CODEWITHSUNDEEP
iphoneaudiocore-audiopitchpitch-tracking
Leachy Peachy
Leachy Peachy

Reputation: 1132

Real-time Pitch Shifting on the iPhone

I have a children's iPhone application that I am writing and I need to be able to shift the pitch of a sound sample using Core Audio. Does anyone have any example code I could look at where this is done. There are many music and game apps in the app store that do this so I know I am not the first one. However, I cannot find any examples of it being done.

Upvotes: 25

Views: 25499

Answers (5)

rptwsthi
rptwsthi

Reputation: 10172

I know it's too late for the person who asked but it is really a valuable link (As I found) for any one else who is looking for the solution of the same problem.

So Here we have latest DIRAC3 with it's own audio player classes which will take care of run time pitch and speed(explore for god knows what more) shifting. Run the sample and have huge round of applause for that.

Upvotes: 4

tahome
tahome

Reputation: 288

Try Dirac - it's the best technology out there and it's available on Win, Linux, MacOS X and iOS. We're using it in all our products (and a couple of others do as well, search for "Capo" on the App Store). They're at version 3 now which has seen a huge increase in performance since previous versions. Hope this helps.

Upvotes: 3

Aran Mulholland
Aran Mulholland

Reputation: 23935

you can use dirac-2 from dsp dimension for pitch shifting on the iphone. quote: -

"DIRAC2 is available as both a commercial object library offering unlimited sample rates and phase locked multichannel support and as a free single channel, 44.1/48kHz LE version."

Upvotes: 15

Anil Sivadas
Anil Sivadas

Reputation: 1698

use the soundtouch open source project to change pitch

Here is the link : http://www.surina.net/soundtouch/

Once you add soundtouch to your project, you have to give the input sound file path, output sound file path and pitch change as the input.

Since it takes more time to process your sound its better to modify soundtouch so that when you record the voice, directly give the data for processing. It will make your application better.

Upvotes: 10

Dave Gamble
Dave Gamble

Reputation: 4174

See: Related question

How much control over pitch do you need... could you precalculate all the different sounds? If the answer is yes, then you can just pick the right sounds and play them.

You could also use Audio Converter Services in conjunction with AVAudioPlayer, which will allow you to resample the audio (which will effectively repitch them, though they'll change duration).

Alternatively, as the related question points out, you could use OpenAL and AL_PITCH

Upvotes: 2

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