在iOS中录制AVAudioRecorder 256 Kbps

Question

I wants to record an audio in iOS (AVAudioRecorder) below code working fine

_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];`

The problem is that the recorded file shows the bit rate as 44 Kbps but I want to record audio of an average bitrate of 256Kbps with a preference for AAC codec, but also compatible with the MP3 codec and the MP4 Audio codec.

Please help me out.

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];

By using above code i reach towards a positive solution as it was able to record audio with bit rate info. The audio has almost 256Kbps bit rate.