I don't know the status of Yuv texture inside ogp, that could be used to reduice bandwith and/or produice a good quality output for video.
I play a bit with pwc the linux drivers for phillips webcam. They clam to deliver yuv 4:2:0 planar. But it's quite hard to find the good matrix parameter. the fourcc website give some of them. mpeg2 YCrCb is yuv with y € [0;1] with value between [16;235] (value came from my memory but you got the idea) and u&v € [-0.5;0.5] with value between [16;239]. But when i look at pwc output Y value goes from 0 to 244. Not even full scale ! So i must change the matrix coordinate to avoid to lose too much quality. I don't know if the mess is the same for all different video capture format. But yuv conversion seems not standard at all. In the fourcc website, a guy speak about using 2.14 fixe format to avoid losing quality. What is provided for OGP ? A fixed function transfer ? I think that a multiplexing manager for 4:4:4 4:2:0 ... should be used followed by a matrix multiply in 2.14 precision at least. The value of the 3x3 matrix should be provided by the drivers. If we choose arbitrary value, it will never be the good one (mpeg 4 avc, does not use the same value than mpeg2, if i remember correctly) Nicolas Boulay _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
