On Sat, 20 Oct 2001, Billy Biggs wrote: > Thanks to the list (specifically Mark and Matt) for all your help > lately. These are the current issues we have with Xv. I'm curious as > to > what coding we can help with, and what is actively being worked on. > > 1) Performance is horrible. All drivers should be using DMA to transfer > images from system memory to video memory. Apparently this is being > done for X 4.2. Which drivers are fixed and which still need work? > > Apparently, some chips can read frames right out of system memory > without copying to video memory at all (rumor says this is true for > i810). Can we improve Xv performance in these cases? > > 2) For interlacing, I like the idea of an XV_FRAME_TYPE attribute: > 0 == frame, 1 == top field, 2 == bottom field. I'm worried about > the DRI API possibly not supporting stride on texture blits (is > this true?) and I'm not sure how to handle this for DMA transfers. > > 3) Xv should be used to expose hardware RGB scaling everywhere, also > with DMA transfers. What cards still need fixing? > > 4) There is no distinction between rendering and display, and > applications have no access to the buffering of frames in video > memory. In order to redraw the screen the entire image must be > re-blit. Consider a user moving the video output window when > displaying a static image. Also we have no way to copy an image to > video memory and then show it later, which could greatly increase > display timing accuracy for high-quality output. A separation, like > what XvMC has, would allow for better quality, much less memory > bandwidth during stills, paused video, and window movement, and > multi-buffering controlled by the application. > > Should we deprecate Xv and move to an XvMC-style API, or would there > be an easy way to add this functionality to Xv? > > It seems to me that Xv maybe should act more like normal XImages. > Why can't the video automatically be respositioned when the window is > positioned? > > 5) Outstanding bugs that I'm aware of in Xv drivers: > - The savage Xv driver fails in 24bpp mode. Is anyone fixing this? > - The i810 driver pukes some bad frames after the size of the input > images changes. (like switch from 720x480 to 704x480 for when > DVD-menus differ from the content). Is this a bug? > > 6) Drivers claim to support modes that the hardware can't actually > optimize. An example is the Savage which claims to support YV12 > although it only supports YUY2. > > 6) libXv.a is only distributed as a non-PIC .a. > > This list taken from discussions on #ogle and #gstreamer on > irc.openprojects.net. > >
_______________________________________________ Xpert mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/xpert
