Ask Your Question

roothema's profile - activity

2013-10-03 07:30:19 -0500 asked a question OpenCV capture forward to V4L2 loopback

Hy!

I'm trying to implement the V4L2 loopback and its working, but the image what i forwards from the opencv capture it has some problems. If i know it right, opencv captures RGB image. In my settings I set the format like this->

header:

# define FRAME_FORMAT  V4L2_PIX_FMT_RGB24
# define FRAME_WIDTH  640
# define FRAME_HEIGHT 480

struct v4l2_capability vid_caps;
struct v4l2_format vid_format;
const char*video_device=VIDEO_DEVICE;
int fdwr;
size_t framesize= FRAME_WIDTH * FRAME_HEIGHT * 3;
size_t linewidth= FRAME_WIDTH * 3;

Video format settings:

vid_format.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
vid_format.fmt.pix.width = FRAME_WIDTH;
vid_format.fmt.pix.height = FRAME_HEIGHT;
vid_format.fmt.pix.pixelformat = FRAME_FORMAT;
vid_format.fmt.pix.sizeimage = framesize;
vid_format.fmt.pix.field = V4L2_FIELD_NONE;
vid_format.fmt.pix.bytesperline = linewidth;
vid_format.fmt.pix.colorspace = V4L2_COLORSPACE_SRGB;

Writing:

    IplImage *frame= NULL; //Preparing frame pointer
    CvCapture *input_camera= cvCaptureFromCAM(1);
    cvSetCaptureProperty(input_camera, CV_CAP_PROP_FRAME_WIDTH, FRAME_WIDTH);
    cvSetCaptureProperty(input_camera, CV_CAP_PROP_FRAME_HEIGHT, FRAME_HEIGHT);

    frame = cvQueryFrame(input_camera);
    write(fdwr, &frame->imageData, framesize);

The problem is my image colors aren't right. Sometimes its green or cyan overlayed. The original yellow color is displayed like purple. Did anyone meet this kind of problem of does somebody know the solution? Thank you for any kind of help!