如何通过 AudioTrack 播放大型 PCM 文件？（目前出现错误）答案

【问题标题】：how to play large PCM file via AudioTrack? (Currently getting errors)如何通过 AudioTrack 播放大型 PCM 文件？（目前出现错误）
【发布时间】：2014-11-04 11:17:22
【问题描述】：

我一直在为我正在制作的应用程序编写一些代码，我需要播放大型 PCM 文件（超过 600mb）。

这是我的 play() 方法的当前代码：

public void play(View view) {
        Toast.makeText(this, "play", Toast.LENGTH_SHORT).show();

// Get the file we want to playback.
        File file = new File(Environment.getExternalStorageDirectory() + File.separator + "ACS.pcm");
// Get the length of the audio stored in the file (16 bit so 2 bytes per short)
// and create a short array to store the recorded audio.
        int musicLength = (int)(file.length()/2);
        short[] music = new short[musicLength];


        try {
// Create a DataInputStream to read the audio data back from the saved file.
            InputStream is = new FileInputStream(file);
            BufferedInputStream bis = new BufferedInputStream(is);
            DataInputStream dis = new DataInputStream(bis);

// Read the file into the music array.
            int i = 0;
            while (dis.available() > 0) {
                music[musicLength-1-i] = dis.readShort();
                i++;
            }


// Close the input streams.
            dis.close();


// Create a new AudioTrack object using the same parameters as the AudioRecord
// object used to create the file.
            AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
                    44100,
                    AudioFormat.CHANNEL_OUT_MONO,
                    AudioFormat.ENCODING_PCM_16BIT,
                    musicLength,
                    AudioTrack.MODE_STREAM);
// Start playback
            audioTrack.play();

// Write the music buffer to the AudioTrack object
            audioTrack.write(music, 0, musicLength);


        } catch (Throwable t) {
            Log.e("AudioTrack","Playback Failed");
        }
    }

然而应用程序崩溃就行了：short[] music = new short[musicLength]; 我相信这是因为该应用程序正在尝试创建一个非常大的数组，因此会占用大量内存（ram）。

崩溃的logcat是：

`11-03 16:31:03.654  16916-16916/com.bacon.corey.audiotimeshift I/art﹕ Alloc sticky concurrent mark sweep GC freed 6307(421KB) AllocSpace objects, 1(12KB) LOS objects, 33% free, 15MB/23MB, paused 678us total 14.444ms
11-03 16:31:03.663  16916-16916/com.bacon.corey.audiotimeshift I/art﹕ Alloc partial concurrent mark sweep GC freed 213(22KB) AllocSpace objects, 0(0B) LOS objects, 40% free, 15MB/26MB, paused 659us total 7.132ms
11-03 16:31:03.679  16916-16916/com.bacon.corey.audiotimeshift I/art﹕ Alloc concurrent mark sweep GC freed 15(12KB) AllocSpace objects, 0(0B) LOS objects, 40% free, 15MB/26MB, paused 830us total 14.191ms
11-03 16:31:03.681  16916-16916/com.bacon.corey.audiotimeshift I/art﹕ Forcing collection of SoftReferences for 641MB allocation
11-03 16:31:03.695  16916-16916/com.bacon.corey.audiotimeshift I/art﹕ Alloc concurrent mark sweep GC freed 11(344B) AllocSpace objects, 0(0B) LOS objects, 39% free, 15MB/26MB, paused 645us total 13.989ms
11-03 16:31:03.700  16916-16916/com.bacon.corey.audiotimeshift E/art﹕ Throwing OutOfMemoryError "Failed to allocate a 672164876 byte allocation with 11094652 free bytes and 176MB until OOM"
11-03 16:31:03.703  16916-16916/com.bacon.corey.audiotimeshift D/AndroidRuntime﹕ Shutting down VM
11-03 16:31:03.713  16916-16916/com.bacon.corey.audiotimeshift E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.bacon.corey.audiotimeshift, PID: 16916
    java.lang.IllegalStateException: Could not execute method of the activity
            at android.view.View$1.onClick(View.java:4007)
            at android.view.View.performClick(View.java:4756)
            at android.view.View$PerformClick.run(View.java:19749)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.reflect.InvocationTargetException
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at android.view.View$1.onClick(View.java:4002)
            at android.view.View.performClick(View.java:4756)
            at android.view.View$PerformClick.run(View.java:19749)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.OutOfMemoryError: Failed to allocate a 672164876 byte allocation with 11094652 free bytes and 176MB until OOM
            at com.bacon.corey.audiotimeshift.MainActivity.play(MainActivity.java:87)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at android.view.View$1.onClick(View.java:4002)
            at android.view.View.performClick(View.java:4756)
            at android.view.View$PerformClick.run(View.java:19749)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)`

我在谷歌上搜索过，但如果不先将 PCM 文件加载到一个短数组中，我似乎找不到任何播放 PCM 文件的方法。如果有人知道解决此问题的方法，并且不介意分享，我将不胜感激。

谢谢科里

【问题讨论】：

嗨，感谢您的建议，但我正在尝试制作一个可以编辑音频文件的应用程序，它需要采用 PCM 格式。谢谢科里

标签： java android arrays audio-streaming audiotrack

【解决方案1】：

问题是您试图一次将 600 多兆字节的文件读入内存，而您的应用无法获得足够的内存来执行此操作。

您需要做的是创建一个较小的缓冲区，并以块的形式读取音频文件，将每个块写入AudioTrack ...循环。

（注意：我只是从AudoioTrack javadoc 所说的内容出发。您最好自己阅读它...）

【讨论】：