Need advice with using funnel on multi-subtitle stream.

[Tim-Philipp Müller]

On Wed, 2013-08-14 at 15:54 +0900, Wonchul Lee wrote:

Hi,

> I am trying to use funnel when playing multiple internal subtitle
> stream(mkv). I intended to get out of subtitle data from gstreamer and
> treat it on application. Thus I used funnel instead of input-selector
> and link it with appsink.

Out of curiosity - do you really need to get all subs at the same time?
Why? (Instead of one selected one)

> mkvdemux subtitle pad1 \ 
> mkvdemux subtitle pad2 - funnel - appsink
> mkvdemux subtitle pad3 /
> 
> 
> 
> However there was a problem with output caps of funnel.
> Lets assume, the caps of subtitle pad 1 is text/x-raw and subtitle pad
> 2 is application/x-ass.
> Then funnel's srcpad and appsink's sinkpad negotiated with text/x-raw
> mime-type.
> In addition, when get the GstSample data from appsink by using
> pull-sample action,
> The caps info in GstSample is always text/x-raw, even actual data is
> application/x-ass.
> 
> 
> Thus, I pushed a caps event on funnel's srcpad before push the buffer
> data.
> Then I saw the caps info in GstSample is correctly changed.
> However I am not sure that this approach is correct.
> Please give me an advice for it.

I suppose it's correct and required for some use cases, but might be
quite expensive/noisy, if caps change before almost every buffer.

Cheers
 -Tim