V4L2采集图片源码分享
V4L2采集图片源码分享
把v4l2采集图片测试程序,贴在这和大家共享,在此基础上可以使实现视频的采集,只不过在pc机上写个上位机进行显示或者直接写个Qt在开发板上显示即可。
采集效果如下:
源码如下:
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <assert.h>
- #include <getopt.h>
- #include <fcntl.h>
- #include <unistd.h>
- #include <errno.h>
- #include <malloc.h>
- #include <sys/stat.h>
- #include <sys/types.h>
- #include <sys/time.h>
- #include <sys/mman.h>
- #include <sys/ioctl.h>
- #include <asm/types.h>
- #include <linux/videodev2.h>
- #define CLEAR(x) memset (&(x), 0, sizeof (x))
- struct buffer {
- void * start;
- size_t length;
- };
- static char * dev_name = "/dev/video0";
- static int fd = -1;
- struct buffer * buffers = NULL;
- FILE *file_fd;
- static unsigned long file_length;
- static unsigned char *file_name;
- int main (int argc,char ** argv)
- {
- struct v4l2_capability cap;
- struct v4l2_format fmt;
- file_fd = fopen("test.jpg", "w");
- fd = open (dev_name, O_RDWR /* required */ | O_NONBLOCK, 0);
- ioctl (fd, VIDIOC_QUERYCAP, &cap);
- CLEAR (fmt);
- fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
- fmt.fmt.pix.width = 640;
- fmt.fmt.pix.height = 480;
- fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
- fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
- ioctl (fd, VIDIOC_S_FMT, &fmt);
- file_length = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;
- buffers = calloc (1, sizeof (*buffers));
- buffers[0].length = file_length;
- buffers[0].start = malloc (file_length);
- for (;;)
- {
- fd_set fds;
- struct timeval tv;
- int r;
- FD_ZERO (&fds);
- FD_SET (fd, &fds);
- /* Timeout. */
- tv.tv_sec = 3;
- tv.tv_usec = 0;
- r = select (fd + 1, &fds, NULL, NULL, &tv);
- if (-1 == r) {
- if (EINTR == errno)
- continue;
- printf ("select");
- }
- if (0 == r) {
- fprintf (stderr, "select timeout\n");
- exit (EXIT_FAILURE);
- }
- if (read (fd, buffers[0].start, buffers[0].length))
- break;
- }
- fwrite(buffers[0].start, buffers[0].length, 1, file_fd);
- free (buffers[0].start);
- close (fd);
- fclose (file_fd);
- exit (EXIT_SUCCESS);
- return 0;
- }
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