[NUT-devel] codec_specific_data

Michael Niedermayer michaelni at gmx.at
Mon Jul 17 23:43:30 CEST 2006


Hi

each stream has one global header in nut, matroska and avi 
too have exactly one global header APIs like the ones from mplayer 
and ffmpeg and directshow AFAIK are also designed based on a single 
global header

but a very small number of codecs are designed so that they have
several global headers but no standarized way (that i know of) of
converting them to a single header, the "ogg codecs" fall in this
category

several solutions exist:
1. store several headers at nut level
2. leave it unspecified
3. specify how these multi packet codecs should be stored be it in nut.txt
   or in a seperate file

if we do specify how these codecs should be stored then we can either
A. invent our own system (this is for all practical proposes is identical
   to storing them at nut level)
B. borrow the system from another container format


leaving it unspecified will lead to a mess of different systems used by
different muxers

storing them at nut level will need them to be converted to a single
packet format during demuxing and to a multi packet format during nut
muxing in most cases

borrowing another system and using that throughout an application will
lead to the least converting around



-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is



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