[MPlayer-dev-eng] Re: OpenGL

[malc]

Reimar Döffinger <Reimar.Doeffinger <at> stud.uni-karlsruhe.de> writes:

> 
> Hello,
> On Wed, Sep 06, 2006 at 02:28:39PM +0000, malc wrote:
> > Currently OpenGL video output with hardware yuv2rgb conversion
> > requires 3 texture units. Following is the version that works
> > with 2 TUs and a back-buffer (i.e. works on GeForce2MX here).
> > Perhaps someone could integrate it into existing framework.
> 
> Unfortunately integrating would be quite a bit of work. Do you have any
> numbers concerning the performance advantage over software conversion?
> In tests I did in the past it was rather unconvincing.
> I assume it is possible to use flipping in the last step instead of
> drawing into the front buffer at once?

With a dumb[i.e. no keyboard polling - no nothing actually] (null based)
video output playing 800x800 mpeg4 with -noslices - it's slightly worse
than xv, and faster than x11/gl(without yuv suboption).

And i don't think flipping is at all possible, the first pass does poor
mans render-to-texture (i.e. writes to frame buffer hence requirment for
24 bpp) if that other buffer is the one currently used by GL you will get
funny looking results of U+V in the lower-left corener of the screen.

>From my little research it looks like there are no other methods of
rendering to texture (openglut can create windows with GLUT_OFFSCREEN
flag though, but i haven't played with that).

P.S. Slightly correct version is available at:
     http://www.boblycat.org/~malc/code/patches/mplayer/yuv.c