Sometimes vs. On Request Pads on Sink Side of Plugin

[Stefan Kost]

hi,

On 11.04.2011 17:35, Greg Wunder wrote:
>
> In my plug-in sink side, I am attempting to ingest 2 incoming sources.
> I always expect to have data for sink 1, but sink 2 may not always
> have data.
> If sink 2 has valid data, I compare the current frame in sink 1 to the
> data in sink 2.
> If I find matching information, I modify the output of the data from
> sink 1.
>

If there is valid data that is been send to sink2, then there is a
source emitting it. Your app would request a sink2 pad from your element
and link src -> sink.

Stefan

>
> Greg
>
> -----Original Message-----
> From: gstreamer-devel-bounces+gwunder=eoir.com at lists.freedesktop.org
> on behalf of Stefan Kost
> Sent: Mon 4/11/2011 10:27 AM
> To: gstreamer-devel at lists.freedesktop.org
> Subject: Re: Sometimes vs. On Request Pads on Sink Side of Plugin
>
> On 08.04.2011 18:53, Greg Wunder wrote:
> >
> > I could not easily find a plug-in that uses a sometimes pad on the
> > sink side.
> > The closest thing I could find were plug-ins like videomixer or mvemux
> > that use "on request" pads (with & without collections).
> > Is there an example of a plug-in with a sometimes pad on the sink side
> > or is this not proper practice in plug-in development or has it just
> > not been tested/done yet?
> >
> Asking the other way around, what is the example where you think you
> would need it. "Sometimes pads" are data driven and thus appear usual as
> src pads.
>
> Stefan
>
> > Greg
> >
> >
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