> > VIDIOCSPICT and VIDIOCSWIN are only used for setting up an overlay
> > window, not for memory capture.
Or for capture using the read() system call. With bttv 0.8.x capture
with read() does actually work (unlike older versions)...
> > For doing memory capture the size/format
> > are passed to each VIDIOMCAPTURE call.
>
> This is a point I am not sure of. The v4l API specification explicitly
> requires that GMBUF is isued AFTER setting the size and format, while
> MCAPTURE is only allowed after GMBUF and mmap. As you can see, this
> prevents using MCAPTURE to set the size/format, and the only other ioctl
> that sets size is SWIN, so this must be the one.
Sure? For v4l1? I can't remember having this seen in Alan's specs
(havn't checked it for some time throuth...). v4l2 _is_ specified
that way (i.e. first set format, then ask buffer size + map stuff),
but IIRC v4l1 is not. As size+format are specified on frame by
frame bases in struct video_mmap I can't see the point of setting
the video format first...
Gerd
--
Get back there in front of the computer NOW. Christmas can wait.
-- Linus "the Grinch" Torvalds, 24 Dec 2000 on linux-kernel
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