QCamera is not working with CMOS-MIPI-OV5640

nikita.panchal09

Hi,

I am having iMX6 development kit with CMOS-MIPI-OV5640. Kit is having Debian Stretch 9.5.

At present, I am trying to play live stream using QT (QCamera functionality). I have developed sample code for that and it is working fine with laptop(ubuntu 16.04) and it's webcam.
But on IMX6 development kit, on the execution of QCamera->start(), the QT application hangs.

Please find code related to camera:
QCamera *pCamera;
//Find Camera
QList<QCameraInfo> cameras = QCameraInfo::availableCameras();
foreach (const QCameraInfo &cameraInfo, cameras){
pCamera = new QCamera(cameraInfo, this); //gives cameraInfo.deviceName() = "/dev/video0"
}
pCameraViewfinder = new QCameraViewfinder(this);
pCameraImageCapture = new QCameraImageCapture(pCamera, this);
pVBoxLayout = new QVBoxLayout();

//Set Camera View
pCamera->setViewfinder(pCameraViewfinder);
pVBoxLayout->addWidget(pCameraViewfinder);
ui->scrollArea->setLayout(pVBoxLayout);

// Start Camera
pCamera->setCaptureMode(QCamera::CaptureVideo);
pCamera→start(); //Hangs at this line, not able to do anything on UI and gives an error.

Looking forward to hearing.

Thank You,
Nikita Panchal

SGaist

Hi and welcome to devnet,

Can you access that camera properly from gstreamer ?

nikita.panchal09

Yes.

I am able to get live stream with :
gst-launch-1.0 imxv4l2videosrc device=/dev/video0 ! imxeglvivsink

SGaist

Do you have any error printed on the command line when running your Qt application ?

nikita.panchal09

Hi Devent,

First of thank you for looking into it.
Qt application itself doesn't print any error on console.

While analyze the problem I identified two things as below:

Difference between Camera Start method on laptop and IMX6.
On laptop: pCamera->start() followes status: LoadingStatus -> LoadedStatus -> StartingStatus -> ActiveStatus.
On IMX6 : pCamera->start() followes status: LoadingStatus
So, It is stuck to change status from "LoadingStatus" to "LoadedStatus".
I got below error with dmesg command:
pid: 1170
uid: [ 1001]
tgid: 1170
total_vm:220354
rss: 150081
nr_ptes: 405
nr_pmds: 0
swapents: 0
oom_score_adj: 0
name: CameraStartApp
Out of memory: Kill process 1170 (CameraStartApp) score 587 or sacrifice child
Killed process 1170 (CameraStartApp) total-vm:881416kB, anon-rss:599680kB, file-rss:0kB, shmem-rss:644kB

SGaist

Looks like a device specific source

@nikita.panchal09 said in QCamera is not working with CMOS-MIPI-OV5640:

imxv4l2videosrc

You should consider modifying the gstreamer plugin to use that one in place of the camerabin it currently uses.

nikita.panchal09

Hi,

Thank you for your answer.
Actually, I am new to GStreamer and qtmultimedia. I would be grateful, if you can provide steps or related website-link to do these things.

Meanwhile, I found the hardcoded value of camera source as "v4l2src" in below files from QT source. Do these both files requires to change to "imxv4l2videosrc" from "v4l2src" and build it again?

qtmultimedia-5.12/src/plugins/gstreamer/mediacapture/qgstreamerv4l2input.cpp:70: GstElement *camera = gst_element_factory_make("v4l2src", "camera_source");
qtmultimedia-5.12/src/plugins/gstreamer/camerabin/camerabinsession.cpp:542: m_videoSrc = gst_element_factory_make("v4l2src", "camera_source");

Thanks.

SGaist

That's what I would try first yes. No need to rebuild all of Qt. Only the GStreamer plugin.

nikita.panchal09

Hi,

I followed below steps:

Downloaded qt-multimedia
Edited mentioned files with "imxv4l2videosrc"
Compiled and Installed.

It works...! I am able to start the camera.

Thank you

nikita.panchal09

Hi,

Currently, I am trying to record video on IMX6(Debian Stretch 9.5). I am using QT multimediawidget "camera" example (Using QCamera and QMediaRecorder).
The problem is, On record start (recorder->record) the camera output is slowed down extremely. and after approximate 15 seconds, It gives below error and streaming gets stopped.
"CameraBin error: "Internal data stream error."

I am able to record video with gstreamer using below command and it works fine.
gst-launch-1.0 imxv4l2videosrc device=/dev/video0 imx-capture-mode=5 fps-n=30 ! queue ! imxvpuenc_h264 bitrate=10000 ! avimux ! filesink location=test.avi

Looking forward to hearing.

Thank You.

SGaist

From the looks of it, imxvpuenc_h264 is likely optimised for your device. I would go check the qgstreamercapturesession.cpp content to see how to possibly modify the pipeline to use that encoder.

nikita.panchal09

Hi,

Thanks for your answer.

While analyzing the problem I found below things as per below:

In the computer, it saves video file as .mkv and in the board, It saves as .ogg
After camera record start it gives error as "CameraBin error: "Internal data stream error."
simultaneously on the console, I am getting "ERROR: v4l2 capture: mxc_v4l_dqueue timeout enc_counter 0" error.
As per your saying I have to write codec "imxvpuenc_h264". But I am confused that where to change it.
I have changed "x264enc" to "imxvpuenc_h264" in file qgstreamervideoencode.cpp. But, while recording It is not executing.

Thanks,
Nikita Panchal

SGaist

What do you mean by "not executing" ?

nikita.panchal09

I have put "qDebug()" on it. It doesn't print on recording start.

SGaist

Maybe a silly question but are you sure you replaced the plugin once you built it ?

nikita.panchal09

Hi,

I have applied "0001-QCamera-can-t-set-recording-container-format-video-a.patch" patch from below link and it works for me.
"https://community.nxp.com/docs/DOC-330047"
Thanks for your support.