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.
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