[gst-devel] New Plugin: gstdvbsrc

Martin Eikermann eikermann at gmx.net
Mon Jul 14 09:48:53 CEST 2003


Hi *,

I'd like to announce a new plugin (DVB) for gstreamer. Intention of the
plugin is to make use of the DVB-API and thus make it possible to watch
digital TV with the gstreamer framework. Unfortunately I'm a gstreamer
and mpeg2 beginner so that there are still some bugs left which I
haven't been able to fix yet. This is mainly related to A/V synchronisation.

In the dvbsrc-plugin i have the following possibilities to retrive the
TV streams:

     1. It is possible to get seperate Video/Audio PES streams from the
DVB-Driver API, but I had no success in feeding this streams directly to
mpeg2dec(ffdec_mpegvideo)/ mad. Is this sane to try this at all??

     2. Current approach is: Get a transport stream from the Driver-API
and transmux it into a program stream (assimilating mpegtools from
metzlerbros.org) inside the dvbsrc-plugin. This works and the program
stream is then demuxed outside the dvbsrc-plugin by mpegdemux. However
A/V is totally out of sync.


The following questions arose while writing the plugin, hopefully
someone can give me a hint on some of these:

     1. I currently assume that a systemstream (accepted by mpegdemux) is
equivalent to a program stream emmited by dvbsrc. Am I wrong? If so, I'm
wondering what's the difference system stream/program stream.
systemstream == mpeg1; programstream == mpeg2 ??

     2. Does anyone knows a lib or some open source code to transmux a
transport stream to a systemstream.

     3. Is it possible to patch mpeg2dec/mad plugins to accept PES
streams? This would make the plugin much simpler.

     4. What is emmited by mpegdemux (elementry streams)?


Greets
    Martin

P.S.: I've attached the plugin sources, so feel free to comment on that too.

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