本文主要是介绍Android拍摄视频流的格式转换（YUV --- RGB） 怎么从网络获取流转换成视频，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
Android允许用户实时捕获摄像头的视频流，这在利用摄像头的AR应用中非常有用。可以利用摄像流实时做画面图像的分析，并做出许多有用的应用。比如人脸识别，条码识别，特定图像替换等等，不过大多数图像处理软件在处理时是需要RGB格式的图像，而默认的视频流是压缩的YUV格式，Android下是YUV420SP，这个格式，虽然可以在程序中修改，但是修改后好像不起作用，也就是说只能得到编码为YUV420SP的视频流，这就需要把YUV420SP的视频流转换成RGB格式的图像，用于图像识别。特贴一个格式转换函数，方便大家使用。
java 代码：
static public void decodeYUV420SP(byte[] rgbBuf, byte[] yuv420sp, int width, int height) {
final int frameSize = width * height;
if (rgbBuf == null)
throw new NullPointerException("buffer 'rgbBuf' is null");
if (rgbBuf.length < frameSize * 3)
throw new IllegalArgumentException("buffer 'rgbBuf' size "
+ rgbBuf.length + " < minimum " + frameSize * 3);
if (yuv420sp == null)
throw new NullPointerException("buffer 'yuv420sp' is null");
if (yuv420sp.length < frameSize * 3 / 2)
throw new IllegalArgumentException("buffer 'yuv420sp' size " + yuv420sp.length
+ " < minimum " + frameSize * 3 / 2);
int i = 0, y = 0;
int uvp = 0, u = 0, v = 0;
int y1192 = 0, r = 0, g = 0, b = 0;
for (int j = 0, yp = 0; j < height; j++) {
uvp = frameSize + (j >> 1) * width;
u = 0;
v = 0;
for (i = 0; i < width; i++, yp++) {
y = (0xff & ((int) yuv420sp[yp])) - 16;
if (y < 0) y = 0;
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]) - 128;
u = (0xff & yuv420sp[uvp++]) - 128;
}
y1192 = 1192 * y;
r = (y1192 + 1634 * v);
g = (y1192 - 833 * v - 400 * u);
b = (y1192 + 2066 * u);
if (r < 0) r = 0; else if (r > 262143) r = 262143;
if (g < 0) g = 0; else if (g > 262143) g = 262143;
if (b < 0) b = 0; else if (b > 262143) b = 262143;
rgbBuf[yp * 3] = (byte)(r >> 10);
rgbBuf[yp * 3 + 1] = (byte)(g >> 10);
rgbBuf[yp * 3 + 2] = (byte)(b >> 10);
}
}
}
在Android的拍照视频预览时就可以截取视频数据。每获得一帧就调用一下接口函数。
我的开发平台是Android 1.5，这个程序实现视频流的获取，程序简单地在第20帧到来的时候，写入到文件中。这样就可以拿到电脑上进行分析。
参考代码：
package com.sunshine;
import java.io.File;
import java.io.RandomAccessFile;
import android.app.Activity;
import android.content.res.Configuration;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.Window;
import android.view.WindowManager;
import android.view.SurfaceHolder.Callback;
public class AndroidVideo extends Activity implements Callback,
Camera.PictureCallback {
private SurfaceView mSurfaceView = null;
private SurfaceHolder mSurfaceHolder = null;
private Camera mCamera = null;
private boolean mPreviewRunning = false;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().setFormat(PixelFormat.TRANSLUCENT);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);
mSurfaceView = (SurfaceView) this.findViewById(R.id.surface_camera);
mSurfaceHolder = mSurfaceView.getHolder();
mSurfaceHolder.addCallback(this);
mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
@Override
public void onPictureTaken(byte[] data, Camera camera) {
try {
Log.v("System.out", "get it!");
File file = new File("/sdcard/camera.jpg");
RandomAccessFile raf = new RandomAccessFile(file, "rw");
raf.write(data);
raf.close();
} catch (Exception ex) {
Log.v("System.out", ex.toString());
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
if (mPreviewRunning) {
mCamera.stopPreview();
}
Camera.Parameters p = mCamera.getParameters();
p.setPreviewSize(width, height);
mCamera.setPreviewCallback(new StreamIt());
mCamera.setParameters(p);
try {
mCamera.setPreviewDisplay(holder);
} catch (Exception ex) {
}
mCamera.startPreview();
mPreviewRunning = true;
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
mCamera = Camera.open();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
mCamera.stopPreview();
mPreviewRunning = false;
mCamera.release();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
try {
super.onConfigurationChanged(newConfig);
if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
} else if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
}
} catch (Exception ex) {
}
}
}
class StreamIt implements Camera.PreviewCallback {
private int tick = 1;
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
// TODO Auto-generated method stub
if (tick == 20) {
System.out.println("data len: " + data.length);
try {
File file = new File("/sdcard/pal.pal");
if (!file.exists())
file.createNewFile();
RandomAccessFile raf = new RandomAccessFile(file, "rw");
raf.write(data);
raf.close();
tick++;
} catch (Exception ex) {
Log.v("System.out", ex.toString());
}
}
tick++;
}
}
xml 布局文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:orientation="vertical">
<SurfaceView android:id="@+id/surface_camera"
android:layout_width="fill_parent" android:layout_height="fill_parent">
</SurfaceView>
</LinearLayout>
注意在项目配置文件中还要加上访问权限
<uses-permission android:name="android.permission.CAMERA" />
通过查资料发现，Android每帧的数据流的格式是YUV420
YUV420转成RGB的函数，见第一部分
Android 端
package com.sunshine;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.net.Socket;
import android.app.Activity;
import android.content.res.Configuration;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.view.SurfaceHolder.Callback;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
public class AndroidVideo extends Activity implements Callback,OnClickListener{
private SurfaceView mSurfaceView = null;
private SurfaceHolder mSurfaceHolder = null;
private Camera mCamera = null;
private boolean mPreviewRunning = false;
//连接相关
private EditText remoteIP=null;
private Button connect=null;
private String remoteIPStr=null;
//视频数据
private StreamIt streamIt=null;
public static Kit kit=null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().setFormat(PixelFormat.TRANSLUCENT);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);
mSurfaceView = (SurfaceView) this.findViewById(R.id.surface_camera);
mSurfaceHolder = mSurfaceView.getHolder();
mSurfaceHolder.addCallback(this);
mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
remoteIP=(EditText)this.findViewById(R.id.remoteIP);
connect=(Button)this.findViewById(R.id.connect);
connect.setOnClickListener(this);
}
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
if (mPreviewRunning) {
mCamera.stopPreview();
}
Camera.Parameters p = mCamera.getParameters();
p.setPreviewSize(width, height);
streamIt=new StreamIt();
kit=new Kit();
mCamera.setPreviewCallback(streamIt);
mCamera.setParameters(p);
try {
mCamera.setPreviewDisplay(holder);
} catch (Exception ex) {
}
mCamera.startPreview();
mPreviewRunning = true;
}
public void surfaceCreated(SurfaceHolder holder) {
mCamera = Camera.open();
}
public void surfaceDestroyed(SurfaceHolder holder) {
mCamera.stopPreview();
mPreviewRunning = false;
mCamera.release();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
try {
super.onConfigurationChanged(newConfig);
if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
} else if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
}
} catch (Exception ex) {
}
}
class Kit implements Runnable {
private boolean run=true;
// private final int dataLen=57600; //307200 OR 230400 76800 OR 57600
private final int tt=28800;
public void run() {
// TODO Auto-generated method stub
try {
Socket socket = new Socket(remoteIPStr, 8899);
DataOutputStream dos = new DataOutputStream(socket
.getOutputStream());
DataInputStream dis = new DataInputStream(socket
.getInputStream());
while (run) {
dos.write(streamIt.yuv420sp, 0, 28800);
dos.write(streamIt.yuv420sp, 28800, 28800);
dis.readBoolean();
Thread.sleep(155);
}
} catch (Exception ex) {
run=false;
ex.printStackTrace();
}
}
}
@Override
public void onClick(View view) {
// TODO Auto-generated method stub
if(view==connect){//连接函数
remoteIPStr=remoteIP.getText().toString();
new Thread(AndroidVideo.kit).start();
}
}
}
class StreamIt implements Camera.PreviewCallback {
public byte[] yuv420sp =null;
private boolean t=true;
public void onPreviewFrame(byte[] data, Camera camera) {
// TODO Auto-generated method stub
// if(t){
// t=false;
// new Thread(AndroidVideo.kit).start();
// }
yuv420sp=data;
}
}
pc端：
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Transparency;
import java.awt.color.ColorSpace;
import java.awt.image.BufferedImage;
import java.awt.image.ComponentColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.DataBufferByte;
import java.awt.image.PixelInterleavedSampleModel;
import java.awt.image.Raster;
import java.awt.image.SampleModel;
import java.awt.image.WritableRaster;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class FlushMe extends Frame {
private static final long serialVersionUID = 1L;
private BufferedImage im;
// 图像信息
// private final int width = 480;
// private final int height = 320;
private static final int width = 240;
private static final int height = 160;
private static final int numBands = 3;
private static final int dataLen = 57600;//307200 OR 230400//57600 76800
private static final int tt = 28800;//14400;//28800;
// 图像数组
private byte[] byteArray = new byte[width * height * numBands];// 图像RGB数组
private byte[] yuv420sp = new byte[dataLen];// 图像YUV数组
private static final int[] bandOffsets = new int[] { 0, 1, 2 };
private static final SampleModel sampleModel = new PixelInterleavedSampleModel(
DataBuffer.TYPE_BYTE, width, height, 3, width * 3,
bandOffsets);
// ColorModel
private static final ColorSpace cs=ColorSpace.getInstance(ColorSpace.CS_sRGB);
private static final ComponentColorModel cm=new ComponentColorModel(cs, false, false,
Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
public FlushMe() {
super("Flushing");
updateIM();
setSize(480, 320);
// 窗口关闭方法
this.addWindowListener(new java.awt.event.WindowAdapter() {
public void windowClosing(java.awt.event.WindowEvent e) {
System.exit(0);
}
});
// 窗口居中
this.setLocationRelativeTo(null);
this.setResizable(false);
this.setVisible(true);
this.getData();
}
public void update(Graphics g){
paint(g);
}
public void paint(Graphics g) {
g.drawImage(im, 0, 0, 480, 320, this);
}
public void getData() {
try {
ServerSocket server = new ServerSocket(8899);
Socket socket = server.accept();
DataInputStream dis = new DataInputStream(socket.getInputStream());
DataOutputStream dos = new DataOutputStream(socket.getOutputStream());
while (true) {
for (int i = 0; i < dataLen / tt; i++) {
dis.read(yuv420sp, i * tt, tt);
}
// 得到数据之后立即更新显示
updateIM();
im.flush();
repaint();
dos.writeBoolean(true);
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
private void updateIM() {
try {
// 解析YUV成RGB格式
decodeYUV420SP(byteArray, yuv420sp, width, height);
DataBuffer dataBuffer = new DataBufferByte(byteArray, numBands);
WritableRaster wr = Raster.createWritableRaster(sampleModel,
dataBuffer, new Point(0, 0));
im = new BufferedImage(cm, wr, false, null);
} catch (Exception ex) {
ex.printStackTrace();
}
}
private static void decodeYUV420SP(byte[] rgbBuf, byte[] yuv420sp,
int width, int height) {
final int frameSize = width * height;
if (rgbBuf == null)
throw new NullPointerException("buffer 'rgbBuf' is null");
if (rgbBuf.length < frameSize * 3)
throw new IllegalArgumentException("buffer 'rgbBuf' size "
+ rgbBuf.length + " < minimum " + frameSize * 3);
if (yuv420sp == null)
throw new NullPointerException("buffer 'yuv420sp' is null");
if (yuv420sp.length < frameSize * 3 / 2)
throw new IllegalArgumentException("buffer 'yuv420sp' size "
+ yuv420sp.length + " < minimum " + frameSize * 3 / 2);
int i = 0, y = 0;
int uvp = 0, u = 0, v = 0;
int y1192 = 0, r = 0, g = 0, b = 0;
for (int j = 0, yp = 0; j < height; j++) {
uvp = frameSize + (j >> 1) * width;
u = 0;
v = 0;
for (i = 0; i < width; i++, yp++) {
y = (0xff & ((int) yuv420sp[yp])) - 16;
if (y < 0)
y = 0;
if ((i & 1) == 0) {
v = (0xff & yuv420sp[uvp++]) - 128;
u = (0xff & yuv420sp[uvp++]) - 128;
}
y1192 = 1192 * y;
r = (y1192 + 1634 * v);
g = (y1192 - 833 * v - 400 * u);
b = (y1192 + 2066 * u);
if (r < 0)
r = 0;
else if (r > 262143)
r = 262143;
if (g < 0)
g = 0;
else if (g > 262143)
g = 262143;
if (b < 0)
b = 0;
else if (b > 262143)
b = 262143;
rgbBuf[yp * 3] = (byte) (r >> 10);
rgbBuf[yp * 3 + 1] = (byte) (g >> 10);
rgbBuf[yp * 3 + 2] = (byte) (b >> 10);
}
}
}
public static void main(String[] args) {
Frame f = new FlushMe();
}
}
网络上获取了一段RGB格式的byte数组，但是，在android上显示出来，并且不保存在手机上，只是显示一下
是RBG格式的String吗？原格式？
要是这样的话可以这样
String s1=new String(b);//b就是byte[]
不过一般网上回来的是inputstream,要是inputstream的话，可以用下面的代码
/**
* InputStream转为String
*
* @param is
* @return
*/
public static String InputStreamToString(InputStream is) {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
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