How to do real-time pitch shifting from mic with Superpowered? [duplicate] - ios

Question

This question already has answers here:
Superpowered: real time pitch shift with timestretcher not working
(2 answers)
Closed 5 years ago.
I'm trying to make a pitch shift in real time from a microphone using superpowerd. I looked at the example that is for the file. Also tried to adapt it. I managed to change the sound, but it turned out very distorted with interference. What am I doing wrong? where to find more information on superpowered and timeStretching?
static bool audioProcessing(void *clientdata,
float **buffers,
unsigned int inputChannels,
unsigned int outputChannels,
unsigned int numberOfSamples,
unsigned int samplerate,
uint64_t hostTime) {
__unsafe_unretained Superpowered *self = (__bridge Superpowered *)clientdata;
float tempBuffer[numberOfSamples * 2 + 16];
SuperpoweredInterleave(buffers[0], buffers[1], tempBuffer, numberOfSamples);
float *outputBuffer = tempBuffer;
SuperpoweredAudiobufferlistElement inputBuffer;
inputBuffer.samplePosition = 0;
inputBuffer.startSample = 0;
inputBuffer.samplesUsed = 0;
inputBuffer.endSample = self->timeStretcher->numberOfInputSamplesNeeded;
inputBuffer.buffers[0] = SuperpoweredAudiobufferPool::getBuffer(self->timeStretcher->numberOfInputSamplesNeeded * 8 + 64);
inputBuffer.buffers[1] = inputBuffer.buffers[2] = inputBuffer.buffers[3] = NULL;
memcpy((float *)inputBuffer.buffers[0], outputBuffer, numberOfSamples * 2 + 16);
self->timeStretcher->process(&inputBuffer, self->outputBuffers);
// Do we have some output?
if (self->outputBuffers->makeSlice(0, self->outputBuffers->sampleLength)) {
while (true) { // Iterate on every output slice.
// Get pointer to the output samples.
int sampleCount = 0;
float *timeStretchedAudio = (float *)self->outputBuffers->nextSliceItem(&sampleCount);
if (!timeStretchedAudio) break;
SuperpoweredDeInterleave(timeStretchedAudio, buffers[0], buffers[1], numberOfSamples);
};
// Clear the output buffer list.
self->outputBuffers->clear();
};
return true;
}

Answer 1

I did the following:
static bool audioProcessing(void *clientdata,
float **buffers,
unsigned int inputChannels,
unsigned int outputChannels,
unsigned int numberOfSamples,
unsigned int samplerate,
uint64_t hostTime) {
__unsafe_unretained Superpowered *self = (__bridge Superpowered *)clientdata;
SuperpoweredAudiobufferlistElement inputBuffer;
inputBuffer.startSample = 0;
inputBuffer.samplesUsed = 0;
inputBuffer.endSample = numberOfSamples;
inputBuffer.buffers[0] = SuperpoweredAudiobufferPool::getBuffer((unsigned int) (numberOfSamples * 8 + 64));
inputBuffer.buffers[1] = inputBuffer.buffers[2] = inputBuffer.buffers[3] = NULL;
SuperpoweredInterleave(buffers[0], buffers[1], (float *)inputBuffer.buffers[0], numberOfSamples);
self->timeStretcher->process(&inputBuffer, self->outputBuffers);
// Do we have some output?
if (self->outputBuffers->makeSlice(0, self->outputBuffers->sampleLength)) {
while (true) { // Iterate on every output slice.
// Get pointer to the output samples.
int numSamples = 0;
float *timeStretchedAudio = (float *)self->outputBuffers->nextSliceItem(&numSamples);
if (!timeStretchedAudio || *timeStretchedAudio == 0) {
break;
}
SuperpoweredDeInterleave(timeStretchedAudio, buffers[0], buffers[1], numSamples);
}
// Clear the output buffer list.
self->outputBuffers->clear();
}
return true;
}
This might not work correctly when changing the speed also, but I wanted live pitch shifting only. People should be able to speak slower or faster themselves.