Android音訊實時傳輸與播放(三):AMR硬編碼與硬解碼
轉載請註明出處!
在Android中我所知道的音訊編解碼有兩種方式:
(一)使用AudioRecord採集音訊,用這種方式採集的是未經壓縮的音訊流;用AudioTrack播放實時音訊流。用這兩個類的話,如果需要對音訊進行編解碼,就需要自己移植編解碼庫了,比如可以移植ilbc,speex等開源編解碼庫。
(二)使用MediaRecorder獲取編碼後的AMR音訊,但由於MediaRecorder的特點,只能將流儲存到檔案中,但通過其他方式是可以獲取到實時音訊流的,這篇文章將介紹用LocalSocket的方法來實現;使用MediaPlayer來播放AMR音訊流,但同樣MediaPlayer也只能播放檔案流,因此我用快取的方式來播放音訊。
以上兩種方式各有利弊,使用方法(一)需移植編解碼庫,但可以播放實時音訊流;使用方法(二)直接硬編硬解碼效率高,但是需要對檔案進行操作。
PS:這篇文章只是給大家一個參考,僅供學習之用,如果真正用到專案中還有很多地方需要優化。
我強烈推薦播放音訊時候用方法(一),方法(二)雖然能夠實現功能,但是實現方式不太好。
接下來看程式碼:
編碼器:
package cn.edu.xmu.zgy.audio.encoder; import java.io.DataInputStream; import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; import cn.edu.xmu.zgy.config.CommonConfig; import android.app.Activity; import android.media.MediaRecorder; import android.net.LocalServerSocket; import android.net.LocalSocket; import android.net.LocalSocketAddress; import android.util.Log; import android.widget.Toast; //blog.csdn.net/zgyulongfei //Email:
[email protected] public class AmrAudioEncoder { private static final String TAG = "ArmAudioEncoder"; private static AmrAudioEncoder amrAudioEncoder = null; private Activity activity; private MediaRecorder audioRecorder; private boolean isAudioRecording; private LocalServerSocket lss; private LocalSocket sender, receiver; private AmrAudioEncoder() { } public static AmrAudioEncoder getArmAudioEncoderInstance() { if (amrAudioEncoder == null) { synchronized (AmrAudioEncoder.class) { if (amrAudioEncoder == null) { amrAudioEncoder = new AmrAudioEncoder(); } } } return amrAudioEncoder; } public void initArmAudioEncoder(Activity activity) { this.activity = activity; isAudioRecording = false; } public void start() { if (activity == null) { showToastText("音訊編碼器未初始化,請先執行init方法"); return; } if (isAudioRecording) { showToastText("音訊已經開始編碼,無需再次編碼"); return; } if (!initLocalSocket()) { showToastText("本地服務開啟失敗"); releaseAll(); return; } if (!initAudioRecorder()) { showToastText("音訊編碼器初始化失敗"); releaseAll(); return; } this.isAudioRecording = true; startAudioRecording(); } private boolean initLocalSocket() { boolean ret = true; try { releaseLocalSocket(); String serverName = "armAudioServer"; final int bufSize = 1024; lss = new LocalServerSocket(serverName); receiver = new LocalSocket(); receiver.connect(new LocalSocketAddress(serverName)); receiver.setReceiveBufferSize(bufSize); receiver.setSendBufferSize(bufSize); sender = lss.accept(); sender.setReceiveBufferSize(bufSize); sender.setSendBufferSize(bufSize); } catch (IOException e) { ret = false; } return ret; } private boolean initAudioRecorder() { if (audioRecorder != null) { audioRecorder.reset(); audioRecorder.release(); } audioRecorder = new MediaRecorder(); audioRecorder.setAudioSource(MediaRecorder.AudioSource.MIC); audioRecorder.setOutputFormat(MediaRecorder.OutputFormat.RAW_AMR); final int mono = 1; audioRecorder.setAudioChannels(mono); audioRecorder.setAudioSamplingRate(8000); audioRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB); audioRecorder.setOutputFile(sender.getFileDescriptor()); boolean ret = true; try { audioRecorder.prepare(); audioRecorder.start(); } catch (Exception e) { releaseMediaRecorder(); showToastText("手機不支援錄音此功能"); ret = false; } return ret; } private void startAudioRecording() { new Thread(new AudioCaptureAndSendThread()).start(); } public void stop() { if (isAudioRecording) { isAudioRecording = false; } releaseAll(); } private void releaseAll() { releaseMediaRecorder(); releaseLocalSocket(); amrAudioEncoder = null; } private void releaseMediaRecorder() { try { if (audioRecorder == null) { return; } if (isAudioRecording) { audioRecorder.stop(); isAudioRecording = false; } audioRecorder.reset(); audioRecorder.release(); audioRecorder = null; } catch (Exception err) { Log.d(TAG, err.toString()); } } private void releaseLocalSocket() { try { if (sender != null) { sender.close(); } if (receiver != null) { receiver.close(); } if (lss != null) { lss.close(); } } catch (IOException e) { e.printStackTrace(); } sender = null; receiver = null; lss = null; } private boolean isAudioRecording() { return isAudioRecording; } private void showToastText(String msg) { Toast.makeText(activity, msg, Toast.LENGTH_SHORT).show(); } private class AudioCaptureAndSendThread implements Runnable { public void run() { try { sendAmrAudio(); } catch (Exception e) { Log.e(TAG, "sendAmrAudio() 出錯"); } } private void sendAmrAudio() throws Exception { DatagramSocket udpSocket = new DatagramSocket(); DataInputStream dataInput = new DataInputStream(receiver.getInputStream()); skipAmrHead(dataInput); final int SEND_FRAME_COUNT_ONE_TIME = 10;// 每次傳送10幀的資料,1幀大約32B // AMR格式見部落格:http://blog.csdn.net/dinggo/article/details/1966444 final int BLOCK_SIZE[] = { 12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0 }; byte[] sendBuffer = new byte[1024]; while (isAudioRecording()) { int offset = 0; for (int index = 0; index < SEND_FRAME_COUNT_ONE_TIME; ++index) { if (!isAudioRecording()) { break; } dataInput.read(sendBuffer, offset, 1); int blockIndex = (int) (sendBuffer[offset] >> 3) & 0x0F; int frameLength = BLOCK_SIZE[blockIndex]; readSomeData(sendBuffer, offset + 1, frameLength, dataInput); offset += frameLength + 1; } udpSend(udpSocket, sendBuffer, offset); } udpSocket.close(); dataInput.close(); releaseAll(); } private void skipAmrHead(DataInputStream dataInput) { final byte[] AMR_HEAD = new byte[] { 0x23, 0x21, 0x41, 0x4D, 0x52, 0x0A }; int result = -1; int state = 0; try { while (-1 != (result = dataInput.readByte())) { if (AMR_HEAD[0] == result) { state = (0 == state) ? 1 : 0; } else if (AMR_HEAD[1] == result) { state = (1 == state) ? 2 : 0; } else if (AMR_HEAD[2] == result) { state = (2 == state) ? 3 : 0; } else if (AMR_HEAD[3] == result) { state = (3 == state) ? 4 : 0; } else if (AMR_HEAD[4] == result) { state = (4 == state) ? 5 : 0; } else if (AMR_HEAD[5] == result) { state = (5 == state) ? 6 : 0; } if (6 == state) { break; } } } catch (Exception e) { Log.e(TAG, "read mdat error..."); } } private void readSomeData(byte[] buffer, int offset, int length, DataInputStream dataInput) { int numOfRead = -1; while (true) { try { numOfRead = dataInput.read(buffer, offset, length); if (numOfRead == -1) { Log.d(TAG, "amr...no data get wait for data coming....."); Thread.sleep(100); } else { offset += numOfRead; length -= numOfRead; if (length <= 0) { break; } } } catch (Exception e) { Log.e(TAG, "amr..error readSomeData"); break; } } } private void udpSend(DatagramSocket udpSocket, byte[] buffer, int sendLength) { try { InetAddress ip = InetAddress.getByName(CommonConfig.SERVER_IP_ADDRESS.trim()); int port = CommonConfig.AUDIO_SERVER_UP_PORT; byte[] sendBuffer = new byte[sendLength]; System.arraycopy(buffer, 0, sendBuffer, 0, sendLength); DatagramPacket packet = new DatagramPacket(sendBuffer, sendLength); packet.setAddress(ip); packet.setPort(port); udpSocket.send(packet); } catch (IOException e) { e.printStackTrace(); } } } }
關於編碼器:前面提到了,MediaRecorder的硬編碼的方式只能將碼流儲存到檔案中,這裡用了LocalSocket的方式將流儲存到記憶體中,然後從緩衝中讀取碼流。由於儲存的格式RAW_AMR格式的,因此需要對讀取到的資料進行解析,從而獲得真正的音訊流。想了解AMR音訊碼流格式的,可以檢視程式碼中附上的網頁連結。由於壓縮過的碼流很小,因此我在實現的時候,組合了int SEND_FRAME_COUNT_ONE_TIME = 10幀的碼流後才往外發送,這樣的方式造成的延遲會加重,大家可以根據自己的需要進行修改。造成延遲的另一因素是LocalSocket緩衝的大小,在這裡我設定的大小是final int bufSize = 1024;程式碼寫的很清楚詳細,有疑問的可以提出。
播放器:
package cn.edu.xmu.zgy.audio.player;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.InetAddress;
import java.net.Socket;
import cn.edu.xmu.zgy.config.CommonConfig;
import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Handler;
import android.util.Log;
//blog.csdn.net/zgyulongfei
//Email: [email protected]
public class AmrAudioPlayer {
private static final String TAG = "AmrAudioPlayer";
private static AmrAudioPlayer playerInstance = null;
private long alreadyReadByteCount = 0;
private MediaPlayer audioPlayer;
private Handler handler = new Handler();
private final String cacheFileName = "audioCacheFile";
private File cacheFile;
private int cacheFileCount = 0;
// 用來記錄是否已經從cacheFile中複製資料到另一個cache中
private boolean hasMovedTheCacheFlag;
private boolean isPlaying;
private Activity activity;
private boolean isChaingCacheToAnother;
private AmrAudioPlayer() {
}
public static AmrAudioPlayer getAmrAudioPlayerInstance() {
if (playerInstance == null) {
synchronized (AmrAudioPlayer.class) {
if (playerInstance == null) {
playerInstance = new AmrAudioPlayer();
}
}
}
return playerInstance;
}
public void initAmrAudioPlayer(Activity activity) {
this.activity = activity;
deleteExistCacheFile();
initCacheFile();
}
private void deleteExistCacheFile() {
File cacheDir = activity.getCacheDir();
File[] needDeleteCacheFiles = cacheDir.listFiles();
for (int index = 0; index < needDeleteCacheFiles.length; ++index) {
File cache = needDeleteCacheFiles[index];
if (cache.isFile()) {
if (cache.getName().contains(cacheFileName.trim())) {
Log.e(TAG, "delete cache file: " + cache.getName());
cache.delete();
}
}
}
needDeleteCacheFiles = null;
}
private void initCacheFile() {
cacheFile = null;
cacheFile = new File(activity.getCacheDir(), cacheFileName);
}
public void start() {
isPlaying = true;
isChaingCacheToAnother = false;
setHasMovedTheCacheToAnotherCache(false);
new Thread(new NetAudioPlayerThread()).start();
}
public void stop() {
isPlaying = false;
isChaingCacheToAnother = false;
setHasMovedTheCacheToAnotherCache(false);
releaseAudioPlayer();
deleteExistCacheFile();
cacheFile = null;
handler = null;
}
private void releaseAudioPlayer() {
playerInstance = null;
if (audioPlayer != null) {
try {
if (audioPlayer.isPlaying()) {
audioPlayer.pause();
}
audioPlayer.release();
audioPlayer = null;
} catch (Exception e) {
}
}
}
private boolean hasMovedTheCacheToAnotherCache() {
return hasMovedTheCacheFlag;
}
private void setHasMovedTheCacheToAnotherCache(boolean result) {
hasMovedTheCacheFlag = result;
}
private class NetAudioPlayerThread implements Runnable {
// 從接受資料開始計算,當快取大於INIT_BUFFER_SIZE時候開始播放
private final int INIT_AUDIO_BUFFER = 2 * 1024;
// 剩1秒的時候播放新的快取的音樂
private final int CHANGE_CACHE_TIME = 1000;
public void run() {
try {
Socket socket = createSocketConnectToServer();
receiveNetAudioThenPlay(socket);
} catch (Exception e) {
Log.e(TAG, e.getMessage() + "從服務端接受音訊失敗。。。");
}
}
private Socket createSocketConnectToServer() throws Exception {
String hostName = CommonConfig.SERVER_IP_ADDRESS;
InetAddress ipAddress = InetAddress.getByName(hostName);
int port = CommonConfig.AUDIO_SERVER_DOWN_PORT;
Socket socket = new Socket(ipAddress, port);
return socket;
}
private void receiveNetAudioThenPlay(Socket socket) throws Exception {
InputStream inputStream = socket.getInputStream();
FileOutputStream outputStream = new FileOutputStream(cacheFile);
final int BUFFER_SIZE = 100 * 1024;// 100kb buffer size
byte[] buffer = new byte[BUFFER_SIZE];
// 收集了10*350b了之後才開始更換快取
int testTime = 10;
try {
alreadyReadByteCount = 0;
while (isPlaying) {
int numOfRead = inputStream.read(buffer);
if (numOfRead <= 0) {
break;
}
alreadyReadByteCount += numOfRead;
outputStream.write(buffer, 0, numOfRead);
outputStream.flush();
try {
if (testTime++ >= 10) {
Log.e(TAG, "cacheFile=" + cacheFile.length());
testWhetherToChangeCache();
testTime = 0;
}
} catch (Exception e) {
// TODO: handle exception
}
// 如果複製了接收網路流的cache,則執行此操作
if (hasMovedTheCacheToAnotherCache() && !isChaingCacheToAnother) {
if (outputStream != null) {
outputStream.close();
outputStream = null;
}
// 將接收網路流的cache刪除,然後重0開始儲存
// initCacheFile();
outputStream = new FileOutputStream(cacheFile);
setHasMovedTheCacheToAnotherCache(false);
alreadyReadByteCount = 0;
}
}
} catch (Exception e) {
errorOperator();
e.printStackTrace();
Log.e(TAG, "socket disconnect...:" + e.getMessage());
throw new Exception("socket disconnect....");
} finally {
buffer = null;
if (socket != null) {
socket.close();
}
if (inputStream != null) {
inputStream.close();
inputStream = null;
}
if (outputStream != null) {
outputStream.close();
outputStream = null;
}
stop();
}
}
private void testWhetherToChangeCache() throws Exception {
if (audioPlayer == null) {
firstTimeStartPlayer();
} else {
changeAnotherCacheWhenEndOfCurrentCache();
}
}
private void firstTimeStartPlayer() throws Exception {
// 當快取已經大於INIT_AUDIO_BUFFER則開始播放
if (alreadyReadByteCount >= INIT_AUDIO_BUFFER) {
Runnable r = new Runnable() {
public void run() {
try {
File firstCacheFile = createFirstCacheFile();
// 設定已經從cache中複製資料,然後會刪除這個cache
setHasMovedTheCacheToAnotherCache(true);
audioPlayer = createAudioPlayer(firstCacheFile);
audioPlayer.start();
} catch (Exception e) {
Log.e(TAG, e.getMessage() + " :in firstTimeStartPlayer() fun");
} finally {
}
}
};
handler.post(r);
}
}
private File createFirstCacheFile() throws Exception {
String firstCacheFileName = cacheFileName + (cacheFileCount++);
File firstCacheFile = new File(activity.getCacheDir(), firstCacheFileName);
// 為什麼不直接播放cacheFile,而要複製cacheFile到一個新的cache,然後播放此新的cache?
// 是為了防止潛在的讀/寫錯誤,可能在寫入cacheFile的時候,
// MediaPlayer正試圖讀資料, 這樣可以防止死鎖的發生。
moveFile(cacheFile, firstCacheFile);
return firstCacheFile;
}
private void moveFile(File oldFile, File newFile) throws IOException {
if (!oldFile.exists()) {
throw new IOException("oldFile is not exists. in moveFile() fun");
}
if (oldFile.length() <= 0) {
throw new IOException("oldFile size = 0. in moveFile() fun");
}
BufferedInputStream reader = new BufferedInputStream(new FileInputStream(oldFile));
BufferedOutputStream writer = new BufferedOutputStream(new FileOutputStream(newFile,
false));
final byte[] AMR_HEAD = new byte[] { 0x23, 0x21, 0x41, 0x4D, 0x52, 0x0A };
writer.write(AMR_HEAD, 0, AMR_HEAD.length);
writer.flush();
try {
byte[] buffer = new byte[1024];
int numOfRead = 0;
Log.d(TAG, "POS...newFile.length=" + newFile.length() + " old=" + oldFile.length());
while ((numOfRead = reader.read(buffer, 0, buffer.length)) != -1) {
writer.write(buffer, 0, numOfRead);
writer.flush();
}
Log.d(TAG, "POS..AFTER...newFile.length=" + newFile.length());
} catch (IOException e) {
Log.e(TAG, "moveFile error.. in moveFile() fun." + e.getMessage());
throw new IOException("moveFile error.. in moveFile() fun.");
} finally {
if (reader != null) {
reader.close();
reader = null;
}
if (writer != null) {
writer.close();
writer = null;
}
}
}
private MediaPlayer createAudioPlayer(File audioFile) throws IOException {
MediaPlayer mPlayer = new MediaPlayer();
// It appears that for security/permission reasons, it is better to
// pass
// a FileDescriptor rather than a direct path to the File.
// Also I have seen errors such as "PVMFErrNotSupported" and
// "Prepare failed.: status=0x1" if a file path String is passed to
// setDataSource(). So unless otherwise noted, we use a
// FileDescriptor here.
FileInputStream fis = new FileInputStream(audioFile);
mPlayer.reset();
mPlayer.setDataSource(fis.getFD());
mPlayer.prepare();
return mPlayer;
}
private void changeAnotherCacheWhenEndOfCurrentCache() throws IOException {
// 檢查當前cache剩餘時間
long theRestTime = audioPlayer.getDuration() - audioPlayer.getCurrentPosition();
Log.e(TAG, "theRestTime=" + theRestTime + " isChaingCacheToAnother="
+ isChaingCacheToAnother);
if (!isChaingCacheToAnother && theRestTime <= CHANGE_CACHE_TIME) {
isChaingCacheToAnother = true;
Runnable r = new Runnable() {
public void run() {
try {
File newCacheFile = createNewCache();
// 設定已經從cache中複製資料,然後會刪除這個cache
setHasMovedTheCacheToAnotherCache(true);
transferNewCacheToAudioPlayer(newCacheFile);
} catch (Exception e) {
Log.e(TAG, e.getMessage()
+ ":changeAnotherCacheWhenEndOfCurrentCache() fun");
} finally {
deleteOldCache();
isChaingCacheToAnother = false;
}
}
};
handler.post(r);
}
}
private File createNewCache() throws Exception {
// 將儲存網路資料的cache複製到newCache中進行播放
String newCacheFileName = cacheFileName + (cacheFileCount++);
File newCacheFile = new File(activity.getCacheDir(), newCacheFileName);
Log.e(TAG, "before moveFile............the size=" + cacheFile.length());
moveFile(cacheFile, newCacheFile);
return newCacheFile;
}
private void transferNewCacheToAudioPlayer(File newCacheFile) throws Exception {
MediaPlayer oldPlayer = audioPlayer;
try {
audioPlayer = createAudioPlayer(newCacheFile);
audioPlayer.start();
} catch (Exception e) {
Log.e(TAG, "filename=" + newCacheFile.getName() + " size=" + newCacheFile.length());
Log.e(TAG, e.getMessage() + " " + e.getCause() + " error start..in transfanNer..");
}
try {
oldPlayer.pause();
oldPlayer.reset();
oldPlayer.release();
} catch (Exception e) {
Log.e(TAG, "ERROR release oldPlayer.");
} finally {
oldPlayer = null;
}
}
private void deleteOldCache() {
int oldCacheFileCount = cacheFileCount - 1;
String oldCacheFileName = cacheFileName + oldCacheFileCount;
File oldCacheFile = new File(activity.getCacheDir(), oldCacheFileName);
if (oldCacheFile.exists()) {
oldCacheFile.delete();
}
}
private void errorOperator() {
}
}
}
關於播放器:由於MediaPlayer的限制,我用了cache的方式來實現音訊的實時播放。即把獲取到的音訊流首先儲存到檔案中,然後當儲存到一定大小的時候就播放之,類似於QQ播放器那樣有快取的,只不過我這裡的處理得挺粗糙。程式碼寫的也挺詳細了,如果有疑問也可以提出來。
注:編碼器和播放器的編寫,我都是站在巨人的肩膀上完成的,參考了一些其他資料。
在後面一篇文章中,我將附上伺服器和客戶端的所有程式碼。
希望朋友們看完能提出意見和建議,也希望看完能有所收穫 ^_^