[MPlayer-dev-eng] Question regarding MPlayer's OpenGL output

[Reimar Döffinger]

On 20 Oct 2011, at 18:28, Mostapha El-Shafey <mostapha at viionsystems.com> wrote:
>> A RGB texture is 3 times as much data, so it is 3 times slower
>> by that alone. Probably GL_BGR_EXT isn't optimized since nobody
>> (except you) uses it and is another multiple times slower.
> 
> Thanks. That pointed me in the right direction. I'm now using little (10%)
> CPU to display multiple video feeds, which is equal to MPlayer performance.
> The problem was using RGB and BGR (3 bytes per pixel). I now use GL_BGRA and
> have my incoming frames decoded into a 4 bytes per pixel frame instead of a
> 3 bytes per pixel frame and that had a huge effect on performance. CPU usage
> went down from 50% (one CPU core) to less than 10%.

That would indicate that you ended up with a GPU/driver combination that can't use DMA for upload of 3-component textures.
I think that is quite rare though, unless you did not align the line starts...