droid中以每秒至少15帧的速度从Camera对象获取原始预览

droid中以每秒至少15帧的速度从Camera对象获取原始预览

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如何在Android中以每秒至少15帧的速度从Camera对象获取原始预览数据?

本文介绍了如何在Android中以每秒至少15帧的速度从Camera对象获取原始预览数据?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我需要至少每秒 15 帧从 Camera 对象获取原始预览数据，但我只能在 110 毫秒内获得一帧，这意味着我每秒只能获得 9 帧.我在下面简要介绍了我的代码.

I need to obtain raw preview data from Camera object at least 15 frame per second, but I can only get a frame in 110 milliseconds which means I can get only 9 frames per second. I brief my code below.

Camera mCamera = Camera.open();
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewFrameRate(30);
parameters.setPreviewFpsRange(15000,30000);
mCamera.setParameters(parameters);
mCamera.addCallbackBuffer(new byte[dataBufferSize]);
//dataBufferSize stands for the byte size for a picture frame
mCamera.addCallbackBuffer(new byte[dataBufferSize]);
mCamera.addCallbackBuffer(new byte[dataBufferSize]);
mCamera.setPreviewDisplay(videoCaptureViewHolder);
//videoCaptureViewHolder is a SurfaceHolder object
mCamera.setPreviewCallbackWithBuffer(new Camera.PreviewCallback() {
  private long timestamp=0;
  public synchronized void onPreviewFrame(byte[] data, Camera camera) {
    Log.v("CameraTest","Time Gap = "+(System.currentTimeMillis()-timestamp));
    timestamp=System.currentTimeMillis();
    //do picture data process
    camera.addCallbackBuffer(data);
    return;
  }
}
mCamera.startPreview();

在上面的简要代码中，dataBufferSize 和 videoCaptureViewHolder 是在其他语句中定义和计算或赋值的.

In the briefed code above, dataBufferSize and videoCaptureViewHolder is defined and calculated or assigned in other statements.

我运行我的代码，我可以在屏幕上看到预览，并得到以下日志:

I run my code, I can see preview on the screen and I get the log below:

...
V/CameraTest( 5396): Time Gap = 105
V/CameraTest( 5396): Time Gap = 112
V/CameraTest( 5396): Time Gap = 113
V/CameraTest( 5396): Time Gap = 115
V/CameraTest( 5396): Time Gap = 116
V/CameraTest( 5396): Time Gap = 113
V/CameraTest( 5396): Time Gap = 115
...

这意味着 onPreviewFrame(byte[] data, Camera camera) 每 110 毫秒调用一次，因此我每秒可以得到不超过 9 帧.而且无论我通过问题 setPreviewFrameRate() 设置什么预览帧率，以及我通过问题 setPreviewFpsRange() 设置什么预览 Fps 范围，日志都是一样的.

This means onPreviewFrame(byte[] data, Camera camera) is called every 110 milliseconds so I can get no more than 9 frames per second. And no matter what preview frame rate I set by issue setPreviewFrameRate() and what preview Fps range I set by issue setPreviewFpsRange(), the log is the same.

有人能帮我解决这个问题吗?我需要每秒至少 15 帧从 Camera 对象获取原始预览数据.提前谢谢你.

Would some one give me some help on this problem? I need to obtain raw preview data from Camera object at least 15 frames per second. Thank you in advance.

我把我的整个代码放在下面.

I put my entire code below.

CameraTest.java

CameraTest.java

package test.cameratest;

import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import android.app.Activity;
import android.graphics.ImageFormat;
import android.hardware.Camera;
import android.hardware.Camera.ErrorCallback;
import android.hardware.Camera.Parameters;
import android.hardware.Camera.Size;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.SurfaceHolder.Callback;

public class CameraTestActivity extends Activity {
    SurfaceView mVideoCaptureView;
    Camera mCamera;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mVideoCaptureView = (SurfaceView) findViewById(R.id.video_capture_surface);
        SurfaceHolder videoCaptureViewHolder = mVideoCaptureView.getHolder();
        videoCaptureViewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        videoCaptureViewHolder.addCallback(new Callback() {
            public void surfaceDestroyed(SurfaceHolder holder) {
            }

            public void surfaceCreated(SurfaceHolder holder) {
                startVideo();
            }

            public void surfaceChanged(SurfaceHolder holder, int format,
                    int width, int height) {
            }
        });
    }
    private void startVideo() {
        SurfaceHolder videoCaptureViewHolder = null;
        try {
            mCamera = Camera.open();
        } catch (RuntimeException e) {
            Log.e("CameraTest", "Camera Open filed");
            return;
        }
        mCamera.setErrorCallback(new ErrorCallback() {
            public void onError(int error, Camera camera) {
            }
        });
        Camera.Parameters parameters = mCamera.getParameters();
        parameters.setPreviewFrameRate(30);
        parameters.setPreviewFpsRange(15000,30000);
        List<int[]> supportedPreviewFps=parameters.getSupportedPreviewFpsRange();
        Iterator<int[]> supportedPreviewFpsIterator=supportedPreviewFps.iterator();
        while(supportedPreviewFpsIterator.hasNext()){
            int[] tmpRate=supportedPreviewFpsIterator.next();
            StringBuffer sb=new StringBuffer();
            sb.append("supportedPreviewRate: ");
            for(int i=tmpRate.length,j=0;j<i;j++){
                sb.append(tmpRate[j]+", ");
            }
            Log.v("CameraTest",sb.toString());
        }

        List<Size> supportedPreviewSizes=parameters.getSupportedPreviewSizes();
        Iterator<Size> supportedPreviewSizesIterator=supportedPreviewSizes.iterator();
        while(supportedPreviewSizesIterator.hasNext()){
            Size tmpSize=supportedPreviewSizesIterator.next();
            Log.v("CameraTest","supportedPreviewSize.width = "+tmpSize.width+"supportedPreviewSize.height = "+tmpSize.height);
        }

        mCamera.setParameters(parameters);
        if (null != mVideoCaptureView)
            videoCaptureViewHolder = mVideoCaptureView.getHolder();
        try {
            mCamera.setPreviewDisplay(videoCaptureViewHolder);
        } catch (Throwable t) {
        }
        Log.v("CameraTest","Camera PreviewFrameRate = "+mCamera.getParameters().getPreviewFrameRate());
        Size previewSize=mCamera.getParameters().getPreviewSize();
        int dataBufferSize=(int)(previewSize.height*previewSize.width*
                               (ImageFormat.getBitsPerPixel(mCamera.getParameters().getPreviewFormat())/8.0));
        mCamera.addCallbackBuffer(new byte[dataBufferSize]);
        mCamera.addCallbackBuffer(new byte[dataBufferSize]);
        mCamera.addCallbackBuffer(new byte[dataBufferSize]);
        mCamera.setPreviewCallbackWithBuffer(new Camera.PreviewCallback() {
            private long timestamp=0;
            public synchronized void onPreviewFrame(byte[] data, Camera camera) {
                Log.v("CameraTest","Time Gap = "+(System.currentTimeMillis()-timestamp));
                timestamp=System.currentTimeMillis();
                try{
                    camera.addCallbackBuffer(data);
                }catch (Exception e) {
                    Log.e("CameraTest", "addCallbackBuffer error");
                    return;
                }
                return;
            }
        });
        try {
            mCamera.startPreview();
        } catch (Throwable e) {
            mCamera.release();
            mCamera = null;
            return;
        }
    }
    private void stopVideo() {
        if(null==mCamera)
            return;
        try {
            mCamera.stopPreview();
            mCamera.setPreviewDisplay(null);
            mCamera.setPreviewCallbackWithBuffer(null);
            mCamera.release();
        } catch (IOException e) {
            e.printStackTrace();
            return;
        }
        mCamera = null;
    }
    public void finish(){
        stopVideo();
        super.finish();
    };
}

AndroidManifest.xml

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="test.cameratest"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="9" android:targetSdkVersion="10" android:maxSdkVersion="10"/>
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.VIBRATE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.RECORD_AUDIO" />
    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
    <uses-permission android:name="android.permission.READ_CONTACTS"/>
    <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.PROCESS_OUTGOING_CALLS"/>
    <uses-permission android:name="android.permission.CALL_PHONE"/>
    <uses-permission android:name="android.permission.BOOT_COMPLETED"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.WRITE_SETTINGS" />
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".CameraTestActivity"
                  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>
</manifest>

推荐答案

我对相机的体验非常复杂，而且依赖于硬件.因此，如果可以的话，请尝试在其他硬件上运行它.

Me experience with the camera stuff has been fiddly and hardware dependent. So try running it on other hardware sometime if you can.

也可能值得尝试更多的相机设置.

Also might be worth trying some more camera settings.

感谢您提供代码示例.

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07-25 17:41
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