在安卓上录制实时OpenCV处理
我的目标是做几件事：
- 使用 OpenCV 和 JavaCameraView 处理来自手机摄像头源的帧
- 在处理后的视频发生时启用录制
我让它们都工作了，但是我必须实现数字2的方式是荒谬的：
- 对于每一帧，将处理后的 Mat 写入图像文件。
- 录制停止后，使用JCodec的Android库将它们拼接成视频文件。
这有效，但它带来了很多缺点：帧速率在录制过程中下降得难以忍受，拼接步骤每帧大约需要半秒，并且超过几秒钟的视频的内存不足 - 那是在我降低相机分辨率以确保图像尽可能小之后。即便如此，视频帧速率也与现实脱节，视频看起来速度惊人。
由于很多原因，这似乎很荒谬，所以我的问题是：有没有更好的方法来做到这一点？
这里有一个小例子，如果有人想运行它。这需要 OpenCV Android 项目在这里提供，JCodec Android 项目在这里提供。
清单.xml：
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="22"
/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@android:style/Theme.NoTitleBar.Fullscreen" >
<activity
android:name=".MainActivity"
android:screenOrientation="landscape"
android:configChanges="orientation|keyboardHidden|screenSize"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.CAMERA"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
主要活动：
package com.example.videotest;
import java.io.File;
import java.util.List;
import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.LoaderCallbackInterface;
import org.opencv.android.OpenCVLoader;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewFrame;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener2;
import org.opencv.core.Mat;
import org.opencv.core.Scalar;
import org.opencv.imgproc.Imgproc;
import android.app.Activity;
import android.media.MediaScannerConnection;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.SurfaceView;
import android.view.View;
import android.view.WindowManager;
import android.widget.Toast;
public class MainActivity extends Activity implements CvCameraViewListener2{
private CameraView cameraView;
private Mat edgesMat;
private final Scalar greenScalar = new Scalar(0,255,0);
private int resolutionIndex = 0;
private MatVideoWriter matVideoWriter = new MatVideoWriter();
private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
@Override
public void onManagerConnected(int status) {
switch (status) {
case LoaderCallbackInterface.SUCCESS:
{
Log.i("VideoTest", "OpenCV loaded successfully");
cameraView.enableView();
} break;
default:
{
super.onManagerConnected(status);
} break;
}
}
};
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
setContentView(R.layout.activity_main);
cameraView = (CameraView) findViewById(R.id.cameraView);
cameraView.setVisibility(SurfaceView.VISIBLE);
cameraView.setCvCameraViewListener(this);
}
@Override
public void onPause()
{
super.onPause();
if (cameraView != null){
cameraView.disableView();
}
}
@Override
public void onResume()
{
super.onResume();
OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_3, this, mLoaderCallback);
}
public void onDestroy() {
super.onDestroy();
if (cameraView != null)
cameraView.disableView();
}
public void onCameraViewStarted(int width, int height) {
edgesMat = new Mat();
}
public void onCameraViewStopped() {
if (edgesMat != null)
edgesMat.release();
edgesMat = null;
}
public Mat onCameraFrame(CvCameraViewFrame inputFrame) {
Mat rgba = inputFrame.rgba();
org.opencv.core.Size sizeRgba = rgba.size();
int rows = (int) sizeRgba.height;
int cols = (int) sizeRgba.width;
int left = cols / 8;
int top = rows / 8;
int width = cols * 3 / 4;
int height = rows * 3 / 4;
//get sub-image
Mat rgbaInnerWindow = rgba.submat(top, top + height, left, left + width);
//create edgesMat from sub-image
Imgproc.Canny(rgbaInnerWindow, edgesMat, 100, 100);
Mat colorEdges = new Mat();
Mat killMe = colorEdges;
edgesMat.copyTo(colorEdges);
Imgproc.cvtColor(colorEdges, colorEdges, Imgproc.COLOR_GRAY2BGRA);
colorEdges = colorEdges.setTo(greenScalar, edgesMat);
colorEdges.copyTo(rgbaInnerWindow, edgesMat);
killMe.release();
colorEdges.release();
rgbaInnerWindow.release();
if(matVideoWriter.isRecording()){
matVideoWriter.write(rgba);
}
return rgba;
}
public void changeResolution(View v){
List<android.hardware.Camera.Size> cameraResolutionList = cameraView.getResolutionList();
resolutionIndex++;
if(resolutionIndex >= cameraResolutionList.size()){
resolutionIndex = 0;
}
android.hardware.Camera.Size resolution = cameraResolutionList.get(resolutionIndex);
cameraView.setResolution(resolution.width, resolution.height);
resolution = cameraView.getResolution();
String caption = Integer.valueOf(resolution.width).toString() + "x" + Integer.valueOf(resolution.height).toString();
Toast.makeText(this, caption, Toast.LENGTH_SHORT).show();
}
public void startVideo(View v){
if(matVideoWriter.isRecording()){
matVideoWriter.stop();
File file = new File(getExternalFilesDir(null), "VideoTest/images/");
for(String img : file.list()){
String scanMe = new File(file, img).getAbsolutePath();
MediaScannerConnection.scanFile(this, new String[]{scanMe}, null, null);
Log.i("VideoTest", "Scanning: " +scanMe);
}
file = new File(file, "video.mp4");
MediaScannerConnection.scanFile(this, new String[]{file.getAbsolutePath()}, null, null);
}
else{
String state = Environment.getExternalStorageState();
Log.i("VideoTest", "state: " + state);
File ext = getExternalFilesDir(null);
Log.i("VideoTest", "ext: " + ext.getAbsolutePath());
File file = new File(getExternalFilesDir(null), "VideoTest/images/");
if(!file.exists()){
boolean success = file.mkdirs();
Log.i("VideoTest", "mkdirs: " + success);
}
else{
Log.i("VideoTest", "file exists.");
}
Log.i("VideoTest", "starting recording: " + file.getAbsolutePath());
matVideoWriter.start(file);
}
}
}
相机视图：
package com.example.videotest;
import java.io.FileOutputStream;
import java.util.List;
import org.opencv.android.JavaCameraView;
import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.util.AttributeSet;
import android.util.Log;
public class CameraView extends JavaCameraView{
private String mPictureFileName;
public CameraView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public List<String> getEffectList() {
return mCamera.getParameters().getSupportedColorEffects();
}
public boolean isEffectSupported() {
return (mCamera.getParameters().getColorEffect() != null);
}
public String getEffect() {
return mCamera.getParameters().getColorEffect();
}
public void setEffect(String effect) {
Camera.Parameters params = mCamera.getParameters();
params.setColorEffect(effect);
mCamera.setParameters(params);
}
public List<android.hardware.Camera.Size> getResolutionList() {
return mCamera.getParameters().getSupportedPreviewSizes();
}
public void setResolution(int width, int height) {
disconnectCamera();
mMaxHeight = height;
mMaxWidth = width;
connectCamera(getWidth(), getHeight());
}
public android.hardware.Camera.Size getResolution() {
return mCamera.getParameters().getPreviewSize();
}
}
MatVideoWriter：
package com.example.videotest;
import java.io.File;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import org.jcodec.api.android.SequenceEncoder;
import org.opencv.core.Mat;
import org.opencv.highgui.Highgui;
import org.opencv.imgproc.Imgproc;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
public class MatVideoWriter {
boolean recording;
File dir;
int imageIndex = 0;
public void start(File dir){
this.dir = dir;
recording = true;
}
public void stop(){
recording = false;
try{
File file = new File(dir, "video.mp4");
SequenceEncoder encoder = new SequenceEncoder(file);
List<File> files = Arrays.asList(dir.listFiles());
Collections.sort(files, new Comparator<File>(){
@Override
public int compare(File lhs, File rhs) {
return lhs.getName().compareTo(rhs.getName());
}
});
for(File f : files){
Log.i("VideoTest", "Encoding image: " + f.getAbsolutePath());
try{
Bitmap frame = BitmapFactory.decodeFile(f.getAbsolutePath());
encoder.encodeImage(frame);
}
catch(Exception e){
e.printStackTrace();
}
}
encoder.finish();
}
catch(Exception e){
e.printStackTrace();
}
}
public void write(Mat mat){
//convert from BGR to RGB
Mat rgbMat = new Mat();
Imgproc.cvtColor(mat, rgbMat, Imgproc.COLOR_BGR2RGB);
File file = new File(dir, "img" + imageIndex + ".png");
String filename = file.toString();
boolean success = Highgui.imwrite(filename, rgbMat);
Log.i("VideoTest", "Success writing img" + imageIndex +".png: " + success);
imageIndex++;
}
public boolean isRecording() {
return recording;
}
}
编辑：我没有收到任何评论或答案，所以我在这里交叉发布到OpenCV论坛。
