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 net.majorkernelpanic.streaming.audio.AACStream;
  import android.os.SystemClock;
  import android.util.Log;
  
  /**
   *   
   *   RFC 3640.  
   *
   *   This packetizer must be fed with an InputStream containing ADTS AAC. 
   *   AAC will basically be rewrapped in an RTP stream and sent over the network.
   *   This packetizer only implements the aac-hbr mode (High Bit-rate AAC) and
   *   each packet only carry a single and complete AAC access unit.
   * 
   */
  public class AACADTSPacketizer extends AbstractPacketizer implements Runnable {
  
  	private final static String TAG = "AACADTSPacketizer";
  
  	private Thread t;
  	private int samplingRate = 8000;
  
  	public AACADTSPacketizer() {
  		super();
  	}
  
  	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 setSamplingRate(int samplingRate) {
  		this.samplingRate = samplingRate;
  		socket.setClockFrequency(samplingRate);
  	}
  
  	public void run() {
  
  		Log.d(TAG,"AAC ADTS packetizer started !");
  
  		// "A packet SHALL carry either one or more complete Access Units, or a
  		// single fragment of an Access Unit.  Fragments of the same Access Unit
  		// have the same time stamp but different RTP sequence numbers.  The
  		// marker bit in the RTP header is 1 on the last fragment of an Access
  		// Unit, and 0 on all other fragments." RFC 3640
  
  		// Adts header fields that we need to parse
  		boolean protection;
  		int frameLength, sum, length, nbau, nbpk, samplingRateIndex, profile;
  		long oldtime = SystemClock.elapsedRealtime(), now = oldtime;
  		byte[] header = new byte[8]; 
  
  		try {
  			while (!Thread.interrupted()) {
  
  				// Synchronisation: ADTS packet starts with 12bits set to 1
  				while (true) {
  					if ( (is.read()&0xFF) == 0xFF ) {
  						header[1] = (byte) is.read();
  						if ( (header[1]&0xF0) == 0xF0) break;
  					}
  				}
  
  				// Parse adts header (ADTS packets start with a 7 or 9 byte long header)
  				fill(header, 2, 5);
  
  				// The protection bit indicates whether or not the header contains the two extra bytes
  				protection = (header[1]&0x01)>0 ? true : false;
  				frameLength = (header[3]&0x03) << 11 | 
  						(header[4]&0xFF) << 3 | 
  						(header[5]&0xFF) >> 5 ;
  				frameLength -= (protection ? 7 : 9);
  
  				// Number of AAC frames in the ADTS frame
  				nbau = (header[6]&0x03) + 1;
  
  				// The number of RTP packets that will be sent for this ADTS frame
  				nbpk = frameLength/MAXPACKETSIZE + 1;
  
  				// Read CRS if any
  				if (!protection) is.read(header,0,2);
  
  				samplingRate = AACStream.AUDIO_SAMPLING_RATES[(header[2]&0x3C) >> 2];
  				profile = ( (header[2]&0xC0) >> 6 ) + 1 ;
  
  				// We update the RTP timestamp
  				ts +=  1024L*1000000000L/samplingRate; //stats.average();
  
  				//Log.d(TAG,"frameLength: "+frameLength+" protection: "+protection+" p: "+profile+" sr: "+samplingRate);
  
  				sum = 0;
  				while (sum<frameLength) {
  
  					buffer = socket.requestBuffer();
  					socket.updateTimestamp(ts);
  
  					// Read frame
  					if (frameLength-sum > MAXPACKETSIZE-rtphl-4) {
  						length = MAXPACKETSIZE-rtphl-4;
  					}
  					else {
  						length = frameLength-sum;
  						socket.markNextPacket();
  					}
  					sum += length;
  					fill(buffer, rtphl+4, length);
  
  					// AU-headers-length field: contains the size in bits of a AU-header
  					// 13+3 = 16 bits -> 13bits for AU-size and 3bits for AU-Index / AU-Index-delta 
  					// 13 bits will be enough because ADTS uses 13 bits for frame length
  					buffer[rtphl] = 0;
  					buffer[rtphl+1] = 0x10; 
  
  					// AU-size
  					buffer[rtphl+2] = (byte) (frameLength>>5);
  					buffer[rtphl+3] = (byte) (frameLength<<3);
  
  					// AU-Index
  					buffer[rtphl+3] &= 0xF8;
  					buffer[rtphl+3] |= 0x00;
  
  					send(rtphl+4+length);
  
  				}
  
  			}
  		} catch (IOException e) {
  			// Ignore
  		} catch (ArrayIndexOutOfBoundsException e) {
  			Log.e(TAG,"ArrayIndexOutOfBoundsException: "+(e.getMessage()!=null?e.getMessage():"unknown error"));
  			e.printStackTrace();
  		} catch (InterruptedException ignore) {}
  
  		Log.d(TAG,"AAC ADTS 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;
  	}
  
  }
  