[gst-devel] Dynamic pipelines

[Sébastien Moutte]

Hi Martin,

I already have this kind of discontinuities with a pipeline which has an 
audio playback bin (queue ! decoder ! audioconvert ! directsoundsink) 
that i was adding and removing from the main pipeline.
after reconnections, i was getting a silence of a few seconds and next 
the sound was coming back.
I think your message "resync after discont with previous sample " could 
come from the ring buffer of the audio sink base class.
You can try to disable synchronization on the audio sink by setting the 
"sync" property to false, it worked for me.

I hope it will help ...
Sebastien

Martin Rubli a écrit :
> Hi,
>
> Given the number of replies I have received (zero ;-), dynamically  
> changing pipelines at play time doesn't seem very popular ...
>
> Has anyone tried this before and got it to work properly? If so, I'd be  
> very grateful for sample code to compare it with mine, so that I know  
> whether my code is wrong or whether I should file a bug against GStreamer.
>
> Thanks!
> Martin
>
>
> On Thu, 25 May 2006 16:02:42 -0700, Martin Rubli  
> <martin_rubli at logitech.com> wrote:
>
>   
>> Hi all,
>>
>> I've been doing some tests with dynamic insertion and removal of  
>> plug-ins.
>>
>> The program I've been using is based on section 17.3 of the Application
>> Development Manual. (BTW: The sample given on that page needs a few
>> changes to work with GStreamer 0.10.)
>>
>> I have tried different scenarios. In each case the pipeline looks
>> something like this and is automatically created. (Using an .ogg file  
>> here
>> but the same thing happens with other audio sources.)
>>
>> filesrc ! oggdemux ! vorbisdec ! audioresample ! audioconvert ! FilterBin
>> ! alsasink
>>
>> The FilterBin is a bin that contains one of the following (defined at
>> compile time):
>> a) identity
>> b) audioresample ! audio/x-raw-int ! identity
>> c) audioresample ! audio/x-raw-int, rate=48000 ! identity
>> d) audioresample ! audio/x-raw-int, rate=8000 ! identity
>>
>> Every 5 seconds the FilterBin is taken out of the pipeline or put back  
>> in,
>> so that e.g. in case d) the audio should toggle between normal and pretty
>> bad quality.
>>
>> The problem is that the behavior is somewhat random for some of the  
>> cases.
>> For cases a and b it works consistently well (audioresample should be a
>> no-op). In cases c and d, however, I sometimes get interruptions of a
>> couple of seconds and the debug log gives lines like:
>>
>> <AlsaSink> resync after discont with previous sample of diff: 425761
>>
>> My questions now: Where do these discontinuities come from and what can I
>> do about it? Are there any more programs out there that do the same  
>> thing?
>>
>> Different variations of changing the pipeline state during the
>> insertion/removal phase didn't help either. The test code is attached.
>>
>> I'd be grateful for any tips ... Cheers,
>> Martin
>>     
>
>
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