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I want to do some DSP effect processing, create effect like flanger, echo, etc. Could it be done via OpenAL? Or should I use enterely different framework/library?

Geri Borbás
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  • I've heard something about EFX, but just cannot see how to do that, how to integrate, where to download, is it integrated already? – Geri Borbás Nov 11 '11 at 15:49

2 Answers2

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Since iOS 5.0 some of the DSP effects are natively supported by OpenAL.

For example, reverb is supported with emulation for more than 10 different spaces (Small/Medium/Large Room, Medium/Large Hall, Plate, Medium/Large Chamber, Cathedral and several variations).

You can find a good reference implementation in the ObjectAL wrapper. The repository is available at https://github.com/kstenerud/ObjectAL-for-iPhone

Grab the source from this repository, load "ObjectAL.xcodeproj" and run the ObjectALDemo target on any iOS 5.0 device (should also work on the simulator). This will give you a good starting point and feeling of what the reverb effect is capable of. I personally recommend taking advantage of the ObjectAL library instead of working with OpenAL directly.

Good luck with your project!

urish
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Just write your own audio library. iOS devices don't have hardware acceleration for OpenAL. It isnt particularly difficult to do, and then you can also use apples audio units (some of which are hardware accelerated).

Skyler Saleh
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  • This wrapper seems ok - http://kstenerud.github.com/ObjectAL-for-iPhone/ -, but I want to include OpenAL's EFX library somehow. – Geri Borbás Nov 11 '11 at 15:48
  • I need some flanger/distorsion/etc. It is ok, if there is a computing time, but the result must be a sound clip with the effect applied. – Geri Borbás Nov 11 '11 at 15:49