Android的音频节目的噩梦 - 的Soundpool，audiotrack arrghh？噩梦、音频、节目、Android
我已经建立了一个简单的音乐编曲的Android应用程序可以播放多种音频文件。
我原来用的Soundpool播放MP3文件和它的工作完全可以在2.3.4与旧宏达电Droid Incredible。然后，我测试了它在运行4.3的Galaxy Nexus和表现得可怕。音频的地方所有的时间和有毛刺/咔嗒/噼噗声。
于是，我花了好几天使用AudioTrack包括MP3德codeR使玩家得到它在两个星系和HTC正常使用。现在，我刚刚测试了一台Nexus 4（4.3运行）和性能是可怕的 - 时间是所有的地方。的Soundpool甚至提供此设备上更好的表现。
我真的很沮丧，不知道该怎么做才能完成我的应用程序，所以我真的AP preciate如果有人可以帮助我。我已经把我的音频播放器的一些code样品如下。我用尽了一切我能想到的，包括改变缓冲区的大小，使用 AudioTrack.MODE_STATIC 等新的谷歌器件具有低延迟的音频所以很奇怪，怎么一切工作方式在我的旧Droid的更好！
在此先感谢
/ **
*扮演检查
* /
公共无效playNote（串音符，浮动体积）
{
PlayThread oldThread = threadMap.get（注）;
如果（oldThread！= NULL）{
//取消计时器
如果（oldThread.timer！= NULL）{
oldThread.timer.cancel（）;
oldThread.timer.purge（）;
oldThread.timer = NULL;
}
//停止
oldThread.requestStop（）;
threadMap.remove（注）;
}
如果在复调音乐//播放
如果（threadMap.size（）＆其中; POLYPHONY）{
PlayThread线程=新PlayThread（注，体积）;
thread.start（）;
threadMap.put（注意，螺纹）;
}
}
/ **
*停止记
* /
公共无效stopNote（串音符，诠释fadeDurationInMs）
{
PlayThread线程= threadMap.get（注）;
如果（线程！= NULL）{
thread.fadeOut（fadeDurationInMs）;
threadMap.remove（注）;
}
}
/ **
*停止所有
* /
公共无效stopAllPlaying（INT fadeDurationInMs）
{
对于（PlayThread螺纹：threadMap.values（））{
如果（线程！= NULL）{
thread.fadeOut（fadeDurationInMs）;
}
}
threadMap.clear（）;
}
/ **
* PlayThread
* /
私有类PlayThread继承Thread
{
串音符;
浮动卷;
浮动fadeVol;
布尔停止;
AudioTrack audioTrack;
定时器定时;
/ **
*构造函数
* /
公共PlayThread（串音符，浮动体积）
{
超（）;
this.note =注;
this.vol =卷;
this.fadeVol =卷;
}
/ **
* 跑
* /
公共无效的run（）
{
尝试 {
android.os.Process.setThreadPriority（android.os.Process.THREAD_PRIORITY_URGENT_AUDIO）;
//创建缓冲区
INT BUFFERSIZE = AudioTrack.getMinBufferSize（SAMPLE_RATE，渠道，AudioFormat.ENCODING_PCM_16BIT）;
Log.v（Constants.TAG，最小缓冲区大小=+ BUFFERSIZE）;
BUFFERSIZE = BUFFERSIZE * 2;
byte []的缓冲区=新的字节[BUFFERSIZE]
// AudioTrack
audioTrack =新AudioTrack（AudioManager.STREAM_MUSIC，SAMPLE_RATE，渠道，AudioFormat.ENCODING_PCM_16BIT，缓冲区大小，AudioTrack.MODE_STREAM）;
audioTrack.setStereoVolume（第一卷，第二卷）;
audioTrack.play（）;
//获取字节数据
byte []的byteData = sampleMap.get（注）;
//转换为输入流
输入的InputStream =新ByteArrayInputStream的（byteData）;
//写audioTrack
INT读取动作= 0;
而（停止与放大器;！＆安培;！（读取动作= input.read（缓冲））= - 1）{
audioTrack.write（缓冲液，0，读取动作）;
}
//完成后...
audioTrack.stop（）;
audioTrack.release（）;
input.close（）;
killThread（本）;
}
赶上（例外五）{}
}
/ **
*设置音量
* /
私人同步无效setVol（浮动newVol）
{
audioTrack.setStereoVolume（newVol，newVol）;
}
/ **
*更新卷
* /
私人同步无效lowerVol（）
{
fadeVol - = 0.01;
如果（fadeVol℃，）体积= 0;
audioTrack.setStereoVolume（fadeVol，fadeVol）;
}
/ **
* 消退
* /
市民同步无效淡出（INT fadeDurationInMs）
{
//开始递减量
如果（fadeDurationInMs大于0）{
定时器=新的定时器（真正的）;
TimerTask的TimerTask的=新的TimerTask（）
{
@覆盖
公共无效的run（）
{
//如果运行时线程打死
尝试 {
//降低音量
lowerVol（）;
}
赶上（例外五）{}
//停止时，音量达到0
如果（fadeVol＆所述; = 0）{
如果（定时器！= NULL）{
timer.cancel（）;
timer.purge（）;
}
停止= TRUE;
}
}
};
//计算延时，则设置为1，如果零
INT延迟=（INT）（fadeDurationInMs /（体积* 100））;
如果（延迟== 0）延迟= 1;
timer.schedule（TimerTask的，延迟，延迟）;
}
}
/ **
*请求停止
* /
市民同步无效requestStop（）
{
//停止单击/弹出停止采样时，
setVol（0.01F）;
setVol（0.005f）;
停止= TRUE;
}
/ **
*杀死线程
* /
私人同步无效killThread（线程theThread）
{
如果（theThread！= NULL）{
theThread = NULL;
}
}
}
解决方案
如用户harikris建议，我会强烈建议您使用OpenSL ES库以获得最佳性能将所有的音频播放和处理code到Android NDK
据我了解，在AudioTrack API是建立在OpenSL ES缓冲队列音频播放器的顶部。所以，你也许可以通过直接与NDK的工作，写一个从你的Java / Android的一层叫的声音工作，C $ C $Ç提高性能。
以上提到的纯音频示例包含code，它会告诉你如何直接从一个URI播放声音文件。根据我的经验，此方法的结果比AudioTrack静态模式更好。
的Soundpool一般为可以从内存中发挥其不是你的音序器一个可扩展的解决方案，特别是如果你引进大文件很短的声音保留。
下面是帮助我与我的应用程序的一些链接： 在OpenSL ES针对Android - 一般信息： http://mobilepearls.com/labs/native-android-api/opensles/
- 一个Android的音频博客有一些很好的例子，code： HTTP：//audioprograming.word$p$pss.com
编辑： 旧手机珍珠的链接似乎已关闭。这里是一个正在运行的：http://mobilepearls.com/labs/native-android-api/ndk/docs/opensles/index.html
I've built a simple music sequencer Android app that plays multiple audio files.
Originally I was using SoundPool to play mp3 files and it worked perfectly on 2.3.4 with an old HTC Droid Incredible. Then I tested it on a Galaxy Nexus running 4.3 and the performance was horrendous. The audio timing all over the place and there were glitches/clicks/pops.
So I spent several days making a player using AudioTrack including an mp3 decoder and got it working perfectly on both the Galaxy and the HTC. Now I've just tested it on a Nexus 4 (running 4.3) and the performance is terrible - the timing is all over the place. SoundPool even offers better performance on this device.
I'm really frustrated and don't know what to do to finish my app so I would really appreciate if someone could help me out. I've put some code samples of my audio player below. I've tried everything I can think of including changing the buffer size, using AudioTrack.MODE_STATIC etc. The new Google devices have low latency audio so it's very strange how everything works way better on my old droid!
Thanks in advance
/**
* Play note
*/
public void playNote(String note, float vol)
{
PlayThread oldThread = threadMap.get(note);
if(oldThread != null) {
//Cancel timer
if(oldThread.timer != null) {
oldThread.timer.cancel();
oldThread.timer.purge();
oldThread.timer = null;
}
//Stop
oldThread.requestStop();
threadMap.remove(note);
}
//Play if within Polyphony
if(threadMap.size() < POLYPHONY) {
PlayThread thread = new PlayThread(note, vol);
thread.start();
threadMap.put(note, thread);
}
}
/**
* Stop note
*/
public void stopNote(String note, int fadeDurationInMs)
{
PlayThread thread = threadMap.get(note);
if(thread != null) {
thread.fadeOut(fadeDurationInMs);
threadMap.remove(note);
}
}
/**
* Stop all
*/
public void stopAllPlaying(int fadeDurationInMs)
{
for(PlayThread thread : threadMap.values()) {
if(thread != null) {
thread.fadeOut(fadeDurationInMs);
}
}
threadMap.clear();
}
/**
* PlayThread
*/
private class PlayThread extends Thread
{
String note;
float vol;
float fadeVol;
boolean stop;
AudioTrack audioTrack;
Timer timer;
/**
* Constructor
*/
public PlayThread(String note, float vol)
{
super();
this.note = note;
this.vol = vol;
this.fadeVol = vol;
}
/**
* Run
*/
public void run()
{
try {
android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);
//Create buffer
int bufferSize = AudioTrack.getMinBufferSize(SAMPLE_RATE, CHANNELS, AudioFormat.ENCODING_PCM_16BIT);
Log.v(Constants.TAG, "min buffersize = " + bufferSize);
bufferSize = bufferSize * 2;
byte[] buffer = new byte[bufferSize];
//AudioTrack
audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, SAMPLE_RATE, CHANNELS, AudioFormat.ENCODING_PCM_16BIT, bufferSize, AudioTrack.MODE_STREAM);
audioTrack.setStereoVolume(vol, vol);
audioTrack.play();
//Get byte data
byte[] byteData = sampleMap.get(note);
//Convert to input stream
InputStream input = new ByteArrayInputStream(byteData);
//Write to audioTrack
int bytesRead = 0;
while(!stop && (bytesRead = input.read(buffer)) != -1) {
audioTrack.write(buffer, 0, bytesRead);
}
//When finished...
audioTrack.stop();
audioTrack.release();
input.close();
killThread(this);
}
catch(Exception e) {}
}
/**
* Set volume
*/
private synchronized void setVol(float newVol)
{
audioTrack.setStereoVolume(newVol, newVol);
}
/**
* Update volume
*/
private synchronized void lowerVol()
{
fadeVol -= 0.01;
if(fadeVol < 0) vol = 0;
audioTrack.setStereoVolume(fadeVol, fadeVol);
}
/**
* Fade out
*/
public synchronized void fadeOut(int fadeDurationInMs)
{
//Start decreasing volume
if(fadeDurationInMs > 0) {
timer = new Timer(true);
TimerTask timerTask = new TimerTask()
{
@Override
public void run()
{
//If thread killed while running
try {
//Lower volume
lowerVol();
}
catch (Exception e) {}
//Stop when volume reaches 0
if(fadeVol <= 0) {
if(timer != null) {
timer.cancel();
timer.purge();
}
stop = true;
}
}
};
//Calculate delay, set to 1 if zero
int delay = (int) (fadeDurationInMs / (vol * 100));
if(delay == 0) delay = 1;
timer.schedule(timerTask, delay, delay);
}
}
/**
* Request stop
*/
public synchronized void requestStop()
{
//Stop click/pop when stopping sample
setVol(0.01f);
setVol(0.005f);
stop = true;
}
/**
* Kill Thread
*/
private synchronized void killThread(Thread theThread)
{
if(theThread != null) {
theThread = null;
}
}
}
解决方案
Like user harikris suggests, I would highly recommend you move all your audio playback and processing code to Android NDK using the OpenSL ES library for the best performance.
As I understand, the AudioTrack API is built on top of OpenSL ES Buffer Queue Audio Player. So you could probably improve performance by working directly with the NDK, writing C code that is called from your Java/Android layer to work with the sound.
The native-audio example mentioned above contains code that will show you how to play a sound file directly from a URI. In my experience, the results from this method are better than AudioTrack in Static Mode.
Soundpool is generally reserved for very short sounds that can be played from memory and its not a scalable solution for your sequencer especially if you introduce large files.
Here are some links that have helped me out with my applications: -General Information on OpenSL ES for Android: http://mobilepearls.com/labs/native-android-api/opensles/
-An Android audio blog with some great example code: http://audioprograming.wordpress.com
Edit: The old mobile pearl link appears to be down. Here's a working one:http://mobilepearls.com/labs/native-android-api/ndk/docs/opensles/index.html
