rrubio wrote: > > We are currently using a Hauppauge ImpactVCB card for display & capture > in our next generation Pencil Tester. Using the 6.4 bttv drivers for > Linux, I'm seeing 4-5 black pixels at either end of the scanline on both > a displayed and captured image. The desire is to display and capture a > 640x480 image. It appears that image scaling is off since we do get 640 > pixels horizontally, yet it looks as if it encompasses some of the > blanking interval. I tried the card in an NT box with the Hauppauge > supplied drivers for NT and there are no extra black pixels on capture. > I emphasize the "capture" portion as I don't believe this to be a > graphics card issue which I know has caused some headaches for others. > The question then is, has this been observed before? Is there a fix? > Are there any utilities available that would allow us to poke at the > registers on the Conexant chip? The guys at Hauppauge haven't played > with Linux enough to help out. Any offerings would be greatly > appreciated. > > Rick Rubio > Dreamworks SKG I have done a fair amount of comparative testing between the windows/linux drivers to try and get the timing right. What I have discovered, is that the Linux drivers are correct, while the Windows drivers crop the image (top and bottom, left and right). The windows operation therefore more closely matches a real TV, in that the borders are cut off (including any blank strips on the edges), while the Linux driver displays the entire active area of the image (which occasionally has these black strips on the sides). The ideal fix to this "problem" would be to add a "crop" switch to the bttv driver to automatically crop the image. There is a Windows program (Bt848_are, or something like that) that has been posted to the list, so if you look around the archives, you should be able to find it. This will allow you to display the register values Windows uses. If you look at the function bt848_set_geo in bttv-driver.c, you can see how the Linux driver calculates its values (a method very similar to the one in the datasheet), and change it to meet your needs. If you do make a new version of bttv-driver.c, please send it to the list so that it can be added as a driver switch! Thanks -justin
