[gst-devel] dspmpeg4sink on maemo

Armando Di Cianno dicianno at obtech.net
Mon May 22 05:46:05 CEST 2006

On May 20, 2006, at 6:29 AM, M M wrote:
> Hi,
> I am trying to receive H263 encoded video streams from  a udpsrc on  
> maemo, but dspmpeg4sink didn't work. I used the following pipeline.
> gst-launch-0.8 udpsrc ! video/x-h263 ! dspmpeg4sink
> and this happens
> RUNNING pipeline . . .
> ERROR: pipeline doesn't want to play.
> I tested a similar pipeline for audio and it works:
> Audio:
> gst-launch-0.8 udpsrc ! dspmp3sink

I had a similar experience.  Audio playback from an mp3 file would  
work with Nokia's proprietary dspmp3sink, but video playback would  
not work with the dspmpeg4sink.  I spent a great deal of time trying  
different gst-launch lines to try to coax video playback.  I came to  
the conclusion that the fact mp3 files play through the mp3 sink is  
just a happy coincidence, while the mpeg4 video sink solely serves  
the osso-media-server that also does some of the video displaying  
work (maybe/probably telling the dspmpeg4sink where and how to draw  
the video).

You should check out KMPlayer for Nokia 770 here: http:// 
www.xs4all.nl/~jjvrieze/ .  I believe the author was the first to  
really inspect the DBUS messaging between the Video Player  
application and the osso-media-server to figure out how to use the  
osso-media-server to get video playback.  You can look at the code  
there (c++ / qt-style), or set up your own inspection of DBUS  
messages for the osso-media-server / video player.  Likely, as I had  
to do, learning DBUS was the hardest part -- the messages/payloads  
are extremely obvious as to their role.

Good luck,
__Armando Di Cianno
dicianno at obtech.net

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