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

[franchan]

Hello,

I'm asked to create a gstreamer plug-in using a proprietary h264
decoder library (binary only :-(.
I based myself on the many gstreamer plug-ins.
So implementing this until getting the chain function to work was smooth.

Then now I'm blocked.
The data that is passed from the qtdemuxer into the plug-in's chain function
does not seem to contain any NAL headers or NAL unit.
Can somebody explain what data format the qtdemux outputs?

As a working reference I used this working pipeline:
gst-launch filesrc location=small.mp4 ! qtdemu name demux
demux.VIDEO_00 ! queue ! ffdec_h264 ! ffmpegcolorspace ! xvimagesink

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.

Thanks in advance,
franchan