diff options
| author | Guennadi Liakhovetski <g.liakhovetski@gmx.de> | 2010-08-27 13:41:44 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2010-10-21 01:06:18 -0200 |
| commit | 79c6ff93c74e793ccceb464ee3698478c812ce79 (patch) | |
| tree | 9750ba1a7d14619e8e74449513af0a31ccf8c803 | |
| parent | 45f4d4e8799ff1d7ef72747203935f1f2533743d (diff) | |
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>
| -rw-r--r-- | drivers/media/video/v4l2-common.c | 24 | ||||
| -rw-r--r-- | include/linux/videodev2.h | 8 |
2 files changed, 32 insertions, 0 deletions
diff --git a/drivers/media/video/v4l2-common.c b/drivers/media/video/v4l2-common.c index 8ee1179be92..31ae1a13861 100644 --- a/drivers/media/video/v4l2-common.c +++ b/drivers/media/video/v4l2-common.c @@ -676,3 +676,27 @@ int v4l_fill_dv_preset_info(u32 preset, struct v4l2_dv_enum_preset *info) return 0; } EXPORT_SYMBOL_GPL(v4l_fill_dv_preset_info); + +struct v4l2_frmsize_discrete *v4l2_find_nearest_format(struct v4l2_discrete_probe *probe, + s32 width, s32 height) +{ + int i; + u32 error, min_error = UINT_MAX; + struct v4l2_frmsize_discrete *size, *best = NULL; + + if (!probe) + return best; + + for (i = 0, size = probe->sizes; i < probe->num_sizes; i++, size++) { + error = abs(size->width - width) + abs(size->height - height); + if (error < min_error) { + min_error = error; + best = size; + } + if (!error) + break; + } + + return best; +} +EXPORT_SYMBOL_GPL(v4l2_find_nearest_format); diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h index b06479f6327..957d5b09384 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] */ |