Hi,
The reason for a lower framerate must not necessarily be in the program,
it can be the hardware - either the clock frequency, your camera is driven
by, or the slow CPU, or the camera host driver, or your frame processing.
Thanks
Guennadi
On Thu, 26 Nov 2015, Ayhan KÃ~\Ã~GÃ~\KMANÄ°SA wrote:
> Hi,
>
>
> I'm trying to get image from aptina mt9v024 sensor using v4l2 library. In
> sensor datasheet that is defined that sensor has 60 fps capability at
> default. But with my code which is below i could get images at 20 fps. How
> can i reach 60 fps? Could you give me an advice that where is my fault?
>
> Thanks.
>
>
> //// CODE ////
>
>
> char *dev_name = "/dev/video0";
> int fd = v4l2_open(dev_name, O_RDWR | O_NONBLOCK, 0);
> if (fd < 0) {
> perror("Cannot open device");
> exit(EXIT_FAILURE);
> }
> cout << "camera init" << endl;
> CLEAR(fmt);
> fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> fmt.fmt.pix.width = 752;
> fmt.fmt.pix.height = 480;
> fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_SBGGR16;
> fmt.fmt.pix.field = V4L2_FIELD_ANY;
> xioctl(fd, VIDIOC_S_FMT, &fmt);
>
>
> CLEAR(req);
> req.count = 2;
> req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> req.memory = V4L2_MEMORY_MMAP;
> xioctl(fd, VIDIOC_REQBUFS, &req);
>
> buffers = (buffer *)calloc(req.count, sizeof(*buffers));
> for (n_buffers = 0; n_buffers < req.count; ++n_buffers) {
> CLEAR(buf);
>
> buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> buf.memory = V4L2_MEMORY_MMAP;
> buf.index = n_buffers;
>
> xioctl(fd, VIDIOC_QUERYBUF, &buf);
>
> buffers[n_buffers].length = buf.length;
> buffers[n_buffers].start = v4l2_mmap(NULL, buf.length,
> PROT_READ | PROT_WRITE, MAP_SHARED,
> fd, buf.m.offset);
>
> if (MAP_FAILED == buffers[n_buffers].start) {
> perror("mmap");
> exit(EXIT_FAILURE);
> }
> }
>
> for (i = 0; i < n_buffers; ++i) {
> CLEAR(buf);
> buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> buf.memory = V4L2_MEMORY_MMAP;
> buf.index = i;
> xioctl(fd, VIDIOC_QBUF, &buf);
> }
> type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> xioctl(fd, VIDIOC_STREAMON, &type);
> while(1)
> {
> do {
> FD_ZERO(&fds);
> FD_SET(fd, &fds);
>
> /* Timeout. */
> tv.tv_sec = 2;
> tv.tv_usec = 0;
>
> r = select(fd + 1, &fds, NULL, NULL, &tv);
> } while ((r == -1 && (errno = EINTR)));
> if (r == -1) {
> perror("select");
> return errno;
> }
>
> CLEAR(buf);
> buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> buf.memory = V4L2_MEMORY_MMAP;
> xioctl(fd, VIDIOC_DQBUF, &buf);
> /* Getting Image */
> Mat bayer16Bit = Mat(fmt.fmt.pix.height, fmt.fmt.pix.width, CV_8UC1, (void
> *)buffers[buf.index].start);
> }
>
>
>
>
> ---------------------------------------------------------------------------------------------------
> ArÅ?. Gör. Ayhan KÃ?Ã?Ã?KMANÄ°SA
> Kocaeli �niversitesi, GömÌlÌ Sistemler ve GörÌntÌleme Sistemleri
> Laboratuvarı
>
> Res. Asst. Ayhan KÃ?Ã?Ã?KMANÄ°SA
> Kocaeli University, Laboratory of Embedded and Vision Systems
>
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