what is the best way to play sound quickly upon fast button presses xcode?

Question

hi i have a soundboard its just a screen with about 8 buttons. each individual button will have its own sound which will be played upon button press There are a couple of ways i could play the sound, such as using SystemSound or AVAudioPlayer system sound so far seems have the quickest response times, avaudioplayer is quite slow, it cant keep up if the user taps on the buttons really fast, i created an audio player for each sound which was quite messy. this is how im playing the sounds at the moment the .h file

@interface MainScreenViewController : UIViewController <AVAudioPlayerDelegate, UITabBarControllerDelegate> {
 AVAudioPlayer *player;
 CFURLRef  keNURL;
 SystemSoundID    keNObject;
 //KE LOUD
 CFURLRef  keLURL;
 SystemSoundID    keLObject;
 //GE NORMAL
 CFURLRef  geNURL;
 SystemSoundID    geNObject;
 //GE LOUD
 CFURLRef  geLURL;
 SystemSoundID    geLObject;
 //NA NORMAL
 CFURLRef  naNURL;
 SystemSoundID    naNObject;
 //NA LOUD
 CFURLRef  naLURL;
 SystemSoundID    naLObject;
 //RA
 CFURLRef  raURL;
 SystemSoundID    raObject;
 //DAGGA CLICK
 CFURLRef  daCURL;
 SystemSoundID    daCObject;
 //TILLI CLICK
 CFURLRef  tiCURL;
 SystemSoundID    tiCObject;

}
@property (nonatomic, retain) AVAudioPlayer *player;
@property (readwrite)    CFURLRef        keNURL;
@property (readonly)    SystemSoundID    keNObject;
@property (readwrite)    CFURLRef        keLURL;
@property (readonly)    SystemSoundID    keLObject;
@property (readwrite)    CFURLRef        geNURL;
@property (readonly)    SystemSoundID    geNObject;
@property (readwrite)    CFURLRef        geLURL;
@property (readonly)    SystemSoundID    geLObject;
@property (readwrite)    CFURLRef        naNURL;
@property (readonly)    SystemSoundID    naNObject;
@property (readwrite)    CFURLRef        naLURL;
@property (readonly)    SystemSoundID    naLObject;
@property (readwrite)    CFURLRef        raURL;
@property (readonly)    SystemSoundID    raObject;
@property (readwrite)    CFURLRef        daCURL;
@property (readonly)    SystemSoundID    daCObject;
@property (readwrite)    CFURLRef        tiCURL;
@property (readonly)    SystemSoundID    tiCObject;
}

then the actions that play the individual sounds

then the .m file, after importing the .h file and the right frame works and synthesizing all the variables, write the code for the action and this is whats in the individual actions.

-(IBAction)geSound{
 AudioServicesPlaySystemSound (self.geNObject);
}

i just wanted to know if systemsound is the way forward for me to create a soundboard. thanks especially when the user will tap on the board really fast alternating between beats. . if not what is the best way to play the sound which responds really well?

Answer 1

Speaking from experience, AVAudioPlayer works quite well at playing multiple sounds at the same time or very quickly one after the other. The best way to use it is to just create one method that you feed in an NSString to play some sound with the name held in that NSString... in that way, you will create a new player for each sound file that you play. Be careful about releasing the allocated players though unless you know you are finished with them.

Unless you have very large sound files which might take a short second to buffer (you'll have to figure out for yourself if you can live with any latency or not), I've never had any issues with it being slow. If it's slow, you're probably doing something against Apple's recommendations in regards to decoding certain files (i.e. for multiple sounds at once, Apple recommends the CAF format since it is hardware decoded versus software decoded): http://developer.apple.com/iphone/library/documentation/AVFoundation/Reference/AVAudioPlayerClassReference/Reference/Reference.html

Update

Here is how I encode my files with a shell script. Put this in a file called batchit.sh in it's own directory. Then place whatever .WAV files you want to encode as a .CAF file in that directory. Open up the Terminal on your Mac, cd to that directory and type sh batchit.sh and let it do it's thing. It will batch convert all the files... Here's the code:

for f in *; do
if  [ "$f" != "batchit.sh" ]
then
    /usr/bin/afconvert -f caff -d ima4 $f 
    echo "$f converted"
fi
done

Here is a sample project... http://www.megaupload.com/?d=5NP6FHR1

Notice I didn't do anything in the audioPlayerDidFinishPlaying method which is a delegate method of AVAudioPlayer. You will need to add code to properly release the players after each is finished playing (hey, I can't do all the work for you :) so that all the memory is allocated correctly. Otherwise you will eventually run out if you indefinitely keep creating players without releasing them. Since it seems like you're having a rough day.. see below for a big hint.

That's all the help I can give though. You gotta learn & earn the rest

- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag {

    // do something here if you want.. you know like maybe release the old players by uncommenting the line below :)

    //[player release];

}

Answer 2

you could create AVAudioPlayer for each sound and then just pause/play it.

Answer 3

Have you tried playing back each sound in its own thread? You could try a basic NSOperation

Answer 4

USE OPEN AL! OMG WOW as soon as i use open al implementing all the methods and instantiating everything. The sound plays sooo fast. what i mean is ABSOLUTELY LOW LATENCY IS WHAT I WAS AFTER AND THATS WHAT I GOT ah wow its working brilliantly I managed to get everything working. Use these tutorials it will help as they have helped me: http://benbritten.com/2008/11/06/openal-sound-on-the-iphone/ and especially the next link im going to post. Thanks to this link i was able t create a soung manager that would be able to play all the sounds i want in any class i am in. http://www.71squared.com/2009/05/iphone-game-programming-tutorial-9-sound-manager/

i suggest everyone to use openAL for low latency on demand sound. specially for games when you need to make sure sound is played there and then when you want it to.