//錄音設置
NSMutableDictionary *recordSetting = [[[NSMutableDictionary alloc]init] autorelease];
//設置錄音格式AVFormatIDKey==kAudioFormatLinearPCM
[recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey];
//設置錄音采樣率(Hz) 如：AVSampleRateKey==8000/44100/96000（影響音頻的質(zhì)量）
[recordSetting setValue:[NSNumber numberWithFloat:44100] forKey:AVSampleRateKey];
//錄音通道數(shù)1 或 2
[recordSetting setValue:[NSNumber numberWithInt:1] forKey:AVNumberOfChannelsKey];
//線性采樣位數(shù)8、16、24、32
[recordSetting setValue:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];
//錄音的質(zhì)量
[recordSetting setValue:[NSNumber numberWithInt:AVAudioQualityHigh] forKey:AVEncoderAudioQualityKey];
