ios7 – 使用iOS 7在iPhone 5s上写入/ dev / null时,AVAudioRecorder停止工作

我有一个应用程序,可以监控背景音频级别而无需录制到文件.我使用写入/ dev / null的技巧来实现这一目标.

此代码适用于iOS 6的iPhone 3GS,iOS 6和iOS 7的iPhone 4,以及iOS 7和iPhone Retina(4英寸64位)的模拟器.

然而,当我在真正的iPhone 5s上试用时,录音机似乎会暂时捕捉音频,然后默默地死掉.

这是代码：

// Inititalize the audio

NSURL *url = [NSURL fileURLWithPath:@"/dev/null"];

NSDictionary *settings = [NSDictionary dictionaryWithObjectsAndKeys:
                          [NSNumber numberWithFloat: 44100.0],AVSampleRateKey,[NSNumber numberWithInt: kAudioFormatAppleLossless],AVFormatIDKey,[NSNumber numberWithInt: 1],AVNumberOfChannelsKey,[NSNumber numberWithInt: AVAudioQualityMax],AVEncoderAudioQualityKey,nil];


NSError *error;

recorder = [[AVAudioRecorder alloc] initWithURL:url settings:settings error:&error];

if (recorder) {
    [recorder preparetoRecord];
    recorder.meteringEnabled = YES;
    [recorder record];
    levelTimer = [NSTimer scheduledTimerWithTimeInterval: 0.03 target: self selector: @selector(levelTimerCallback:) userInfo: nil repeats: YES];
    //        peakLevelTimer = [NSTimer scheduledTimerWithTimeInterval: 2.0 target: self selector: @selector(peakLevelTimerCallback:) userInfo: nil repeats: YES];
} else {
    NSLog(@"There was an error setting up the recorder.");        
    NSLog([error description]);
}

可能会发生什么想法？

有人可以建议一个解决方法吗？写入真实文件有效,但我不想填充设备上的任何空间只是为了监听音频.有没有办法写入一个只能蒸发到空气中的小文件缓冲区？有效地实现我自己的/ dev / null？

解决方法

在测试我的iOS 7应用程序时遇到了同样的问题.

我通过创建一个初始文件来解决缺少/ dev / null的问题,然后在录制开始后删除了几秒钟.录音仍然继续适用于我的应用程序,并且没有存储数据文件.

- (void)startRecording
{
  // New recording path.
  Nsstring *recorderFilePath = [Nsstring stringWithFormat:@"%@/%@.caf",[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"],@"cache"];
  NSURL *url = [NSURL fileURLWithPath:recorderFilePath];

  AVAudioRecorder recorder = [[ AVAudioRecorder alloc] initWithURL:url settings:recordSetting error:&err];

  if([recorder preparetoRecord])
  {
    [recorder record];
    NSTimer deleteFileTimer = [NSTimer scheduledTimerWithTimeInterval:15 target:self selector:@selector(removeRecordingFile) userInfo:nil repeats:NO];
  }
}

- (void)removeRecordingFile
{
  // Remove the data file from the recording.
  Nsstring *recorderFilePath = [Nsstring stringWithFormat:@"%@/%@.caf",@"cache"];
  NSFileManager *fileManager = [NSFileManager defaultManager];
  NSError *error = nil;

  BOOL success = [fileManager removeItemAtPath:recorderFilePath error:&error];

  if(success) 
  {
      NSLog(@"Deleted recording file");
  }
  else
  {
      NSLog(@"Could not delete file -:%@ ",[error localizedDescription]);
  }
}