Android下通过Mediarecorder获取H.263视频帧并通过RTP简单发送

功能如题。参考了此文：

http://blog.csdn.net/zblue78/article/details/6083374

 

本人觉得上文中的代码还有些bug，而且不是针对H.263，所以自己编写了一个。本工程除了截取H263视频帧外的代码仍不完善，待以后有时间的时候继续修改。还有就是代码中实现了RTP的包头编写，但payload部分并不是按照RFC2190来组织，少了一个payload header的实现。

 

完整的Android工程在此下载：

http://download.csdn.net/detail/qwertyuj/3865413

 

下面是实现视频帧截取的主要代码：

		    public void run() {  
		        final int READ_SIZE = 1024;	//bytes count for every reading from 'inputStreamForReceive'
		        final int BUFFER_SIZE_RECEIVE = READ_SIZE * 128;
		        final int BUFFER_SIZE_RTP = READ_SIZE * 20;
		        stateMachineOfFrameReceiving STM_Recv = stateMachineOfFrameReceiving.FRAMEHEAD_NOTFOUND;
		        int i;
		        byte[] PSC_checkArr = new byte[3];
		        byte[] RTP_pocket_buffer = new byte[BUFFER_SIZE_RTP];
		        byte[] bufferForReceive = new byte[BUFFER_SIZE_RECEIVE]; 	//64K
		        int num = 0;  
		        InputStream inputStreamForReceive = null;

		        //udp
		        final int RTP_PORT_SENDING = 8000;
		        final int RTP_PORT_DEST = 8000;
		        DatagramSocket socketSendRPT = null;
		        DatagramPacket RtpPocket = null;
		        InetAddress PC_IpAddress = null;
		        try { 
		        	PC_IpAddress = InetAddress.getByName("192.168.1.100");
		        } 
		        catch (UnknownHostException e){
		        	e.printStackTrace();
		        } 
		        
		        try{
		        	socketSendRPT = new DatagramSocket(RTP_PORT_SENDING);
		        }
		        catch (SocketException e){
		        	e.printStackTrace();
		        }
  
		       
		        
		      //get the data stream from mediaRecorder
		        try {  
		            inputStreamForReceive = receiver.getInputStream();	
		        } catch (IOException e1) {  
		            return;  
		        } 
		        
		        //create a media file to store captured video data
		        try {  
		            File file = new File("/sdcard/stream02.h263");  
		            Log.d(TAG, "File created!"); 
		            if (file.exists())  
		                file.delete();//delete old file
		            raf = new RandomAccessFile(file, "rw");  
		        } catch (Exception ex) {  
		            Log.v("System.out", ex.toString());  
		        }	
		        

		        
		        int offsetInBufferForReceive = 0;
 		        m_timer.schedule(m_timerTask, 1000, 1000);	//timer for statistics
      
 		        STM_Recv = stateMachineOfFrameReceiving.FRAMEHEAD_NOTFOUND;
 		        PSC_checkArr[0] = (byte)0xFF;
				PSC_checkArr[1] = (byte)0xFF;
				PSC_checkArr[2] = (byte)0xFF;
 		        while (true && !threadCanStop) { 
			        //1. read data from receive stream until to the end
 		        	offsetInBufferForReceive = 0;
			        do {  
			            try {  
			                num = inputStreamForReceive.read(bufferForReceive, offsetInBufferForReceive, READ_SIZE);//copy data to buffer
			                if(num < 0){	// there's nothing in there
			                	//wait for a while
						        try {  
						            Thread.currentThread().sleep(5); 
						        } catch (InterruptedException e1) {  
						        	e1.printStackTrace();  
						        }
						        break;
			                }
			                
			                offsetInBufferForReceive += num; //offsetInBufferForReceive points to next position can be wrote
			                if (num < READ_SIZE || offsetInBufferForReceive == BUFFER_SIZE_RECEIVE) {  //indicating the end of this reading
			                    break;  																 // or bufferForReceive is full
			                }  
			            } catch (IOException e) {  
			                break;  
			            }  
			        }while(false);//do
			        
			        //2. find Picture Start Code (PSC) (22 bits) in bufferForReceive
			        for(i=0; i< offsetInBufferForReceive; i++){
			        	PSC_checkArr[0] = PSC_checkArr[1];
			        	PSC_checkArr[1] = PSC_checkArr[2];
			        	PSC_checkArr[2] = bufferForReceive[i];
			        	
			        	//see if got the PSC
			        	if(PSC_checkArr[0] == 0 && PSC_checkArr[1] == 0 && (PSC_checkArr[2] & (byte)0xFC) == (byte)0x80)
			        	{
			        		//found the PSC
			        		if(STM_Recv == stateMachineOfFrameReceiving.FRAMEHEAD_NOTFOUND)
			        		{
			        			STM_Recv = stateMachineOfFrameReceiving.FRAMEHEAD_FOUND;
			        			//copy current byte to packet buffer
			        			intializeRTP_PocketBuffer(RTP_pocket_buffer);
			        			RTP_pocket_buffer[offsetInRTP_pocket_buffer] = bufferForReceive[i];
			        			offsetInRTP_pocket_buffer++;
			        		}
			        		else if(STM_Recv == stateMachineOfFrameReceiving.FRAMEHEAD_FOUND)
			        		{
			        			//delete two zeros in the end of the buffer
			        			offsetInRTP_pocket_buffer -= 2;

			        			//TODO:3. send the packet, and reset the buffer
			        			RtpPocket = new DatagramPacket(RTP_pocket_buffer, offsetInRTP_pocket_buffer, PC_IpAddress, RTP_PORT_DEST);  
			        			try {
			        				socketSendRPT.send(RtpPocket);
			        				Log.v(TAG, "Sent bytes: " + String.valueOf(offsetInRTP_pocket_buffer));  
			        			} catch (IOException e) {
			        				e.printStackTrace();
								}
			        			
			        			/*
						        try { 
						        	raf.write(RTP_pocket_buffer, 0, offsetInRTP_pocket_buffer);  
						        	//raf.close();
						        } catch (IOException e1) {  
						            e1.printStackTrace();  
						        }
						        */
						        
						        intCapturedFrameCount++;	//for statistics
			        			//copy current byte to packet buffer
			        			intializeRTP_PocketBuffer(RTP_pocket_buffer);
			        			RTP_pocket_buffer[offsetInRTP_pocket_buffer] = bufferForReceive[i];
			        			offsetInRTP_pocket_buffer++;
			        			
			        		}
	
			        	}
			        	else//if NOT got the PSC
			        	{
			        		if(STM_Recv == stateMachineOfFrameReceiving.FRAMEHEAD_NOTFOUND)
			        		{
			        			continue;
			        		}
			        		else if(STM_Recv == stateMachineOfFrameReceiving.FRAMEHEAD_FOUND)
			        		{
			        			//copy current byte to packet buffer
			        			RTP_pocket_buffer[offsetInRTP_pocket_buffer] = bufferForReceive[i];
			        			offsetInRTP_pocket_buffer++;
			        		}
			        	}//if(PSC_checkArr[0] == 0 && PSC_checkArr[1] == 0 && (PSC_checkArr[2] & (byte)0xFC) == (byte)0x80)
			        	
			        	//4. if RTP_pocket_buffer is full then discard all the bytes in it
			        	if(offsetInRTP_pocket_buffer >= BUFFER_SIZE_RTP)
			        	{
			        		STM_Recv = stateMachineOfFrameReceiving.FRAMEHEAD_NOTFOUND;
			        		offsetInRTP_pocket_buffer = 0;
			        	}
			        	
			        }//for(i=0; i< offsetInBufferForReceive; i++)
			        
			        
		        }// while (true && !threadCanStop)
 		        
 		        m_timer.cancel();
		        
		        releaseMediaRecorder();
		        
		    }  
		})