本文共 15653 字，大约阅读时间需要 52 分钟。

一、目的

本文的围绕Android的MediaCodec编解码进行展开，将摄像头采集的视频数据编码成H264数据，然后封装成RTP协议，利用UDP进行传输；接收端接收到RTP数据后进行解包成H264数据，然后交给MediaCodec进行解码显示，结构图如下：

二、MediaCodec编码

import java.nio.ByteBuffer;import android.annotation.SuppressLint;import android.media.MediaCodec;import android.media.MediaCodecInfo;import android.media.MediaFormat;import android.util.Log;public class AvcEncoder {	private MediaCodec mediaCodec;	int m_width;	int m_height;	byte[] m_info = null;	private int mColorFormat;	private MediaCodecInfo codecInfo;	 private static final String MIME_TYPE = "video/avc"; // H.264 Advanced Video	private byte[] yuv420 = null; 	@SuppressLint("NewApi")	public AvcEncoder(int width, int height, int framerate, int bitrate) { 				m_width  = width;		m_height = height;		Log.v("xmc", "AvcEncoder:"+m_width+"+"+m_height);		yuv420 = new byte[width*height*3/2];		    mediaCodec = MediaCodec.createEncoderByType("video/avc");	    MediaFormat mediaFormat = MediaFormat.createVideoFormat("video/avc", width, height);	    mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, bitrate);	    mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, framerate);	    mediaFormat.setInteger(MediaFormat.KEY_COLOR_FORMAT, MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface);    	    mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 1);//关键帧间隔时间 单位s  	    	    mediaCodec.configure(mediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);	    mediaCodec.start();	}		@SuppressLint("NewApi")	public void close() {	    try {	        mediaCodec.stop();	        mediaCodec.release();	    } catch (Exception e){ 	        e.printStackTrace();	    }	}	@SuppressLint("NewApi")	public int offerEncoder(byte[] input, byte[] output) {			Log.v("xmc", "offerEncoder:"+input.length+"+"+output.length);		int pos = 0;		swapYV12toI420(input, yuv420, m_width, m_height);	    try {	        ByteBuffer[] inputBuffers = mediaCodec.getInputBuffers();	        ByteBuffer[] outputBuffers = mediaCodec.getOutputBuffers();	        int inputBufferIndex = mediaCodec.dequeueInputBuffer(-1);	        if (inputBufferIndex >= 0) {	            ByteBuffer inputBuffer = inputBuffers[inputBufferIndex];	            inputBuffer.clear();	            inputBuffer.put(input);	            mediaCodec.queueInputBuffer(inputBufferIndex, 0, input.length, 0, 0);	            	        }	        MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();	        int outputBufferIndex = mediaCodec.dequeueOutputBuffer(bufferInfo,0);	       	        while (outputBufferIndex >= 0) {	            ByteBuffer outputBuffer = outputBuffers[outputBufferIndex];	            byte[] outData = new byte[bufferInfo.size];	            outputBuffer.get(outData);	            if(m_info != null){            		            	System.arraycopy(outData, 0,  output, pos, outData.length);	 	            pos += outData.length;	            		            }else{//保存pps sps 只有开始时 第一个帧里有， 保存起来后面用 	            	 ByteBuffer spsPpsBuffer = ByteBuffer.wrap(outData);	            	 Log.v("xmc", "swapYV12toI420:outData:"+outData);	            	 Log.v("xmc", "swapYV12toI420:spsPpsBuffer:"+spsPpsBuffer);//	            		            	 for(int i=0;i
   
     yuv      private void swapYV12toI420(byte[] yv12bytes, byte[] i420bytes, int width, int height) {       	Log.v("xmc", "swapYV12toI420:::"+width+"+"+height);    	Log.v("xmc", "swapYV12toI420:::"+yv12bytes.length+"+"+i420bytes.length+"+"+width * height);    	System.arraycopy(yv12bytes, 0, i420bytes, 0, width*height);    	System.arraycopy(yv12bytes, width*height+width*height/4, i420bytes, width*height,width*height/4);    	System.arraycopy(yv12bytes, width*height, i420bytes, width*height+width*height/4,width*height/4);      }     //public static void arraycopy(Object src,int srcPos,Object dest,int destPos,int length)    //src:源数组；	srcPos:源数组要复制的起始位置；    //dest:目的数组；	destPos:目的数组放置的起始位置；	length:复制的长度。}
   

三、封装成RTP

import java.io.IOException;import java.nio.ByteBuffer;public class RtpStream {	private static final String TAG = "RtpStream";	private int payloadType;	private int sampleRate;	private RtpSocket socket;	private short sequenceNumber;	private long timeold;	public RtpStream(int pt, int sampleRate, RtpSocket socket){		this.payloadType = pt;		this.sampleRate = sampleRate;		this.socket = socket;	}		public void addPacket(byte[] data, int offset, int size, long timeUs) throws IOException{		addPacket(null, data, offset, size, timeUs);	}	public void addPacket(byte[] prefixData, byte[] data, int offset, int size, long timeUs) throws IOException{			/*		RTP packet header		Bit offset[b]	0-1	2	3	4-7	8	9-15	16-31		0			Version	P	X	CC	M	PT	Sequence Number  31		32			Timestamp									 63		64			SSRC identifier								 95		*/		ByteBuffer buffer = ByteBuffer.allocate(500000);		buffer.put((byte)(2 << 6));		buffer.put((byte)(payloadType));		buffer.putShort(sequenceNumber++);		buffer.putInt((int)(timeUs));		buffer.putInt(12345678);		buffer.putInt(size);		if(prefixData != null)			buffer.put(prefixData);		buffer.put(data, offset, size);				sendPacket(buffer, buffer.position());	}		protected void sendPacket(ByteBuffer buffer, int size) throws IOException{		socket.sendPacket(buffer.array(), 0, size);		buffer.clear();	}}

四、UDP发送

import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.util.Timer;import java.util.TimerTask;public class RtpUdp implements RtpSocket {	private DatagramSocket mSocket;	private InetAddress mInetAddress;	private int mPort;		public RtpUdp(String ip, int port, boolean broadcast){		try {			mInetAddress = InetAddress.getByName(ip);			mPort = port;			mSocket = new DatagramSocket();			mSocket.setBroadcast(broadcast);						} catch (Exception e) {			e.printStackTrace();		}	}		public void close(){		mSocket.close();	}		@Override	public void sendPacket(final byte[] data,final int offset, final int size) {		try{			DatagramPacket p;			p = new DatagramPacket(data, offset, size, mInetAddress, mPort);			mSocket.send(p);		} catch (IOException e) {			e.printStackTrace();		}	}}

import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.SocketException;import java.net.UnknownHostException;import java.util.List;import android.graphics.ImageFormat;import android.hardware.Camera;import android.hardware.Camera.PreviewCallback;import android.os.Bundle;import android.os.StrictMode;import android.annotation.SuppressLint;import android.app.Activity;import android.util.Log;import android.view.Menu;import android.view.SurfaceHolder;import android.view.SurfaceHolder.Callback;import android.view.SurfaceView;import com.android.screenrecorder.rtp.RtpSenderWrapper;import com.encode.androidencode.AvcEncoder;public class MainActivity extends Activity implements SurfaceHolder.Callback, PreviewCallback {	DatagramSocket socket;	InetAddress address;		AvcEncoder avcCodec;    public Camera m_camera;      SurfaceView   m_prevewview;    SurfaceHolder m_surfaceHolder;    //屏幕分辨率，每个机型不一样，机器连上adb后输入wm size可获取    int width = 800;    int height = 480;    int framerate = 30;//每秒帧率    int bitrate = 2500000;//编码比特率，    private RtpSenderWrapper mRtpSenderWrapper;        byte[] h264 = new byte[width*height*3];	@SuppressLint("NewApi")	@Override	protected void onCreate(Bundle savedInstanceState) {		Log.v("xmc", "MainActivity__onCreate");		StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()        .detectDiskReads()        .detectDiskWrites()        .detectAll()   // or .detectAll() for all detectable problems        .penaltyLog()        .build());StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()        .detectLeakedSqlLiteObjects()        .detectLeakedClosableObjects()        .penaltyLog()        .penaltyDeath()        .build());				super.onCreate(savedInstanceState);		setContentView(R.layout.activity_main);		//创建rtp并填写需要发送数据流的地址，直播中需要动态获取客户主动请求的地址		mRtpSenderWrapper = new RtpSenderWrapper("192.168.253.15", 5004, false);		avcCodec = new AvcEncoder(width,height,framerate,bitrate);				m_prevewview = (SurfaceView) findViewById(R.id.SurfaceViewPlay);		m_surfaceHolder = m_prevewview.getHolder(); // 绑定SurfaceView，取得SurfaceHolder对象		m_surfaceHolder.setFixedSize(width, height); // 预览大小設置		m_surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);		m_surfaceHolder.addCallback((Callback) this);				}	@Override	public boolean onCreateOptionsMenu(Menu menu) {		getMenuInflater().inflate(R.menu.main, menu);		return true;	}	@Override	public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {		}	@SuppressLint("NewApi")	@SuppressWarnings("deprecation")	@Override	public void surfaceCreated(SurfaceHolder arg0) {		Log.v("xmc", "MainActivity+surfaceCreated");		try {			m_camera = Camera.open();			m_camera.setPreviewDisplay(m_surfaceHolder);			Camera.Parameters parameters = m_camera.getParameters();			parameters.setPreviewSize(width, height);			parameters.setPictureSize(width, height);			parameters.setPreviewFormat(ImageFormat.YV12);			m_camera.setParameters(parameters);				m_camera.setPreviewCallback((PreviewCallback) this);			m_camera.startPreview();		} catch (IOException e){			e.printStackTrace();		}		}	@Override	public void surfaceDestroyed(SurfaceHolder arg0) {		Log.v("xmc", "MainActivity+surfaceDestroyed");		m_camera.setPreviewCallback(null);  //！！这个必须在前，不然退出出错		m_camera.release();		m_camera = null; 		avcCodec.close();	}	@Override	public void onPreviewFrame(byte[] data, Camera camera) {		Log.v("xmc", "MainActivity+h264 start");		int ret = avcCodec.offerEncoder(data, h264);		if(ret > 0){			//实时发送数据流		    mRtpSenderWrapper.sendAvcPacket(h264, 0, ret, 0);		}		Log.v("xmc", "MainActivity+h264 end");		Log.v("xmc", "-----------------------------------------------------------------------");	}}

六、对端解码显示

import android.content.Context;import android.graphics.SurfaceTexture;import android.media.MediaCodec;import android.media.MediaFormat;import android.util.AttributeSet;import android.util.Log;import android.view.Surface;import android.view.TextureView;import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.SocketException;import java.nio.ByteBuffer;public class ClientTextureView extends TextureView implements  TextureView.SurfaceTextureListener{    private static  final String MIME_TYPE = "video/avc";    private static final String TAG = "ClientTextureView" ;    private MediaCodec decode;    byte[] rtpData =  new byte[80000];    byte[] h264Data = new byte[80000];    int timestamp = 0;    DatagramSocket socket;    public ClientTextureView(Context context, AttributeSet attrs) {        super(context, attrs);        setSurfaceTextureListener(this);        try {            socket = new DatagramSocket(5004);//绔彛鍙�            socket.setReuseAddress(true);            socket.setBroadcast(true);        } catch (SocketException e) {            e.printStackTrace();        }    }    @Override    public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {        new PreviewThread(new Surface(surface),800,480);//鎵嬫満鐨勫垎杈ㄧ巼    }    @Override    public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {    }    @Override    public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {        if (socket != null){            socket.close();            socket = null;        }        return false;    }    @Override    public void onSurfaceTextureUpdated(SurfaceTexture surface) {    }    private  class  PreviewThread extends  Thread {        DatagramPacket datagramPacket = null;        public PreviewThread(Surface surface, int width , int height){            Log.e(TAG, "PreviewThread: gou zhao");            decode = MediaCodec.createDecoderByType(MIME_TYPE);            final MediaFormat format = MediaFormat.createVideoFormat(MIME_TYPE,width,height);            format.setInteger(MediaFormat.KEY_BIT_RATE,  40000);            format.setInteger(MediaFormat.KEY_FRAME_RATE, 20);            format.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 1);            byte[] header_sps = {0, 0, 0, 1, 103, 66, 0 , 41, -115, -115, 64, 80 , 30 , -48 , 15 ,8,-124, 83, -128};            byte[] header_pps = {0,0 ,0, 1, 104, -54, 67, -56};            format.setByteBuffer("csd-0", ByteBuffer.wrap(header_sps));            format.setByteBuffer("csd-1", ByteBuffer.wrap(header_pps));            decode.configure(format,surface,null,0);            decode.start();            start();        }        @Override        public void run() {            byte[] data = new byte[80000];            int h264Length = 0;            while (true){                if (socket != null){                    try {                        datagramPacket = new DatagramPacket(data,data.length);                        socket.receive(datagramPacket);//鎺ユ敹鏁版嵁                    } catch (IOException e) {                        e.printStackTrace();                    }                }                rtpData =  datagramPacket.getData();                if (rtpData != null ){                    if (rtpData[0] == -128 && rtpData[1] == 96){                        Log.e(TAG, "run:xxx");                        int l1 = (rtpData[12]<<24)& 0xff000000;                        int l2 = (rtpData[13]<<16)& 0x00ff0000;                        int l3 = (rtpData[14]<<8) & 0x0000ff00;                        int l4 = rtpData[15]&0x000000FF;                        h264Length = l1+l2+l3+l4;                        Log.e(TAG, "run: h264Length="+h264Length);                        System.arraycopy(rtpData,16, h264Data,0,h264Length);                        Log.e(TAG, "run:h264Data[0]="+h264Data[0]+","+h264Data[1]+","+h264Data[2]+","+h264Data[3]                                +","+h264Data[4]+","+h264Data[5]+","+h264Data[6]+","+h264Data[7]                                +","+h264Data[8]+","+h264Data[9]+","+h264Data[10]                                +","+h264Data[11]+","+h264Data[12]+","+h264Data[13]                                +","+h264Data[14]+","+h264Data[15]+","+h264Data[16]                                +","+h264Data[17]+","+h264Data[18]+","+h264Data[19]                                +","+h264Data[20]+","+h264Data[21]+","+h264Data[22]);//鎵撳嵃sps銆乸ps                        offerDecoder(h264Data,h264Data.length);                        Log.e(TAG, "run: offerDecoder=");                    }                }            }        }    }    //瑙ｇ爜h264鏁版嵁    private void offerDecoder(byte[] input, int length) {         Log.d(TAG, "offerDecoder: ");        try {            ByteBuffer[] inputBuffers = decode.getInputBuffers();            int inputBufferIndex = decode.dequeueInputBuffer(0);            if (inputBufferIndex >= 0) {                ByteBuffer inputBuffer = inputBuffers[inputBufferIndex];                inputBuffer.clear();                try{                    inputBuffer.put(input, 0, length);                }catch (Exception e){                    e.printStackTrace();                }                decode.queueInputBuffer(inputBufferIndex, 0, length, 0, 0);            }            MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();            int outputBufferIndex = decode.dequeueOutputBuffer(bufferInfo, 0);            while (outputBufferIndex >= 0) {                //If a valid surface was specified when configuring the codec,                //passing true renders this output buffer to the surface.                decode.releaseOutputBuffer(outputBufferIndex, true);                outputBufferIndex = decode.dequeueOutputBuffer(bufferInfo, 0);            }        } catch (Throwable t) {            t.printStackTrace();        }    }}