Vidiot (brown@xxxxxxxxxxxxxxxxxx): > > Ok, how about that there tends to be a transition from black to > > picture at the beginning and end of every scanline. But ok, I'd > > like someone's opinion on this. Should I provide an option to > > discount them? Like, is the active picture area 4:3 or should i > > just let the whole scanline area be 4:3? You're definitely on the > > way to convincing me to rip out my little bias feature. :) > > OK, here is the spec. I understand that the spec is pretty clear, but I'm wondering about small amounts of error on the sides where there is no picture. Is it worth it for my application to allow for always discounting a few samples on either side of the scanline, and treating what's left as a 4:3 image? You're right that not all of it is error, clearly some black is part of the active line, so I've ripped out my code until I decide what's best to do. > Don't look at a local TV station. If you can, find someone who has a > C-Band sat system, like me, and work with the color bars they use > before feeds, both analog and digital (MPEG-2), to get the best NTSC > standard signal possible. Sure but I do want to watch local TV.. :) > If you can capture line 19 and your local station uses the VIR signal, > then you can use your local station and capture that line. The spec > is referenced from the beginning of the horizontal sync pulse: > > 12 usec - pulse to chroma reference > 24 usec - chroma reference width > 12 usec - luminance reference level > 12 usec - black level reference level > > Chroma reference at 70 IRE, burst size 40 IRE > Luminance reference at 50 IRE > Black level reference at 7.5 IRE > > Hope this helps. Thanks this is a good idea. I'll post some examples tonight if I get a chance. -- Billy Biggs vektor@xxxxxxxxxxxx
