Ivor Cox wrote: > > Hi Ben > > I only tried full size, but the effect is that of a grid - but intermittent. > The PCI latency idea seems reasonable as my PC is a bit skinny. > > I am familiar with the effects of interlaced fields - it is definitely more > nasty than that. > > The effect is best described as getting a blotchy image with the blotches in > the correct location and black in the gaps and the blotches fit into small > rectangular zones so that repeated captures on a still scene gradually fill > out the blotches to full rectangles but never completes the picture, leaving > the dark grid. > The horizontal lines get deeper going right at quarter width steps. The > vertical lines are concentrated in the middle two quarter widths and are > pretty constant over the full height. > The rectangles are of the order of 16-32 pixels. Also I capture the whole > image but am only delivering one field in my test. > > Cheers, and thanks for your attention > > Ivor I don't think any P75 came out with a PCI2.1 bus which is a requirement for bt848 cards. I have used a bt848 on a PCI2.0 bus before, but had serious problems with DMA (black lines/dropped data). If you are feeling lucky, you could try the following (in bttv-driver.c): Search for the only occurence of BT848_GPIO_DMA_CTL_PKTP_32 , and replace the _32 with _16 or _8 or _4 . Each of these progressively increase the "greedyness" of the Bt848, and may get you slightly better performance (at the expense of the performance of the rest of the system. -justin
