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authorPaul Elder <paul.elder@ideasonboard.com>2018-08-28 02:10:01 -0400
committerPaul Elder <paul.elder@ideasonboard.com>2019-02-06 01:48:50 -0500
commit9889a1223028a14ac2fd56323fc813b62087c918 (patch)
treec7f462a4b949cc98b9923d2eee374d1f3b858e19 /lib
parent8bee8cdb3c98c6489bd525a5588e391f8ae3aaa1 (diff)
v4l2: add v4l2_set_frame_rate
We would like to be able to set the frame rate of video sources. This patch adds such a function for v4l2-based video sources to use. Signed-off-by: Paul Elder <paul.elder@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Diffstat (limited to 'lib')
-rw-r--r--lib/v4l2.c20
-rw-r--r--lib/v4l2.h14
2 files changed, 34 insertions, 0 deletions
diff --git a/lib/v4l2.c b/lib/v4l2.c
index 9030270..de6ed88 100644
--- a/lib/v4l2.c
+++ b/lib/v4l2.c
@@ -500,6 +500,26 @@ int v4l2_set_format(struct v4l2_device *dev, struct v4l2_pix_format *format)
return 0;
}
+int v4l2_set_frame_rate(struct v4l2_device *dev, unsigned int fps)
+{
+ struct v4l2_streamparm parm;
+ int ret;
+
+ memset(&parm, 0, sizeof parm);
+ parm.type = dev->type;
+ parm.parm.capture.timeperframe.numerator = 1;
+ parm.parm.capture.timeperframe.denominator = fps;
+
+ ret = ioctl(dev->fd, VIDIOC_S_PARM, &parm);
+ if (ret < 0) {
+ printf("%s: unable to set frame rate (%d).\n", dev->name, errno);
+ return -errno;
+ }
+
+ dev->fps = fps;
+ return 0;
+}
+
/* -----------------------------------------------------------------------------
* Buffers management
*/
diff --git a/lib/v4l2.h b/lib/v4l2.h
index 8d7b3c5..7bacf5d 100644
--- a/lib/v4l2.h
+++ b/lib/v4l2.h
@@ -31,6 +31,7 @@ struct v4l2_device
struct list_entry formats;
struct v4l2_pix_format format;
struct v4l2_rect crop;
+ unsigned int fps;
struct video_buffer_set buffers;
};
@@ -86,6 +87,19 @@ int v4l2_get_format(struct v4l2_device *dev, struct v4l2_pix_format *format);
int v4l2_set_format(struct v4l2_device *dev, struct v4l2_pix_format *format);
/*
+ * v4l2_set_frame_rate - Set the frame rate
+ * @dev: Device instance
+ * @fps: Frame rate
+ *
+ * Set the frame rate specified by @fps.
+ * The device can modify the requested format and size, in which case @dev->fps
+ * will be updated to reflect the modified setting.
+ *
+ * Return 0 on success or a negative error code on failure.
+ */
+int v4l2_set_frame_rate(struct v4l2_device *dev, unsigned int fps);
+
+/*
* v4l2_get_crop - Retrieve the current crop rectangle
* @dev: Device instance
* @rect: Crop rectangle structure to be filled