what is the difference between using QCamera::supportedViewfinderResolutions and QCameraImageCapture::supportedResolutions?

Mozzie

Hi
I am using Qt5.12.10 multimedia module,
I found, with the same camera, on Windows I can get all resolution of my camera by using QCamera::supportedViewfinderResolutions(), but on Linux (Ubuntu18.04) , it return empty list.

after test Qt camera example, I found I can got resolutions by using QCameraImageCapture::supportedResolutions().

so, what is the difference between using QCamera::supportedViewfinderResolutions and QCameraImageCapture::supportedResolutions? which way is the correct way to write a cross application?

Thanks for your time.

SGaist

Hi,

If memory serves well, the second one is for the size of the images the encoder can generate.

The first one is for the viewfinder to show.

Did you ensure that the camera is loaded before checking that one ?

Mozzie

@SGaist
thank you ver much.

I check it when the camera state is QCamera::ActiveState, this is working on windows not on linux

connect(camera, &QCamera::stateChanged, this, [this](QCamera::State state){
	qDebug() << "QCamera::State" << state;
	if (QCamera::ActiveState == state) {

#ifdef QT_DEBUG
		for (const auto& rate : camera->supportedViewfinderFrameRateRanges(settings)) {
			qDebug() << "rate: " << rate.minimumFrameRate << rate.maximumFrameRate;
		}
		qDebug() << camera->supportedViewfinderPixelFormats();
		qDebug() << camera->supportedViewfinderResolutions();
#endif
		QList<QCameraViewfinderSettings > ViewSets = camera->supportedViewfinderSettings();
		foreach (QCameraViewfinderSettings ViewSet, ViewSets) {
			qDebug() << "haha" << ViewSet.pixelFormat() 
					 << " " << ViewSet.resolution().width()
					 << " " << ViewSet.resolution().height() 
					 << "," << ViewSet.minimumFrameRate();
		}
	}
}, Qt::QueuedConnection);

SGaist

Is it the same camera ?
Is it properly detected on Linux ?

Mozzie

@SGaist
hi
it is the same camera, and it can be properly detected on Linux,
the Qt camera example can work with my camera on Linux, just I can not get all resolution of my camera by using QCamera::supportedViewfinderResolutions() on Linux

SGaist

Can GStreamer return that information ?

Mozzie

@SGaist
I am sorry, I fogot this question so long.

the output of gst-device-monitor-1.0 is

Device found:

	name  : LAIQU-RX Camera : LAIQU-RX Came
	class : Video/Source
	caps  : video/x-raw, format=(string)YUY2, width=(int)1920, height=(int)1080, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)5/1;
	        video/x-raw, format=(string)YUY2, width=(int)1600, height=(int)896, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)5/1;
	        video/x-raw, format=(string)YUY2, width=(int)1280, height=(int)720, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)10/1;
	        video/x-raw, format=(string)YUY2, width=(int)1024, height=(int)768, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)15/1;
	        video/x-raw, format=(string)YUY2, width=(int)960, height=(int)720, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)10/1;
	        video/x-raw, format=(string)YUY2, width=(int)1024, height=(int)576, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)15/1;
	        video/x-raw, format=(string)YUY2, width=(int)800, height=(int)600, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)20/1;
	        video/x-raw, format=(string)YUY2, width=(int)864, height=(int)480, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)10/1;
	        video/x-raw, format=(string)YUY2, width=(int)800, height=(int)448, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)20/1;
	        video/x-raw, format=(string)YUY2, width=(int)640, height=(int)480, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        video/x-raw, format=(string)YUY2, width=(int)640, height=(int)360, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        video/x-raw, format=(string)YUY2, width=(int)352, height=(int)288, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        video/x-raw, format=(string)YUY2, width=(int)320, height=(int)240, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        image/jpeg, width=(int)1920, height=(int)1080, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        image/jpeg, width=(int)1600, height=(int)896, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        image/jpeg, width=(int)1280, height=(int)1024, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        image/jpeg, width=(int)1280, height=(int)720, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction){ 30/1, 5/1 };
	        image/jpeg, width=(int)960, height=(int)720, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        image/jpeg, width=(int)1024, height=(int)576, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        image/jpeg, width=(int)960, height=(int)544, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        image/jpeg, width=(int)800, height=(int)600, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction){ 30/1, 5/1 };
	        image/jpeg, width=(int)864, height=(int)480, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        image/jpeg, width=(int)800, height=(int)448, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        image/jpeg, width=(int)640, height=(int)480, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction){ 30/1, 5/1 };
	        image/jpeg, width=(int)640, height=(int)360, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        image/jpeg, width=(int)352, height=(int)288, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	        image/jpeg, width=(int)320, height=(int)240, pixel-aspect-ratio=(fraction)1/1, framerate=(fraction)30/1;
	properties:
		udev-probed = true
		device.bus_path = pci-0000:00:0c.0-usb-0:2:1.0
		sysfs.path = /sys/devices/pci0000:00/0000:00:0c.0/usb1/1-2/1-2:1.0/video4linux/video0
		device.bus = usb
		device.subsystem = video4linux
		device.vendor.id = 0c45
		device.vendor.name = "LAIQU-RX\\x20Camera\\x20"
		device.product.id = 6366
		device.product.name = "LAIQU-RX\ Camera\ :\ LAIQU-RX\ Came"
		device.serial = LAIQU-RX_Camera_LAIQU-RX_Camera_SN0001
		device.capabilities = :capture:
		device.api = v4l2
		device.path = /dev/video0
		v4l2.device.driver = uvcvideo
		v4l2.device.card = "LAIQU-RX\ Camera\ :\ LAIQU-RX\ Came"
		v4l2.device.bus_info = usb-0000:00:0c.0-2
		v4l2.device.version = 328805 (0x00050465)
		v4l2.device.capabilities = 2225078273 (0x84a00001)
		v4l2.device.device_caps = 69206017 (0x04200001)
	gst-launch-1.0 v4l2src ! ...

SGaist

Can you test a more recent version of Qt ?

Mozzie

@SGaist said in what is the difference between using QCamera::supportedViewfinderResolutions and QCameraImageCapture::supportedResolutions?:

an you test a more recent version of Qt ?

em.........I will try, give me some time

Mozzie

@SGaist

One more thing, what information do you need from test?

SGaist

As silly as it may sound: does it work ?
If so, then the backend has been updated and all is well. You can back port the possible fixes if need and if it's not working then this will be material for a potential ticket to open.