v4l2视频采集程序

v4l2视频采集程序

2011-11-15 08:14 995人阅读 评论(3) 收藏 举报

structvideobufferionullimage

/*

* V4L2 video capture example

*

* This program can be used and distributed without restrictions.

*/

#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 <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> /* for videodev2.h */

#include <linux/videodev2.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;

static int fd = -1;

struct buffer * buffers= NULL;

static unsigned int n_buffers= 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 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,int len)

{

unsigned short int *rep;

rep=(unsigned short int *)p;

int i=0,bits_per_pixel =16;

int line_x =line_y = 0;

int xres=600;

int InfoHead.ciHeight=480;

//向framebuffer中写BMP图片

int ftp=open("/dev/fb0",O_RDWR);

printf("ftp:%d\n",ftp);

while(!feof(p))

{

PIXEL *pix;

unsigned short int tmp;

//rc = fread( (char *)&pix, 1, sizeof(unsigned short int), fp);

//if (rc != sizeof(unsigned short int))

//{

// break;

//}

pix=*(rep+i++);

location = line_x * bits_per_pixel / 8 + (InfoHead.ciHeight - line_y - 1) * xres * bits_per_pixel / 8;

//显示每一个像素

tmp=pix.red<<0 | pix.green<<5 | pix.blue<<11;

*((unsigned short int*)(ftp + location)) = tmp;

line_x++;

if (line_x == InfoHead.ciWidth )

{

line_x = 0;

line_y++;

if(line_y == InfoHead.ciHeight)

{

break;

}

}

}

printf("len:%d\n",len);

fputc ('.', stdout);

fflush (stdout);

}

static int read_frame(void)

{

struct v4l2_buffer buf;

unsigned int i;

switch (io) {

case IO_METHOD_READ:

if (-1 == read (fd, buffers[0].start, buffers[0].length)) {

switch (errno) {

case EAGAIN:

return 0;

case EIO:

/* Could ignore EIO, see spec. */

/* fall through */

default:

errno_exit ("read");

}

}

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,buffers[buf.index].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,);

if (-1 == xioctl (fd, VIDIOC_QBUF, &buf))

errno_exit ("VIDIOC_QBUF");

break;

}

return 1;

}

static void mainloop (void){

unsigned int count;

count = 100;

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.index = i;

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;

unsigned int page_size;

page_size = getpagesize ();

buffer_size = (buffer_size + page_size - 1) & ~(page_size - 1);

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 = memalign (/* boundary */ page_size,

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");

}

}

if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {

fprintf (stderr, "%s is no video capture device\n",

dev_name);

exit (EXIT_FAILURE);

}

switch (io) {

case IO_METHOD_READ:

if (!(cap.capabilities & V4L2_CAP_READWRITE)) {

fprintf (stderr, "%s does not support read i/o\n",

dev_name);

exit (EXIT_FAILURE);

}

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",

dev_name);

exit (EXIT_FAILURE);

}

break;

}

/* Select video input, video standard and tune here. */

CLEAR (cropcap);

cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

if (0 == xioctl (fd, VIDIOC_CROPCAP, &cropcap)) {

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:

/* Cropping not supported. */

break;

default:

/* Errors ignored. */

break;

}

}

} else {

/* Errors ignored. */

}

CLEAR (fmt);

fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

fmt.fmt.pix.width = 600;

fmt.fmt.pix.height = 480;

fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;

fmt.fmt.pix.field = 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. */

/* Buggy driver paranoia. */

min = fmt.fmt.pix.width * 2;

if (fmt.fmt.pix.bytesperline < min)

fmt.fmt.pix.bytesperline = min;

min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;

if (fmt.fmt.pix.sizeimage < min)

fmt.fmt.pix.sizeimage = min;

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 void usage (FILE *fp, int argc, char ** argv)

{

fprintf (fp,

"Usage: %s [options]\n\n"

"Options:\n"

"-d | --device name Video device name [/dev/video]\n"

"-h | --help Print this message\n"

"-m | --mmap Use memory mapped buffers\n"

"-r | --read Use read() calls\n"

"-u | --userp Use application allocated buffers\n"

"",

argv[0]);

}

static const char short_options [] = "d:hmru";

static const struct option

long_options [] = {

{ "device", required_argument, NULL, 'd' },

{ "help", no_argument, NULL, 'h' },

{ "mmap", no_argument, NULL, 'm' },

{ "read", no_argument, NULL, 'r' },

{ "userp", no_argument, NULL, 'u' },

{ 0, 0, 0, 0 }

};

int main(int argc, char ** argv)

{

dev_name = "/dev/video0";

for (;;)

{

int index;

int c;

c = getopt_long (argc, argv, short_options, long_options, &index);

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 'm':

io = IO_METHOD_MMAP;

break;

case 'r':

io = IO_METHOD_READ;

break;

case 'u':

io = IO_METHOD_USERPTR;

break;

default:

usage (stderr, argc, argv);

exit (EXIT_FAILURE);

}

}

open_device();

init_device();

start_capturing();

mainloop();

stop_capturing();

uninit_device();

close_device();

exit(EXIT_SUCCESS);

return 0;

}