[Spice-devel] [PATCH spice-gtk 1/2] gstreamer: use custom playbin sink

[Snir Sheriber]

Hi,


On 01/04/2018 11:26 AM, Christophe Fergeau wrote:
> On Sun, Dec 31, 2017 at 05:46:24PM +0200, Snir Sheriber wrote:
>> Use custom playbin sink instead of just appsink.
>> In order to allow playbin to choose decoders that requires
>> more complex pipelines (e.g. pipeline that requires color
>> space conversion & uses gl memory).
> What is gstreamer take on that? Are these playbin limitations something
> we have to live with? Are they considered bugs which might be fixed in
> future versions?

I haven't seen bugs related, I'll have another look (i tried to
ask on their irc about that but no reply yet..). but it does
sound plausible that playbin would be able to do that.

>
>> The new sink composed as such:
>> ... ! autovideoconvert ! gldownload ! appsink
> Is autovideoconvert just a passthrough in the non-hardware accelerated
> scenario? Or is this going to add some additional processing of the
> data?

hw decoders are often limited with their output colorspace
and hence it's likely that the element that is using it will be
also limited, for that reason color conversion element is also
likely to be needed.

> I think appsink is needed so that the decoded stream can be used with
> the canvas. Do you expect situations where we are going to hardware
> decode some stream, and then do some compositing using the canvas? Or
> are the streams we want to hardware decode always going to correspond to
> the full display, with no composition to do? In the latter case, I would
> say that we don't even want to use appsink, but just use glsink or
> whatever is appropriate.

Yes, if it's full screen case avoiding the canvas will be much
better.. using glsink or something similar is the next step.

>
> Christophe