Cocoa: Simple audio recording

Question

I'm trying to implement some simple audio recording functionality in my application and I can't quite figure out to do it. I've been pointed to this example, but I can't get it to run in XCode, and it appears to be written in C++.

What I need to be able to do is record audio to a file, and then be able to get the current timestamp of the recording whilst recording. I would appreciate any help with this. Thanks!

Answer 1

The above mentioned AVFoundation framework is iOS only. Dealing with audio on OS X is quite painful in the beginning. CoreAudio, while it is one of the best components I worked with, does require some time spent learning and understanding. You may want to consider for exampel using https://github.com/syedhali/EZAudio for your task.

Answer 2

You can record and play audio using the AVFoundation framework. Firstly you will need to implement this within your .h file and add a framework or library's within your xcode project settings like so:

After adding into your project settings import AVFoundation into your .h file like so:

#import <AVFoundation/AVFoundation.h>

Now Implement your delegates within your .h file:

@interface ViewController : UIViewController <AVAudioRecorderDelegate, AVAudioPlayerDelegate>

After this declare your AVAudioRecorder and AVAudioPlayer in your .h file like so:

@interface ViewController () {
     AVAudioRecorder *recorder;
     AVAudioPlayer *player;
IBOutlet UIButton *stopButton;
IBOutlet UIButton *playButton ;
}

- (IBAction)recordPauseTapped:(id)sender;
- (IBAction)stopTapped:(id)sender;
- (IBAction)playTapped:(id)sender;

Now set up everything in the -(Void)ViewDidLoad{} :

- (void)viewDidLoad
{
     [super viewDidLoad];

     // Disable Stop/Play button when application launches
     [stopButton setEnabled:NO];
     [playButton setEnabled:NO];

     // Set the audio file
     NSArray *pathComponents = [NSArray arrayWithObjects:
                                [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject],
                                @"MyAudioMemo.m4a",
                                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
     recorder = [[AVAudioRecorder alloc] initWithURL:outputFileURL settings:recordSetting error:NULL];
     recorder.delegate = self;
     recorder.meteringEnabled = YES;
     [recorder prepareToRecord];
}

Now Implement the recording Button Like so...

- (IBAction)recordPauseTapped:(id)sender {
     // Stop the audio player before recording
     if (player.playing) {
         [player stop];
     }

     if (!recorder.recording) {
         AVAudioSession *session = [AVAudioSession sharedInstance];
         [session setActive:YES error:nil];

         // Start recording
         [recorder record];
         [recordPauseButton setTitle:@"Pause" forState:UIControlStateNormal];

     } else {

         // Pause recording
         [recorder pause];
         [recordPauseButton setTitle:@"Record" forState:UIControlStateNormal];
     }

     [stopButton setEnabled:YES];
     [playButton setEnabled:NO];
}

Now Implement the StopButton IBAction:

- (IBAction)stopTapped:(id)sender {
     [recorder stop];

     AVAudioSession *audioSession = [AVAudioSession sharedInstance];
     [audioSession setActive:NO error:nil];
}

Next Implement the playTapped IBAction like so:

- (IBAction)playTapped:(id)sender {
     if (!recorder.recording){
         player = [[AVAudioPlayer alloc] initWithContentsOfURL:recorder.url error:nil];
         [player setDelegate:self];
         [player play];
     }
}

Lastly Implement the required AVPlayer Delegate by doing this:

- (IBAction)playTapped:(id)sender {
     if (!recorder.recording){
         player = [[AVAudioPlayer alloc] initWithContentsOfURL:recorder.url error:nil];
         [player setDelegate:self];
         [player play];
     }
}

And that's it! The Finished Product should look something like this...

For more info take a look at These Links:

Link1

Link2

Link3

Documentation Links:

Link 1

Hope This Helps.