[gst-devel] what format is exchanged between qtdemux and ffdec_h264

[Jan Schmidt]

On Thu, 2008-10-02 at 16:04 +0300, Felipe Contreras wrote:
> On Thu, Oct 2, 2008 at 10:53 AM, franchan <francis.meyvis at gmail.com> wrote:
> > I dumped some GstBuffer data and I think it is part
> > of the 'mdat' mp4 box for the mp4 container (small.mp4)
> > What is passed to the ffdec_h264 is the same as what it passed to my
> > plug-in wrapper.
> > The proprietary decoder library hints that it does not understand the
> > syntax of the content.
> > I already tried to glue some 00 00 01 NAL prefix in front but
> > this does not solve the problem.
> 
> Aside from raw frames the capabilities are also passed. Parts of the
> capabilities is the codec-data, maybe that's what you want:
> 270000010fc2fe0af08f88800000010e18642bc23c80

The data emerging from qtdemux isn't raw H.264 frames - it's
encapsulated into a packed format for the mp4 container. You need to
read out the NAL units by parsing the codec_data to get some detail
about the bytestream and to extract the SPS and PPS packets.

Check out:

http://www.geocities.com/xhelmboyx/quicktime/formats/mp4-layout.txt

Cheers,
Jan.
-- 
Jan Schmidt <thaytan at noraisin.net>