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MPEGGroup / FileFormat

MPEG file format discussions
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Definition of syntax interpretation #42

Open lkondrad opened 2 years ago

lkondrad commented 2 years ago

ISO/IEC 14496-12:4.2 clearly specifies how to interpret the syntax sub-clauses.

The definitions of boxes are given in the syntax description language (SDL) defined in ISO/IEC 14496-1.

In ISO/IEC 14496-15, and probably other derived specifications, there is nothing mention about how to interpret syntax sub-clauses. We just assumed that is the same as for the base specification.

I think it would be good to provide such information explicitly.

edrthomas commented 2 years ago

I agree that a paragraph that makes explicit what the convention is in the current document is better.

By the way, part 12 goes a bit further than just SDL defined ISO/IEC 14496-1. The clause 4.2 you mention defines new types like strings and overloads the interpretation of '=' for instance. So it is almost a new version of SDL defined in part 12.

dwsinger commented 2 years ago

we probably ought to say that we use the SDL as defined in 14496-1, with the additions in 14496-12, and random errors introduced by the editors; in all specs based on 14496-12.

dwsinger commented 2 years ago

let's work out what the extensions are and improve 4.2.1 by at least documenting them

cconcolato commented 2 months ago

Some elements of this issue are addressed in the 8th edition, with some NB comments on the = operator. We should probably close this issue and add a mandate to make all File Format specs SDL-compatible.