This may not be the right place to ask, but I have a feeling that the right expertise may well be in this group... The V4L(2) streaming capture to mmap-ed buffers works *great*, excellent performance and very little CPU overhead. However, I'm having less luck at the other side: transferring from system memory to the video card. I can't get X to do DMA transfers; instead, the X server completely clogs up the CPU doing transfers at video rates. (Note that I can't use V4L hardware preview, the images have to be processed). At the advice of an XFree guru (of all people), I tried the nvidia closed-source drivers, as they should have good 2D acceleration. No luck, no DMA. I considered a motherboard with on-board video which shares video and main memory (so that the non-DMA transfers will at least be fast). No luck, there's no XFree support for decent (i.e. recent) chipsets with on-board graphics. As a last alternative, people have suggested that I use OpenGL to transfer images as textures and (hopefully!) get DMA transfers. I'll try that, lacking a better alternative, but I'm not very hopeful. Is there a better way?! Am I missing something? Heeeeeeelp... ;-) - Reinoud
