[FFmpeg-devel] GSOC update on the CDXL demuxer

[Michael Niedermayer]

On Tue, Apr 14, 2009 at 09:59:31PM +0200, Reimar D?ffinger wrote:
> On Tue, Apr 14, 2009 at 08:42:53PM +0200, Michael Niedermayer wrote:
> > On Tue, Apr 14, 2009 at 08:19:21PM +0200, Reimar D?ffinger wrote:
> > > On Tue, Apr 14, 2009 at 02:09:36PM -0400, Ronald S. Bultje wrote:
> > > > On Tue, Apr 14, 2009 at 2:02 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> > > > > the format has chunk size and previous chunk size, it has width&height&sample
> > > > > rate per chunk, assuming these dont change you have a shitload of things you
> > > > > can check
> > > > 
> > > > It doesn't have sample rate. Palette size can change since it doesn't
> > > > have to be there.
> > > 
> > > Hm, I just noticed the current demuxer doesn't handle that...
> > > It might complicate things a bit for the video support.
> > > Does anyone know if it's allowed to mix different encoding methods in a
> > > CDXL file?
> > > 
> > > > All I can think of is matching w/h or prev size to
> > > > current size, but that requires two packets, which is much more than
> > > > the max probe size that we use right now. Chunks are >10kb. Probe size
> > > > is 4kb, IIRC.
> > > 
> > > Probe size is whatever the application provides. 32kB for MPlayer,
> > > FFmpeg I think increases probe size if it does not get a match but I do
> > > not know the limit.
> > 
> > the probe buffer size increasing is done in av_open_input_file()
> > if mplayer limits that somehow, this is a bug in mplayer ...
> 
> MPlayer uses av_probe_input_format, also 1 MB is a lot if the input is
> e.g. a stream via some slow network connection. That's no problem for
> FFmpeg, after all if it tries to read that much it wouldn't work at all
> otherwise, but for MPlayer there might be a native demuxer that handles
> the format, and prereading 1MB for nothing is not reasonable.

but mplayer could retry with a larger buffer if it didnt detect anything
with a smaller one ... (maybe excluding the less reliable detections)

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Frequently ignored awnser#1 FFmpeg bugs should be sent to our bugtracker. User
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