Audio and Sound

SystemSound API

• For short sounds only, less than 5 sec
• for .caf .aif or .wav only
• No control and immediate playback

      Steps to coding
        1. Register the sound
        2. Play the sound
        3. Optionally can get call back when finished

      Eg:

              NSURL *url = [[NSBundle mainBundle] pathForResource: @"audiofilename" ofType: @"ext"];  
              SystemSoundID id;
              AudioServicesCreateSystemSoundID((CFURLRef)url, &id);
              AudioServicesPlaySystemSound(id);   // to play the sound file

AVAudioPlayer Class

• High level simple API for playing back long sound (>5sec)
• Support play, stop, loop, pause, seek
• Support many more sound formats

     Steps to coding

• Include the AVFoundation header into the .h file. Eg:

             #import <AVFoundation/AVFoundation.h>

Create AVAudioPlayer from file URL or data, Eg:

             AVAudioPlayer *player;
             NSString *path = [[NSBundle mainBundle] pathForResource: @"audiofilename" ofType: @"ext"];
             NSURL *url = [NSURL fileURLWithPath: path];
             player = [[AVAudioPlayer alloc] initWithContentsOfURL:url error: NULL];

• Start or stop player as needed. Eg:

             if   (!player.playing) {
                   [player play];
             } else {
                   [player pause];
             }

• Add AVAudionFoundation Frameworks objects code to the project. Eg:

             In Xcode, under Groups and file Section, Under Frameworks, add ->
            Exsisting Frameworks. Select the AVaudioFoundation.framework to add to the
            Frameworks section.