska V5:
- Matroska V5 was mentioned as the future document for new work and additions, leveraging the modular nature of Matroska and the use of Markdown/XML for generation.

Decisions and Action Items

Decision: The previous meeting minutes were approved.
Decision: draft-ietf-cellar-tags (tags-15) will proceed to Working Group Last Call (WGLC).
Decision: The font/x-otf media type will be registered as a historic media type via the IANA media type registration process.
Action Item 2024-01-26-1 (Spencer): Draft and submit an IANA media type registration for font/x-otf, marking it as historic.
Action Item 2024-01-26-2 (Steve, Jerome): Follow up with GitHub user bb1g for input on the ITU EBU R 128 loudness tag for tags-15.
Action Item 2024-01-26-3 (Steve): Submit errata for RFC 9559 based on the approved and merged PRs 946 and 932.
Action Item 2024-01-26-4 (Steve, Jerome, Dave): Review PR 937 concerning SMPTE bit interpretation for codec-14.
Action Item 2024-01-26-5 (Jerome): Rebase PRs 745 and 446 for codec-14.
Action Item 2024-01-26-6 (Working Group): Investigate a publicly accessible normative reference for the DVD specification or explore liaison options for draft-ietf-cellar-chapter-codecs (chapter-codecs-5).
Action Item 2024-01-26-7 (Michael): Follow up with the IETF Secretariat regarding Robert Sparks' organizational owner status for GitHub and DataTracker access.

Next Steps

The Working Group will focus on:

Initiating Working Group Last Call for draft-ietf-cellar-tags.
Resolving outstanding pull requests for draft-ietf-cellar-codec to prepare it for Working Group Last Call.
Addressing the referencing issue for draft-ietf-cellar-chapter-codecs.
Continuing to monitor and contribute to FFV1 V4 development on the ffmpeg-devel mailing list.
Spencer to progress the font/x-otf IANA registration.