MediaRecorder IOException:准备失败

Question

我想用MediaRecorder录制语音，我的代码是：

 public void record(View v) {
       Log.d(TAG, "record");

    this.mediaRecorder.setAudioChannels(1);
    this.mediaRecorder.setAudioSamplingRate(44100);
    this.mediaRecorder.setAudioEncodingBitRate(64000);
    this.mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    this.mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
    this.mediaRecorder.setOutputFile(this.file.getAbsolutePath());
    this.mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
    try {
        this.mediaRecorder.prepare();
        this.mediaRecorder.start();

        // update the buttons
        this.setButtonsEnabled(false, true, false);
    } catch (IOException e) {
        Log.e(TAG, "Failed to record()", e);
    }
}

或

   public void record(View v) {
    Log.d(TAG, "record");
    this.mediaRecorder = new MediaRecorder();
    this.mediaRecorder.setAudioChannels(1);
    this.mediaRecorder.setAudioSamplingRate(8000);

    this.mediaRecorder.setAudioEncodingBitRate(16);
    this.mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    this.mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.RAW_AMR);
    this.mediaRecorder.setOutputFile(this.file.getAbsolutePath());

    this.mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

    try {
        this.mediaRecorder.prepare();
        this.mediaRecorder.start();

        // update the buttons
        this.setButtonsEnabled(false, true, false);
    } catch (IOException e) {
        Log.e(TAG, "Failed to record()", e);
    }
}

在三星电脑上，一切都可以，但在戴尔电脑上，两种方法都不能成功

下面是logcat：

 02-01 13:56:51.094: E/AudioRecorderDemoActivity(1397): Failed to record()
 02-01 13:56:51.094: E/AudioRecorderDemoActivity(1397): java.io.IOException: prepare failed.
 02-01 13:56:51.094: E/AudioRecorderDemoActivity(1397):     at android.media.MediaRecorder._prepare(Native Method)
 02-01 13:56:51.094: E/AudioRecorderDemoActivity(1397):     at android.media.MediaRecorder.prepare(MediaRecorder.java:524)
 02-01 13:56:51.094: E/AudioRecorderDemoActivity(1397):     at com.marakana.android.audiorecorderdemo.AudioRecorderDemoActivity.record(AudioRecorderDemoActivity.java:69)
 02-01 14:05:20.074: E/AndroidRuntime(1790): FATAL EXCEPTION: main
 02-01 14:05:20.074: E/AndroidRuntime(1790): java.lang.IllegalStateException: Could not execute method of the activity

Answer 1

首先，你的代码看起来很好。是否已将所需权限添加到清单文件？

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />

如果是，请尝试替换：

this.mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);

通过

this.mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);

不要忘记检查视频文件的路径是否正确。

Answer 2

这是一个很大的问题，但有一个非常小的解决方案

在大多数情况下，我们从this.file.getAbsolutePath()获得的文件名包含file:///作为前缀

    ////////////////////////////////////////////////* INCORRECT CODE */
    this.mediaRecorder.setOutputFile(this.file.getAbsolutePath());
    /*the above line sets a file url beginning with a "file:///"
    //however, since this setOutputFile requires us to send a
    //string referring to the uri, we will have to get rid of the
    //"file:///" and simply write the uri */
    ////////////////////////////////////////////////* CORRECTED CODE BELOW */
    this.mediaRecorder.setOutputFile(this.file.getAbsolutePath().substring(8));
    /*the above line of code extracts the string uri eliminating
    // file:/// */

希望这个答案对你有帮助

Answer 3

我删掉了

this.mediaRecorder.setAudioEncodingBitRate(16);

方法2，现在它起作用了。