On Mon, 27 Nov 2000, Justin Schoeman wrote: > > The mmap()ed memory area is definitely NOT guaranteed to be user > writable, so this would not be a good idea. So it might be read-only? Is there any reason to make it read-only? > > Also V4L and V4L2 have no concept of adjusting the analog TV timing > > parameters. A crude workaround is to scale and crop the image to trick the > > driver into giving the desired timing. This won't work for non-overlay > > capture. > > OK v4l2 does have "digital zoom" capabilities that can let you select a > rectangular subpicture. I have not implemented it for bttv2, but if > anybody wants to, they are welcome! That's not exactly what I was talking about. The are various parameters, the bt848 has HSCALE/HACTIVE/HDELAY, VSCALE/VACTIVE/VDELAY, that can be used to fine tune the size and position of the captured portion of the video signal. Does V4L2 let me pan the image to the left a few pixels worth? What if you are interesting in multiple subsections of the image? For example, you're looking for a object to enter the picture on the left or right edge, and don't care about the center.
