How to fix the issue about cvCreateCameraCapture

edit

I have built opencv(with ffmpeg) for android arm64-v8a successfully, however, cvCreateCameraCapture return null. cvCreateFileCapture work well. I found we need to set the following item for support camera. -DWITH_V4L=1 -DHAVE_CAMV4L2=ON

Now, v4l have been built in opencv, however, the following interface in cap_libv4l.cpp can not open device successfully.

static void icvInitCapture_V4L() {
...
deviceHandle = open(deviceName, O_RDONLY);
...
}

That open function failed because of permission denied.

I think my android app don't have related permission. However, i add the following setting in AndroidManifest.xml.

<uses-permission android:name="android.permission.CAMERA"/>
<uses-feature android:name="android.hardware.camera" android:required="false"/>
<uses-feature android:name="android.hardware.camera.autofocus" android:required="false"/>

And opencv functions are called in a thread in my app. My app is a service for android.

How to fix the permission issue for my app?

Any idea?

Change my app to system app?

Update 2018/12/27.

I found that deviceName is /dev/video*. So I checked the permission of those video in path /dev as below,

1|gts4lltechn:/dev $ ls -l | grep video ls: ./event-log-tags: Permission denied

And my app's permission is as below,

u0_a191 20375 995 4406488 82904 0 0 S xxx.xxx.xxx+

I don't have su permission, how to fix the issue?