On Fri, 19 Nov 2010, Laurent Pinchart wrote:
> Some buggy sensors generate corrupt frames when the stream is started.
> This new operation returns the number of corrupt frames to skip when
> starting the stream.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> ---
> include/media/v4l2-subdev.h | 4 ++++
> 1 files changed, 4 insertions(+), 0 deletions(-)
>
> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> index 04878e1..b196966 100644
> --- a/include/media/v4l2-subdev.h
> +++ b/include/media/v4l2-subdev.h
> @@ -291,9 +291,13 @@ struct v4l2_subdev_pad_ops {
> * This is needed for some sensors, which always corrupt
> * several top lines of the output image, or which send their
> * metadata in them.
> + * @g_skip_frames: number of frames to skip at stream start. This is needed for
> + * buggy sensors that generate faulty frames when they are
> + * turned on.
> */
> struct v4l2_subdev_sensor_ops {
> int (*g_skip_top_lines)(struct v4l2_subdev *sd, u32 *lines);
> + int (*g_skip_frames)(struct v4l2_subdev *sd, u32 *frames);
Well, yes, this would be useful, but, I think, it is a part of a larger
problem - general video quality from sensors. Like, I think, there are
other situations, when the sensor driver knows, that the next few frames
will be of poor quality. E.g., when changing some parameters, which will
make the sensor re-adjust auto-exposure, auto-gain or something similar.
So, we can either just handle this one specific case, or try to design a
more generic approach, or leave frame quality analysis completely to the
user-space. Like - for a normal generic mplayer, just streaming video to
an output device - you don't really care in most cases. If recording video
- you edit it afterwords, if building an industrial quality
purpose-designed application - it will, probably, take care of these
things itself. And yes, there is also out-of-band data, that can carry
such quality-related information. So, this is just one bit of a bigger
problem, no idea though, wheather it's worth trying to tackle all those
issues at once or better just fix this one small specific problem.
> };
>
> struct v4l2_subdev_ops {
> --
> 1.7.2.2
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
