int checkFormat(int nChannels, int nSamplesPerSec, int nBitsPerSample)
{
int good;
good = isFormatSupported(nChannels, nSamplesPerSec, nBitsPerSample);
return good;
}
QVideoSurfaceFormat QAbstractVideoSurface::nearestFormat(const QVideoSurfaceFormat &format) const
{
return isFormatSupported(format)
? format
: QVideoSurfaceFormat();
}
int VideoCaptureV4L2::openDevice(int device, int w, int h, VideoCaptureFormat capFormat) {
std::vector<LinuxCaptureDevice> devices = getDeviceList();
if(device >= devices.size()) {
return 0;
}
LinuxCaptureDevice cap = devices[device];
fd = open(cap.path.c_str(), O_RDWR | O_NONBLOCK, 0);
if(fd == -1) {
printf("ERROR: cannot open: %s\n", cap.path.c_str());
fd = 0;
return 0;
}
// query capabilities
struct v4l2_capability caps;
memset(&caps, 0, sizeof(caps));
if (ioctl(fd, VIDIOC_QUERYCAP, &caps) == -1) {
printf("ERROR: cannot detect capabilities of camera.\n");
return 0;
}
// test if we can use this device as capture device
if(!(caps.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
printf("ERROR: cannot use device for video capture.\n");
return 0;
}
// check the io type
io_method = LINCAP_IO_METHOD_READ;
bool can_io_readwrite = (caps.capabilities & V4L2_CAP_READWRITE) == V4L2_CAP_READWRITE;
bool can_io_stream = (caps.capabilities & V4L2_CAP_STREAMING) == V4L2_CAP_STREAMING;
if(!can_io_readwrite && !can_io_stream) {
printf("ERROR: cannot use read() or memory streaming with this device.\n");
return 0;
}
if(can_io_stream) {
io_method = LINCAP_IO_METHOD_MMAP;
}
if(!isFormatSupported(capFormat, w, h, 1)) {
printf("ERROR: cannot set pixelformat and size: %dx%d\n", w,h);
return 0;
}
width = w;
height = h;
// initialize IO
if(io_method == LINCAP_IO_METHOD_MMAP) {
initMMAP();
}
else if(io_method == LINCAP_IO_METHOD_READ) {
printf("ERROR: this device can use read()/write() io, but we did not yet program this.\n");
::exit(0);
}
else if(io_method == LINCAP_IO_METHOD_USERPTR) {
printf("ERROR: this device can use i/o with userptr, but we need to program it.\n");
::exit(EXIT_FAILURE);
}
is_opened = true;
return 1;
}
