hi! I have a serious problem with the BT8x8 chip. I have to grab four channels at the highest framerate. I don't need the full frametrate (25 fps), but I need as high as possible, the higher the better. I looked for this problem in the archive and there was a thread about it but no solution. I use 4 not synced video inputs (PAL). There are two problems: 1. If I change the channel after each field then the BT chip sometimes swaps the top and bottom field. I don't know why. The BT documentation says it determines the top/bottom field from the first HSYNC after the VSYNC rising edge (in phase with the VSYNC or not). I can get the video signal stable if I use a second read and drop the first picture. But the framerate is too low this time. 2. The framerate independently from the stableness is low. 8 fps/channel for two channels. Well there is a Piccolo (Eurosys, using BT chip) card and a windows driver and it can do about 16 fps for two signals and 4-5 for 4 signals (and of course it never swaps fields). So how that card and driver can do it? OK, there is an external muxer for the inputs, so only one input is used of the BT chip. I think this is not a big difference since the muxer in the BT chip is also an "external" device. Does anyone have ideas about it? Why does it swaps fields at all??? thoughts from me: it swaps because the BT chip has an internal sync to correct bad V&HSYNCs, such as VHS video. Because the mux is independent from the chip and when another source is selected it simply follows its internal timer and doesn't care of extra SYNC pulses. Would it help if we reseted the chip after the channel switch? Or simply force the chip resync (if it's possible) I can get fields swapped if I grab full size picture (768x576) in interlaced mode as well. Thx, gabor
