sparse audio stream and GAP event

[Wonchul Lee]

Dear sebastian,

Thanks for your reply,
I have one more question.

I try to handle audio stream what has gap in the middle of contents.
We create GAP event when demux meet the gap region in that contents.

However when I try to pause a pipeline in the middle of the gap, then
it never goes to paused state(preroll).
Because there is no audio data for a while, and GAP event is already
consumed at sink.
Demux doesn't care about the pipeline states, so it seems not to
determine send GAP event again or not.
It may need some mechanism for handle it.

So, I am curious about that some of the element already properly can handle it.

Wonchul Lee

2014-10-22 16:37 GMT+09:00 Sebastian Dröge <sebastian at centricular.com>:
> On Mi, 2014-10-22 at 09:33 +0900, Wonchul Lee wrote:
>> Hello,
>>
>> I meet some contents what audio stream is missing at the last part of it.
>> As you know, If I do seek to missing stream position, audio sink never go to preroll status.
>> It means pipeline can not go to PAUSED and PLAYING states because audio sink can not get any buffer.
>>
>> I understand the GAP event is for handling these missing part of the streams.
>> In addition, some of the core and base plugins are already implemented about GAP event.
>>
>> Thus It seems that every demux has a role of detecting the gap in the stream and create the event, although it has not been implemented yet.
>> I just want to know what my thought about it is correct or if you has a general idea for it please let me know.
>
> That's correct, every demuxer has to detect gaps and send the GAP events
> for those... and then the decoders should also do something sensible
> about them, e.g. generating silence. The audio decoder base class should
> do that already but there might be bugs about that.
> And of course the sinks should also pre-roll when they receive a GAP
> event so that the pipeline can go to PLAYING no matter if there's a gap
> or not.
>
> --
> Sebastian Dröge, Centricular Ltd · http://www.centricular.com
>
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