/*
* V4L2 video capture example
*
* This program can be used and distributed without restrictions.
*
* This program is provided with the V4L2 API
* see https://linuxtv.org/docs.php for more information
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <getopt.h> /* getopt_long() */
#include <fcntl.h> /* low-level i/o */
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <linux/videodev2.h>
#define CLEAR(x) memset(&(x), 0, sizeof(x))
enum io_method {
IO_METHOD_READ,
IO_METHOD_MMAP,
IO_METHOD_USERPTR,
};
struct buffer {
void *start;
size_t length;
};
static char *dev_name;
static enum io_method io = IO_METHOD_MMAP;
static int fd = -1;
struct buffer *buffers;
static unsigned int n_buffers;
static int out_buf;
static int frame_count = 1;
int width = 1280;
int height = 720;
int format = V4L2_PIX_FMT_MJPEG;
/*
在长字符串中根据给定短字符串分割字符串,
需要在外部声明指向指针变量的数据,获取数据后在外部free掉
input :输入长串
splitstr:输入子串
output :保存输出结果
num :子串个数
*/
int StrSplit(char * input, char* splitstr, char ** output, int *num)
{
int tmplen = 0;
int totallen = 0;
int count = 0;
int nRtn = 0;
char *p = input;
int nSrcLen = strlen(input);
int nSplStrLen = strlen(splitstr);
if (input == NULL || nSrcLen == 0) //如果传入的地址为空或长度为0,直接终止
{
return -1;
}
if (splitstr == NULL || nSplStrLen == 0) //如未指定分割的字符串,直接终止
{
return -1;
}
//若第一个字符与短串相同,按短串长度比较
while((*p != '\0'))
{
if (*p == splitstr[0])
{
if (0 == strncmp(p, splitstr, nSplStrLen))
{
//开辟内存,地址放在output[count]中
output[count] = (char*)malloc(tmplen+1);
//把分割出的字串拷贝到output[count]内存中
strncpy(output[count], input + totallen, tmplen);
//添加截止符
(output[count])[tmplen] = '\0';
//printf("output[%d]: [%s]\n", count, output[count]);
//字串个数加一
count++;
//p移动的长度增加
totallen += (tmplen + nSplStrLen);
//p指向新的地址
p += nSplStrLen;
//下个字串长度
tmplen = 0;
continue;
}
}
p++;
tmplen++;
}
//最后一个字串
output[count] = (char*)malloc(tmplen+1);
strncpy(output[count], input + totallen, tmplen);
(output[count])[tmplen] = '\0';
//printf("output[%d]: [%s]\n", count, output[count]);
count++;
*num = count;
return 0;
}
static void errno_exit(const char *s)
{
fprintf(stderr, "%s error %d, %s\\n", s, errno, strerror(errno));
exit(EXIT_FAILURE);
}
static int xioctl(int fh, int request, void *arg)
{
int r;
do {
r = ioctl(fh, request, arg);
} while (-1 == r && EINTR == errno);
return r;
}
static void process_image(const void *p, int size)
{
char file_name[256] = {0};
static int cunt = 0;
cunt++;
snprintf(file_name,256,"%d.jpg",cunt);
int sf_fd = open(file_name, O_RDWR | O_CREAT, 0777);
if (sf_fd < 0)
{
printf("open save image file failed\n");
return ;
}
int w_size = write(sf_fd, p , size);
if (w_size != size)
{
printf("write image failed,wirte w_size = %d\n",w_size);
return;
}
close(sf_fd);
fflush(stderr);
fflush(stdout);
}
static int read_frame(void)
{
struct v4l2_buffer buf;
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) {
switch (errno) {
case EAGAIN:
{
printf("EAGAIN\n");
break;
}
case EIO:
{
printf("Could ignore EIO, see spec\n");
break;
}
default:
errno_exit("VIDIOC_DQBUF");
}
}
assert(buf.index < n_buffers);
process_image(buffers[buf.index].start, buffers[buf.index].length);
if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
errno_exit("VIDIOC_QBUF");
return 1;
}
static void mainloop(void)
{
unsigned int count;
count = frame_count;
while (count-- > 0) {
for (;;) {
fd_set fds;
struct timeval tv;
int r;
FD_ZERO(&fds);
FD_SET(fd, &fds);
/* Timeout. */
tv.tv_sec = 2;
tv.tv_usec = 0;
r = select(fd + 1, &fds, NULL, NULL, &tv);
if (-1 == r) {
if (EINTR == errno)
continue;
errno_exit("select");
}
if (0 == r) {
fprintf(stderr, "select timeout\n");
continue;
}
if (read_frame())
break;
/* EAGAIN - continue select loop. */
}
}
}
static void stop_capturing(void)
{
enum v4l2_buf_type type;
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (-1 == xioctl(fd, VIDIOC_STREAMOFF, &type))
errno_exit("VIDIOC_STREAMOFF");
}
static void start_capturing(void)
{
unsigned int i;
enum v4l2_buf_type type;
for (i = 0; i < n_buffers; ++i) {
struct v4l2_buffer buf;
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = i;
if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
errno_exit("VIDIOC_QBUF");
}
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (-1 == xioctl(fd, VIDIOC_STREAMON, &type))
errno_exit("VIDIOC_STREAMON");
}
static void uninit_device(void)
{
unsigned int i;
for (i = 0; i < n_buffers; ++i)
if (-1 == munmap(buffers[i].start, buffers[i].length))
errno_exit("munmap");
free(buffers);
}
static void init_mmap(void)
{
struct v4l2_requestbuffers req;
CLEAR(req);
req.count = 4;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_MMAP;
if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) {
if (EINVAL == errno) {
fprintf(stderr, "%s does not support "
"memory mappingn", dev_name);
exit(EXIT_FAILURE);
} else {
errno_exit("VIDIOC_REQBUFS");
}
}
if (req.count < 2) {
fprintf(stderr, "Insufficient buffer memory on %s\\n",
dev_name);
exit(EXIT_FAILURE);
}
buffers = calloc(req.count, sizeof(*buffers));
if (!buffers) {
fprintf(stderr, "Out of memory\\n");
exit(EXIT_FAILURE);
}
for (n_buffers = 0; n_buffers < req.count; ++n_buffers) {
struct v4l2_buffer buf;
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = n_buffers;
if (-1 == xioctl(fd, VIDIOC_QUERYBUF, &buf))
errno_exit("VIDIOC_QUERYBUF");
buffers[n_buffers].length = buf.length;
buffers[n_buffers].start =
mmap(NULL /* start anywhere */,
buf.length,
PROT_READ | PROT_WRITE /* required */,
MAP_SHARED /* recommended */,
fd, buf.m.offset);
if (MAP_FAILED == buffers[n_buffers].start)
errno_exit("mmap");
}
}
static void init_device(void)
{
struct v4l2_capability cap;
struct v4l2_format fmt;
struct v4l2_streamparm Stream_Parm;
if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &cap)) {
if (EINVAL == errno) {
fprintf(stderr, "%s is no V4L2 device\\n",
dev_name);
exit(EXIT_FAILURE);
} else {
errno_exit("VIDIOC_QUERYCAP");
}
}
if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
fprintf(stderr, "%s is no video capture device\\n",
dev_name);
exit(EXIT_FAILURE);
}
if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
fprintf(stderr, "%s does not support streaming i/o\\n",
dev_name);
exit(EXIT_FAILURE);
}
/* Select video input, video standard and tune here. */
CLEAR(fmt);
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
fmt.fmt.pix.width = width;
fmt.fmt.pix.height = height;
fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_MJPEG;
fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt))
errno_exit("VIDIOC_S_FMT");
memset(&(Stream_Parm), 0, sizeof(Stream_Parm));
Stream_Parm.type=V4L2_BUF_TYPE_VIDEO_CAPTURE;
Stream_Parm.parm.capture.timeperframe.denominator = 5;
Stream_Parm.parm.capture.timeperframe.numerator =1;
if(ioctl(fd,VIDIOC_S_PARM,&Stream_Parm)==-1)
{
printf("VIDIOC_S_PARM = %s",strerror(errno));
return ;
}
init_mmap();
}
static void close_device(void)
{
if (-1 == close(fd))
errno_exit("close");
fd = -1;
}
static void open_device(void)
{
struct stat st;
if (-1 == stat(dev_name, &st)) {
fprintf(stderr, "Cannot identify '%s': %d, %s\\n",
dev_name, errno, strerror(errno));
exit(EXIT_FAILURE);
}
if (!S_ISCHR(st.st_mode)) {
fprintf(stderr, "%s is no devicen", dev_name);
exit(EXIT_FAILURE);
}
fd = open(dev_name, O_RDWR /* required */ | O_NONBLOCK, 0);
if (-1 == fd) {
fprintf(stderr, "Cannot open '%s': %d, %s\\n",
dev_name, errno, strerror(errno));
exit(EXIT_FAILURE);
}
}
static void usage(FILE *fp, int argc, char **argv)
{
fprintf(fp,
"Usage: %s [options]\n"
"Version 1.3\n"
"Options:\n"
"-d | --device name Video device name [%s]\n"
"-h | --help Print this messagen\n"
"-s | --size set image size\n"
"-c | --count %d Number of image\n"
"",
argv[0], dev_name, frame_count);
}
static const char short_options[] = "d:h:s:c:";
static const struct option
long_options[] = {
{ "device", required_argument, NULL, 'd' },
{ "help", no_argument, NULL, 'h' },
{ "size", required_argument, NULL, 's' },
{ "count", required_argument, NULL, 'c' },
{ 0, 0, 0, 0 }
};
int main(int argc, char **argv)
{
char *apbyRtn[5] = {0}; //指针类型的数组,每个元素保存一个指针,必须足够大
int num = 0;
dev_name = "/dev/video0";
for (;;) {
int idx;
int c;
c = getopt_long(argc, argv,
short_options, long_options, &idx);
if (-1 == c)
break;
switch (c) {
case 0: /* getopt_long() flag */
break;
case 'd':
dev_name = optarg;
break;
case 'h':
usage(stdout, argc, argv);
exit(EXIT_SUCCESS);
case 's':
printf("test\n");
StrSplit(optarg,"*",apbyRtn,&num);
//获取结果并释放
for (int i = 0; i < num; i++)
{
if (0 == i)
{
width = strtol(apbyRtn[i],NULL, 0);
}
if (1 == i)
{
height = strtol(apbyRtn[i],NULL, 0);
}
free(apbyRtn[i]);
}
printf("image size = %d*%d\n",width,height);
break;
case 'c':
errno = 0;
frame_count = strtol(optarg, NULL, 0);
if (errno)
errno_exit(optarg);
break;
default:
usage(stderr, argc, argv);
exit(EXIT_FAILURE);
}
}
open_device();
init_device();
start_capturing();
mainloop();
stop_capturing();
uninit_device();
close_device();
return 0;
}