Gunther Mayer wrote: > > Hi, > > the 1st line of the tv picture is constantly dashed here, e.g. > - - - -- - -- -- - - -- -- ---------------------- > > This is a cosmetic problem but nevertheless annoying ! > I think this problem existed since the early days of bttv. > > Do others see this artefact, too? > Any clueful hints on causes for this? > > Regards, Gunther > > P.S. > Further data/Kind-of-Workaround: > When switching to "grabdisplay" in the default size 384x288 > the line is fine (and the pictures increases sligtly in size, > both horizontal and vertical) ! > > This does not help as soon as vsize>288, so this could be > a subtle scaling problem in the BTTV-Risc code or similar? > > Side note: With "grabdisplay" unfortunately the last line is wrong:-( > | ------------------- | > > The artefacts combination depends on the tv channel selected: > RTL (CH60) in the only channel without artefacts, here! I am pretty sure the operation of bttv is correct. The problem comes in, because bttv will capture the ENTIRE video image (including the half-line scans). Many broadcasters transmit some information (looks like a timestamp to me) in the first half of the first visible display line, and this is probably what you are seeing. Analog TVs cut off the top, bottom, and borders of the visible image, so you don't usually see this. -justin
