CELLAR -- Jan 27 1800 UTC

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Agenda / Notes

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👥 Participants (please add yourself as you join)

• Spencer Dawkins
• Robert Sparks
• Martijn van Beurden
• Steve Lhomme
• Jérôme Martinez
• Dave Rice

Regrets:

📣 Note Well

https://www.ietf.org/about/note-well/
Please be KIND to each other.

👀 Previous meeting minutes

• Are any corrections needed to the December interim minutes?
• No corrections on the minutes, so approved on the call.

🔥 Hot Topics

🗣️ Working Group Documents

See https://datatracker.ietf.org/group/cellar/documents/

draft-ietf-cellar-tags

• draft-ietf-cellar-tags-20 is in IESG Evaluation
• Several DISCUSS positions, but Steve thinks he has resolved
  DISCUSSes and COMMENTs from the IESG, except for the question about
  UTF-8 (PR 255)
• As far as we can tell, MATROSKA has ALWAYS used capital letters -
  does "mixed case" mean it's an unofficial tag? Robert says current
  practice is that identifiers are either registered (so there's a
  document that describes what to do with the identifier) or
  unregistered (so there's no description of what to do with the
  identifier, except "don't die when you see it")
• Action: for the working group, this week is our big opportunity to
  comment before Steve submits -21
• Action: Spencer to close with ADs (and with IANA) to make sure
  we have addressed all DISCUSSes and COMMENTs, and then this draft
  will be approved

draft-ietf-cellar-codec

• We JUST got our AD Evaluation for -16 on the mailing list
• Action: Spencer to confirm with Stephan Wegner that the IESG and
  reviewers can get copies of specifications for references in this
  draft (ISO and ITU-T)

draft-ietf-cellar-chapter-codecs

What we said at the previous meeting

• draft-ietf-cellar-chapter-codecs-05 is Expired, but we said we were
  waiting to return to this draft
• Still correct? Yes, we can return to this in 2026

draft-ietf-cellar-ffv1-v4

What we said at the previous meeting

• draft-ietf-cellar-ffv1-v4-22 is Expired - time to submit an update?
• Jérôme has time to work on this in 2026
• Need to resynchronize with implementations
• Need to address ffmpeg ffv1-v4 questions and work on performance
  improvements
• We are working on hardware acceleration for ffv1-v3, and want to
  bring that forward

Errata Reports

Reported errata on EBML

• We have proposed dispositions for Errata ID: 8615 (Suggesting
  Verified) and Errata ID: 8616 (Suggesting Verified, but our AD
  might prefer Held for Document Update)

• (Robert, do you have the action to follow up with Orie?)

• Robert will discuss these with Orie

• We'll talk via email to decide whether we are submitting a document
  that will update RFC 8794, or simply perform update as part of
  Matroska v5 work
• https://www.rfc-editor.org/rfc/rfc8794.html#section-17.1
  The following one-octet Element IDs are RESERVED: 0xFF and 0x80.
• We need to do something formal in order to tell IANA to change the
  registration procedure

Starting on an Internet-Draft for matroska v5

• The Github version of what will become -00 is here
• We do want to make it easier for newcomers to figure out what
  specification/version they need to look at in Github

Discussion about our charter to support v5

• Why does this need to be v5? We don't really use version numbers
  at the protocol level (Matroska does backwards compatibility)
• Matroska does backwards-compatibility, so Matroska version numbers
  don't mean what version numbers mean in many protocols at the IETF
• We haven't been using Matroska extension documents for very long -
  before, there was one big document that defined Matroska v2, etc.
• v5 really is more of a feature set than a version number
• We do need to make a decision about whether we would make changes
  that are NOT backward-compatible in v5.
• Robert will look for similar uses of XML container versioning with
  other groups
• Robert also needs a strong motivation for why IETF is the right
  place to do a Matroska v5
• Martijn pointed out that rechartering would also provide a home for
  any FLAC extensions

Request for guidance on registering Audio Vivid 3D audio codec for use with Matroska

• Spencer forwarded this request to the mailing list here
• Action: Steve will propose text for a reply to the request, so
  that the working group can assist with that.

Next meeting dates

| Meeting | Date |
|----------
| interim-2026-cellar-02 | 2026-02-24 |
| interim-2026-cellar-03 | 2026-04-28 |
| interim-2026-cellar-04 | 2026-05-26 |
| interim-2026-cellar-05 | 2026-06-23 |
| interim-2026-cellar-06 | 2026-08-25 |
| interim-2026-cellar-07 | 2026-09-22 |
| interim-2026-cellar-08 | 2026-10-27 |
| interim-2026-cellar-09 | 2026-12-08 |