V4L/DVB: V4L2: add a generic function to find the nearest discrete format to the required one

Many video drivers implement a fixed set of frame formats and thus face a task
of finding the best match for a user-requested format. Implementing this in a
generic function has also an advantage, that different drivers with similar
supported format sets will select the same format for the user, which improves
consistency across drivers.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index b06479f63271..957d5b093847 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -397,6 +397,14 @@ struct v4l2_frmsize_discrete {
         __u32                   height;         /* Frame height [pixel] */
 };
 
+struct v4l2_discrete_probe {
+        const struct v4l2_frmsize_discrete      *sizes;
+        int                                     num_sizes;
+};
+
+struct v4l2_frmsize_discrete *v4l2_find_nearest_format(struct v4l2_discrete_probe *probe,
+                                                       s32 width, s32 height);
+
 struct v4l2_frmsize_stepwise {
         __u32                   min_width;      /* Minimum frame width [pixel] */
         __u32                   max_width;      /* Maximum frame width [pixel] */