How to implement pitch detection (getNotes() ?) on iOS ?

[happyriri]

Hi !

How to implement pitch detection (getNotes() ?) on iOS ?

I don't see any informations on the documentation.

Thanks !

[ivannador]

Hello!

The class LiveAnalyzer will help you achieve what you need.

Please find the relevant documentation here: https://docs.superpowered.com/reference/latest/live-analyzer?lang=cpp The iOS integration guide can be found here: https://docs.superpowered.com/getting-started/how-to-integrate/ios?lang=cpp

Hope this helps!

Ivan

[happyriri]

Thanks for your help !

I have this code in my SuperpoweredBridge Objective-C++ :

#include "Superpowered.h"
#include "SuperpoweredSimple.h"
#import "SuperpoweredBridge.h"
#import "../libs/Superpowered/SuperpoweredAnalyzer.h"
#import "SuperpoweredIOSAudioIO.h"

@implementation SuperpoweredBridge {
    SuperpoweredIOSAudioIO *audioIO;
    Superpowered::LiveAnalyzer *analyzer;
}

static bool audioProcessing(void *clientdata, float *input, float *output, unsigned int numberOfFrames, unsigned int samplerate, uint64_t hostTime) {
    __unsafe_unretained SuperpoweredBridge *self = (__bridge SuperpoweredBridge *)clientdata;
    //printf("numberOfFrames : %d", numberOfFrames);
    self->analyzer->process(input, numberOfFrames);
    if (self->analyzer->keyIndex == -1) {
        printf("Unkown");
    } else {
        printf("Note : %s ", Superpowered::musicalChordNames[self->analyzer->keyIndex]);
    }
    return false;
}

- (id)init {
    self = [super init];
    if (!self) return nil;
    Superpowered::Initialize("ExampleLicenseKey-WillExpire-OnNextUpdate");

    analyzer = new Superpowered::LiveAnalyzer(
        44100
    );

    audioIO = [[SuperpoweredIOSAudioIO alloc] initWithDelegate:(id<SuperpoweredIOSAudioIODelegate>)self preferredBufferSize:12 preferredSamplerate:44100 audioSessionCategory:AVAudioSessionCategoryRecord channels:2 audioProcessingCallback:audioProcessing clientdata:(__bridge void *)self];
    [audioIO start];
    return self;
}

- (void)dealloc {
    delete analyzer;
    audioIO = nil;
}

@end

I get a note output but only once every x seconds. And sometime the note is -1.

Can you help me ?

Thanks

[ivannador]

Your code seems fine, but you should make sure to set the actual sample rate of the LiveAnalyzer in the process call.

According to the docs: The update frequency is 2 seconds. So it is expected to only have a result each 2 seconds. -1 means the LiveAnalyzer could not find the dominant key in that chunk. Make sure to set the actual sample rate, that might help.

[happyriri]

Oh so Superpowered only show results every 2 seconds ??! This is not as speed as I thought ! :(

I want real time pitch detection (multiple results every second), have you the possibiliy to do so ?

Thanks again for all you help !

[ivannador]

The Superpowered LiveAnalyzer's purpose is more oriented towards detecting the dominant key of music instead of the lowest possible latency pitch detection for singing for example. With that said, Superpowered provides high performance FFT utilities to implement your own pitch detection algorithms or you can easily interface a C++-based third party real-time pitch detection algorithm with Superpowered.