视频采集图片的问题，有图有代码

yst1571661 · 发表于 2014-4-10 19:15:55

使用V4L2做图片采集，查询到摄像头制式是YUYV，设置，申请帧缓存，读取，存储，得到.raw的文件，拿到windows下用picasa打开出现如下图片，请问可能是什么方面的原因？贴代码如下

/*
* V4L2 video capture example
*/
#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 <asm/types.h> /* for videodev2.h */
#include <linux/videodev2.h>
//#include "YUV2JPEG.h"
#define CLEAR(x) memset (&(x), 0, sizeof (x))
typedef enum
{
IO_METHOD_READ,
IO_METHOD_MMAP,
IO_METHOD_USERPTR,
} io_method;
struct buffer
{
void *start;
size_t length;
};
static char *dev_name = NULL;
static io_method io = IO_METHOD_MMAP;
/* can be V4L2_PIX_FMT_YUV420 or V4L2_PIX_FMT_PWC2 */
static int pixel_format = V4L2_PIX_FMT_YUYV;
static int fd = -1;
struct buffer *buffers = NULL;
static unsigned int n_buffers = 0;
static unsigned int width = 640;
static unsigned int height = 480;
static unsigned int count = 2;
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 fd, int request, void *arg)
{
int r;
do
r = ioctl(fd, request, arg);
while (-1 == r && EINTR == errno);
return r;
}
static void process_image(const void *p, ssize_t size)
{
static int no_image = 0;
char filename[1024];
int fd;
ssize_t written = 0;
snprintf(filename, sizeof(filename), "/mnt/webcam-%5.5d.%s",
no_image++, pixel_format == V4L2_PIX_FMT_YUYV ? "raw" : "raw");
// snprintf(filename,sizeof(filename),"/mnt/picture%d.jpg",no_image++);
fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, S_IRUSR | S_IWUSR);
if (fd < 0)
{
fputc('*', stdout);
fflush(stdout);
return;
}
do
{
int ret;
ret = write(fd, p + written, size - written);
if (ret < 0)
{
fputc('+', stdout);
fflush(stdout);
return;
}
written += ret;
}
while (written < size);
close(fd);
// YUV2JPEG((unsigned char *)p,640,480,filename);
fputc('.', stdout);
fflush(stdout);
}
static int read_frame(void)
{
struct v4l2_buffer buf;
unsigned int i;
ssize_t read_bytes;
unsigned int total_read_bytes;
switch (io)
{
case IO_METHOD_READ:
total_read_bytes = 0;
do
{
read_bytes = read(fd, buffers[0].start, buffers[0].length);
if (read_bytes < 0)
{
switch (errno)
{
case EIO:
case EAGAIN:
continue;
default:
errno_exit("read");
}
}
total_read_bytes += read_bytes;
} while (total_read_bytes < buffers[0].length);
process_image(buffers[0].start, buffers[0].length);
break;
case IO_METHOD_MMAP:
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:
return 0;
case EIO:
/* Could ignore EIO, see spec. */
/* fall through */
default:
errno_exit("VIDIOC_DQBUF");
}
}
assert(buf.index < n_buffers);
process_image(buffers[buf.index].start, buf.length);
if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
errno_exit("VIDIOC_QBUF");
break;
case IO_METHOD_USERPTR:
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_USERPTR;
if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf))
{
switch (errno)
{
case EAGAIN:
return 0;
case EIO:
/* Could ignore EIO, see spec. */
/* fall through */
default:
errno_exit("VIDIOC_DQBUF");
}
}
for (i = 0; i < n_buffers; ++i)
if (buf.m.userptr == (unsigned long) buffers[i].start
&& buf.length == buffers[i].length)
break;
assert(i < n_buffers);
process_image((void *) buf.m.userptr, buf.length);
if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
errno_exit("VIDIOC_QBUF");
break;
}
return 1;
}
static void mainloop(void)
{
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");
exit(EXIT_FAILURE);
}
if (read_frame())
break;
/* EAGAIN - continue select loop. */
}
}
}
static void stop_capturing(void)
{
enum v4l2_buf_type type;
switch (io)
{
case IO_METHOD_READ:
/* Nothing to do. */
break;
case IO_METHOD_MMAP:
case IO_METHOD_USERPTR:
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (-1 == xioctl(fd, VIDIOC_STREAMOFF, &type))
errno_exit("VIDIOC_STREAMOFF");
break;
}
}
static void start_capturing(void)
{
unsigned int i;
enum v4l2_buf_type type;
switch (io)
{
case IO_METHOD_READ:
/* Nothing to do. */
break;
case IO_METHOD_MMAP:
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");
break;
case IO_METHOD_USERPTR:
for (i = 0; i < n_buffers; ++i)
{
struct v4l2_buffer buf;
CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_USERPTR;
buf.m.userptr = (unsigned long) buffers[i].start;
buf.length = buffers[i].length;
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");
break;
}
}
static void uninit_device(void)
{
unsigned int i;
switch (io)
{
case IO_METHOD_READ:
free(buffers[0].start);
break;
case IO_METHOD_MMAP:
for (i = 0; i < n_buffers; ++i)
if (-1 == munmap(buffers[i].start, buffers[i].length))
errno_exit("munmap");
break;
case IO_METHOD_USERPTR:
for (i = 0; i < n_buffers; ++i)
free(buffers[i].start);
break;
}
free(buffers);
}
static void init_read(unsigned int buffer_size)
{
buffers = calloc(1, sizeof(*buffers));
if (!buffers)
{
fprintf(stderr, "Out of memory\n");
exit(EXIT_FAILURE);
}
buffers[0].length = buffer_size;
buffers[0].start = malloc(buffer_size);
if (!buffers[0].start)
{
fprintf(stderr, "Out of memory\n");
exit(EXIT_FAILURE);
}
}
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 mapping\n", 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_userp(unsigned int buffer_size)
{
struct v4l2_requestbuffers req;
CLEAR(req);
req.count = 4;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_USERPTR;
if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req))
{
if (EINVAL == errno)
{
fprintf(stderr, "%s does not support "
"user pointer i/o\n", dev_name);
exit(EXIT_FAILURE);
}
else
{
errno_exit("VIDIOC_REQBUFS");
}
}
buffers = calloc(4, sizeof(*buffers));
if (!buffers)
{
fprintf(stderr, "Out of memory\n");
exit(EXIT_FAILURE);
}
for (n_buffers = 0; n_buffers < 4; ++n_buffers)
{
buffers[n_buffers].length = buffer_size;
buffers[n_buffers].start = malloc(buffer_size);
if (!buffers[n_buffers].start)
{
fprintf(stderr, "Out of memory\n");
exit(EXIT_FAILURE);
}
}
}
static void init_device(void)
{
struct v4l2_capability cap;
struct v4l2_cropcap cropcap;
struct v4l2_crop crop;
struct v4l2_format fmt;
unsigned int min;
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");
}
}
printf("cam name:%s\n driver name:%s\n driver version:%d\n businfo:%s\n"
,cap.card,cap.driver,cap.version,cap.bus_info);
if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE))
{
fprintf(stderr, "%s is no video capture device\n",cap.card);
exit(EXIT_FAILURE);
}
else
{
printf("%s is video capture device\n",cap.card);
}
switch (io)
{
case IO_METHOD_READ:
if (!(cap.capabilities & V4L2_CAP_READWRITE))
{
fprintf(stderr, "%s does not support read i/o\n",cap.card);
exit(EXIT_FAILURE);
}
else
{
printf("%s support read i/o\n",cap.card);
}
break;
case IO_METHOD_MMAP:
case IO_METHOD_USERPTR:
if (!(cap.capabilities & V4L2_CAP_STREAMING))
{
fprintf(stderr, "%s does not support streaming i/o\n",cap.card);
exit(EXIT_FAILURE);
}
else
{
printf("%s support streaming i/o\n",cap.card);
}
break;
}
/* Select video input, video standard and tune here. */
cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (-1 == xioctl(fd, VIDIOC_CROPCAP, &cropcap))
{
/* Errors ignored. */
}
crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
crop.c = cropcap.defrect; /* reset to default */
if (-1 == xioctl(fd, VIDIOC_S_CROP, &crop))
{
switch (errno)
{
case EINVAL:
printf("Cropping not supported\n");
/* Cropping not supported. */
break;
default:
/* Errors ignored. */
break;
}
}
CLEAR(fmt);
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
fmt.fmt.pix.width = width;
fmt.fmt.pix.height = height;
fmt.fmt.pix.pixelformat = pixel_format;
fmt.fmt.pix.field = V4L2_FIELD_SEQ_BT;//V4L2_FIELD_INTERLACED;
if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt))
errno_exit("VIDIOC_S_FMT");
/* Note VIDIOC_S_FMT may change width and height. */
width = fmt.fmt.pix.width;
height = fmt.fmt.pix.height;
switch (io)
{
case IO_METHOD_READ:
init_read(fmt.fmt.pix.sizeimage);
break;
case IO_METHOD_MMAP:
init_mmap();
break;
case IO_METHOD_USERPTR:
init_userp(fmt.fmt.pix.sizeimage);
break;
}
}
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 device\n", 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 const char short_options[] = "c:d:f:hmrs:u";
static const struct option long_options[] = {
{"count", required_argument, NULL, 'c'},
{"device", required_argument, NULL, 'd'},
{"format", required_argument, NULL, 'f'},
{"help", no_argument, NULL, 'h'},
{"mmap", no_argument, NULL, 'm'},
{"read", no_argument, NULL, 'r'},
{"size", required_argument, NULL, 's'},
{"userp", no_argument, NULL, 'u'},
{0, 0, 0, 0}
};
static int video_fmtdesc(int fd)
{
/***********Format Enumeration************/
int ret = 0;
struct v4l2_fmtdesc fmtdes;
CLEAR(fmtdes);
fmtdes.index = 0;
fmtdes.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
printf("\n****vidioc enumeration stream format informations:****\n");
while (1) {
ret = ioctl(fd, VIDIOC_ENUM_FMT, &fmtdes);
if (ret < 0)
break;
printf("{ pixelformat = %c%c%c%c, description = %s }\n",
(fmtdes.pixelformat & 0xFF),
(fmtdes.pixelformat >> 8) & 0xFF,
(fmtdes.pixelformat >> 16) & 0xFF,
(fmtdes.pixelformat >> 24) & 0xFF,
fmtdes.description);
if (fmtdes.type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
printf("video capture type:\n");
if (fmtdes.pixelformat == V4L2_PIX_FMT_YUYV)
printf("V4L2_PIX_FMT_YUYV\n");
fmtdes.index++;
}
return 0;
}
int main(int argc, char **argv)
{
dev_name = "/dev/video0";
open_device();
init_device();
video_fmtdesc(fd);
start_capturing();
mainloop();
stop_capturing();
uninit_device();
close_device();
exit(EXIT_SUCCESS);
return 0;
}

复制代码

yst1571661 · 发表于 2014-4-12 12:35:19

还在纠结中，有谁帮忙分析下？

yst1571661 · 发表于 2014-4-24 20:55:36

现在把图片转换为RGB24模式，但是有不规则横纹出现，有遇到过类似问题的吗？

qs6361036 · 发表于 2016-5-4 21:35:09

是不是屏的问题

视频采集图片的问题，有图有代码

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阿莫论坛20周年了！感谢大家的支持与爱护！！

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