content: /*
   * Copyright (C) 2011-2014 GUIGUI Simon, fyhertz@gmail.com
   * 
   * This file is part of libstreaming (https://github.com/fyhertz/libstreaming)
   * 
   * Spydroid is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 3 of the License, or
   * (at your option) any later version.
   * 
   * This source code is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   * 
   * You should have received a copy of the GNU General Public License
   * along with this source code; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package net.majorkernelpanic.streaming.rtp;
  
  import java.io.IOException;
  
  import android.util.Log;
  
  /**
   * 
   *   RFC 3267.
   *   
   *   AMR Streaming over RTP.
   *   
   *   Must be fed with an InputStream containing raw amr nb
   *   Stream must begin with a 6 bytes long header: "#!AMR\n", it will be skipped
   *   
   */
  public class AMRNBPacketizer extends AbstractPacketizer implements Runnable {
  
  	public final static String TAG = "AMRNBPacketizer";
  
  	private final int AMR_HEADER_LENGTH = 6; // "#!AMR\n"
  	private static final int AMR_FRAME_HEADER_LENGTH = 1; // Each frame has a short header
  	private static final int[] sFrameBits = {95, 103, 118, 134, 148, 159, 204, 244};
  	private int samplingRate = 8000;
  
  	private Thread t;
  
  	public AMRNBPacketizer() {
  		super();
  		socket.setClockFrequency(samplingRate);
  	}
  
  	public void start() {
  		if (t==null) {
  			t = new Thread(this);
  			t.start();
  		}
  	}
  
  	public void stop() {
  		if (t != null) {
  			try {
  				is.close();
  			} catch (IOException ignore) {}
  			t.interrupt();
  			try {
  				t.join();
  			} catch (InterruptedException e) {}
  			t = null;
  		}
  	}
  
  	public void run() {
  
  		int frameLength, frameType;
  		long now = System.nanoTime(), oldtime = now;
  		byte[] header = new byte[AMR_HEADER_LENGTH];
  
  		try {
  
  			// Skip raw amr header
  			fill(header,0,AMR_HEADER_LENGTH);
  			
  			if (header[5] != '\n') {
  				Log.e(TAG,"Bad header ! AMR not correcty supported by the phone !");
  				return;
  			}
  
  			while (!Thread.interrupted()) {
  
  				buffer = socket.requestBuffer();
  				buffer[rtphl] = (byte) 0xF0;
  				
  				// First we read the frame header
  				fill(buffer, rtphl+1,AMR_FRAME_HEADER_LENGTH);
  
  				// Then we calculate the frame payload length
  				frameType = (Math.abs(buffer[rtphl + 1]) >> 3) & 0x0f;
  				frameLength = (sFrameBits[frameType]+7)/8;
  
  				// And we read the payload
  				fill(buffer, rtphl+2,frameLength);
  
  				//Log.d(TAG,"Frame length: "+frameLength+" frameType: "+frameType);
  
  				// RFC 3267 Page 14: "For AMR, the sampling frequency is 8 kHz"
  				// FIXME: Is this really always the case ??
  				ts += 160L*1000000000L/samplingRate; //stats.average();
  				socket.updateTimestamp(ts);
  				socket.markNextPacket();
  
  				//Log.d(TAG,"expected: "+ expected + " measured: "+measured);
  				
  				send(rtphl+1+AMR_FRAME_HEADER_LENGTH+frameLength);
  				
  			}
  
  		} catch (IOException e) { 
  		} catch (InterruptedException e) {}
  
  		Log.d(TAG,"AMR packetizer stopped !");
  
  	}
  
  	private int fill(byte[] buffer, int offset,int length) throws IOException {
  		int sum = 0, len;
  		while (sum<length) {
  			len = is.read(buffer, offset+sum, length-sum);
  			if (len<0) {
  				throw new IOException("End of stream");
  			}
  			else sum+=len;
  		}
  		return sum;
  	}
  
  
  }
  