forked from tTh/FloatImg
another snipper of code / libv4l2
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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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