From: Hans Verkuil
While the documentation says that VIDIOC_CROPCAP is compulsory for
all video capture and output devices, in practice VIDIOC_CROPCAP is
only implemented for devices that can do cropping and/or scaling.
Update the documentation to no longer require VIDIOC_CROPCAP if the
driver does not support cropping or scaling or non-square pixels.
Signed-off-by: Hans Verkuil
---
Documentation/DocBook/media/v4l/common.xml | 145 +---
Documentation/DocBook/media/v4l/vidioc-cropcap.xml | 10 +-
2 files changed, 75 insertions(+), 80 deletions(-)
diff --git a/Documentation/DocBook/media/v4l/common.xml
b/Documentation/DocBook/media/v4l/common.xml
index 9378d7b..454258b 100644
--- a/Documentation/DocBook/media/v4l/common.xml
+++ b/Documentation/DocBook/media/v4l/common.xml
@@ -628,7 +628,7 @@ are available for the device.
if (-1 == ioctl (fd, &VIDIOC-G-STD;, &std_id)) {
/* Note when VIDIOC_ENUMSTD always returns EINVAL this
is no video device or it falls under the USB exception,
- and VIDIOC_G_STD returning EINVAL is no error. */
+ and VIDIOC_G_STD returning ENOTTY is no error. */
perror ("VIDIOC_G_STD");
exit (EXIT_FAILURE);
@@ -905,9 +905,9 @@ inserted.
Source and target rectangles are defined even if the device
does not support scaling or the VIDIOC_G/S_CROP
ioctls. Their size (and position where applicable) will be fixed in
-this case. All capture and output device must support the
-VIDIOC_CROPCAP ioctl such that applications can
-determine if scaling takes place.
+this case. All capture and output device that support cropping
+and/or scaling and/or have non-square pixels must support the
VIDIOC_CROPCAP
+ioctl such that applications can determine if scaling takes
place.
Cropping Structures
@@ -1032,24 +1032,21 @@ devices.)
&v4l2-cropcap; cropcap;
&v4l2-crop; crop;
-memset (&cropcap, 0, sizeof (cropcap));
+memset(&cropcap, 0, sizeof(cropcap));
cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-if (-1 == ioctl (fd, &VIDIOC-CROPCAP;, &cropcap)) {
- perror ("VIDIOC_CROPCAP");
- exit (EXIT_FAILURE);
-}
-
-memset (&crop, 0, sizeof (crop));
-crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-crop.c = cropcap.defrect;
+if (0 == ioctl(fd, &VIDIOC-CROPCAP;, &cropcap)) {
+ memset(&crop, 0, sizeof(crop));
+ crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+ crop.c = cropcap.defrect;
-/* Ignore if cropping is not supported (EINVAL). */
+ /* Ignore if cropping is not supported (ENOTTY). */
-if (-1 == ioctl (fd, &VIDIOC-S-CROP;, &crop)
-&& errno != EINVAL) {
- perror ("VIDIOC_S_CROP");
- exit (EXIT_FAILURE);
+ if (-1 == ioctl(fd, &VIDIOC-S-CROP;, &crop)
+ && errno != ENOTTY) {
+ perror("VIDIOC_S_CROP");
+ exit(EXIT_FAILURE);
+ }
}
@@ -1063,11 +1060,11 @@ if (-1 == ioctl (fd, &VIDIOC-S-CROP;, &crop)
&v4l2-cropcap; cropcap;
&v4l2-format; format;
-reset_cropping_parameters ();
+reset_cropping_parameters();
/* Scale down to 1/4 size of full picture. */
-memset (&format, 0, sizeof (format)); /* defaults */
+memset(&format, 0, sizeof(format)); /* defaults */
format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
@@ -1075,9 +1072,9 @@ format.fmt.pix.width = cropcap.defrect.width >> 1;
format.fmt.pix.height = cropcap.defrect.height >> 1;
format.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
-if (-1 == ioctl (fd, &VIDIOC-S-FMT;, &format)) {
- perror ("VIDIOC_S_FORMAT");
- exit (EXIT_FAILURE);
+if (-1 == ioctl(fd, &VIDIOC-S-FMT;, &format)) {
+ perror("VIDIOC_S_FORMAT");
+ exit(EXIT_FAILURE);
}
/* We could check the actual image size now, the actual scaling factor
@@ -1092,33 +1089,30 @@ if (-1 == ioctl (fd, &VIDIOC-S-FMT;, &format)) {
&v4l2-cropcap; cropcap;
&v4l2-crop; crop;
-memset (&cropcap, 0, sizeof (cropcap));
+memset(&cropcap, 0, sizeof (cropcap));
cropcap.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
-if (-1 == ioctl (fd, VIDIOC_CROPCAP;, &cropcap)) {
- perror ("VIDIOC_CROPCAP");
- exit (EXIT_FAILURE);
-}
-
-memset (&crop, 0, sizeof (crop));
+if (0 == ioctl(fd, &VIDIOC-CROPCAP;, &cropcap)) {
+ memset(&crop, 0, sizeof (crop));
-crop.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
-crop.c = cropcap.defrect;
+ crop.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
+ crop.c = cropcap.defrect;
-/* Scale the width and height to 50 % of their original size
- and center the output. */
+ /* Scale the width and height to 50 % of their original size
+ and center the output. */
-crop.c.width /= 2;
-crop.c.height /= 2;
-crop.c.left += crop.c.width / 2;
-crop.c.top += crop.c.height / 2;
+ crop.c.width /= 2;
+ crop.c.height /= 2;
+ crop.c.left += crop.c.width / 2;
+ crop.c.top += crop.c.height / 2;
-/* Ignore if cropping is not supported (EINVAL). */
+ /* Ignore if cropping is not supported (ENOTTY). */
-if (-1 == ioctl (fd, VIDIOC_S_CRO
