> > What exactly is bad with the v4l2 specs? There is a detailed > > description of all formats at http://www.thedirks.org/v4l2/v4l2fmt.htm > > > > Gerd > > Gerd, you are correct that they are documented very well. I was > complaining about the fact that the definitions for the V4l2 pixel > formats have very little to in common with the way that the xvideo > extensions defines them. Since it is at least somewhat logical to > display captured video using xvideo, it would be nice if there was a > bit of linking. pixelformat actually is a fourcc too (check the header file). I don't know where they come from. Bill? > And this may be pie in the sky, because I don't know about how dma > transfers work and the such, but it would be super sweet if you could > get shared memory from X windows to use with the xvideo extension, > and then get the capture card to capture straight to those buffers. > I realize that it would only cut out a little bit (one memcpy per > display), but it would still be sweet. Would that be possible? Depends. First, the hardware must be able to provide the ximage format wanted in hardware (chances are good with bttv). Second, the piece of memory you want to capture to must be DMA-able. bttv 0.8.x tries to do zerocopy reads, i.e. you can pass the shm segment pointer to read() syscall. Gerd -- #include </dev/tty>
