> Adaptor #1: "NV05 Video Blitter" > number of ports: 32 > port base: 104 > operations supported: PutImage > > I can in fact request 32 Xv ports. One of them uses what looks like > chroma key overlay, and the rest seem to be cut in through some > other method. The nvidia stuff is rather proprietary so its hard to be sure. The two things cards normally support are one or more scaled overlays merged by chromakey, colourkey or sometimes bitmask, and in addition some cards have a 'take an image, scale it, colour convert and blit to screen' operation, which means copying each frame from memory to the video card. The video card overlay you normally DMA from the capture card to a surface on the video card which you colour key, so your TV watching requires no CPU at all. The PutImage stuff is really a DVD accelerator.
