【发布时间】：2015-09-15 09:56:55
【问题描述】：
我正在通过网络以 RTP 数据包的形式获取实时音频流，我必须编写代码来捕获、缓冲和播放音频流。
问题
现在为了解决这个问题，我编写了两个线程，一个用于捕获音频，另一个用于播放它。 现在，当我启动两个线程时，我的捕获线程运行速度比播放线程慢 :(
缓冲区要求
- RTP 音频数据包。
- 8kHz，16 位线性采样（线性 PCM）。
- 将在每个 RTP 数据包中发送 4 帧 20 毫秒的音频。
- 在 AudioStart=24（# of 20ms 帧）到达之前不要播放。
- 播放时 ... 如果缓冲区中 20 毫秒的帧数达到 0 ... 停止播放，直到 AudioStart 帧被缓冲然后重新启动。
-
播放时...如果缓冲区中的 20 毫秒帧数超过 AudioBufferHigh=50 然后删除 24 帧（以最简单的方式 - 删除 从缓冲区或只删除接下来的 6 条 RTP 消息）。
到目前为止我做了什么..
代码
BufferManager.java
public abstract class BufferManager {
protected static final Integer ONE = new Integer(1);
protected static final Integer TWO = new Integer(2);
protected static final Integer THREE = new Integer(3);
protected static final Integer BUFFER_SIZE = 5334;//5.334KB
protected static volatile Map<Integer, ByteArrayOutputStream> bufferPool = new ConcurrentHashMap<>(3, 0.9f, 2);
protected static volatile Integer captureBufferKey = ONE;
protected static volatile Integer playingBufferKey = ONE;
protected static Boolean running;
protected static volatile Integer noOfFrames = 0;
public BufferManager() {
//captureBufferKey = ONE;
//playingBufferKey = ONE;
//noOfFrames = new Integer(0);
}
protected void switchCaptureBufferKey() {
if(ONE.intValue() == captureBufferKey.intValue())
captureBufferKey = TWO;
else if(TWO.intValue() == captureBufferKey.intValue())
captureBufferKey = THREE;
else
captureBufferKey = ONE;
//printBufferState("SWITCHCAPTURE");
}//End of switchWritingBufferKey() Method.
protected void switchPlayingBufferKey() {
if(ONE.intValue() == playingBufferKey.intValue())
playingBufferKey = TWO;
else if(TWO.intValue() == playingBufferKey.intValue())
playingBufferKey = THREE;
else
playingBufferKey = ONE;
}//End of switchWritingBufferKey() Method.
protected static AudioFormat getFormat() {
float sampleRate = 8000;
int sampleSizeInBits = 16;
int channels = 1;
boolean signed = true;
boolean bigEndian = true;
return new AudioFormat(sampleRate, sampleSizeInBits, channels, signed, bigEndian);
}
protected int getByfferSize() {
return bufferPool.get(ONE).size()
+ bufferPool.get(TWO).size()
+ bufferPool.get(THREE).size();
}
protected static void printBufferState(String flag) {
int a = bufferPool.get(ONE).size();
int b = bufferPool.get(TWO).size();
int c = bufferPool.get(THREE).size();
System.out.println(flag + " == TOTAL : [" + (a + b +c) + "bytes] ");
// int a,b,c;
// System.out.println(flag + "1 : [" + (a = bufferPool.get(ONE).size()) + "bytes], 2 : [" + (b = bufferPool.get(TWO).size())
// + "bytes] 3 : [" + (c = bufferPool.get(THREE).size()) + "bytes], TOTAL : [" + (a + b +c) + "bytes] ");
}
}//End of BufferManager Class.
AudioCapture.java
public class AudioCapture extends BufferManager implements Runnable {
private static final Integer RTP_HEADER_SIZE = 12;
private InetAddress ipAddress;
private DatagramSocket serverSocket;
long lStartTime = 0;
public AudioCapture(Integer port) throws UnknownHostException, SocketException {
super();
running = Boolean.TRUE;
bufferPool.put(ONE, new ByteArrayOutputStream(BUFFER_SIZE));
bufferPool.put(TWO, new ByteArrayOutputStream(BUFFER_SIZE));
bufferPool.put(THREE, new ByteArrayOutputStream(BUFFER_SIZE));
this.ipAddress = InetAddress.getByName("0.0.0.0");
serverSocket = new DatagramSocket(port, ipAddress);
}
@Override
public void run() {
System.out.println();
byte[] receiveData = new byte[1300];
DatagramPacket receivePacket = null;
lStartTime = System.currentTimeMillis();
receivePacket = new DatagramPacket(receiveData, receiveData.length);
byte[] packet = new byte[receivePacket.getLength() - RTP_HEADER_SIZE];
ByteArrayOutputStream buff = bufferPool.get(captureBufferKey);
while (running) {
if(noOfFrames <= 50) {
try {
serverSocket.receive(receivePacket);
packet = Arrays.copyOfRange(receivePacket.getData(), RTP_HEADER_SIZE, receivePacket.getLength());
if((buff.size() + packet.length) > BUFFER_SIZE) {
switchCaptureBufferKey();
buff = bufferPool.get(captureBufferKey);
}
buff.write(packet);
noOfFrames += 4;
} catch (SocketException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} // End of try-catch block.
} else {
//System.out.println("Packet Ignored, Buffer reached to its maximum limit ");
}//End of if-else block.
} // End of while loop.
}//End of run() Method.
}
AudioPlayer.java
public class AudioPlayer extends BufferManager implements Runnable {
long lStartTime = 0;
public AudioPlayer() {
super();
}
@Override
public void run() {
AudioFormat format = getFormat();
DataLine.Info info = new DataLine.Info(SourceDataLine.class, format);
SourceDataLine line = null;
try {
line = (SourceDataLine) AudioSystem.getLine(info);
line.open(format);
line.start();
} catch (LineUnavailableException e1) {
e1.printStackTrace();
}
while (running) {
if (noOfFrames >= 24) {
ByteArrayOutputStream out = null;
try {
out = bufferPool.get(playingBufferKey);
InputStream input = new ByteArrayInputStream(out.toByteArray());
byte buffer[] = new byte[640];
int count;
while ((count = input.read(buffer, 0, buffer.length)) != -1) {
if (count > 0) {
InputStream in = new ByteArrayInputStream(buffer);
AudioInputStream ais = new AudioInputStream(in, format, buffer.length / format.getFrameSize());
byte buff[] = new byte[640];
int c = 0;
if((c = ais.read(buff)) != -1)
line.write(buff, 0, buff.length);
}
}
} catch (IOException e) {
e.printStackTrace();
}
/*byte buffer[] = new byte[1280];
try {
int count;
while ((count = ais.read(buffer, 0, buffer.length)) != -1) {
if (count > 0) {
line.write(buffer, 0, count);
}
}
} catch (IOException e) {
e.printStackTrace();
}*/
out.reset();
noOfFrames -= 4;
try {
if (getByfferSize() >= 10240) {
Thread.sleep(15);
} else if (getByfferSize() >= 5120) {
Thread.sleep(25);
} else if (getByfferSize() >= 0) {
Thread.sleep(30);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
} else {
// System.out.println("Number of frames :- " + noOfFrames);
}
}
}// End of run() method.
}// End of AudioPlayer Class class.
任何帮助或指向有用链接的指针都会非常感谢...
【问题讨论】：
标签： java audio buffer audio-streaming rtp