int v4l2_init() {
struct v4l2_capability video_cap;
if (xioctl(video_fd, VIDIOC_QUERYCAP, &video_cap) == -1)
return v4l2_error("VIDIOC_QUERYCAP");
if (!(video_cap.capabilities & V4L2_CAP_VIDEO_CAPTURE))
return v4l2_error("No video capture device");
if (!(video_cap.capabilities & V4L2_CAP_STREAMING))
return v4l2_error("No capture streaming");
struct v4l2_format video_fmt;
video_fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
video_fmt.fmt.pix.width = width;
video_fmt.fmt.pix.height = height;
video_fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
video_fmt.fmt.pix.field = V4L2_FIELD_ANY;
if (xioctl(video_fd, VIDIOC_S_FMT, &video_fmt) == -1)
v4l2_error("VIDIOC_S_FMT");
// Query V4L2 controls:
v4l2_query_ctrl(V4L2_CID_BASE,
V4L2_CID_LASTP1);
v4l2_query_ctrl(V4L2_CID_PRIVATE_BASE,
V4L2_CID_PRIVATE_BASE+20);
v4l2_query_ctrl(V4L2_CID_CAMERA_CLASS_BASE+1,
V4L2_CID_CAMERA_CLASS_BASE+20);
// Logitech specific controls:
v4l2_query_ctrl(V4L2_CID_FOCUS,
V4L2_CID_FOCUS+1);
v4l2_query_ctrl(V4L2_CID_LED1_MODE,
V4L2_CID_LED1_MODE+1);
v4l2_query_ctrl(V4L2_CID_LED1_FREQUENCY,
V4L2_CID_LED1_FREQUENCY+1);
v4l2_query_ctrl(V4L2_CID_DISABLE_PROCESSING,
V4L2_CID_DISABLE_PROCESSING+1);
v4l2_query_ctrl(V4L2_CID_RAW_BITS_PER_PIXEL,
V4L2_CID_RAW_BITS_PER_PIXEL+1);
// Initialize memory map
v4l2_init_mmap();
return 0;
}
bool BaseV4L2VideoCapture::InitializeDevice() {
Limitation brightness;
Limitation contrast;
Limitation hue;
Limitation saturation;
Limitation sharpness;
Limitation gamma;
Limitation backlightCompensation;
// 1. Get constraint of each capture filters
if(!v4l2_query_ctrl(V4L2_CID_BRIGHTNESS, &brightness))
return false;
if(!v4l2_query_ctrl(V4L2_CID_CONTRAST, &contrast))
return false;
if(!v4l2_query_ctrl(V4L2_CID_HUE, &hue))
return false;
if(!v4l2_query_ctrl(V4L2_CID_SATURATION, &saturation))
return false;
if(!v4l2_query_ctrl(V4L2_CID_SHARPNESS, &sharpness))
return false;
if(!v4l2_query_ctrl(V4L2_CID_GAMMA, &gamma))
return false;
if(!v4l2_query_ctrl(V4L2_CID_BACKLIGHT_COMPENSATION, &backlightCompensation))
return false;
// 2. Instantiate VideoCaptureFiltersCapability
// TODO : polymorphic the constructor for different support
_pVideoCaptureFiltersCapability = new VideoCaptureFiltersCapability(brightness, contrast, hue, saturation, sharpness, gamma, backlightCompensation);
// Below is for debug sake
//_pVideoCaptureFiltersCapability->PrintConstraintValues();
// Set capture filters to default here if needed
// 3. Initialize VideoCaptureFilters
InitVideoCaptureFilters();
return true;
}