Pull-mode video sink in playback

[Bruce Tsai]

> On Jan 6, 2017, at 5:45 PM, Sebastian Dröge <sebastian at centricular.com> wrote:
> 
> On Fri, 2017-01-06 at 16:14 +0800, Yi-Lung Tsai wrote:
>> There is a function named "activate_pull" in GstBaseSink indicating a
>> sink could be in pull-mode.
>> I wonder is it possible to develop a videosink in pull-mode for
>> playback purpose.
>> If so, is there any example or sample code to do similar tasks?
> 
> In theory that would be possible, but it's completely untested and will
> probably not work without further changes. And most importantly, you
> will need an element in front of your sink that can actually be pulled
> from.
> 
> There were some experiments with that in 0.10 times and audio sinks,
> but not much came out of that because IIRC the advantages were rather
> minimal and did not warrant the added complexity.
> 
> 
> Why would you like to have a pull mode video sink?
> 
> -- 
> Sebastian Dröge, Centricular Ltd · http://www.centricular.com_______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel


Thanks for the information.

We have an existing rendering engine for image and video.
However, it is designed in pull mode, from the view point of pipeline.
I wrote a video sink to integrate push-mode pipeline and pull-mode rendering engine.
This makes things a bit complicated and we suffered performance issue.

Our strategy now is setting render-delay to get video frame earlier in video sink.
Then let rendering engine get the buffer and render the buffer at the right time.
We are still working on it, and meanwhile I tried to find alternatives.
But pull-mode video sink is more complicated than I thought.

--
Yi-Lung (Bruce) Tsai
wagamama.tsai at gmail.com

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