Billy Biggs wrote: > > Mark Vojkovich ([EMAIL PROTECTED]): Thanks, both of you, for your comments. My server still dies, but I'm feeling a little more confident now.
> > On Mon, 4 Feb 2002, Steve Kirkendall wrote: > > > > I'd be surprised if a voodoo card could do 2048x2048. It's one of the > > worst overlay hardware. Doesn't seem to do the correct YUV->RGB > > colorspace conversion either (ie. not CCIR601). > > Arguably we shouldn't be using the 601 transfer functions anyway, we > should use the ITU-R BT.709 ones instead since CRTs are likely closer to > the HDTV standard. I'd also add that MPEG2 video actually specifies the > 709 transfer function (those mmx'ified yuv2rgb routines everywhere are > usually doing the outdated transfer). > > Do you know what conversion they are using? I tried both, and 709 looks a lot better than 601. My XMMS plugin starts with an RGB image intended for a window, and converts it to a YUV image just so I can use the XVideo scaling hardware. I can toggle between windowed RGB and full-screen YUV with a single keystroke, so color differences are easy to spot. 601 conversion resulted in an objectionable amount of color drift. 709 still has some trouble with shades of magenta, but other than that it looks very good. So... Do you think this is just a quirk of the Voodoo3 card? If 601 would look better on other cards, then it might be worthwhile to add an option for selecting the conversion formula. Or does XVideo have some flag tucked in the XvFormatInfo struct to indicate the conversion rule, so I can automatically choose the correct conversion? _______________________________________________ Xpert mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/xpert
