AVAudioRecorder 256 Kbps的iOS中

Question

我想在iOS的(AVAudioRecorder)录制下面的代码的音频工作记录罚款

_fileName = [NSString stringWithFormat:@"Record_%@.m4a",[DateAndTimeUtil stringFromDate:[NSDate date] withFormatterString:@"HH_mm_ss_dd_MM_yyyy"]];NSArray *pathComponents = [NSArray arrayWithObjects: 
           [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject], 
           _fileName, 
           nil]; 

NSURL *outputFileURL = [NSURL fileURLWithPathComponents:pathComponents]; 

// Setup audio session 
AVAudioSession *session = [AVAudioSession sharedInstance]; 
[session setCategory:AVAudioSessionCategoryPlayAndRecord error:nil]; 

// Define the recorder setting 
NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc] init]; 

[recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey]; 
[recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey]; 
[recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey]; 

// Initiate and prepare the recorder 
audioRecorder = [[AVAudioRecorder alloc] initWithURL:outputFileURL settings:recordSetting error:nil]; 
audioRecorder.delegate = self; 
audioRecorder.meteringEnabled = YES; 
[audioRecorder prepareToRecord];` 

的问题是，录制的文件显示比特率设置为44 Kbps的，但我想记录的音频平均比特率为256Kbps，首选AAC编解码器，但也兼容MP3编解码器和MP4音频编解码器。

请帮我一把。

Answer 1

_fileName = [NSString stringWithFormat:@"Record_%@.mp4",[DateAndTimeUtil stringFromDate:[NSDate date] withFormatterString:@"HH_mm_ss_dd_MM_yyyy"]]; 
NSArray *pathComponents = [NSArray arrayWithObjects: 
          [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject], 
          _fileName, 
          nil]; 

NSURL *outputFileURL = [NSURL fileURLWithPathComponents:pathComponents]; 

// Setup audio session 
AVAudioSession *session = [AVAudioSession sharedInstance]; 
[session setCategory:AVAudioSessionCategoryPlayAndRecord error:nil]; 

// Define the recorder setting 
NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc] init]; 

[recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey]; 
[recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey]; 
[recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey]; 
[recordSetting setValue:[NSNumber numberWithInteger:AVAudioQualityHigh] forKey:AVEncoderAudioQualityKey]; 
[recordSetting setValue:[NSNumber numberWithInt:32] forKey:AVLinearPCMBitDepthKey]; 
[recordSetting setValue:[NSNumber numberWithInt:128000] forKey:AVEncoderBitRatePerChannelKey]; 
[recordSetting setValue:[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsBigEndianKey]; 
[recordSetting setValue:[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsFloatKey]; 
[recordSetting setValue:[NSNumber numberWithBool:NO] forKey:AVEncoderBitDepthHintKey]; 


// Initiate and prepare the recorder 
audioRecorder = [[AVAudioRecorder alloc] initWithURL:outputFileURL settings:recordSetting error:nil]; 
audioRecorder.delegate = self; 
audioRecorder.meteringEnabled = YES; 
[audioRecorder prepareToRecord]; 

通过使用上面的代码，我达到了一个积极的解决方案，因为它能够记录音频与比特率信息。音频具有几乎256Kbps的比特率。