Adam Baker wrote:
On Friday 16 January 2009, Olivier Lorin wrote:
<snip discussion of cameras needing image flipping capability in libv4l>
The use of the buffer flags makes the life easier as this flag
is read for every image. So we can solve for the flip/rotation
issues with the help of two new buffer flags: V4L2_BUF_FLAG_NEEDS_HFLIP
and V4L2_BUF_FLAG_NEEDS_VFLIP.
A driver has to set them properly. Does the rotation or flip(s)
apply to every image (e.g. sensor upside down) or change with frames
(e.g. Genesys webcams), that no more matters .
I can do the patch these days.
I do not remember if there is h/v flip functions in the libv4l,
maybe they have to be added.
Regards,
Nol
That sounds like a sensible approach. The flip code is already in libv4l but
is currently controlled by a static table (v4lconvert_flags) of cameras that
need it.
It doesn't address the issue of whether libv4l should also provide gamma
adjustment, auto white balance and auto gain for cameras that could benefit
from it. Again that could be done with a static table but keeping the
knowledge in libv4l in step with the list of supported cameras in the kernel
won't be easy.
Ack, but keeping a list in the kernel, just to be able to query it from
userspace also seems silly. So atleast for "static" upside down info for UVC
cams it was decided it would be best to just put the table in userspace.
Regards,
Hans
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