[MPlayer-dev-eng] NUT cleanup

Alexander Strasser eclipse7 at gmx.net
Sat Sep 17 10:16:54 CEST 2005


Alexander Strasser wrote:
> Alexander Strasser wrote:
> > 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.
> >   There might also be cases with multiple streams per class which don't
> > need dispostion at all.
> > 
> >   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.
> > 
> >   I might be wrong or too tired or both, anyway waiting for some comments
> > to correct me in that case.
> 
>   After reading first comments i think this should be discussed a
> bit further. I am in a hurry now.
> 
>   Anyway, i don't mind if it gets commited in this form for now.

  I propose the attached patch which modifies the first paragraph of
semantic requirements section. (I hope it is correct english.)

  Also i think education of NUT users is the best means to get properly
disposition/language tagged streams.
  Rich AFAIK you wanted to write up some introductory NUT material,
maybe you can incorporate a section about disposition and language fields?

  Alex (beastd)
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Index: DOCS/tech/mpcf.txt
===================================================================
RCS file: /cvsroot/mplayer/main/DOCS/tech/mpcf.txt,v
retrieving revision 1.75
diff -u -r1.75 mpcf.txt
--- DOCS/tech/mpcf.txt	17 Sep 2005 05:46:20 -0000	1.75
+++ DOCS/tech/mpcf.txt	17 Sep 2005 08:10:01 -0000
@@ -608,8 +608,9 @@
 
 			Semantic requirements
 
-If more than one stream of a given stream class is present, each one MUST
+If more than one stream of a given stream class is present, each one SHOULD
 have info tags specifying disposition, and if applicable, language.
+It highly improves usability and is therefore strongly encouraged.
 
 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


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