Re: [Cellar] On the multiplicity of Info elements

2016-01-11 22:44 GMT+01:00 Timothy B. Terriberry <tterribe@xiph.org>:
> Dave Rice wrote:
>>
>> implementation of this recommendation has been minimal.  To change
>> the SHOULD to a MUST, would invalidate approximately 99.8% of
>> Matroska files and 100% of webm files. I realize that this reason
>
>
> Well, in the IETF (in contrast with the traditional approach of, say, MPEG)
> we are allowed to specify requirements on muxers separately from demuxers.
> So it's perfectly permissible to say a muxer MUST include CRCs while
> simultaneously saying a demuxer MUST be able to read a file without them.
> Then you wouldn't invalidate the existing media, just the existing software
> that produced them.

That sounds like a good way to do it. CRC requirements can only be on
the muxer side, and defined at the semantic level.

> However, if you don't think it's worth trying to force muxers to change
> their implementation (or don't believe that a SHOULD or MUST in a spec will
> actually cause them to change), then perhaps the most appropriate level for
> this requirement is MAY?
>
>> Perhaps the recommendation for CRC-32 usage (in Level 1 Elements and
>> Identically-Recurring Elements) should be removed from the EBML
>> Specification and moved to the Matroska EBML Schema.
>
>
> That might also be reasonable (I hold no strong opinion).

Yes, they should move to the Matroska side of the specs.

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-- 
Steve Lhomme
Matroska association Chairman