Code suddenly stops at self.cam = QCamera() , PyQt5.9.2, Qt5.9.3, Python3.5

JonB

@Xenoshell
Look, I don't know your situation, but maybe it's possible that your multimedia is "out of sync" with the rest of your Qt installed? Like I said, I'm surprised then that it works for root but not other users, but who knows....

Since no-one else seems to be posting to help you on your camera issue, you might want to try a new thread purely about how to correctly install Qt with multimedia under your OS, get it all sorted out properly, and then see if miraculously that solves your problem....

Xenoshell

@JNBarchan
Ok i am gonna do that.

JonB

@Xenoshell

Just so you know, I was @JNBarchan but now I have had a change of identity and I am @JonB!

@Xenoshell has raised the new installation question to (begin to) sort this out at https://forum.qt.io/topic/85955/reinstall-qt5-with-qtmultimedia-using-ubuntu-mate

Xenoshell

@JonB I just tried my code after the installation and somehow it doesnt stop at qcamera anymore, but now the window that pops out is black and i get a bunch of errors in the terminal.

1
2
3
4
5
Venus USB2.0 Camera: Venus USB2
[<PyQt5.QtMultimedia.QCameraInfo object at 0x72ddd3f0>]
/dev/video0
6

(python3:2758): GLib-GObject-WARNING **: g_object_set_valist: object class 'GstVaapiSink' has no property named '0\xff\xf7\x81\xbb'

(python3:2758): GLib-GObject-WARNING **: g_object_set_valist: object class 'GstVaapiSink' has no property named '0\xff\xf7Ż'

(python3:2758): GLib-GObject-WARNING **: g_object_set_valist: object class 'GstVaapiSink' has no property named '0\xff\xf7	\xbc'

(python3:2758): GLib-GObject-WARNING **: g_object_set_valist: object class 'GstVaapiSink' has no property named '0\xff\xf7M\xbc'
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
7
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
CameraBin error: "Internal data flow error."
CameraBin error: "Internal data flow error."

I dont know if now this is because my installation of qt5 is faulted or something else. Do i have to reinstall PyQt5 too?
@SGaist here is my code again.

import sys
from PyQt5 import QtCore , QtWidgets, QtGui, QtMultimedia, QtMultimediaWidgets
from PyQt5.QtCore import QObject, pyqtSignal, pyqtSlot
from PyQt5.QtWidgets import QApplication, QPushButton, QMainWindow
from PyQt5.QtMultimedia import QCamera, QCameraInfo, QMediaObject, QCameraViewfinderSettings, QCameraImageCapture
from PyQt5.QtMultimediaWidgets import QCameraViewfinder


class Camera(QObject):
    def __init__(self, parent = QObject()):
        super(Camera, self).__init__(parent)
        print("3")
        self.cam = QCamera("/dev/video0".encode())   #QCameraInfo.defaultCamera()
        print("4")
        self.caminfo = QCameraInfo(self.cam)
        self.camvfind = QCameraViewfinder()
        self.camvfindset = QCameraViewfinderSettings()
        self.cammode = self.cam.CaptureMode(0)
        self.camimgcap = QCameraImageCapture(self.cam)

    def iniCamera(self):
        print(self.caminfo.description())
        print(self.caminfo.availableCameras())
        
        for caminfo in QCameraInfo.availableCameras():
            print(caminfo.deviceName())
        
        if self.cam.isCaptureModeSupported(self.cammode):
            print("Capturemode supported")
    
    def startVid(self):
        #self.camimgcap.CaptureDestination(2)
        
        self.camvfind.show()
        
        self.cam.setViewfinder(self.camvfind)
        
        self.cam.setCaptureMode(self.cammode)
        
        self.cam.start()
        
        

if __name__ == '__main__':
    print("1")
    app = QtWidgets.QApplication(sys.argv)
    print("2")
    cam = Camera()
    print("5")
    cam.iniCamera()
    print("6")
    cam.startVid()
    print("7")
    sys.exit(app.exec_())

JonB

@Xenoshell
Well I think that's actually progress!!

Experts will know better than I, but obviously it looks like there are issues which need fixing, which hopefully will then mean you can use the camera OK!

You do not have to do any PyQt re-installs. However, you should ensure that the version of PyQt matches whatever version you have now for Qt. And don't blame me if they don't match, I have a nasty feeling I might have read somewhere that PyQt only goes up to Qt 5.9 at present till the new year. If your Qt is 5.10 we'll have to hope that PyQt 5.9 works sufficiently with it --- you'd have to Google.

But before you look at PyQt, wait for an expert here to explain what your error messages indicate.

P.S.
You say it used to work when run as sudo. Is that still the case now, or same behaviour regardless?

Xenoshell

@JonB i just tested it and sudo doesnt make a difference anymore. I guess thats a good thing. But yeah i dont see a camera feed

Xenoshell

@SGaist @JonB, hello i wish you a happy new year. I am gonna be now more active. SGaist, can you please interpret the newest output i recieved? My screen doesnt lock up anymore and all but i still have a black screen?

Maybe thats a dumb question but do i need a .ui file for all of this to work? Currently i have besides the qt5.py file no other related to all this? I figured that i can add all of the GUI stuff after the code actually works. Am i wrong with that assumption?

Greets

Xeno

Xenoshell

I activated OpenGL for the Raspberry Pi and now the error changed a little bit. It produces actually more errors.
I googled for the vc4_drv_video.so and it solution was to just activate OpenGL which did nothing.

blz@blz-desktop:~/Schreibtisch$ python3 qt5.py
1
2
3

(gst-plugin-scanner:1628): GLib-GObject-WARNING **: cannot register existing type 'ClutterGstVideoSink'

(gst-plugin-scanner:1628): GLib-GObject-CRITICAL **: g_type_add_interface_static: assertion 'G_TYPE_IS_INSTANTIATABLE (instance_type)' failed

(gst-plugin-scanner:1628): GLib-CRITICAL **: g_once_init_leave: assertion 'result != 0' failed

(gst-plugin-scanner:1628): GStreamer-CRITICAL **: gst_element_register: assertion 'g_type_is_a (type, GST_TYPE_ELEMENT)' failed
4
5
Venus USB2.0 Camera: Venus USB2
[<PyQt5.QtMultimedia.QCameraInfo object at 0x72e273f0>]
/dev/video0
6

(python3:1626): GLib-GObject-WARNING **: g_object_set_valist: object class 'GstVaapiSink' has no property named '0\xff\xf7\x81\xbb'

(python3:1626): GLib-GObject-WARNING **: g_object_set_valist: object class 'GstVaapiSink' has no property named '0\xff\xf7Ż'

(python3:1626): GLib-GObject-WARNING **: g_object_set_valist: object class 'GstVaapiSink' has no property named '0\xff\xf7	\xbc'

(python3:1626): GLib-GObject-WARNING **: g_object_set_valist: object class 'GstVaapiSink' has no property named '0\xff\xf7M\xbc'
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
7
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
CameraBin error: "Internal data flow error."
CameraBin error: "Internal data flow error."

JonB

@Xenoshell

libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1

I assume this is the root of your problems. So does file /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so even exist?

Also, nothing to do with Qt, you're supposed to be able to run command vainfo: https://wiki.archlinux.org/index.php/Hardware_video_acceleration

Xenoshell

@JonB I just looked in the folder and i dont have the file vc4_drv_video.so. I just have vc4_dri.so. Also i didnt have vainfo and after installing vainfo and running the command the output was:

blz@blz-desktop:~$ vainfo
libva info: VA-API version 0.39.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib/arm-linux-gnueabihf/dri/vc4_drv_video.so
libva info: va_openDriver() returns -1
vaInitialize failed with error code -1 (unknown libva error),exit

I looked at the link you attached and i just dont know what do download. I have a ARM CPU because of my raspberry pi. I have no intel cpu or even a gpu. What can i do to fix that problem?

JonB

@Xenoshell
Again, I'm afraid I have no answer to your question. I'm only trying to point you in what I think is the right direction. I note there is a "Raspberry Pi" sub-forum here, I don't know if you'd get more help there, or perhaps on the web.

My point here is: everything you seem to be showing indicates that you have a fundamental problem with your Linux driver situation. Qt in itself does not seem to be relevant. Until you can get through vainfo without it reporting error I presume your camera is not going to work.

From my very limited understanding, VA-API or similar is to do with video hardware acceleration. If you say you "haven't got a GPU", are you supposed to be in this area at all??

I'm wondering whether your whole system is misconfigured. Forget Qt. You have a camera, which I think you said had some installation instructions. Go back to that. Goggle for setting up your camera under Linux, or Raspberry Pi. Go the camera's forum, or perhaps a dedicated Raspberry Pi forum on the web. That's the angle you should be approaching this from.

One thing I've asked you before but don't think you answered: are you able to use that camera at all completely outside of the code you're trying to write in Qt? I assume there must be some generic piece of software that's supposed to work with the camera from, say, System Settings? Like, it should just allow you to enable the camera and perhaps show what it is seeing? I think the Qt angle is like trying to run before you can walk....

Xenoshell

@JonB Yeah i dont expect you to know everything... The camera actually works on a normal camera showing program that was installed with ubuntu mate, so i know the camera is working. I am actually posting on other forums too, the thing is i dont get much info from them either.

Also one question you didnt answer was if i need the .ui file for all of this to work.

JonB

@Xenoshell

Also one question you didnt answer was if i need the .ui file for all of this to work.

That's 'coz I wouldn't have a clue, as I don't use them! But as I say, you can forget Qt till vainfo looks happy.

The camera actually works on a normal camera showing program that was installed with ubuntu mate

I don't suppose you can get the source for that program from somewhere.... ?

Xenoshell

@JonB Well its called cheese and a quick google brought me to this github

JonB

@Xenoshell
So I see that says:

How to get your camera working:
To get your camera working with cheese, you will have to ensure that it works
with the Gstreamer Framework and Video4Linux2 (V4L2) or Video4Linux (V4L). To
test this, you can use the 'gstreamer-properties' tool.

I don't know (again!), but it looks to me as though that interface is not the same thing as vainfo which uses VA API? Have a look at https://en.wikipedia.org/wiki/Video_Acceleration_API ? And that talks about "Software supporting VA API: GStreamer through gstreamer-vaapi[19]" . So maybe you need to get that configured....

I'm going to leave this to you, as I know nothing....

JonB

@Xenoshell
There is literally like one occurrence on the whole of the Interweb of your error in vainfo (va_openDriver() returns -1)!
https://bugs.launchpad.net/ubuntu/+source/libva-utils/+bug/1719150
It was suggested:

Please install mesa-va-drivers and try gain.

I suggest you try that.... :)