Adding a pitchshifter effect to the Existing Multieffect example for pod

Projects and Examples
1

Has anyone implemented a Pitchshifter effect for the Multieffect example for pod? I have tried so many different things and cannot get it to work correctly.

Here is my code:

#include "daisysp.h"
#include "daisy_pod.h"

// Set max delay time to 0.75 of samplerate.
#define MAX_DELAY static_cast<size_t>(48000 * 2.5f)
#define REV 0
#define DEL 1
#define CRU 2
#define PIT 3

using namespace daisysp;
using namespace daisy;

PitchShifter  ps;

static DaisyPod pod;

static ReverbSc  DSY_SDRAM_BSS                                rev;
static DelayLine<float, MAX_DELAY> DSY_SDRAM_BSS dell;
static DelayLine<float, MAX_DELAY> DSY_SDRAM_BSS delr;
static Tone                                      tone;
static Parameter deltime, cutoffParam, crushrate;
int              mode = REV;

float currentDelay, feedback, delayTarget, cutoff, shifted, unshifted;

int   crushmod, crushcount;
float crushsl, crushsr, drywet;


//Helper functions
void Controls();

void GetReverbSample(float &outl, float &outr, float inl, float inr);

void GetDelaySample(float &outl, float &outr, float inl, float inr);

void GetCrushSample(float &outl, float &outr, float inl, float inr);

void GetPitchShifterSample(float &outl, float &outr, float inl, float inr);


void AudioCallback(AudioHandle::InterleavingInputBuffer  in,
                   AudioHandle::InterleavingOutputBuffer out,
                   size_t                                size)
{
    float outl, outr, inl, inr;

    Controls();

    //audio
    
    for(size_t i = 0; i < size; i += 2)
    {
        inl = in[i];
        inr = in[i + 1];

        switch(mode)
        {
            case REV: GetReverbSample(outl, outr, inl, inr); break;
            case DEL: GetDelaySample(outl, outr, inl, inr); break;
            case CRU: GetCrushSample(outl, outr, inl, inr); break;
            case PIT: GetPitchShifterSample(outl, outr, inl, inr); break;
            default: outl = outr = 0;
        }

        // left out
        out[i] = outl;

        // right out
        out[i + 1] = outr;
    }
}

int main(void)
{
    // initialize pod hardware and oscillator daisysp module
    float sample_rate;

    //Inits and sample rate
    pod.Init();
    pod.SetAudioBlockSize(4);
    sample_rate = pod.AudioSampleRate();
    rev.Init(sample_rate);
    dell.Init();
    delr.Init();
    tone.Init(sample_rate);
    ps.Init(sample_rate);
    // set transposition 1 octave up (12 semitones)
    


    //set parameters
    deltime.Init(pod.knob1, sample_rate * .05, MAX_DELAY, deltime.LOGARITHMIC);
    cutoffParam.Init(pod.knob1, 500, 20000, cutoffParam.LOGARITHMIC);
    crushrate.Init(pod.knob2, 1, 50, crushrate.LOGARITHMIC);

    //reverb parameters
    rev.SetLpFreq(18000.0f);
    rev.SetFeedback(0.85f);

    //delay parameters
    currentDelay = delayTarget = sample_rate * 0.75f;
    dell.SetDelay(currentDelay);
    delr.SetDelay(currentDelay);

    // start callback
    pod.StartAdc();
    pod.StartAudio(AudioCallback);
    while(1) {}
}

void UpdateKnobs(float &k1, float &k2)
{
    k1 = pod.knob1.Process();
    k2 = pod.knob2.Process();

    switch(mode)
    {
        case REV:
            drywet = k1;
            rev.SetFeedback(k2);
            break;
        case DEL:
            delayTarget = deltime.Process();
            feedback    = k2;
            break;
        case CRU:
            cutoff = cutoffParam.Process();
            tone.SetFreq(cutoff);
            crushmod = (int)crushrate.Process();
            break;
        case PIT:
            ps.SetFun(k1);
            ps.SetTransposition(12.0f * k2);
    }
}

void UpdateEncoder()
{
    mode = mode + pod.encoder.Increment();
    mode = (mode % 4 + 4) % 4;
}
void Controls()
{
    float k1, k2;
    delayTarget = feedback = drywet = 0;

    pod.ProcessAnalogControls();
    pod.ProcessDigitalControls();

    UpdateKnobs(k1, k2);

    UpdateEncoder();

}

void GetReverbSample(float &outl, float &outr, float inl, float inr)
{
    rev.Process(inl, inr, &outl, &outr);
    outl = drywet * outl + (1 - drywet) * inl;
    outr = drywet * outr + (1 - drywet) * inr;
}

void GetDelaySample(float &outl, float &outr, float inl, float inr)
{
    fonepole(currentDelay, delayTarget, .00007f);
    delr.SetDelay(currentDelay);
    dell.SetDelay(currentDelay);
    outl = dell.Read();
    outr = delr.Read();

    dell.Write((feedback * outl) + inl);
    outl = (feedback * outl) + ((1.0f - feedback) * inl);

    delr.Write((feedback * outr) + inr);
    outr = (feedback * outr) + ((1.0f - feedback) * inr);
}

void GetCrushSample(float &outl, float &outr, float inl, float inr)
{
    crushcount++;
    crushcount %= crushmod;
    if(crushcount == 0)
    {
        crushsr = inr;
        crushsl = inl;
    }
    outl = tone.Process(crushsl);
    outr = tone.Process(crushsr);
}

void GetPitchShifterSample(float &outl, float &outr, float inl, float inr)
{ 
outl = ps.Process(inl);
outr = ps.Process(inl);
}

Apologies for the noob questions, I am not very proficient in coding C++ . Any help is greatly appreciated.

2

Hey Syndicate!

Since you mentioned on Discord that you still want to figure out how to pass audio from the input to the pitchshifter effect in the pitchshifter.cpp, I suggest analyzing how the input audio are processed in the multieffect example and try to implement that in pitchshifter.cpp first.
And once that’s working then you can try to put that algorithm into the multieffect code.

That being said, multieffect example is a pretty big one to tackle if you’re just getting started with C++. So I suggest going step by step with DSP examples first and then hardware tutorials (libDaisy tutorial is highly recommended!). Afterwards, you can revisit the multieffect example with much more knowledge :slight_smile: