dynamically audio elements remove issue

[Stefan Sauer]

On 12/11/2011 05:44 AM, Leslie Li wrote:
> Hi all,
>
> I have a pipeline like this:
>
> v4l2src->caps->h264enc->v_tee->
>                                                            qtmux->filesink
> alsasrc->queue->caps->faac->a_tee->
>
> I have set an event_probe on qtmux src pad, if I press stop button on ui, I
> will do the following stuff:
>
> 1. send eos on qtmux video_00 and audio_00 sink pads
> 2. then received a event in event_probe callback, in the callback, I unlink
> v_tee src0 pad from video_00,
>     remove v_tee src0; unlink a_tee src0 from audio_00, remove a_tee src0;
> remove event_probe of qtmux src pad
>     then generate an application message, to wake up application thread
> 3. in application thread, after done step 1, I use a gst_bus_poll on
> pipeline bus to wait for a application message 
>      coming, after get the message, I set qtmux and filesink to NULL state,
> then remove them from pipeline;
>      set pipeline state to PAUSED,
>      set v_tee, h264enc... video elements to NULL state, then remove them
> out of pipeline;
>      set a_tee, alsasrc...audio elements to NULL state, before this step, I
> have checked that v_tee and a_tee  
>      have none src pad on it, but, sometimes, the application thread will
> block forever if I do 
>      gst_element_set_state(alsasrc, GST_STATE_NULL), the same thing happens
> on a_tee or any element in audio 
>      path, but video path are always ok and never get any blocking. This
> happens only sometimes, I guess that the
>      time I press stop button, the alsa path maybe in some special state, so
> it will block.
Try to get backtraces in gdb to see where it stalls when it does. Also
it might be a good idea to make a test-app where you try to simplify it
as much as possible (ideally everything in one file).

Stefan
> my requirement is to make up a multitask pipeline, and it can split
> video/audio encoded stream into rtp and/or qtmux on demand, after talking
> with nice guys in IRC for days, I got the above solution, but the audio path
> seems still having problem with it, any suggestion will be very appreciated,
> and if there is another more effective and reasonable solution, that will be
> great.
>
> Leslie
>
>
> --
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