Android Open Source - voicelink A A C L A T M Packetizer

• Back to Development/voice  ↑

From Project

Back to project page voicelink.

License

The source code is released under:

Apache License

Java Source Code

/*
 * Copyright (C) 2011-2014 GUIGUI Simon, fyhertz@gmail.com
 * /* w  w w  .j  a v  a  2  s .c o  m*/
 * 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.audio.send;

import java.io.IOException;

import android.annotation.SuppressLint;
import android.media.MediaCodec.BufferInfo;
import android.util.Log;

/**
 * RFC 3640.
 * 
 * Encapsulates AAC Access Units in RTP packets as specified in the RFC 3640.
 * This packetizer is used by the AACStream class in conjunction with the
 * MediaCodec API introduced in Android 4.1 (API Level 16).
 * 
 */
@SuppressLint("NewApi")
public class AACLATMPacketizer implements Runnable {

  private final static String TAG = "AACLATMPacketizer";

  private Thread t;

  protected static final int rtphl = SendSocket.RTP_HEADER_LENGTH;

  // Maximum size of RTP packets
  protected final static int MAXPACKETSIZE = SendSocket.MTU - 28;

  public SendSocket sendSocket = null;
  public MediaCodecInputStream mMediaCodecInputStream = null;
  protected byte[] buffer;

  protected long ts = 0;

  public AACLATMPacketizer() {
    super();
  }

  public void start() {
    if (t == null) {
      t = new Thread(this);
      t.start();
    }
  }

  public void stop() {
    if (t != null) {
      mMediaCodecInputStream.close();
      
      t.interrupt();
      try {
        t.join();
      } catch (InterruptedException e) {
      }
      t = null;
    }
  }

  public void setSamplingRate(int samplingRate) {
    sendSocket.setClockFrequency(samplingRate);
  }

  @SuppressLint("NewApi")
  public void run() {

    Log.d(TAG, "AAC LATM packetizer started !");

    int length = 0;
    long oldts;
    BufferInfo bufferInfo;

    try {
      while (!Thread.interrupted()) {
        buffer = sendSocket.requestBuffer();
        length = mMediaCodecInputStream.read(buffer, rtphl + 4, MAXPACKETSIZE - (rtphl + 4));

        if (length > 0) {

          bufferInfo = mMediaCodecInputStream.getLastBufferInfo();
          // Log.d(TAG,"length: "+length+" ts: "+bufferInfo.presentationTimeUs);
          oldts = ts;
          ts = bufferInfo.presentationTimeUs * 1000;

          // Seems to happen sometimes
          if (oldts > ts) {
            sendSocket.commitBuffer();
            continue;
          }

          sendSocket.markNextPacket();
          sendSocket.updateTimestamp(ts);

          // 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) (length >> 5);
          buffer[rtphl + 3] = (byte) (length << 3);

          // AU-Index
          buffer[rtphl + 3] &= 0xF8;
          buffer[rtphl + 3] |= 0x00;

          send(rtphl + length + 4);

        } else {
          sendSocket.commitBuffer();
        }

      }
    } catch (IOException e) {
    } catch (ArrayIndexOutOfBoundsException e) {
      Log.e(TAG, "ArrayIndexOutOfBoundsException: " + (e.getMessage() != null ? e.getMessage() : "unknown error"));
      e.printStackTrace();
    } catch (InterruptedException ignore) {
    }

    Log.d(TAG, "AAC LATM packetizer stopped !");

  }

  /** Updates data for RTCP SR and sends the packet. */
  protected void send(int length) throws IOException {
    sendSocket.commitBuffer(length);
  }

  /** Used in packetizers to estimate timestamps in RTP packets. */
  protected static class Statistics {

    public final static String TAG = "Statistics";

    private int count = 700, c = 0;
    private float m = 0, q = 0;
    private long elapsed = 0;
    private long start = 0;
    private long duration = 0;
    private long period = 10000000000L;
    private boolean initoffset = false;

    public Statistics() {
    }

    public Statistics(int count, int period) {
      this.count = count;
      this.period = period;
    }

    public void reset() {
      initoffset = false;
      q = 0;
      m = 0;
      c = 0;
      elapsed = 0;
      start = 0;
      duration = 0;
    }

    public void push(long value) {
      elapsed += value;
      if (elapsed > period) {
        elapsed = 0;
        long now = System.nanoTime();
        if (!initoffset || (now - start < 0)) {
          start = now;
          duration = 0;
          initoffset = true;
        }
        // Prevents drifting issues by comparing the real duration of
        // the
        // stream with the sum of all temporal lengths of RTP packets.
        value += (now - start) - duration;
        // Log.d(TAG,
        // "sum1: "+duration/1000000+" sum2: "+(now-start)/1000000+" drift: "+((now-start)-duration)/1000000+" v: "+value/1000000);
      }
      if (c < 5) {
        // We ignore the first 20 measured values because they may not
        // be accurate
        c++;
        m = value;
      } else {
        m = (m * q + value) / (q + 1);
        if (q < count)
          q++;
      }
    }

    public long average() {
      long l = (long) m;
      duration += l;
      return l;
    }

  }

}

Java Source Code List

• Back to Development/voice  ↑