435 lines
9.2 KiB
C
435 lines
9.2 KiB
C
#include <errno.h>
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#include <fcntl.h>
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#include <linux/videodev2.h>
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#include <sys/ioctl.h>
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#include <sys/mman.h>
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#include <asm/errno.h>
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#include <gtk/gtk.h>
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#define CLEAR(x) memset(&(x), 0, sizeof(x))
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enum io_method {
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IO_METHOD_READ,
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IO_METHOD_MMAP,
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IO_METHOD_USERPTR,
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};
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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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struct buffer *buffers;
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static unsigned int n_buffers;
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static char *dev_name;
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static enum io_method io = IO_METHOD_MMAP;
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static int force_format_width = 640;
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static int force_format_height = 480;
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GObject *preview_image;
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static int xioctl(int fd, int request, void *arg) {
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int r;
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do r = ioctl(fd, request, arg);
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while (-1 == r && EINTR == errno);
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return r;
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}
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static void errno_exit(const char *s) {
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fprintf(stderr, "%s error %d, %s\\n", s, errno, strerror(errno));
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exit(EXIT_FAILURE);
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}
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static void start_capturing(int fd) {
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unsigned int i;
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enum v4l2_buf_type type;
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switch (io) {
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case IO_METHOD_READ:
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/* Nothing to do. */
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break;
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case IO_METHOD_MMAP:
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for (i = 0; i < n_buffers; ++i) {
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struct v4l2_buffer buf;
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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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if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
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errno_exit("VIDIOC_QBUF");
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}
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type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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if (-1 == xioctl(fd, VIDIOC_STREAMON, &type))
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errno_exit("VIDIOC_STREAMON");
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break;
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case IO_METHOD_USERPTR:
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for (i = 0; i < n_buffers; ++i) {
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struct v4l2_buffer buf;
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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_USERPTR;
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buf.index = i;
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buf.m.userptr = (unsigned long) buffers[i].start;
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buf.length = buffers[i].length;
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if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
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errno_exit("VIDIOC_QBUF");
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}
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type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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if (-1 == xioctl(fd, VIDIOC_STREAMON, &type))
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errno_exit("VIDIOC_STREAMON");
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break;
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}
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}
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static void init_mmap(int fd) {
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struct v4l2_requestbuffers req;
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CLEAR(req);
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req.count = 4;
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req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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req.memory = V4L2_MEMORY_MMAP;
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if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) {
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if (EINVAL == errno) {
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fprintf(stderr, "%s does not support "
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"memory mappingn", dev_name);
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exit(EXIT_FAILURE);
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} else {
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errno_exit("VIDIOC_REQBUFS");
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}
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}
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if (req.count < 2) {
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fprintf(stderr, "Insufficient buffer memory on %s\\n",
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dev_name);
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exit(EXIT_FAILURE);
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}
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buffers = calloc(req.count, sizeof(*buffers));
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if (!buffers) {
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fprintf(stderr, "Out of memory\\n");
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exit(EXIT_FAILURE);
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}
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for (n_buffers = 0; n_buffers < req.count; ++n_buffers) {
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struct v4l2_buffer buf;
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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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if (-1 == xioctl(fd, VIDIOC_QUERYBUF, &buf))
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errno_exit("VIDIOC_QUERYBUF");
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buffers[n_buffers].length = buf.length;
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buffers[n_buffers].start =
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mmap(NULL /* start anywhere */,
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buf.length,
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PROT_READ | PROT_WRITE /* required */,
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MAP_SHARED /* recommended */,
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fd, buf.m.offset);
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if (MAP_FAILED == buffers[n_buffers].start)
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errno_exit("mmap");
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}
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}
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static void init_device(int fd) {
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struct v4l2_capability cap;
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struct v4l2_cropcap cropcap;
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struct v4l2_crop crop;
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struct v4l2_format fmt;
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unsigned int min;
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if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &cap)) {
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if (EINVAL == errno) {
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fprintf(stderr, "%s is no V4L2 device\\n",
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dev_name);
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exit(EXIT_FAILURE);
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} else {
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errno_exit("VIDIOC_QUERYCAP");
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}
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}
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if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
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fprintf(stderr, "%s is no video capture device\\n",
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dev_name);
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exit(EXIT_FAILURE);
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}
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switch (io) {
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case IO_METHOD_READ:
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if (!(cap.capabilities & V4L2_CAP_READWRITE)) {
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fprintf(stderr, "%s does not support read i/o\\n",
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dev_name);
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exit(EXIT_FAILURE);
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}
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break;
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case IO_METHOD_MMAP:
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case IO_METHOD_USERPTR:
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if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
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fprintf(stderr, "%s does not support streaming i/o\\n",
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dev_name);
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exit(EXIT_FAILURE);
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}
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break;
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}
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/* Select video input, video standard and tune here. */
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CLEAR(cropcap);
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cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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if (0 == xioctl(fd, VIDIOC_CROPCAP, &cropcap)) {
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crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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crop.c = cropcap.defrect; /* reset to default */
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if (-1 == xioctl(fd, VIDIOC_S_CROP, &crop)) {
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switch (errno) {
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case EINVAL:
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/* Cropping not supported. */
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break;
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default:
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/* Errors ignored. */
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break;
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}
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}
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} else {
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/* Errors ignored. */
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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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if (force_format_width > 0) {
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fmt.fmt.pix.width = force_format_width;
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fmt.fmt.pix.height = force_format_height;
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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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printf("Requesting a cooler format!\n");
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if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt))
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errno_exit("VIDIOC_S_FMT");
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/* Note VIDIOC_S_FMT may change width and height. */
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} else {
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/* Preserve original settings as set by v4l2-ctl for example */
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if (-1 == xioctl(fd, VIDIOC_G_FMT, &fmt))
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errno_exit("VIDIOC_G_FMT");
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}
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/* Buggy driver paranoia. */
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min = fmt.fmt.pix.width * 2;
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if (fmt.fmt.pix.bytesperline < min)
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fmt.fmt.pix.bytesperline = min;
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min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;
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if (fmt.fmt.pix.sizeimage < min)
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fmt.fmt.pix.sizeimage = min;
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switch (io) {
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case IO_METHOD_READ:
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//init_read(fmt.fmt.pix.sizeimage);
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break;
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case IO_METHOD_MMAP:
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init_mmap(fd);
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break;
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case IO_METHOD_USERPTR:
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//init_userp(fmt.fmt.pix.sizeimage);
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break;
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}
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}
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static void process_image(const void *p, int size) {
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GdkPixbuf *pixbuf;
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pixbuf = gdk_pixbuf_new_from_data(p, GDK_COLORSPACE_RGB, FALSE, 8, 640, 480, 2 * 640, NULL, NULL);
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gtk_image_set_from_pixbuf(preview_image, pixbuf);
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}
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static int read_frame(int fd) {
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struct v4l2_buffer buf;
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unsigned int i;
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switch (io) {
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case IO_METHOD_READ:
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if (-1 == read(fd, buffers[0].start, buffers[0].length)) {
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switch (errno) {
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case EAGAIN:
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return 0;
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case EIO:
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/* Could ignore EIO, see spec. */
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/* fall through */
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default:
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errno_exit("read");
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}
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}
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process_image(buffers[0].start, buffers[0].length);
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break;
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case IO_METHOD_MMAP:
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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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if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) {
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switch (errno) {
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case EAGAIN:
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return 0;
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case EIO:
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/* Could ignore EIO, see spec. */
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/* fall through */
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default:
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errno_exit("VIDIOC_DQBUF");
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}
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}
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//assert(buf.index < n_buffers);
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process_image(buffers[buf.index].start, buf.bytesused);
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if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
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errno_exit("VIDIOC_QBUF");
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break;
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case IO_METHOD_USERPTR:
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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_USERPTR;
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if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) {
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switch (errno) {
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case EAGAIN:
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return 0;
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case EIO:
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/* Could ignore EIO, see spec. */
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/* fall through */
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default:
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errno_exit("VIDIOC_DQBUF");
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}
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}
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for (i = 0; i < n_buffers; ++i)
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if (buf.m.userptr == (unsigned long) buffers[i].start
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&& buf.length == buffers[i].length)
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break;
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//assert(i < n_buffers);
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process_image((void *) buf.m.userptr, buf.bytesused);
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if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))
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errno_exit("VIDIOC_QBUF");
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break;
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}
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return 1;
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}
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static void get_frame(int fd) {
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for (;;) {
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fd_set fds;
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struct timeval tv;
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int r;
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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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if (-1 == r) {
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if (EINTR == errno)
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continue;
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errno_exit("select");
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}
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if (0 == r) {
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fprintf(stderr, "select timeout\\n");
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exit(EXIT_FAILURE);
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}
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if (read_frame(fd))
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break;
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/* EAGAIN - continue select loop. */
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}
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}
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int main(int argc,
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char *argv[]) {
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GtkBuilder *builder;
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GObject *window;
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GObject *preview_box;
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GError *error = NULL;
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gtk_init(&argc, &argv);
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/* Construct a GtkBuilder instance and load our UI description */
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builder = gtk_builder_new();
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if (gtk_builder_add_from_file(builder, "camera.glade", &error) == 0) {
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g_printerr("Error loading file: %s\n", error->message);
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g_clear_error(&error);
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return 1;
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}
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/* Connect signal handlers to the constructed widgets. */
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window = gtk_builder_get_object(builder, "window");
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preview_box = gtk_builder_get_object(builder, "preview_box");
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preview_image = gtk_builder_get_object(builder, "preview");
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g_signal_connect (window, "destroy", G_CALLBACK(gtk_main_quit), NULL);
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/* Load the css */
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GtkCssProvider *provider = gtk_css_provider_new();
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gtk_css_provider_load_from_path(provider, "camera.css", NULL);
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GtkStyleContext *context;
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context = gtk_widget_get_style_context(preview_box);
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gtk_style_context_add_provider(context, GTK_STYLE_PROVIDER(provider), GTK_STYLE_PROVIDER_PRIORITY_USER);
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/* Grab a frame from the camera */
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int fd;
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fd = open("/dev/video0", O_RDWR);
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if (fd == -1) {
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g_printerr("Error opening video device: /dev/video0\n");
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return 1;
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}
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init_device(fd);
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start_capturing(fd);
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get_frame(fd);
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/* Show application */
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gtk_widget_show(window);
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gtk_main();
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return 0;
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} |