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William Liu
Member
Hi,
My game is using cocos2d and box2d. After add sound effect to my game with SimpleAudioEngine, my game's fps drop down from 60 to 40. I don't understand the reason? How can I use SimpleAudioEngine with high effectivity(don't affect fps)?
My device is ipod touch + IOS4.
Thanks,
William
Steve Oldmeadow
Administrator
Maybe you are doing something stupid? It is pretty hard to say without seeing your source code.
@Steve, this is actually something it also happens to me, sometimes I feel a drop on the framerate when I play a sound for the first time, I am sure it's my code, I basically did a small sound engine using the AVAudioPlayer for background mp3 files and the AudioServices for simple wav effects, here is some code:
#import "Sound.h"
@implementation Sound
+(id) createWithContentsOfFile:(NSString *) path {
return [[[self alloc] initWithContentsOfFile: path] autorelease];
}
-(id) initWithContentsOfFile:(NSString *) path {
self = [super init];
if (self != nil) {
NSURL * filepath = [[NSURL alloc] initFileURLWithPath: path];
NSRange range = [path rangeOfString:@".mp3" options:NSCaseInsensitiveSearch];
if (range.location > 0) {
useSystemSound = NO;
} else {
useSystemSound = YES;
}
//useSystemSound = NO;
if (useSystemSound) {
AudioServicesCreateSystemSoundID((CFURLRef)filepath, &soundID);
} else {
audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:filepath error:NULL];
}
[filepath release];
}
return self;
}
-(BOOL) prepare {
if (useSystemSound) {
return NO;
} else {
return [audioPlayer prepareToPlay];
}
}
-(void) play {
if (!playing) {
if (useSystemSound) {
AudioServicesPlaySystemSound(soundID);
} else {
audioPlayer.numberOfLoops = 0;
if (!audioPlayer.playing) [audioPlayer play];
}
playing = YES;
[NSTimer scheduledTimerWithTimeInterval:0.2 target:self selector:@selector(onCompletion:) userInfo:nil repeats:NO];
}
}
-(void) onCompletion:(NSTimer *) sender {
playing = NO;
}
-(void) setVolume:(float)volume {
if (useSystemSound) {
} else {
audioPlayer.volume = volume;
}
}
-(void) loop {
if (useSystemSound) {
AudioServicesPlaySystemSound(soundID);
} else {
audioPlayer.numberOfLoops = -1;
[audioPlayer play];
}
}
-(void) stop {
if (useSystemSound) {
} else {
[audioPlayer stop];
}
}
-(void) dealloc
{
if (useSystemSound) {
AudioServicesDisposeSystemSoundID(soundID);
} else {
[audioPlayer stop];
[audioPlayer release];
}
[super dealloc];
}
@endI basically create an array of sounds encapsulated on a Mixer class, if it's a mp3 I use AVAudioPlayer, if not I use the AudioServices, and call the prepare (only affects the AVAudioPlayer really).
My understanding was that it's better to play uncompressed files for small effects, as they should be faster than mp3 files. For the background music I don't really care if there is a small delay anyway.
The first time I call one of the effects (AudioServices) I can feel the framerate drop.
Is not really bothering me too much, as it's only the very first time, actually, it's the very first time I call one effect (AudioServices), any, so after one of them is called, I can call any other effect with no delay, weird, like if I were missing some kind of preparation?
Steve Oldmeadow
Administrator
@William Liu - again, we can't really help you without seeing source code. I've seen people do things as stupid as playing every sound multiple times (up to 128) or playing a sound for every collision call back in a physics engine. The problem may not even be the audio, sometimes it is just the straw that breaks the camel's back. You should use Instruments to determine where your performance bottle necks are.
@Steve yeah I agree with you, most times if not always is our code. Anyway, on my case, I have traced and sound plays only once. As I said, the fps drop occurs only the first time I call an AudioServices sound, but I just realised it only happens on the simulator! So really not bothering me.
Correction: it does happen on the device as well. On the simulator only happens the first time I build the app after a build clean, it's very noticeable. On the device seems to happens every time but it's less noticeable, but there is a fps drop as well.
Ummm.... The one code sample is using AudioServices, and not SimpleAudioEngine. Not sure how this would be a CocosDenshion issue? When I use the preload, I have no lag or framerate drop on my end on a variety of devices/iOS combinations.
For me, I have a Loading Scene where I load all the sounds, and images, etc...
For example, the preload for me looks like:
[[SimpleAudioEngine sharedEngine] preloadEffect:@"pause.mp3"];
And it works just fine after that. When I play the sound, it looks like:
[[SimpleAudioEngine sharedEngine] playEffect:@"pause.mp3" pitch:1.0f pan:0.0f gain:[prefs floatForKey:@"soundfxvol"]];
Steve Oldmeadow
Administrator
it is quite frustrating
As frustrating as people who post on threads without bothering to read anything that was said before?
Please post your source code and also run Instruments. Are you using a physics engine? If so I am willing to bet the CPU utilisation of CocosDenshion is nothing compared to the physics engine.
ok,
so besides background music, i do quite a few things with audio (and am not done yet)
first off i preload everything when i start the app
1. probably the most intensive is a sound effect every .2 to .25 seconds for reload time.
2. when a bullet hits a guy a sound effect is played
3. when bombs drop or explode it is played
those are the main ones
i preload like this
[[SimpleAudioEngine sharedEngine] preloadEffect:@"shootSingle.caf"];and play them like this
[[SimpleAudioEngine sharedEngine] playEffect:@"shootSingle.caf"];I believe Steve is wanting a bit more on the source code to better understand how you are setting everything up. Along with that, the debug output as the app starts up, along with debug output when you are experiencing this slow down. This would be the CocosDenshion debug output specifically, and would be more beneficial than the one line snippets you posted.
Steve Oldmeadow
Administrator
@finder39 - sabshire is correct, throw me a frickin' bone! You use playEffect to play your effects, no sh*t Sherlock - you think I didn't know that.
What I want to see is all your code where you are triggering sounds. The issue is not with CocosDenshion, it is with your code. For example, you say you trigger a sound when a bullet hits a guy? If you are using a physics engine and triggering the sound from the collision callback you have a big problem already, that is going to trigger the sound way more times than is necessary. The latency is so low with fast devices you probably don't even realise you are triggering multiple sounds.
Steve Oldmeadow
Administrator
@finder39 - I don't have time to go through that code to see if you have logic errors. A simple test is to put a log statement in playEffect and see how many times it is getting called, if it is getting called very frequently e.g more than 32 times in one frame then you need to make some changes.
Even if you don't have logic errors you still need to ensure that you aren't playing sounds too frequently. There is no point in playing the same sound multiple times within the same frame, doing so will actually increase the volume of playback. Similarly you probably want to avoid playing the same sound too close together, doing so will cause audio artifacts. It is up to you to work out how to achieve this, CocosDenshion just gives you the raw materials, it doesn't care if you try to play the same sound 200 times in 1 millisecond just the same as cocos2d doesn't care if you draw the same sprite in the same position 200 times in a frame.
Steve Oldmeadow
Administrator
How often are you playing effects though? Don't forget to use Instruments too to see where the bottlenecks are.
Steve Oldmeadow
Administrator
Check the Apple WWDC 2010 presentations on using Instruments, I can't tell you the names off the top of my head. From memory there is one specifically on performance.
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