这段代码以前有用。然后，也许我在某处改变了某些东西（或者如果我知道Android正确，则更新会在媒体播放器中引入错误）。它停止在某些设备上工作！特别是我的Nexus S（2.3.6）。
应用程序下载了文件test.m4a（17 775 201字节）。为了验证其完整性，我将其复制到SD并在我的PC上播放。没问题！二进制 - 将它与原始文件进行比较，它匹配100％。
try {
_mediaPlayer = new MediaPlayer();
_mediaPlayer.setOnCompletionListener(this);
_mediaPlayer.setOnPreparedListener(this);
_mediaPlayer.setOnSeekCompleteListener(this);
_mediaPlayer.setOnBufferingUpdateListener(this);
_mediaPlayer.setOnInfoListener(this);
_mediaPlayer.setOnErrorListener(this);
// I even tried reading the file from SD card. Same error...
File file = new File("/data/data/com.mycompany.myapp/files/MediaCache/Test.m4a");
// file.isFile() == true
// file.length() == expected value!
FileInputStream is = new FileInputStream(file);
_mediaPlayer.setDataSource(is.getFD()); // Throws!
// If I use the filename as parameter, it throws later when preparing the media player...
_mediaPlayer.prepareAsync();
}
catch (Exception e) {
// java.io.IOException: setDataSourceFD failed.: status=0x80000000
e.printStackTrace();
}
问：当文件确实有效时，什么可能导致IOException setDataSourceFD？
更新：这是我在Nexus S（2.3.6）上无法播放的98 kB音频文件：http://www.2shared.com/audio/wUKoRiQk/test.html
我的一个朋友运行一些中兴设备（2.2），它似乎工作。我不明白！
我想告诉你MediaPlayer正在运行并正常运行。以下是我的假设。不要太认真对待他们。
这是您的test.m4a文件，其编码格式使MediaPlayer无法解码，因此抛出错误，表示无法创建MediaPlayer供您使用。好像你用计算机上的一些FFmpeg编解码器编码了它。如果您尝试在不使用高级编解码器（如FFmpeg）的情况下创建文件会更好，因为Android无法动态解码高级编解码器。
但是，我没有解释为什么有些智能手机可以播放你的M4A文件，而有些则不能。我的建议是使用Audacity已安装的简单OGG格式，用于所有Android项目，因为Audacity具有的OGG编解码器非常简单，Android可以即时解码。我并没有声称许多开发人员主要使用OGG，只是在使用简单的编解码器时OGG似乎没有很多与MediaPlayer和SoundPool有关的问题。需要更多的研究......
甚至我的书，开始Android 4游戏开发，依赖于OGG文件。
这是我的证明如下。这是我在你的链接中使用的文件“test.m4a”。我这样做是为了让它在无限循环中运行，使其成为100％的证据证明：
03-18 01:05:22.826: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:22.826: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:22.936: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:22.936: I/MediaPlayer(1289): IOException...
03-18 01:05:22.936: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:22.936: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:23.037: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:23.046: I/MediaPlayer(1289): IOException...
03-18 01:05:23.046: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:23.046: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:23.146: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:23.146: I/MediaPlayer(1289): IOException...
03-18 01:05:23.146: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:23.156: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:23.256: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:23.256: I/MediaPlayer(1289): IOException...
03-18 01:05:23.256: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:23.256: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:23.366: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:23.366: I/MediaPlayer(1289): IOException...
03-18 01:05:23.366: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:23.366: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:23.476: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:23.476: I/MediaPlayer(1289): IOException...
03-18 01:05:23.476: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:23.476: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:23.586: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:23.586: I/MediaPlayer(1289): IOException...
03-18 01:05:23.586: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:23.586: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:23.696: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:23.696: I/MediaPlayer(1289): IOException...
03-18 01:05:23.696: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:23.696: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:23.806: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:23.806: I/MediaPlayer(1289): IOException...
03-18 01:05:23.806: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:23.806: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:23.917: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:23.917: I/MediaPlayer(1289): IOException...
03-18 01:05:23.917: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:23.917: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:24.026: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:24.026: I/MediaPlayer(1289): IOException...
03-18 01:05:24.026: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:24.026: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:24.136: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:24.136: I/MediaPlayer(1289): IOException...
03-18 01:05:24.136: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:24.136: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:24.246: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:24.246: I/MediaPlayer(1289): IOException...
03-18 01:05:24.246: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:24.246: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:24.356: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:24.356: I/MediaPlayer(1289): IOException...
03-18 01:05:24.356: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:24.356: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:24.466: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:24.466: I/MediaPlayer(1289): IOException...
03-18 01:05:24.466: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:24.466: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:24.856: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:24.856: I/MediaPlayer(1289): IOException...
03-18 01:05:24.856: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:24.856: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:25.017: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:25.017: I/MediaPlayer(1289): IOException...
03-18 01:05:25.017: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:25.017: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:25.146: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:25.157: I/MediaPlayer(1289): IOException...
03-18 01:05:25.157: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:25.157: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:25.266: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:25.266: I/MediaPlayer(1289): IOException...
03-18 01:05:25.266: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:25.266: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:25.376: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:25.376: I/MediaPlayer(1289): IOException...
03-18 01:05:25.376: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:25.376: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:25.486: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:25.486: I/MediaPlayer(1289): IOException...
03-18 01:05:25.486: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:25.486: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:25.586: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:25.586: I/MediaPlayer(1289): IOException...
03-18 01:05:25.586: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:25.586: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:25.696: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:25.696: I/MediaPlayer(1289): IOException...
03-18 01:05:25.696: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:25.696: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:25.806: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:25.806: I/MediaPlayer(1289): IOException...
03-18 01:05:25.806: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:25.806: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:25.916: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:25.916: I/MediaPlayer(1289): IOException...
03-18 01:05:25.916: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:25.916: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:26.026: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:26.026: I/MediaPlayer(1289): IOException...
03-18 01:05:26.026: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:26.026: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:26.136: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:26.136: I/MediaPlayer(1289): IOException...
03-18 01:05:26.136: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:26.136: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:26.246: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:26.246: I/MediaPlayer(1289): IOException...
03-18 01:05:26.246: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:26.246: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:26.356: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:26.356: I/MediaPlayer(1289): IOException...
03-18 01:05:26.356: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:26.356: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:26.466: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:26.466: I/MediaPlayer(1289): IOException...
03-18 01:05:26.466: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:26.466: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:26.577: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:26.577: I/MediaPlayer(1289): IOException...
03-18 01:05:26.577: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:26.577: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:26.697: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:26.697: I/MediaPlayer(1289): IOException...
03-18 01:05:26.697: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:26.697: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:26.807: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:26.807: I/MediaPlayer(1289): IOException...
03-18 01:05:26.807: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:26.807: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:26.917: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:26.917: I/MediaPlayer(1289): IOException...
03-18 01:05:26.917: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:26.917: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:27.027: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:27.027: I/MediaPlayer(1289): IOException...
03-18 01:05:27.027: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:27.027: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:27.137: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:27.137: I/MediaPlayer(1289): IOException...
03-18 01:05:27.137: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:27.137: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:27.236: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:27.236: I/MediaPlayer(1289): IOException...
03-18 01:05:27.236: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:27.236: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:27.347: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:27.347: I/MediaPlayer(1289): IOException...
03-18 01:05:27.347: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:27.347: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:27.457: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:27.457: I/MediaPlayer(1289): IOException...
03-18 01:05:27.457: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:27.457: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:27.567: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:27.567: I/MediaPlayer(1289): IOException...
03-18 01:05:27.567: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:27.567: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:27.677: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:27.677: I/MediaPlayer(1289): IOException...
03-18 01:05:27.677: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:27.677: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:27.787: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:27.787: I/MediaPlayer(1289): IOException...
03-18 01:05:27.787: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:27.787: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:27.907: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:27.907: I/MediaPlayer(1289): IOException...
03-18 01:05:27.907: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:27.907: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:28.007: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:28.017: I/MediaPlayer(1289): IOException...
03-18 01:05:28.017: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:28.017: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:28.127: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:28.127: I/MediaPlayer(1289): IOException...
03-18 01:05:28.127: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:28.127: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:28.237: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:28.237: I/MediaPlayer(1289): IOException...
03-18 01:05:28.237: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:28.237: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:28.347: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:28.347: I/MediaPlayer(1289): IOException...
03-18 01:05:28.347: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:28.347: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:28.457: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:28.457: I/MediaPlayer(1289): IOException...
03-18 01:05:28.457: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:28.457: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:28.567: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:28.567: I/MediaPlayer(1289): IOException...
03-18 01:05:28.567: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:28.567: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:28.677: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:28.677: I/MediaPlayer(1289): IOException...
03-18 01:05:28.677: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:28.677: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:28.787: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:28.787: I/MediaPlayer(1289): IOException...
03-18 01:05:28.787: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:28.787: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:28.907: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:28.907: I/MediaPlayer(1289): IOException...
03-18 01:05:28.907: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:28.907: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:29.017: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:29.017: I/MediaPlayer(1289): IOException...
03-18 01:05:29.017: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:29.017: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:29.127: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:29.127: I/MediaPlayer(1289): IOException...
03-18 01:05:29.127: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:29.127: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:29.237: E/MediaPlayer(1289): Unable to to create media player
03-18 01:05:29.237: I/MediaPlayer(1289): IOException...
03-18 01:05:29.237: D/MediaPlayer(1289): Making sure it is in IDLE state...
03-18 01:05:29.237: D/MediaPlayer(1289): Setting Data Source...
03-18 01:05:29.327: D/dalvikvm(1289): Calling exit(1)
现在，这是我制作的代码，如下所示：
package nttu.edu.test;
import java.io.IOException;
import android.app.Activity;
import android.content.res.AssetFileDescriptor;
import android.content.res.AssetManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.TextView;
public class MediaPlayerTest extends Activity implements OnTouchListener {
MediaPlayer player = null;
TextView tv;
public final String fileName = "sounds/test.m4a";
AssetManager asset;
AssetFileDescriptor afd;
public void onCreate(Bundle b) {
super.onCreate(b);
tv = new TextView(this);
tv.setOnTouchListener(this);
tv.setText("Touch to start playing the music.");
Log.d("MediaPlayer", "Creating MediaPlayer.");
player = new MediaPlayer();
try {
asset = this.getAssets();
afd = asset.openFd(fileName);
}
catch (Exception e) {
}
while (true) {
try {
Log.d("MediaPlayer", "Making sure it is in IDLE state...");
player.reset();
Log.d("MediaPlayer", "Setting Data Source...");
player.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getLength());
Log.d("MediaPlayer", "Now initialized. Preparing it.");
player.prepare();
break;
}
catch (IllegalArgumentException e) {
Log.i("MediaPlayer", "IllegalArgumentException...");
}
catch (IllegalStateException e) {
Log.i("MediaPlayer", "IllegalStateException...");
}
catch (IOException e) {
Log.i("MediaPlayer", "IOException...");
}
}
try {
afd.close();
}
catch (IOException e) {
}
setContentView(tv);
Log.d("MediaPlayer", "Everything is prepared and ready to play the music file.");
}
public boolean onTouch(View v, MotionEvent e) {
if (e.getAction() == MotionEvent.ACTION_UP) {
Log.d("MediaPlayer", "Playing the audio.");
if (player.getAudioSessionId() != 0) {
player.start();
Log.d("MediaPlayer", "Success!");
}
}
return true;
}
protected void onResume() {
super.onResume();
}
protected void onPause() {
super.onPause();
if (player.getAudioSessionId() != 0) {
player.pause();
if (isFinishing()) {
player.stop();
player.release();
}
}
}
}
注意代码片段顶部附近的最终String变量。如果我用这个代替那行：
public final String fileName = "sounds/test.ogg";
并将您的“test.m4a”文件重新编码为Ogg Vorbis文件，并且代码中没有其他更改，我可以正常播放OGG文件。以下是OGG文件的更改日志：
03-18 01:14:21.547: D/gralloc_goldfish(1335): Emulator without GPU emulation detected.
03-18 01:14:23.467: D/dalvikvm(1335): GC_CONCURRENT freed 50K, 4% free 5952K/6151K, paused 7ms+3ms
03-18 01:14:24.647: D/MediaPlayer(1335): Creating MediaPlayer.
03-18 01:14:24.657: D/MediaPlayer(1335): Making sure it is in IDLE state...
03-18 01:14:24.657: D/MediaPlayer(1335): Setting Data Source...
03-18 01:14:24.707: D/MediaPlayer(1335): Now initialized. Preparing it.
03-18 01:14:24.927: D/MediaPlayer(1335): Everything is prepared and ready to play the music file.
03-18 01:14:26.797: D/MediaPlayer(1335): Playing the audio.
03-18 01:14:26.817: D/MediaPlayer(1335): Success!
然后它停在这里。周围没有循环。
更多证据支持我的答案：
Link 1: Android SDK Reference (Do look at the State Diagram, very important!)
还有一张图片（你的“test.m4a”图片和你的文件重新编码成一个OGG文件，并排放置。）：
分析test.m4a文件显示该文件根本没有M4A标头（只是比较了记事本中的第一个字节。这是您找到文件格式的标识符的地方，例如fourcc）。
它看起来与RAW AAC文件完全相同，Android不支持该文件。中兴Blade手机必须有一些额外的非标准AAC内容。
非常简单的解决方案。首先使用你的路径设置FileInputStream。在setDataSource中设置FileDescriptor之后。让我们看看
MediaPlayer mp = new MediaPlayer();
String audioStoragePath =Environment.getExternalStorageDirectory() +"/Download/audio.mp3";
//File sdIconStorageDir = new File(iconsStoragePath);
Log.d("AudioStartService"," path " + audioStoragePath);
try {
FileInputStream is = new FileInputStream(audioStoragePath);
mp.setDataSource(is.getFD());
mp.prepare();
mp.start();
} catch (Exception e) {
e.printStackTrace();
}
这对我有用。