mipi csi camera is not detected in the simple browser application running on imx8mplus board

[Rajesh_M]

Hi @SGaist,
Thank you for giving your time . I am able to stream the camera by using the declarative camera .But I am not able to access the camera from the qtwebengine browser applications .I am even able to stream the camera by using gstlaunch1.0 command .Usb camera is detected in those examples which I tried but mipi camera is not detetcted.

root@imx8mpevk:~# v4l2-ctl --list-device
 ():
        /dev/v4l-subdev0

FSL Capture Media Device (platform:32c00000.bus:camera):
        /dev/media0

mxc-isi-cap (platform:32e00000.isi:cap_devic):
        /dev/video3

mxc-isi-m2m (platform:32e00000.isi:m2m_devic):
        /dev/video2

vsi_v4l2dec (platform:vsi_v4l2dec):
        /dev/video1

vsi_v4l2enc (platform:vsi_v4l2enc):
        /dev/video0

root@imx8mpevk:~# v4l2-ctl --all -d /dev/video3
Driver Info:
        Driver name      : mxc-isi-cap
        Card type        : mxc-isi-cap
        Bus info         : platform:32e00000.isi:cap_devic
        Driver version   : 6.1.36
        Capabilities     : 0x84201000
                Video Capture Multiplanar
                Streaming
                Extended Pix Format
                Device Capabilities
        Device Caps      : 0x04201000
                Video Capture Multiplanar
                Streaming
                Extended Pix Format
Priority: 2
Format Video Capture Multiplanar:
        Width/Height      : 640/480
        Pixel Format      : 'RGBP' (16-bit RGB 5-6-5)
        Field             : None
        Number of planes  : 1
        Flags             :
        Colorspace        : sRGB
        Transfer Function : Default
        YCbCr/HSV Encoding: ITU-R 601
        Quantization      : Full Range
        Plane 0           :
           Bytes per Line : 1280
           Size Image     : 614400
Crop Capability Video Output:
        Bounds      : Left 0, Top 0, Width 640, Height 480
        Default     : Left 0, Top 0, Width 640, Height 480
        Pixel Aspect: 1/1
Selection Video Output: compose, Left 0, Top 0, Width 640, Height 480, Flags:
Selection Video Output: compose_default, Left 0, Top 0, Width 640, Height 480, Flags:
Selection Video Output: compose_bounds, Left 0, Top 0, Width 640, Height 480, Flags:
Streaming Parameters Video Capture:
        Capabilities     : timeperframe
        Frames per second: 30.000 (30/1)
        Read buffers     : 0

User Controls

                horizontal_flip 0x00980914 (bool)   : default=0 value=0
                  vertical_flip 0x00980915 (bool)   : default=0 value=0
                alpha_component 0x00980929 (int)    : min=0 max=255 step=1 default=0 value=0

Output of mipi camera which is on video node3

[Rajesh_M]

@SGaist I am able to stream the mipi csi camera using the qtdeclarative camera example

[SGaist]

I wonder whether you need to grant permission to access the camera as shown here.

[Rajesh_M]

@SGaist , It is not giving the popup for accessing the camera whereas when an usb camera is connected it is giving the popup .It is not required to give permissions.
When I have gone through the debug log I got this

[1048:1059:1019/091825.355046:VERBOSE1:media_stream_manager.cc(1112)] video capture: VideoCaptureManager::OnDeviceInfosReceived: Recevied 0 device infos.
[1048:1059:1019/091825.355136:VERBOSE1:media_stream_manager.cc(1112)] MDM::DevicesEnumerated({type=VIDEO_INPUT}, {labels])
[1134:1134:1019/091825.355427:VERBOSE1:webrtc_logging.cc(35)] UMP::SelectVideoDeviceSettings. request_id=0.
[1134:1134:1019/091825.355653:VERBOSE1:webrtc_logging.cc(35)] UMP::GetUserMediaRequestFailed({request_id=0})
[1134:1134:1019/091825.356001:VERBOSE1:webrtc_logging.cc(35)] UMP::DelayedGetUserMediaRequestFailed({request_id=0}, {result=NO_HARDWARE}) 

No hardware found .Is this due to chromium or qtwebengine not able to find this mipi csi camera combination? .Can you help me plese resolve this fastly?

[SGaist]

@Rajesh_M Fastly ? No, I can't as I do not own the required hardware to do further testing.

However, it does sound like an hardware detection issue.

[Rajesh_M]

@SGaist , Firstly thank you for your response. I have one doubt ,like the mipi csi camera is detected in all the qtmultimedia applications and I am able to stream the camera using gstlaunch-1.0 command but why it is not detected only in webengine applications. But how qtmultimedia is detetcing and qtwebengine is not detecting if it is a hardware detection failure. Then how the hardware is not detecting the camera only in webengine applications. I assume that this is due to chromium in webengine applications. Can you share some of your thoughts regarding this?

Please help me understand the cause for this problem.

[SGaist]

@Rajesh_M the thing is, QtMultimedia uses either the native system's API or since 6.5, the ffmpeg backend. Chromium in this regard used its own stack (I mean it does not use QtMultimedia but I don't know exactly how it integrates the hardware layer). From the looks of it, it does not properly see your camera but I don't know whether it's a limitation or a bug.

[Rajesh_M]

@SGaist I am able to stream the camera in the imx6 with qt5 with chromium version of 65 .I assume that the camera is not detected due to the some undealed cases in the chromium in the thing that I am using .As I am using the qt6 with chromium version 98.So is there any way to downgrade the chromium in qt6.If yes can you tell how can we do this and what is the minimum possible version that we can downgrade

[SGaist]

Although not recommended, you should be able to build an older tag of the module.

[Rajesh_M]

@SGaist Do you know any way to add the MPLANE device support to the qtwebengine ? as the camera device that I have connected is a multiplanar device .

[SGaist]

@Rajesh_M from the looks of it, it was implemented and then removed. See this thread.

[Rajesh_M]

@SGaist ,I have tried to apply that patch to the version 98 and now it is detecting the cameras but unable to stream it in the browser and giving this error

[1531:1539:1116/044816.475847:ERROR:v4l2_capture_delegate.cc(988)] Dequeued v4l2 buffer contains invalid length (0 bytes).
[1531:1539:1116/044816.509127:ERROR:v4l2_capture_delegate.cc(988)] Dequeued v4l2 buffer contains invalid length (0 bytes).

Can you please help me solve this by providing your insights ?

[Rajesh_M]

@SGaist Also can you please help me to downgrade the chromium version to 50 in the qt6(qtwebengine) if you have some time as I have found it very difficult to do without any expertise in qt.

[Rajesh_M]

@SGaist I am using this layer for that https://code.qt.io/cgit/yocto/meta-qt6.git/tree/recipes-qt/qt6 .please help me to downgrade to the 50-based branch if possible