PCM - > AAC（编码器） - > PCM（解码器）如何实时进行正确的优化？
PCM - > AAC（编码器） - > PCM（解码器）如何实时进行正确的优化？
提问于 2018-03-13 06:57:03
我在努力实现
AudioRecord (MIC) ->
PCM -> AAC Encoder
AAC -> PCM Decode
-> AudioTrack?? (SPEAKER)MediaCodec在安卓4.1+上(API 16)。
首先，我成功地实现了PCM -> AAC Encoder通过MediaCodec如下所示
private boolean setEncoder(int rate)
{
encoder = MediaCodec.createEncoderByType("audio/mp4a-latm");
MediaFormat format = new MediaFormat();
format.setString(MediaFormat.KEY_MIME, "audio/mp4a-latm");
format.setInteger(MediaFormat.KEY_CHANNEL_COUNT, 1);
format.setInteger(MediaFormat.KEY_SAMPLE_RATE, 44100);
format.setInteger(MediaFormat.KEY_BIT_RATE, 64 * 1024);//AAC-HE 64kbps
format.setInteger(MediaFormat.KEY_AAC_PROFILE, MediaCodecInfo.CodecProfileLevel.AACObjectHE);
encoder.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
return true;
}输入：PCM比特率=44100(Hz)x16(位)x1(单片)=705600位/秒
输出：aac-HE比特率=64x1024(位)=65536位/秒
解码器配置文件设置如下：
private boolean setDecoder(int rate)
{
decoder = MediaCodec.createDecoderByType("audio/mp4a-latm");
MediaFormat format = new MediaFormat();
format.setString(MediaFormat.KEY_MIME, "audio/mp4a-latm");
format.setInteger(MediaFormat.KEY_CHANNEL_COUNT, 1);
format.setInteger(MediaFormat.KEY_SAMPLE_RATE, 44100);
format.setInteger(MediaFormat.KEY_BIT_RATE, 64 * 1024);//AAC-HE 64kbps
format.setInteger(MediaFormat.KEY_AAC_PROFILE, MediaCodecInfo.CodecProfileLevel.AACObjectHE);
decoder.configure(format, null, null, 0);
return true;
}因为UDPserver数据包缓冲区大小是1024
- UDPserver：接收1024字节由于这是压缩的aac数据，我希望解码的大小将是大约1024
x11，但是实际结果是 - 音频解码器：8192字节解码
解码器代码如下：
IOudpPlayer = new Thread(new Runnable()
{
public void run()
{
SocketAddress sockAddress;
String address;
int len = 1024;
byte[] buffer2 = new byte[len];
DatagramPacket packet;
byte[] data;
ByteBuffer[] inputBuffers;
ByteBuffer[] outputBuffers;
ByteBuffer inputBuffer;
ByteBuffer outputBuffer;
MediaCodec.BufferInfo bufferInfo;
int inputBufferIndex;
int outputBufferIndex;
byte[] outData;
try
{
decoder.start();
isPlaying = true;
while (isPlaying)
{
try
{
packet = new DatagramPacket(buffer2, len);
ds.receive(packet);
sockAddress = packet.getSocketAddress();
address = sockAddress.toString();
Log.d("UDP Receiver"," received !!! from " + address);
data = new byte[packet.getLength()];
System.arraycopy(packet.getData(), packet.getOffset(), data, 0, packet.getLength());
Log.d("UDP Receiver", data.length + " bytes received");
//===========
inputBuffers = decoder.getInputBuffers();
outputBuffers = decoder.getOutputBuffers();
inputBufferIndex = decoder.dequeueInputBuffer(-1);
if (inputBufferIndex >= 0)
{
inputBuffer = inputBuffers[inputBufferIndex];
inputBuffer.clear();
inputBuffer.put(data);
decoder.queueInputBuffer(inputBufferIndex, 0, data.length, 0, 0);
}
bufferInfo = new MediaCodec.BufferInfo();
outputBufferIndex = decoder.dequeueOutputBuffer(bufferInfo, 0);
while (outputBufferIndex >= 0)
{
outputBuffer = outputBuffers[outputBufferIndex];
outputBuffer.position(bufferInfo.offset);
outputBuffer.limit(bufferInfo.offset + bufferInfo.size);
outData = new byte[bufferInfo.size];
outputBuffer.get(outData);
Log.d("AudioDecoder", outData.length + " bytes decoded");
decoder.releaseOutputBuffer(outputBufferIndex, false);
outputBufferIndex = decoder.dequeueOutputBuffer(bufferInfo, 0);
}
//===========
}
catch (IOException e)
{
}
}
decoder.stop();
}
catch (Exception e)
{
}
}
});完整的代码：
https：//gist.github.com/kenokabe/9029256
还需要得到许可：
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.RECORD_AUDIO"></uses-permission>所以我的问题是
- 能正确地优化我的示例代码以使其正常工作吗？
- 这是一个正确的方式来使用
AudioTrack API来动态播放解码的PCM原始数据，并且可以告诉我正确的方法吗？
Stack Overflow用户
发布于 2018-03-13 11:46:58
在测试之后，我从修改代码中得到了以下结果：
package com.example.app;
import android.app.Activity;
import android.media.AudioManager;
import android.media.MediaCodecInfo;
import android.media.MediaFormat;
import android.os.Bundle;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.AudioTrack;
import android.media.MediaCodec;
import android.media.MediaRecorder.AudioSource;
import android.util.Log;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketAddress;
import java.net.SocketException;
import java.nio.ByteBuffer;
public class MainActivity extends Activity
{
private AudioRecord recorder;
private AudioTrack player;
private MediaCodec encoder;
private MediaCodec decoder;
private short audioFormat = AudioFormat.ENCODING_PCM_16BIT;
private short channelConfig = AudioFormat.CHANNEL_IN_MONO;
private int bufferSize;
private boolean isRecording;
private boolean isPlaying;
private Thread IOrecorder;
private Thread IOudpPlayer;
private DatagramSocket ds;
private final int localPort = 39000;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
IOrecorder = new Thread(new Runnable()
{
public void run()
{
int read;
byte[] buffer1 = new byte[bufferSize];
ByteBuffer[] inputBuffers;
ByteBuffer[] outputBuffers;
ByteBuffer inputBuffer;
ByteBuffer outputBuffer;
MediaCodec.BufferInfo bufferInfo;
int inputBufferIndex;
int outputBufferIndex;
byte[] outData;
DatagramPacket packet;
try
{
encoder.start();
recorder.startRecording();
isRecording = true;
while (isRecording)
{
read = recorder.read(buffer1, 0, bufferSize);
// Log.d("AudioRecoder", read + " bytes read");
//------------------------
inputBuffers = encoder.getInputBuffers();
outputBuffers = encoder.getOutputBuffers();
inputBufferIndex = encoder.dequeueInputBuffer(-1);
if (inputBufferIndex >= 0)
{
inputBuffer = inputBuffers[inputBufferIndex];
inputBuffer.clear();
inputBuffer.put(buffer1);
encoder.queueInputBuffer(inputBufferIndex, 0, buffer1.length, 0, 0);
}
bufferInfo = new MediaCodec.BufferInfo();
outputBufferIndex = encoder.dequeueOutputBuffer(bufferInfo, 0);
while (outputBufferIndex >= 0)
{
outputBuffer = outputBuffers[outputBufferIndex];
outputBuffer.position(bufferInfo.offset);
outputBuffer.limit(bufferInfo.offset + bufferInfo.size);
outData = new byte[bufferInfo.size];
outputBuffer.get(outData);
// Log.d("AudioEncoder ", outData.length + " bytes encoded");
//-------------
packet = new DatagramPacket(outData, outData.length,
InetAddress.getByName("127.0.0.1"), localPort);
ds.send(packet);
//------------
encoder.releaseOutputBuffer(outputBufferIndex, false);
outputBufferIndex = encoder.dequeueOutputBuffer(bufferInfo, 0);
}
// ----------------------;
}
encoder.stop();
recorder.stop();
}
catch (Exception e)
{
e.printStackTrace();
}
}
});
IOudpPlayer = new Thread(new Runnable()
{
public void run()
{
SocketAddress sockAddress;
String address;
int len = 2048
byte[] buffer2 = new byte[len];
DatagramPacket packet;
byte[] data;
ByteBuffer[] inputBuffers;
ByteBuffer[] outputBuffers;
ByteBuffer inputBuffer;
ByteBuffer outputBuffer;
MediaCodec.BufferInfo bufferInfo;
int inputBufferIndex;
int outputBufferIndex;
byte[] outData;
try
{
player.play();
decoder.start();
isPlaying = true;
while (isPlaying)
{
try
{
packet = new DatagramPacket(buffer2, len);
ds.receive(packet);
sockAddress = packet.getSocketAddress();
address = sockAddress.toString();
// Log.d("UDP Receiver"," received !!! from " + address);
data = new byte[packet.getLength()];
System.arraycopy(packet.getData(), packet.getOffset(), data, 0, packet.getLength());
// Log.d("UDP Receiver", data.length + " bytes received");
//===========
inputBuffers = decoder.getInputBuffers();
outputBuffers = decoder.getOutputBuffers();
inputBufferIndex = decoder.dequeueInputBuffer(-1);
if (inputBufferIndex >= 0)
{
inputBuffer = inputBuffers[inputBufferIndex];
inputBuffer.clear();
inputBuffer.put(data);
decoder.queueInputBuffer(inputBufferIndex, 0, data.length, 0, 0);
}
bufferInfo = new MediaCodec.BufferInfo();
outputBufferIndex = decoder.dequeueOutputBuffer(bufferInfo, 0);
while (outputBufferIndex >= 0)
{
outputBuffer = outputBuffers[outputBufferIndex];
outputBuffer.position(bufferInfo.offset);
outputBuffer.limit(bufferInfo.offset + bufferInfo.size);
outData = new byte[bufferInfo.size];
outputBuffer.get(outData);
// Log.d("AudioDecoder", outData.length + " bytes decoded");
player.write(outData, 0, outData.length);
decoder.releaseOutputBuffer(outputBufferIndex, false);
outputBufferIndex = decoder.dequeueOutputBuffer(bufferInfo, 0..页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/-100004249
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