[FFmpeg-devel] [RFC] comment mpegvideo_split

[Michael Niedermayer]

On Fri, Apr 04, 2008 at 02:18:16AM +0100, M?ns Rullg?rd wrote:
> Michael Niedermayer <michaelni at gmx.at> writes:
> 
> > On Thu, Apr 03, 2008 at 11:20:15PM +0100, M?ns Rullg?rd wrote:
> >> Michael Niedermayer <michaelni at gmx.at> writes:
> >> 
> >> > On Thu, Apr 03, 2008 at 11:05:18PM +0200, Baptiste Coudurier wrote:
> >> >> Michael Niedermayer wrote:
> >> >> > On Thu, Apr 03, 2008 at 03:52:19PM +0200, Baptiste Coudurier wrote:
> >> >> > [...]
> >> >> >> FYI:
> >> >> >> ffmpeg -i <file.m2v> -vcodec copy test.nut does not work as is.
> >> >> > 
> >> >> > fixed
> >> >> > 
> >> >> 
> >> >> Hehe yes, though I doubt mplayer using libmpeg2 can decode mpeg2
> >> >> in nut :/
> >> >
> >> > It likely would just need a 2 line change ...
> >> >
> >> > Anyway, maybe we should just disable the mpeg1/2 header split
> >> > thing. Ive read the nut spec again and it only recommands to put
> >> > global headers in
> >> 
> >> MPEG2 does not have global headers.  Splitting the stream like this is
> >> arguably creating an invalid MPEG2 stream.  If Nut wants to store it
> >> in a special way, the Nut demuxer should reassemble it to a compliant
> >> form.
> >
> > If MPEG2 does not have global headers then nut does not say anything
> > about spliting them.
> 
> Then why was something acting as though that were the case?

Because i thought that mpeg1/2 had been well designed and the global parts
seperated. But the sequence header can change thus it does not qualify as
global. Though i must admit that calling it "sequence header" is slightly
wrong, as the quant tables it contains do not apply to the whole sequence.

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In a rich man's house there is no place to spit but his face.
-- Diogenes of Sinope
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