Dynamic pipelines

[Stirling Westrup]

The secret is to not add any elements to a pipeline that aren't going to be
used by the pipeline. I have a very similar setup in my application and I
ended up creating output bins for the audio and video outputs. Then on a
pad-added signal I insert the needed bin and connect it to the pad.

On EOS, after the pipeline is put into the ready state I pull the two bins
back out of the pipeline in anticipation of the next file to play.



On Mon, May 13, 2013 at 5:05 PM, Jorge Fernandez Monteagudo <
jorgefm at cirsa.com> wrote:

> Hi all!
>
> I have implemented this pipeline by code:
>
> gst-launch-0.10 filesrc location=test.mp4 ! qtdemux name=demux \
>    demux.video_00 ! queue max-size-buffers=2 max-size-time=0
> max-size-bytes=0 ! ffdec_h264 ! xvimagesink \
>    demux.audio_00 ! queue max-size-buffers=8000 max-size-time=0
> max-size-bytes=0 ! faad ! alsasink
>
> When I try to play a 'test.mp4' without audio channel the pipeline is
> frozen. I use the qtdemux callback
> "pad-added" to link the demux with the queues. When no audio channel is
> present no link is made from
> demux and audio queue. The problem is that the elements has been added
> initially to the pipeline but
> they never has data, then they can change to ready or playing state
>
>   // Compose the pipeline.
>   gst_bin_add_many( GST_BIN( pipeline ), filesrc, demux,
>                     video_queue, video_decode, video_sink,
>                     audio_queue, audio_decode, audio_sink, NULL );
>
>   // Link all elements that can be automatically linked because they have
> "Always" pads.
>   if( gst_element_link_many( filesrc, demux, NULL ) != TRUE ||
>       gst_element_link_many( video_queue, video_decode, NULL ) != TRUE ||
>       gst_element_link_many( video_decode, video_sink, NULL ) != TRUE ||
>       gst_element_link_many( audio_queue, audio_decode, NULL ) != TRUE ||
>       gst_element_link_many( audio_decode, audio_sink, NULL ) != TRUE ) {
>     TRACEMSG( "%s - One element could not be linked.\n", __FUNCTION__ );
>     gst_object_unref( pipeline );
>     return NULL;
>   }
>
> I think its a begginer question but how can I solve this? Ideally I would
> like to know if it's
> possible to generate the correct pipeline at runtime? What's the correct
> way to implement this?
>
> Thanks!!
> Jorge
>
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-- 
Stirling Westrup
Programmer, Entrepreneur.
https://www.linkedin.com/e/fpf/77228
http://www.linkedin.com/in/swestrup
http://technaut.livejournal.com
http://sourceforge.net/users/stirlingwestrup
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