NSMutableDictionary *recordSettings =   
      [[NSMutableDictionary alloc] initWithCapacity:10];   
      //1 ID號   
      [recordSettings setObject:   
       [NSNumber numberWithInt: kAudioFormatLinearPCM] forKey: AVFormatIDKey];   
      float sampleRate =   
       [pcmSettingsViewController.sampleRateField.text floatValue];   
      //2 采樣率   
      [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 采樣位數  默認 16   
      [recordSettings setObject:   
       [NSNumber numberWithInt:bitDepth] forKey:AVLinearPCMBitDepthKey];   
          
      //5   
      [recordSettings setObject:   
       [NSNumber numberWithBool:   
         pcmSettingsViewController.bigEndianSwitch.on]   
        forKey:AVLinearPCMIsBigEndianKey];   
        
      //6 采樣信號是整數還是浮點數   
      [recordSettings setObject:   
       [NSNumber numberWithBool:   
         pcmSettingsViewController.floatingSamplesSwitch.on]   
        forKey:AVLinearPCMIsFloatKey]   
 
 
;