[MPlayer-dev-eng] patch: YUV4MPEG2 demuxer

Alex Beregszaszi alex at naxine.org
Thu Dec 27 13:54:51 CET 2001


Hi,

On Thu, Dec 27, 2001 at 01:50:25PM +0100, Rik Snel wrote:
> Hello,
> 
> On Thu, 27 Dec 2001, Alex Beregszaszi wrote:
> > > > > Scenario: mjpegtools generate header "YUV4MPEG2 BLA BLA BLA\n". The first
> > > > > call to read_stream_char reads the header. (because the rest is not
> > > > > available yet) Some check_fileformat functions want to see more of the
> > > > i've moved detection code upper, so it won't lose the header.
> > > > anyway, -cache option solve your original problem.
> > > It works, thanks. 
> > I hacked the older YUV4MPEG format support into your demuxer, it works
> > fine. You can produce samples with XAWTV.
> Cool, but there is a slight problem if it try to use it with the old
> mjpeg tools:
> 
> 'Slow source' problem again (as above). The YUV4MPEG header is shorter
> than the YUV4MPEG2 header. Only 19 bytes are available (in the beginnig),
> the ASF checker wants more, so the header is lost. The Y4M checker should
> be moved so that it appears before the asf check. (the AVI check
> only takes 8 bytes, so that is okay) (indeed -cache solves
> the problem, but it is not the default)

I think every demuxer should be seek to the beginning after *_file_check,
and than read the header in demux_open too. It would solve the problem.

> 
> Greetings,
> 
> Rik.
> 
> --------
> Nothing is ever a total loss; it can always serve as a bad example.
> 
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--
alex



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