V4L2摄像头获取单幅图片测试程序

#根据网上常见的一个测试程序修改而来 by rockie cheng

#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;

}

本篇文章来源于 Linux公社网站(www.linuxidc.com) 原文链接：http://www.linuxidc.com/Linux/2011-03/33021.htm