Detect if effect or music finishes - SimpleAudioEngine

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Detect if effect or music finishes - SimpleAudioEngine

(17 posts) (3 voices)

Started 1 year ago by stamfa
Latest reply from hobbyCoder

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stamfa
Member

Hello, I'm new to Objective-C and of course to cocos2d too. Although I am learning the language without problems, I encountered a problem related to the sound engine. I'm writing a little card game, and before the players start to play, a .WAV music plays and stops. The problem is that I don't know how to detect if that .WAV file finished, and I need to detect that in order to get the game started. I am using SimpleAudioEngine, with the effects preloaded. But if you give me another options to implement instead of SimpleAudioEngine, I have no problems.

Thank you for your time.

Posted 1 year ago #
Steve Oldmeadow
Administrator
OpenAL - the API that is used for effects doesn't provide callbacks for sound completion. Therefore you have to poll to determine when the sound has finished. The easiest way to do that is create a CDSoundSource object for your sound, call the play method and then keep checking the isPlaying property until it returns NO.

Alternatively you can use a CDLongAudioSource object and assign a delegate that will be notified via the cdAudioSourceDidFinishPlaying method when the sound stops playing. The CDAudioManager has a "spare" CDLongAudioSource that you can get like so:
```
CDLongAudioSource* mySound = [[CDAudioManager sharedManager] audioSourceForChannel:kASC_Right];
[mySound load:@"mysound.wav"];
mySound.delegate = self;
[mySound play];
```
Posted 1 year ago #
stamfa
Member

Thank you, that solved my problem.

Posted 1 year ago #
hobbyCoder
Member

Alternatively you can use a CDLongAudioSource object and assign a delegate that will be notified via the cdAudioSourceDidFinishPlaying method when the sound stops playing.

Apologies for asking- how do I actually implement the CDLongAudioSource Protocol? Is there a sample project that shows me which methods are required? I'm a bit lost...

I have a cocos2d scene that will display three menu items, randomly chosen, and a narrator will read them in order. To do this I need a way to chain the sound playback one after the other. Is this the right approach to doing that?

Posted 1 year ago #
Steve Oldmeadow
Administrator
```
@protocol CDLongAudioSourceDelegate <NSObject>
@optional
/** The audio source completed playing */
- (void) cdAudioSourceDidFinishPlaying:(CDLongAudioSource *) audioSource;
/** The file used to load the audio source has changed */
- (void) cdAudioSourceFileDidChange:(CDLongAudioSource *) audioSource;
@end
```
The @optional part means that you don't have to implement any of the methods. Obviously if you want to find out when the source stops playing then you need to implement cdAudioSourceDidFinishPlaying. CDAudioManager implements the protocol so you can look at the source code for that.

A really simple approach to your problem would be to stick the file names for the three options in an NSMutableArray, have a playNext method that loads the current sound from the array, assigns the delegate and then increments the index into the array. Then in cdAudioSourceDidFinishPlaying check if there are any more sounds to play and if so call playNext otherwise stop.
Posted 1 year ago #
hobbyCoder
Member

Thank you for the quick and informative response. This should get me going pretty quickly. I'm still learning how to code, and protocols and delegates are still a bit exotic for my tiny little brain, but I'm getting there. I am in your debt.

Posted 1 year ago #
hobbyCoder
Member

Thanks again Steve, I tackled the problem exactly as you suggested and it works great. One issue that I do have with this approach though... if the app is sent to the background, or the phone is put to sleep, etc. the audio sometimes doesn't resume when the app returns. Worse, the cdAudioSourceDidFinishPlaying method doesn't get called reliably- this is pretty bad since I trigger game events by the end of various audio clips... and they never get triggered in these situations.

Is this a limitation of the underlying APIs, or is it possible I could improve this behavior?

Posted 1 year ago #
Steve Oldmeadow
Administrator

^ are you using the latest version of CocosDenshion. There are various bugs in different versions of the operating system that can cause the audio session to be interrupted but never resumed which causes loss of OpenAL audio.

I added code around the time of the 4.2 beta that works around those bugs. If you are using the latest version of CocosDenshion then please post the console output of a debug build and tell me which device and OS combination is causing a problem.

Can you please elaborate on cdAudioSourceDidFinishPlaying not being reliable? Is this only when the device is put in standby or does it happen in other situations as well.

Posted 1 year ago #
hobbyCoder
Member

Can you please elaborate on cdAudioSourceDidFinishPlaying not being reliable? Is this only when the device is put in standby or does it happen in other situations as well.

Hi Steve,

I have rebuilt my project from scratch using the Cocos2d release candidate and Xcode 4, and still see this behavior in my app. I've been testing with an iPhone 4, and an iPod Touch current generation, one is running 4.2.x and the other 4.3. Putting the device into standby prevents cdAudioSourceDidFinishPlaying from being called, at least as I have it coded, and multi-tasking to other apps behaves in the same way. Background music audio resumes perfectly but my CDLongAudioSource objects don't resume play and thus don't trigger a DidFinishPlaying event.

My whole understanding of delegation is pretty flimsy, so maybe I'm the problem... but I don't know how to troubleshoot it. The only console message that seems relevant is the logged line: "AudioStreamBasicDescription: 2 ch, 44100 Hz, 'lpcm' (0x00000C2C) 8.24-bit little-endian signed integer, deinterleaved." Which I get whenever first invoking the sound engine of course, if that helps?

I'm considering just killing multi-tasking support in the 1.0 release of my app while I work on this issue more / learn more about, well, everything. Thank you so much for CocosDenshion though - this is a very audio driven app, and it's turned out to be fantastic, I hope to do very well on the App Store next month, and owe you no small debt of gratitude.

Posted 9 months ago #
Steve Oldmeadow
Administrator
@hobbycoder - do you have a resign handler set up?

e.g
```
[[CDAudioManager sharedManager] setResignBehavior:kAMRBStopPlay autoHandle:YES];
```
If you don't do that CocosDenshion won't handle all audio stuff that needs to be done when the app resigns.
Posted 9 months ago #
hobbyCoder
Member
I do have that very line of code in my AppDelegate's applicationDidFinishLaunching method. It's been a while since I experimented with this particular problem so I'll methodically verify that it occurs regardless of which Cocos2d scene I'm in at the time, compare with the Simulator, try a fresh app with essentially no other code in it, etc. looking for a clue. I've had even bigger coding problems (not audio related) so this had been shelved for the last two months. heh

Maybe the problem is way I'm declaring which classes are supposed to be CDLongAudioScourceDelegates... in my project I have following code in the header files for several cocos2d scenes (any scene that needs to react to the didFinishPlaying event):
```
// The next code block is from Cocos2d's CDAudioManager.h....

@class CDLongAudioSource;
@protocol CDLongAudioSourceDelegate <NSObject>
@optional
/** The audio source completed playing */
- (void) cdAudioSourceDidFinishPlaying:(CDLongAudioSource *) audioSource;
/** The file used to load the audio source has changed */
- (void) cdAudioSourceFileDidChange:(CDLongAudioSource *) audioSource;
@end
```
This is probably really dumb isn't it? The compiler warns me that the "Duplicate protocol definition of 'CDLongAudioSourceDelegate' is ignored". However, it's working (aside from surviving under multi-tasking)... these classes are getting the didFinishPlaying call they're looking for.
Posted 9 months ago #
Steve Oldmeadow
Administrator

@hobbyCoder - instead of redefining the protocol you should just import CDAudioManager.h into the header that declares a class that implements the protocol. If your didFinishPlaying call is getting called then the issue is nothing to do with how you are declaring the delegates.

The FadeToGrey demo is the one that I use for testing this sort of stuff. If you can recreate the problem on that and send me the code then I can look into it.

Also, you need to increase the CD_DEBUG level in your build settings to see verbose logging.

Posted 9 months ago #
Steve Oldmeadow
Administrator

Background music audio resumes perfectly but my CDLongAudioSource objects don't resume play and thus don't trigger a DidFinishPlaying event.

If that is the case we need to determine what is different between background music and the other CDLongAudioSources.

Stepping into -(void)audioPlayerEndInterruption:(AVAudioPlayer *) should provide a clue.

Also, do not use the simulator for testing this stuff - it doesn't work in the simulator.

Posted 9 months ago #
hobbyCoder
Member
Thanks. Just to be painfully clear, the code would look something like this right?
```
CDLongAudioSource* mySound = [[CDAudioManager sharedManager] audioSourceForChannel:kASC_Right];
[mySound load:@"mysound.wav"];
mySound.delegate = self;
mySound.backgroundMusic = YES;
[mySound play];
```
So far even that hasn't convinced my CDLongAudioSource objects to resume play, but I'll keep trying to isolate it. Tomorrow I'll take the FadeToGrey demo and change it as minimally as I can to replicate my own code. Either that will fix it and show me what I'm doing wrong or I'll find something nice and specific you can look at. Thanks again.
Posted 9 months ago #
hobbyCoder
Member

For what it's worth, the background music that's playing and resuming flawlessly is invoked with:
[[SimpleAudioEngine sharedEngine] playBackgroundMusic:@"JazzBkgNoMelody.mp3"];

Posted 9 months ago #
Steve Oldmeadow
Administrator

^ I realised what I had said before about backgroundMusic was wrong. That is a special case because you don't want background music to resume if the user started playing some other music when they swapped out of your app. For non-background music you want it to resume regardless which is what the audioPlayerEndInterruption method should be doing. See my edited reply.

Posted 9 months ago #
hobbyCoder
Member

aha - I didn't even notice the edit. Gotcha.

Posted 9 months ago #

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