1.4 GStreamer and the Black Sheep GL plugins

[Matthew Waters]

On 29/07/14 22:32, Lasse Laursen wrote:
> Dear other Gstreamer devels,
>
> First of all - congrats on making a 1.4.0 release. I much appreciate
> all the hard work you chaps and chapettes are putting into this fine
> SDK! I'm putting GStreamer to work in my project for the past year,
> and I hope to really ramp up its work load in the coming weeks.
>
> Now - I know it's not really polite conversation to refer to the
> black-sheep bad plugins, but since I'm not really whining and moaning
> about quality I thought it might still be ok... If I've understood
> things correctly, there is a real glimagesink available which should
> work in some shape or form, ready for me to pipe the result of a
> gstreamer pipeline directly into a part of an OpenGL window, correct?

"a part of an OpenGL window" could mean a couple of things.

The GstVideoOverlay use case where you have a window handle that you
want the sink's output to be displayed into.  In the background, this
occurs using window system specific functionality and is supported by
glimagesink.

The other use case specific to GL is if you want to use the GL video
texture in your already existing OpenGL scene.  There are a couple of
options available here:
1. the "client-draw" signal of glimagesink.
2. appsink
3. fakesink's "handoff" signal
4. write your own?

> Even if the answer is yes - would there be any other
> proper/concievable way of doing this without the use of a generic
> appsink that then just manually copies the data into an OpenGL texture?

More context?

There are other elements beside glimagesink that do other operations
with GL.  glcolorscale will convert between formats and upload/download
to/from GL for you based on the caps on either side as will all of the
other gl elements in gst-plugins-bad.  There's also a glfilter element
that will transform the video stream using a user supplied GLSL program.

There's also a library that can upload and convert between different
video formats using GLSL.

> I looked deeper into this half a year ago, and thought I remembered
> seeing some tutorials about letting Gstreamer own a small portion in a
> windows windo, and letting it do its thing, but I've not been able to
> come up with anything while I searched today. Is it even possible to
> to pipe gStreamers output directly into a window it does not itself
> create, without the use of an appsink or the likes?
>
> Regards,
> Lasse
>