[MPlayer-dev-eng] NUT cleanup

[Alexander Strasser]

Hi,
 
Michael Niedermayer wrote:
> 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"

  This would be ok for me too.

> or so, maybe there should be a "N/A" disposition & lang ...

  I don't see why simply ommiting them should cause any problems
if the spec says it is allowed (e.g. muxers accept it).
But perhaps I am missing something.

> >   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

  I changed my oppinion about this and i see it differently now.
After thinking about it again: It should stay as it is now.
  Because it's needed for a typical purpose demuxer to behave
this way to avoid increasing tolerance about those kind of files
and/or further spreading of them.
  Thanks for clearing it up.

  Alex (beastd)