How do I record audio in iLBC format? I got some help from Question #1010343, and implemented this code:
NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc] initWithCapacity:10];
[recordSetting setValue:[NSNumber numberWithInt:kAudioFormatAppleIMA4] forKey:AVFormatIDKey];
// [recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey]; // doesn't work: no error, but no sound
// [recordSetting setValue:[NSNumber numberWithInt:kAudioFormatiLBC] forKey:AVFormatIDKey]; // doesn't work: no error, but not sound
[recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];
[recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey];
[recordSetting setObject:[NSNumber numberWithInt:12800] forKey:AVEncoderBitRateKey];
[recordSetting setObject:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];
[recordSetting setObject:[NSNumber numberWithInt: AVAudioQualityHigh] forKey: AVEncoderAudioQualityKey];
recorder = [[AVAudioRecorder alloc] initWithURL:audioFile settings:recordSetting error: &avError ];
[recorder setDelegate:self];
[recorder recordForDuration:(NSTimeInterval) secLeft];
[recorder record];
Like above, it works fine. Good recording. Easy playback. You notice the other formats commented out. If I try either of them, I get nothing. I want smaller files, and according to Question #7279643, which gives this valuable info:
Here are the results for few encoding supported by iPhone:
Size of audio file of duration 10 sec.
kAudioFormatMPEG4AAC : 164 kB
kAudioFormatAppleLossless : 430 kB
kAudioFormatAppleIMA4 : 475 kB
kAudioFormatULaw : 889 kB
kAudioFormatALaw : 889 KB
I should be able to record in iLBC. But if I try, I get nothing. Is there something else that I need to change either in recording or playback when I use a format other than IMA4 format?
Here's my playback code:
NSError *avError;
AVAudioSession *audioSession = [AVAudioSession sharedInstance];
[audioSession setCategory:AVAudioSessionCategoryPlayback error:&avError];
[audioSession setActive:YES error:&avError];
if( !avError ) {
if( [audioPlayer isPlaying] ) {
[audioPlayer stop ];
}
while( ![audioPlayer isPlaying] ) {
AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithContentsOfURL:audioFile error:nil];
self.audioPlayer = player;
self.audioPlayer.numberOfLoops = 0;
[audioPlayer prepareToPlay];
[audioPlayer play];
}
} else {
NSLog(@"Playback Error: %@", avError );
}
