Re: [Cellar] WGLC draft-ietf-cellar-matroska --- status of this document

[Jerome Martinez <[e-mail]>]

On 09/04/2022 01:50, Michael Richardson wrote:
> Martijn van Beurden <[e-mail]> wrote:
>      > Under 2, Status of this document, it says
>      >> Note that versions 1, 2, and 3 have been finalized. Version 4 is
>      >> currently work in progress. There MAY be further additions to v4.
>
> I think version 3, same as flac.

Issue there is that Matroska v4 brings new stuff good to have in the 
standard.
There is no version upgrade until there is a breaking change, that means 
that v4 is stable there, and that there MAY be additions, and theses 
additions will not break the v4 standard, like a minor version.
Note that this is same for FFV1, FFV1 version 3 has a micro_version 
number (currently 4, numbers 0-3 are reserved for past use) and in the 
future there may be a micro_version 5 which would add new info 
compatible with decoders not aware of the new features.
Actually also like HTTP, version 1 got lot of updates and browsers are 
expected to skip the new HTTP headers, that does not mean that HTTP 1 
should not have been standardized a long time ago.

IMO Matroska standard should include version 4, knowing that version 4 
may receive updates in the future.
Suggestion of wording:

***
Note that versions 1, 2 and 3 are no more maintained, no new elements 
are expected in files with theses version numbers.
Version 4 is the current version, and new elements are expected to be 
defined in the future.
For all versions, a software reading files with unknown elements SHOULD 
ignore them.
***

This would permit a version "4.1" (or "version 4 extension X, or 
whatever else for the naming :) ) compatible with version 4 in the future.

Jérôme