ObjectAL slow motion effect in cocos2d

Question

How can I create slow motion effect for all currently playig sounds and music in my game? I'm using cocos2d v2.1 and ObjectAL.

I can set timescale for scheduler, but how I can do this for sound together?

Answer 1

Keep references to the CDSoundSource of each sound and bg output:

CDSoundSource *bgMusic = [[SimpleAudioEngine sharedEngine]soundSourceForFile:@"mysong1.mp3"];

[mySoundArray addObject:bgMusic];

Then create a method to ramp down the pitch of all references at a scheduled interval:

-(void)testUpdate:(ccTime)dt
{
    float myRampVal = 0.05f;
    float finalPitch = 0.5f;

    for(CDSoundSource *sound in mySoundArray)
    {
        sound.pitch -= myRampVal;

        if(sound.pitch < finalPitch)
        {
             sound.pitch = finalPitch;
        }
    }
}

Schedule by calling the following when you want to lower the pitch:

[self schedule:@selector(audioDownRamp:) interval:0.1f];