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/* V4L2 video picture grabber
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Copyright (C) 2009 Mauro Carvalho Chehab <mchehab@infradead.org> |
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation version 2 of the License. |
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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*/ |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <fcntl.h> |
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#include <errno.h> |
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#include <sys/ioctl.h> |
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#include <sys/types.h> |
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#include <sys/time.h> |
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#include <sys/mman.h> |
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#include <linux/videodev2.h> |
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#include <libv4l2.h> |
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#define CLEAR(x) memset(&(x), 0, sizeof(x)) |
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struct buffer { |
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void *start; |
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size_t length; |
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}; |
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static void xioctl(int fh, int request, void *arg) |
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{ |
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int r; |
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do { |
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r = v4l2_ioctl(fh, request, arg); |
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} while (r == -1 && ((errno == EINTR) || (errno == EAGAIN))); |
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if (r == -1) { |
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fprintf(stderr, "error %d, %s\n", errno, strerror(errno)); |
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exit(EXIT_FAILURE); |
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} |
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} |
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int main(int argc, char **argv) |
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{ |
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struct v4l2_format fmt; |
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struct v4l2_buffer buf; |
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struct v4l2_requestbuffers req; |
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enum v4l2_buf_type type; |
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fd_set fds; |
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struct timeval tv; |
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int r, fd = -1; |
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unsigned int i, n_buffers; |
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char *dev_name = "/dev/video0"; |
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char out_name[256]; |
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FILE *fout; |
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struct buffer *buffers; |
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fd = v4l2_open(dev_name, O_RDWR | O_NONBLOCK, 0); |
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if (fd < 0) { |
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perror("Cannot open device"); |
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exit(EXIT_FAILURE); |
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} |
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CLEAR(fmt); |
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fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; |
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fmt.fmt.pix.width = 640; |
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fmt.fmt.pix.height = 480; |
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fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_RGB24; |
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fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; |
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xioctl(fd, VIDIOC_S_FMT, &fmt); |
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if (fmt.fmt.pix.pixelformat != V4L2_PIX_FMT_RGB24) { |
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printf("Libv4l didn't accept RGB24 format. Can't proceed.\n"); |
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exit(EXIT_FAILURE); |
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} |
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if ((fmt.fmt.pix.width != 640) || (fmt.fmt.pix.height != 480)) |
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printf("Warning: driver is sending image at %dx%d\n", |
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fmt.fmt.pix.width, fmt.fmt.pix.height); |
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CLEAR(req); |
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req.count = 2; |
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req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; |
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req.memory = V4L2_MEMORY_MMAP; |
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xioctl(fd, VIDIOC_REQBUFS, &req); |
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buffers = calloc(req.count, sizeof(*buffers)); |
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for (n_buffers = 0; n_buffers < req.count; ++n_buffers) { |
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CLEAR(buf); |
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buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; |
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buf.memory = V4L2_MEMORY_MMAP; |
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buf.index = n_buffers; |
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xioctl(fd, VIDIOC_QUERYBUF, &buf); |
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buffers[n_buffers].length = buf.length; |
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buffers[n_buffers].start = v4l2_mmap(NULL, buf.length, |
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PROT_READ | PROT_WRITE, MAP_SHARED, |
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fd, buf.m.offset); |
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if (MAP_FAILED == buffers[n_buffers].start) { |
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perror("mmap"); |
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exit(EXIT_FAILURE); |
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} |
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} |
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for (i = 0; i < n_buffers; ++i) { |
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CLEAR(buf); |
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buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; |
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buf.memory = V4L2_MEMORY_MMAP; |
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buf.index = i; |
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xioctl(fd, VIDIOC_QBUF, &buf); |
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} |
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type = V4L2_BUF_TYPE_VIDEO_CAPTURE; |
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xioctl(fd, VIDIOC_STREAMON, &type); |
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for (i = 0; i < 20; i++) { |
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do { |
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FD_ZERO(&fds); |
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FD_SET(fd, &fds); |
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/* Timeout. */ |
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tv.tv_sec = 2; |
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tv.tv_usec = 0; |
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r = select(fd + 1, &fds, NULL, NULL, &tv); |
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} while ((r == -1 && (errno = EINTR))); |
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if (r == -1) { |
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perror("select"); |
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return errno; |
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} |
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CLEAR(buf); |
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buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; |
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buf.memory = V4L2_MEMORY_MMAP; |
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xioctl(fd, VIDIOC_DQBUF, &buf); |
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sprintf(out_name, "out%03d.ppm", i); |
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fout = fopen(out_name, "w"); |
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if (!fout) { |
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perror("Cannot open image"); |
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exit(EXIT_FAILURE); |
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} |
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fprintf(fout, "P6\n%d %d 255\n", |
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fmt.fmt.pix.width, fmt.fmt.pix.height); |
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fwrite(buffers[buf.index].start, buf.bytesused, 1, fout); |
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fclose(fout); |
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sleep(30); |
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xioctl(fd, VIDIOC_QBUF, &buf); |
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} |
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type = V4L2_BUF_TYPE_VIDEO_CAPTURE; |
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xioctl(fd, VIDIOC_STREAMOFF, &type); |
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for (i = 0; i < n_buffers; ++i) |
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v4l2_munmap(buffers[i].start, buffers[i].length); |
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v4l2_close(fd); |
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return 0; |
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} |
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