72 lines
1.5 KiB
C
72 lines
1.5 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <errno.h>
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#include <sys/ioctl.h>
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#include <string.h>
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#include <linux/videodev2.h>
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#include <libv4l2.h>
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#include "controls.h"
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extern int verbosity;
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int set_controls(int fd, int brightness, int contrast)
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{
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struct v4l2_queryctrl queryctrl;
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struct v4l2_control control;
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memset (&queryctrl, 0, sizeof (queryctrl));
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queryctrl.id = V4L2_CID_BRIGHTNESS;
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if (-1 == ioctl (fd, VIDIOC_QUERYCTRL, &queryctrl)) {
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if (errno != EINVAL) {
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perror ("VIDIOC_QUERYCTRL");
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exit (EXIT_FAILURE);
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} else {
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printf ("V4L2_CID_BRIGHTNESS is not supported\n");
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}
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} else if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED) {
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printf ("V4L2_CID_BRIGHTNESS is not supported\n");
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} else {
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memset (&control, 0, sizeof (control));
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control.id = V4L2_CID_BRIGHTNESS;
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control.value = queryctrl.default_value;
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if (-1 == ioctl (fd, VIDIOC_S_CTRL, &control)) {
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perror ("VIDIOC_S_CTRL");
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exit (EXIT_FAILURE);
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}
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}
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memset (&control, 0, sizeof (control));
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control.id = V4L2_CID_CONTRAST;
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if (0 == ioctl (fd, VIDIOC_G_CTRL, &control)) {
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control.value += 1;
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/* The driver may clamp the value or return ERANGE, ignored here */
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if (-1 == ioctl (fd, VIDIOC_S_CTRL, &control)
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&& errno != ERANGE) {
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perror ("VIDIOC_S_CTRL");
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exit (EXIT_FAILURE);
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}
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/* Ignore if V4L2_CID_CONTRAST is unsupported */
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} else if (errno != EINVAL) {
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perror ("VIDIOC_G_CTRL");
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exit (EXIT_FAILURE);
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}
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control.id = V4L2_CID_AUDIO_MUTE;
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control.value = 1; /* silence */
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/* Errors ignored */
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ioctl (fd, VIDIOC_S_CTRL, &control);
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return 0;
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}
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