[MPlayer-dev-eng] NUT cleanup

Michael Niedermayer michaelni at gmx.at
Fri Sep 9 02:08:47 CEST 2005


Hi

On Fri, Sep 09, 2005 at 01:44:52AM +0200, Alexander Strasser wrote:
> Hi,
> 
> Oded Shimon wrote:
> > +			Semantic requirements
> > +
> > +If more than one stream of a given stream class is present, each one MUST
> > +have info tags specifying disposition, and if applicable, language.
> > +
> > +A demuxer MUST NOT demux a stream which contains more than one stream, or which
> > +is wrapped in a structure to facilitate more than one stream or otherwise
> > +duplicate the role of a container. any such file is to be considered invalid.
> 
>   While i find the idea of the section good i find it way to strict.
> Or wrongly expressed --- i am not sure...
> 
>   What for example if i remux a file from a different format with multiple
> streams per class but the original file does not contain fields for
> disposition (and/or language). I don't want my muxer to just insert `random'
> valid fields just to be compliant with the nut specification. IMHO that
> would even be backwards with regard to the spirit of the semantic requirements
> section. So I will end up with a invalid nut file.

you (the user) should fill in the disposition (and/or language) for the streams
the muxer should fail if the information is missing
maybe the requirement is good maybe its bad, i dont know (and dont care,
either way is fine with me)


>   There might also be cases with multiple streams per class which don't
> need dispostion at all.

indeed .... maybe we should say someting like "must have ... if applicable"
or so, maybe there should be a "N/A" disposition & lang ...


> 
>   Similar thing but maybe not so important goes for the second paragraph,
> what is wrong with demuxing the suspicious stream `at level 1' for trying
> to repair the sick combination. Ok, it might be nontrivial, but maybe possible.
>   And i think the level 2 demuxing is out of the scope of the nut demuxer anyway.

well the idea is not to forbid repair but forbid silently playing the file
so that idiots cant generate broken files as everone will complain that its
not playable but needs to be "repaired" first

[...]
-- 
Michael




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