IPhone之AVAudioRecorder

#import <AVFoundation/AVFoundation.h>  需要引入
 

//獲取document目錄的路徑
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    - (NSString*) documentsPath {
     if (! _documentsPath) {
      NSArray *searchPaths =
       NSSearchPathForDirectoriesInDomains
       (NSDocumentDirectory, NSUserDomainMask, YES);
      _documentsPath = [searchPaths objectAtIndex: 0];
      [_documentsPath retain];
     }
     return _documentsPath;
    }

    //(document目錄的路徑)
     NSString *destinationString = [[self documentsPath]
       stringByAppendingPathComponent:filenameField.text];
     NSURL *destinationURL = [NSURL fileURLWithPath: destinationString];
    //初始化AVAudioRecorder
     NSError *recorderSetupError = nil;
     AVAudioRecorder audioRecorder = [[AVAudioRecorder alloc] initWithURL:destinationURL
       settings:recordSettings error:&recorderSetupError];
     [recordSettings release];

 

第二個參數  settings是一個容納鍵值對的NSDictionary有四種一般的鍵

1:一般的音頻設置

2:線性PCM設置

3:編碼器設置

4:採樣率轉換設置

 

NSMutableDictionary  需要加入五個設置值(線性PCM)

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    NSMutableDictionary *recordSettings =
      [[NSMutableDictionary alloc] initWithCapacity:10];
      //1 ID號
      [recordSettings setObject:
       [NSNumber numberWithInt: kAudioFormatLinearPCM] forKey: AVFormatIDKey];
      float sampleRate =
       [pcmSettingsViewController.sampleRateField.text floatValue];
      //2 採樣率
      [recordSettings setObject:
       [NSNumber numberWithFloat:sampleRate] forKey: AVSampleRateKey];

      //3 通道的數目
      [recordSettings setObject:
       [NSNumber numberWithInt:
        (pcmSettingsViewController.stereoSwitch.on ? 2 : 1)]
       forKey:AVNumberOfChannelsKey];
      int bitDepth =
       [pcmSettingsViewController.sampleDepthField.text intValue];

      //4 採樣位數  默認 16
      [recordSettings setObject:
       [NSNumber numberWithInt:bitDepth] forKey:AVLinearPCMBitDepthKey];

      //5
      [recordSettings setObject:
       [NSNumber numberWithBool:
         pcmSettingsViewController.bigEndianSwitch.on]
        forKey:AVLinearPCMIsBigEndianKey];

      //6 採樣信號是整數還是浮點數
      [recordSettings setObject:
       [NSNumber numberWithBool:
         pcmSettingsViewController.floatingSamplesSwitch.on]
        forKey:AVLinearPCMIsFloatKey]


;

 

AVAudioRecorder成功創建後,使用他非常直接.它的三個基本方法如下

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-(void) startRecording {
 [audioRecorder record];
}
-(void) pauseRecording {
 [audioRecorder pause];
 recordPauseButton.selected = NO;
}
-(void) stopRecording {
 [audioRecorder stop];
}