Android-based rk3399 supports multiple USB cameras at the same time
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- 1. Preface
- 2. CameraHal_Module.h
- 3. CameraHal_Module.cpp
- 4. Compile & Burn Image
- 5. App verification
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1. Preface
Android system supports 2 cameras by default, one front camera and one rear camera To support a larger number of cameras, the code of the Android Hal layer must be modified.
Insert image description here
2. CameraHal_Module.h
Modify CAMERAS_SUPPORT_MAX
3. CameraHal_Module.cpp
Modify the code related to the variable camInfoTmp[] in the camera_get_number_of_cameras() function
4. Compile & Burn Image
For the modifications in this part to take effect, full compilation is required.
./build.sh
./build.sh mkimage
./build.sh mkupdate
5. App verification
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"> <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" /> <uses-permission android:name="android.permission.CAMERA" /> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> <uses-featureandroid:name="android.hardware.camera"android:required="false" /> <uses-featureandroid:name="android.hardware.camera.autofocus"android:required="false" /> <applicationandroid:allowBackup="true" android:dataExtractionRules="@xml/data_extraction_rules" android:fullBackupContent="@xml/backup_rules" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/Theme.CameraApplication"tools:targetApi="31"> <activityandroid:name=".MainActivity" android:exported="true"> <intent-filter><action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter><meta-dataandroid:name="android.app.lib_name"android:value="" /> </activity> </application> </manifest>
MainActivity.java
package com.example.cameraapplication;
import androidx.appcompat.app.AppCompatActivity;
import android.hardware.Camera;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.Toast;import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private static final String TAG = MainActivity.class.getSimpleName();
Camera camera1, camera2, camera3, camera4;
SurfaceHolder surfaceHolder1, surfaceHolder2, surfaceHolder3, surfaceHolder4;
SurfaceView surfaceView1, surfaceView2, surfaceView3, surfaceView4;
List<Camera> cameraList = new ArrayList<>();
List<SurfaceHolder> surfaceHolderList = new ArrayList<>();
List<SurfaceView> surfaceViewList = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
surfaceView1 = findViewById(R.id.camera_surface_view1);
surfaceView2 = findViewById(R.id.camera_surface_view2);
surfaceView3 = findViewById(R.id.camera_surface_view3);
surfaceView4 = findViewById(R.id.camera_surface_view4);
cameraList.add(camera1);
cameraList.add(camera2);
cameraList.add(camera3);
cameraList.add(camera4);
surfaceHolderList.add(surfaceHolder1);
surfaceHolderList.add(surfaceHolder2);
surfaceHolderList.add(surfaceHolder3);
surfaceHolderList.add(surfaceHolder4);
surfaceViewList.add(surfaceView1);
surfaceViewList.add(surfaceView2);
surfaceViewList.add(surfaceView3);
surfaceViewList.add(surfaceView4);
for(int i=0; i<cameraList.size(); i + + ){
initCamera(i, cameraList.get(i), surfaceHolderList.get(i), surfaceViewList.get(i));
}
int number = Camera.getNumberOfCameras();//Get the number of cameras
Toast.makeText(MainActivity.this, "Number of cameras:" + number, Toast.LENGTH_LONG).show();
}
private void initCamera(int number, Camera camera, SurfaceHolder surfaceHolder, SurfaceView surfaceView){
try{
camera = Camera.open(number);
surfaceHolder = surfaceView.getHolder();
surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
final Camera mCamera = camera;
surfaceHolder.addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceCreated(SurfaceHolder surfaceHolder) {
try {
if (mCamera!=null) {
mCamera.setPreviewDisplay(surfaceHolder);
mCamera.setDisplayOrientation(90);mCamera.startPreview();
}
}
catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
releaseCamera(mCamera);
}
});
}catch (Exception e){
e.printStackTrace();
}
}
/*** Release camera resources*/
private void releaseCamera(Camera camera) {
if (camera != null) {
camera.setPreviewCallback(null);
camera.stopPreview();
camera.release();
camera = null;
}
}
/*** Release camera resources*/
private void releaseAllCamera() {
for(int i=0; i<cameraList.size(); i + + ){
if (cameraList.get(i) != null) {
cameraList.get(i).setPreviewCallback(null);
cameraList.get(i).stopPreview();
cameraList.get(i).release();
cameraList.set(i, null);
}
}
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<!-- <TextView-->
<!-- android:layout_gravity="center"-->
<!-- android:layout_margin="10dp"-->
<!-- android:layout_width="wrap_content"-->
<!-- android:layout_height="wrap_content"-->
<!-- android:text="Number of cameras:"-->
<!-- app:layout_constraintBottom_toBottomOf="parent"-->
<!-- app:layout_constraintEnd_toEndOf="parent"-->
<!-- app:layout_constraintStart_toStartOf="parent"-->
<!-- app:layout_constraintTop_toTopOf="parent" />-->
<LinearLayoutandroid:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_weight="1">
<SurfaceViewandroid:id="@ + id/camera_surface_view1"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"/>
<SurfaceViewandroid:id="@ + id/camera_surface_view2"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"/>
</LinearLayout>
<LinearLayoutandroid:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_weight="1">
<SurfaceViewandroid:id="@ + id/camera_surface_view3"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"/>
<SurfaceViewandroid:id="@ + id/camera_surface_view4"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"/>
</LinearLayout>
</LinearLayout>