Ответ 1
Я хотел бы сказать вам, что MediaPlayer работает и работает правильно. Ниже приведены все мои гипотезы. Не относитесь к ним слишком серьезно.
Это ваш файл test.m4a, который закодирован в формате, который MediaPlayer не может декодировать, поэтому выкидывает ошибку, говоря, что не может создать MediaPlayer для вас. Похоже, вы закодировали его в некоторых кодеках FFmpeg, которые у вас были на вашем компьютере. Было бы лучше, если бы вы попытались создать файл без использования продвинутых кодеков, таких как FFmpeg, поскольку Android не может декодировать продвинутые кодеки "на лету".
Однако у меня нет ответа на вопрос, почему некоторые смартфоны могут воспроизводить ваш файл M4A, а другие - нет. Мое предложение для вас - использовать простой формат OGG, который Audacity уже установил, для всех ваших Android-проектов, потому что OGG-кодек, какой Audacity имеет, достаточно просто для Android, чтобы декодировать "на лету". Я не утверждаю, что многие разработчики используют в основном OGG, просто у OGG, похоже, не много проблем с MediaPlayer и SoundPool при использовании простых кодеков. Нужно больше исследовать...
Даже моя книга "Начало разработки Android 4" зависит от файлов OGG.
Вот мое доказательство ниже. Это файл "test.m4a", который я использую из вашей ссылки. Я сделал это так, чтобы он работал в бесконечной петле, делая это 100% доказательством:
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)
Теперь, здесь код, который я сделал, показан ниже:
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();
}
}
}
}
Обратите внимание на конечную переменную String в верхней части фрагмента кода. Если я заменю эту строку следующим образом:
public final String fileName = "sounds/test.ogg";
И перекодируйте свой файл test.m4a в файл Ogg Vorbis, и никаких других изменений в коде, я не могу нормально воспроизвести файл OGG. Вот журналы изменений для файла OGG:
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!
И затем он останавливается здесь. Там нет цикла.
Больше доказательств в поддержку моего ответа:
Ссылка 1: Ссылка на Android SDK (посмотрите на диаграмму состояния, очень важно!)
И изображение (изображение вашего "test.m4a" и ваш файл перекодированы в файл OGG, размещенный бок о бок.):