Audio query

jbernabeu

I am trying to implement sound, and I would like to be able to know the time a music is playing to swap it with the same music (with an effect) at the same time. Is this possible ???

How could I do it ???

Any sound framework ???

Any help ??? 🙂

Daniel

I just checked the underlying APIs -- in theory, it should be possible to add a "currentTime" property to the SPSoundChannel class (and thus, to both SPALSoundChanneld and SPAVSoundChannel).

Unfortunately, I don't have the time to add that right now, but perhaps you could give it a go yourself!

For OpenAL, here are two articles that might help. For the AVAudioPlayer, you'd just need to forward to the "currentTime" property of the player objects.

Good luck! 🙂

jbernabeu

Daniel,

If I try to change it, would you like that I commit the files ???

BERNABEU

TTStu

Hi jbernabeu,

I asked this a couple of weeks ago, and Shilo kindly pointed me in the right direction in this thread:

http://forum.sparrow-framework.org/topic/get-current-time-from-spsoundchannel

Basically the same as what Daniel says above.

So, credit to Shilo (I just filled in the blanks), I came up with this:

//
// SPSoundChannel+CurrentTime.h
//
//

#import "SPSoundChannel.h"

@class AVAudioPlayer;

@interface SPSoundChannel (CurrentTime)

@property (nonatomic, readonly) float currentTime;

@end

//
// SPSoundChannel+CurrentTime.m
//
//

#import "SPSoundChannel+CurrentTime.h"
#import "SPAVSoundChannel.h"
#import "SPALSoundChannel.h"

@interface SPAVSoundChannel ()
{
    AVAudioPlayer *_player;
}
@end

@implementation SPAVSoundChannel (CurrentTime)

- (float)currentTime
{
    return _player.currentTime;
}

@end

@implementation SPSoundChannel (CurrentTime)

- (float)currentTime
{
    // OVERRIDE AS REQUIRED
    return 0.0f;
}

@end

@implementation SPALSoundChannel (CurrentTime)

- (float)currentTime
{
    // OVERRIDE AS REQUIRED
    return 0.0f;
}

@end

HTH 🙂

Daniel

Ah, great! I overlooked that thread, thanks for posting it!
I'll add that to my TODO-list.

jbernabeu

The current time is the first part of the query, now I see that I will be able to do it ...

But ... how is the best way to make the swap ??? I mean is there a way to tell the player something like 'PLAY THIS MUSIC FROM THIS POINT' ??

BERNABEU

TTStu

Use the juggler/onenterframe to poll the currenttime and if > time { swap; } 🙂

jbernabeu

First of all thanks for all the answers !!!!!

But I want to swap to the other file in the same current time in both files, so how could I begin to play a file in a given position ???

Shilo

For AVAudioPlayer, you just need to set the "currentTime" property before calling "play" (as Daniel suggested). More detail here: https://developer.apple.com/library/ios/DOCUMENTATION/AVFoundation/Reference/AVAudioPlayerClassReference/Reference/Reference.html#//apple_ref/occ/instp/AVAudioPlayer/currentTime

Using OpenAL to play a audio file from a specific time is a bit more tricky, but I believe the solution is here:
http://stackoverflow.com/questions/434599/openal-how-does-one-jump-to-a-particular-offset-more-than-once

I just realized Daniel linked the same article above.

My post is officially useless, thank you Daniel! 😉

Daniel

LOL, no, Shilo, you summarized it perfectly!
My post was obviously a little ambiguous! 😉