How to get camera supported resolutions using Qt5?
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Today I had the chance to test my sample from OSX and I got the same result, the method QCameraImageCapture::supportedResolutions() doesn't work here neither:
$ uname -a
Darwin MacBook-Pro.local 13.1.0 Darwin Kernel Version 13.1.0: Thu Jan 16 19:40:37 PST 2014; root:xnu-2422.90.20~2/RELEASE_X86_64 x86_64$ qmake -version
QMake version 3.0
Using Qt version 5.3.0 in /Users/test/Qt5.3.0/5.3/clang_64/lib$ ./camera.app/Contents/MacOS/camera
Camera description: "Cámara FaceTime HD (integrada)"
Camera status: QCamera::LoadedStatus
Camera resolution list size: 0 -
Testing the same example but this time using Qt 5.3.1 from Linux, same result:
$ ./camera
Camera description: "USB2.0 UVC WebCam"
Camera status: QCamera::LoadedStatus
CameraBinImageEncoder::supportedResolutions()
Camera resolution list size: 0The method supportedResolutions() always returns an empty list :(
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Surprisingly I couldn't find a bug report about this (for linux)...
Now here it is:
https://bugreports.qt-project.org/browse/QTBUG-40545Follow, upvote, comment. Make some noise!
(There is a bug report for windows, but there it is just not supported...
https://bugreports.qt-project.org/browse/QTBUG-32743 ) -
It looks like that gstreamer on Linux is not returing any value in: camerabinsession.cpp
@ GstCaps *supportedCaps = 0;
g_object_get(G_OBJECT(m_camerabin),
(mode == QCamera::CaptureStillImage) ?
SUPPORTED_IMAGE_CAPTURE_CAPS_PROPERTY : SUPPORTED_VIDEO_CAPTURE_CAPS_PROPERTY,
&supportedCaps, NULL);
if (!supportedCaps)
return res;@I was trying calling gstreamer out of QT and was getting NULL as well. Is it a bug in GStreamer?
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It looks like that gstreamer on Linux is not returing any value in: camerabinsession.cpp
@ GstCaps *supportedCaps = 0;
g_object_get(G_OBJECT(m_camerabin),
(mode == QCamera::CaptureStillImage) ?
SUPPORTED_IMAGE_CAPTURE_CAPS_PROPERTY : SUPPORTED_VIDEO_CAPTURE_CAPS_PROPERTY,
&supportedCaps, NULL);
if (!supportedCaps)
return res;@I was trying calling gstreamer out of QT and was getting NULL as well. Is it a bug in GStreamer?
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Hi,
Either that or the device doesn't return the information. Do you have any other way to retrieve that information on your system ?
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Hi,
Either that or the device doesn't return the information. Do you have any other way to retrieve that information on your system ?
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Well, v4l2 is returning:
@$ v4l2-ctl --list-formats-ext
ioctl: VIDIOC_ENUM_FMT
Index : 0
Type : Video Capture
Pixel Format: 'YUYV'
Name : YUV 4:2:2 (YUYV)
Size: Discrete 640x480
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Size: Discrete 640x360
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.067s (15.000 fps)
...@The structure GstCaps *supportedCaps from previous code, has 0 length, but it's valid but @gst_caps_is_any(supportedCaps) == true@
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Well, v4l2 is returning:
@$ v4l2-ctl --list-formats-ext
ioctl: VIDIOC_ENUM_FMT
Index : 0
Type : Video Capture
Pixel Format: 'YUYV'
Name : YUV 4:2:2 (YUYV)
Size: Discrete 640x480
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.067s (15.000 fps)
Size: Discrete 640x360
Interval: Discrete 0.033s (30.000 fps)
Interval: Discrete 0.067s (15.000 fps)
...@The structure GstCaps *supportedCaps from previous code, has 0 length, but it's valid but @gst_caps_is_any(supportedCaps) == true@
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I've digged deeper into GStreamer plugin gstcamerabin2.c, here it's querying for pad capabilities @pad = gst_element_get_static_pad (element, padname);
caps = gst_pad_query_caps (pad, NULL);@ and then the query failing "GstPAd.html":http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPad.html
...gst_pad_query_caps returns all possible caps a pad can operate with, using the pad's CAPS query function, If the query fails, this function will return filter , if not NULL, otherwise ANY.
And this ANY is what's returned into QT and then returned as empty QList. I thing we should use another gstreamer input element aka v4l2src which is stable. Camerabin2 is marked as unstable and under development.
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I've digged deeper into GStreamer plugin gstcamerabin2.c, here it's querying for pad capabilities @pad = gst_element_get_static_pad (element, padname);
caps = gst_pad_query_caps (pad, NULL);@ and then the query failing "GstPAd.html":http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPad.html
...gst_pad_query_caps returns all possible caps a pad can operate with, using the pad's CAPS query function, If the query fails, this function will return filter , if not NULL, otherwise ANY.
And this ANY is what's returned into QT and then returned as empty QList. I thing we should use another gstreamer input element aka v4l2src which is stable. Camerabin2 is marked as unstable and under development.
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Thanks for sharing your findings !
Do you have that with gstreamer0.1 ? Did you check gstreamer 1 ?
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Thanks for sharing your findings !
Do you have that with gstreamer0.1 ? Did you check gstreamer 1 ?
