[gst-devel] gst-plugins-gl, OpenGL and stuff

[Richard Spindler]

Hi,

2008/5/19 KwangYul Seo <kwangyul.seo at gmail.com>:
> Do you have any progress in forming a Linux+Video+OpenGL working group?

Not yet, but I was made aware of a very cool implementation of OpenGL
Color-Space Conversion at

http://yuvtools.wiki.sourceforge.net/

The code is very readable and flexible in regard to different color-formats.

Unfortunately I head some difficulties running this code on my ATI
hardware, due to issues with the handling of non-power-of-2 textures
on ATI Hardware. It works for some video sizes which happen to fit
into that limitation. I think it should work better on nvidia
hardware.

Other than that, I found that the "FreeFrame" Video Filter Plugin
Specification http://freeframe.sf.net/ specifies reusable OpenGL based
image processing algorithms. Eventually something similar should be
possible for "pluggable" colorspace conversion.

Currently I am using the "gavl" library for software colorspace
conversion, which has a rich collection of low-level convertors, and
could serve as a good fallback option for low-end opengl hardware.
This library is a sub-project from http://gmerlin.sf.net/

> Currently I am looking for a colorspace conversion solution implemented
> using OpenGL. It is not hard to find one, but most solutions use high-end
> video card extensions and do not provide any software fallback.

I've been playing around with creating some kind of Abstraction-Layer
for the code from yuvtools, such that it can be easily replaced by an
alternative implementation, but so far I am not quite satisfied with
my work, so I have not yet published anything.

> I think we must build reusable software to do low level tasks such as image
> composition, video mixsing and colorspace conversion which are repeated over
> and over again in constructing various video applications.

I totally agree, and in my opinion the most promising project in that
respect is gmerlin/gavl. I've been in close contact with its lead
developer, and I think it is really great. It is more "low-level" then
gstreamer, but for some types of applications this is actually an
advantage.

Cheers
-Richard



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