[Android Q&A, Help & Troubleshooting] busybox_wode:
kill $( lsof |grep /dev/video|awk '{print $2}')

kill $( lsof |grep /dev/video*|awk '{print $2}')

---------- Post added at 04:29 PM ---------- Previous post was at 04:16 PM ----------

#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 force_format;

static int frame_count = 70;

static void errno_exit(const char *s)

{

fprintf(stderr, "43 %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;

}

//process_image(数据指针，大小)

static void process_image(const void *p, int size)

{

if (out_buf)

fwrite(p, size, 1, stdout);

fflush(stderr);

fprintf(stderr, ".");

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, buf.bytesused);

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.start

&& buf.length == buffers.length)

break;

assert(i < n_buffers);

process_image((void *)buf.m.userptr, buf.bytesused);

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

errno_exit("VIDIOC_QBUF");

break;

}

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, "190 select timeout\n");

exit(EXIT_FAILURE);

}

if (read_frame())

break;

/* EAGAIN - continue select loop. */

}

}

}

//VIDIOC_STREAMOFF

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;

}

}

//VIDIOC_STREAMON

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.start;

buf.length = buffers.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;

}

}

//释放申请的内存

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.start, buffers.length))

errno_exit("munmap");

break;

case IO_METHOD_USERPTR:

for (i = 0; i < n_buffers; ++i)

free(buffers.start);

break;

}

free(buffers);

}

static void init_read(unsigned int buffer_size)

{

buffers = calloc(1, sizeof(*buffers));

if (!buffers) {

fprintf(stderr, "302 Out of memory\n");

exit(EXIT_FAILURE);

}

buffers[0].length = buffer_size;

buffers[0].start = malloc(buffer_size);

if (!buffers[0].start) {

fprintf(stderr, "310 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, "327 %s does not support "

"memory mappingn", dev_name);

exit(EXIT_FAILURE);

} else {

errno_exit("VIDIOC_REQBUFS");

}

}

if (req.count < 2) {

fprintf(stderr, "336 Insufficient buffer memory on %s\n",

dev_name);

exit(EXIT_FAILURE);

}

buffers = calloc(req.count, sizeof(*buffers));

if (!buffers) {

fprintf(stderr, "344 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, "385 %@s does not support "

"user pointer i/on", dev_name);

exit(EXIT_FAILURE);

} else {

errno_exit("VIDIOC_REQBUFS");

}

}

buffers = calloc(4, sizeof(*buffers));

if (!buffers) {

fprintf(stderr, "396 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, "405 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, "421 @%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, "430 %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, "438 %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, "447 %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;

if (force_format) {

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;

if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt))

errno_exit("VIDIOC_S_FMT");

/* Note VIDIOC_S_FMT may change width and height. */

} else {

/* Preserve original settings as set by v4l2-ctl for example */

if (-1 == xioctl(fd, VIDIOC_G_FMT, &fmt))

errno_exit("VIDIOC_G_FMT");

}

/* 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, "536 Cannot identify '%s': %d, %s\n",

dev_name, errno, strerror(errno));

exit(EXIT_FAILURE);

}

if (!S_ISCHR(st.st_mode)) {

fprintf(stderr, "542 %s is no devicen", dev_name);

exit(EXIT_FAILURE);

}

fd = open(dev_name, O_RDWR /* required */ | O_NONBLOCK, 0);

if (-1 == fd) {

fprintf(stderr, "548 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"

"Version 1.3\n"

"Options:\n"

"-d | --device name Video device name [%s]n"

"-h | --help Print this messagen"

"-m | --mmap Use memory mapped buffers [default]n"

"-r | --read Use read() callsn"

"-u | --userp Use application allocated buffersn"

"-o | --output Outputs stream to stdoutn"

"-f | --format Force format to 640x480 YUYVn"

"-c | --count Number of frames to grab [%i]n"

"",

argv[0], dev_name, frame_count);

}

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

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' },

{ "output", no_argument, NULL, 'o' },

{ "format", no_argument, NULL, 'f' },

{ "count", required_argument, NULL, 'c' },

{ 0, 0, 0, 0 }

};

int main(int argc, char **argv)

{

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 'm':

io = IO_METHOD_MMAP;

break;

case 'r':

io = IO_METHOD_READ;

break;

case 'u':

io = IO_METHOD_USERPTR;

break;

case 'o':

out_buf++;

break;

case 'f':

force_format++;

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();

fprintf(stderr, "\n");

return 0;

}

root@markw:/data # gcc /sdcard/camera.c

root@markw:/data #

root@markw:/data # ./a.out

43 VIDIOC_QUERYCAP error 25, Not a typewriter