Pretty high quality pitch Shifting effect using smbPitchShift

servers/audio/effects/audio_effect_pitch_shift.cpp

@@ -0,0 +1,297 @@
+#include "audio_effect_pitch_shift.h"
+#include "servers/audio_server.h"
+/****************************************************************************
+*
+* NAME: smbPitchShift.cpp
+* VERSION: 1.2
+* HOME URL: http://blogs.zynaptiq.com/bernsee
+* KNOWN BUGS: none
+*
+* SYNOPSIS: Routine for doing pitch shifting while maintaining
+* duration using the Short Time Fourier Transform.
+*
+* DESCRIPTION: The routine takes a pitchShift factor value which is between 0.5
+* (one octave down) and 2. (one octave up). A value of exactly 1 does not change
+* the pitch. numSampsToProcess tells the routine how many samples in indata[0...
+* numSampsToProcess-1] should be pitch shifted and moved to outdata[0 ...
+* numSampsToProcess-1]. The two buffers can be identical (ie. it can process the
+* data in-place). fftFrameSize defines the FFT frame size used for the
+* processing. Typical values are 1024, 2048 and 4096. It may be any value <=
+* MAX_FRAME_LENGTH but it MUST be a power of 2. osamp is the STFT
+* oversampling factor which also determines the overlap between adjacent STFT
+* frames. It should at least be 4 for moderate scaling ratios. A value of 32 is
+* recommended for best quality. sampleRate takes the sample rate for the signal
+* in unit Hz, ie. 44100 for 44.1 kHz audio. The data passed to the routine in
+* indata[] should be in the range [-1.0, 1.0), which is also the output range
+* for the data, make sure you scale the data accordingly (for 16bit signed integers
+* you would have to divide (and multiply) by 32768).
+*
+* COPYRIGHT 1999-2015 Stephan M. Bernsee <s.bernsee [AT] zynaptiq [DOT] com>
+*
+* 						The Wide Open License (WOL)
+*
+* Permission to use, copy, modify, distribute and sell this software and its
+* documentation for any purpose is hereby granted without fee, provided that
+* the above copyright notice and this license appear in all source copies.
+* THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT EXPRESS OR IMPLIED WARRANTY OF
+* ANY KIND. See http://www.dspguru.com/wol.htm for more information.
+*
+*****************************************************************************/
+
+
+void SMBPitchShift::PitchShift(float pitchShift, long numSampsToProcess, long fftFrameSize, long osamp, float sampleRate, float *indata, float *outdata,int stride) {
+
+
+	/*
+		Routine smbPitchShift(). See top of file for explanation
+		Purpose: doing pitch shifting while maintaining duration using the Short
+		Time Fourier Transform.
+		Author: (c)1999-2015 Stephan M. Bernsee <s.bernsee [AT] zynaptiq [DOT] com>
+	*/
+
+	double magn, phase, tmp, window, real, imag;
+	double freqPerBin, expct;
+	long i,k, qpd, index, inFifoLatency, stepSize, fftFrameSize2;
+
+	/* set up some handy variables */
+	fftFrameSize2 = fftFrameSize/2;
+	stepSize = fftFrameSize/osamp;
+	freqPerBin = sampleRate/(double)fftFrameSize;
+	expct = 2.*M_PI*(double)stepSize/(double)fftFrameSize;
+	inFifoLatency = fftFrameSize-stepSize;
+	if (gRover == 0) gRover = inFifoLatency;
+
+	/* initialize our static arrays */
+
+	/* main processing loop */
+	for (i = 0; i < numSampsToProcess; i++){
+
+		/* As long as we have not yet collected enough data just read in */
+		gInFIFO[gRover] = indata[i*stride];
+		outdata[i*stride] = gOutFIFO[gRover-inFifoLatency];
+		gRover++;
+
+		/* now we have enough data for processing */
+		if (gRover >= fftFrameSize) {
+			gRover = inFifoLatency;
+
+			/* do windowing and re,im interleave */
+			for (k = 0; k < fftFrameSize;k++) {
+				window = -.5*cos(2.*M_PI*(double)k/(double)fftFrameSize)+.5;
+				gFFTworksp[2*k] = gInFIFO[k] * window;
+				gFFTworksp[2*k+1] = 0.;
+			}
+
+
+			/* ***************** ANALYSIS ******************* */
+			/* do transform */
+			smbFft(gFFTworksp, fftFrameSize, -1);
+
+			/* this is the analysis step */
+			for (k = 0; k <= fftFrameSize2; k++) {
+
+				/* de-interlace FFT buffer */
+				real = gFFTworksp[2*k];
+				imag = gFFTworksp[2*k+1];
+
+				/* compute magnitude and phase */
+				magn = 2.*sqrt(real*real + imag*imag);
+				phase = atan2(imag,real);
+
+				/* compute phase difference */
+				tmp = phase - gLastPhase[k];
+				gLastPhase[k] = phase;
+
+				/* subtract expected phase difference */
+				tmp -= (double)k*expct;
+
+				/* map delta phase into +/- Pi interval */
+				qpd = tmp/M_PI;
+				if (qpd >= 0) qpd += qpd&1;
+				else qpd -= qpd&1;
+				tmp -= M_PI*(double)qpd;
+
+				/* get deviation from bin frequency from the +/- Pi interval */
+				tmp = osamp*tmp/(2.*M_PI);
+
+				/* compute the k-th partials' true frequency */
+				tmp = (double)k*freqPerBin + tmp*freqPerBin;
+
+				/* store magnitude and true frequency in analysis arrays */
+				gAnaMagn[k] = magn;
+				gAnaFreq[k] = tmp;
+
+			}
+
+			/* ***************** PROCESSING ******************* */
+			/* this does the actual pitch shifting */
+			memset(gSynMagn, 0, fftFrameSize*sizeof(float));
+			memset(gSynFreq, 0, fftFrameSize*sizeof(float));
+			for (k = 0; k <= fftFrameSize2; k++) {
+				index = k*pitchShift;
+				if (index <= fftFrameSize2) {
+					gSynMagn[index] += gAnaMagn[k];
+					gSynFreq[index] = gAnaFreq[k] * pitchShift;
+				}
+			}
+
+			/* ***************** SYNTHESIS ******************* */
+			/* this is the synthesis step */
+			for (k = 0; k <= fftFrameSize2; k++) {
+
+				/* get magnitude and true frequency from synthesis arrays */
+				magn = gSynMagn[k];
+				tmp = gSynFreq[k];
+
+				/* subtract bin mid frequency */
+				tmp -= (double)k*freqPerBin;
+
+				/* get bin deviation from freq deviation */
+				tmp /= freqPerBin;
+
+				/* take osamp into account */
+				tmp = 2.*M_PI*tmp/osamp;
+
+				/* add the overlap phase advance back in */
+				tmp += (double)k*expct;
+
+				/* accumulate delta phase to get bin phase */
+				gSumPhase[k] += tmp;
+				phase = gSumPhase[k];
+
+				/* get real and imag part and re-interleave */
+				gFFTworksp[2*k] = magn*cos(phase);
+				gFFTworksp[2*k+1] = magn*sin(phase);
+			}
+
+			/* zero negative frequencies */
+			for (k = fftFrameSize+2; k < 2*fftFrameSize; k++) gFFTworksp[k] = 0.;
+
+			/* do inverse transform */
+			smbFft(gFFTworksp, fftFrameSize, 1);
+
+			/* do windowing and add to output accumulator */
+			for(k=0; k < fftFrameSize; k++) {
+				window = -.5*cos(2.*M_PI*(double)k/(double)fftFrameSize)+.5;
+				gOutputAccum[k] += 2.*window*gFFTworksp[2*k]/(fftFrameSize2*osamp);
+			}
+			for (k = 0; k < stepSize; k++) gOutFIFO[k] = gOutputAccum[k];
+
+			/* shift accumulator */
+			memmove(gOutputAccum, gOutputAccum+stepSize, fftFrameSize*sizeof(float));
+
+			/* move input FIFO */
+			for (k = 0; k < inFifoLatency; k++) gInFIFO[k] = gInFIFO[k+stepSize];
+		}
+	}
+
+
+
+}
+
+
+void SMBPitchShift::smbFft(float *fftBuffer, long fftFrameSize, long sign)
+/*
+	FFT routine, (C)1996 S.M.Bernsee. Sign = -1 is FFT, 1 is iFFT (inverse)
+	Fills fftBuffer[0...2*fftFrameSize-1] with the Fourier transform of the
+	time domain data in fftBuffer[0...2*fftFrameSize-1]. The FFT array takes
+	and returns the cosine and sine parts in an interleaved manner, ie.
+	fftBuffer[0] = cosPart[0], fftBuffer[1] = sinPart[0], asf. fftFrameSize
+	must be a power of 2. It expects a complex input signal (see footnote 2),
+	ie. when working with 'common' audio signals our input signal has to be
+	passed as {in[0],0.,in[1],0.,in[2],0.,...} asf. In that case, the transform
+	of the frequencies of interest is in fftBuffer[0...fftFrameSize].
+*/
+{
+	float wr, wi, arg, *p1, *p2, temp;
+	float tr, ti, ur, ui, *p1r, *p1i, *p2r, *p2i;
+	long i, bitm, j, le, le2, k;
+
+	for (i = 2; i < 2*fftFrameSize-2; i += 2) {
+		for (bitm = 2, j = 0; bitm < 2*fftFrameSize; bitm <<= 1) {
+			if (i & bitm) j++;
+			j <<= 1;
+		}
+		if (i < j) {
+			p1 = fftBuffer+i; p2 = fftBuffer+j;
+			temp = *p1; *(p1++) = *p2;
+			*(p2++) = temp; temp = *p1;
+			*p1 = *p2; *p2 = temp;
+		}
+	}
+	for (k = 0, le = 2; k < (long)(log(fftFrameSize)/log(2.)+.5); k++) {
+		le <<= 1;
+		le2 = le>>1;
+		ur = 1.0;
+		ui = 0.0;
+		arg = M_PI / (le2>>1);
+		wr = cos(arg);
+		wi = sign*sin(arg);
+		for (j = 0; j < le2; j += 2) {
+			p1r = fftBuffer+j; p1i = p1r+1;
+			p2r = p1r+le2; p2i = p2r+1;
+			for (i = j; i < 2*fftFrameSize; i += le) {
+				tr = *p2r * ur - *p2i * ui;
+				ti = *p2r * ui + *p2i * ur;
+				*p2r = *p1r - tr; *p2i = *p1i - ti;
+				*p1r += tr; *p1i += ti;
+				p1r += le; p1i += le;
+				p2r += le; p2i += le;
+			}
+			tr = ur*wr - ui*wi;
+			ui = ur*wi + ui*wr;
+			ur = tr;
+		}
+	}
+}
+
+
+void AudioEffectPitchShiftInstance::process(const AudioFrame *p_src_frames,AudioFrame *p_dst_frames,int p_frame_count) {
+
+	float sample_rate = AudioServer::get_singleton()->get_mix_rate();
+
+	float *in_l = (float*)p_src_frames;
+	float *in_r = in_l + 1;
+
+	float *out_l = (float*)p_dst_frames;
+	float *out_r = out_l + 1;
+
+	shift_l.PitchShift(base->pitch_scale,p_frame_count,2048,4,sample_rate,in_l,out_l,2);
+	shift_r.PitchShift(base->pitch_scale,p_frame_count,2048,4,sample_rate,in_r,out_r,2);
+
+}
+
+
+Ref<AudioEffectInstance> AudioEffectPitchShift::instance() {
+	Ref<AudioEffectPitchShiftInstance> ins;
+	ins.instance();
+	ins->base=Ref<AudioEffectPitchShift>(this);
+
+
+	return ins;
+}
+
+void AudioEffectPitchShift::set_pitch_scale(float p_adjust) {
+
+	pitch_scale=p_adjust;
+}
+
+float AudioEffectPitchShift::get_pitch_scale() const {
+
+	return pitch_scale;
+}
+
+
+void AudioEffectPitchShift::_bind_methods() {
+
+	ClassDB::bind_method(_MD("set_pitch_scale","rate"),&AudioEffectPitchShift::set_pitch_scale);
+	ClassDB::bind_method(_MD("get_pitch_scale"),&AudioEffectPitchShift::get_pitch_scale);
+
+	ADD_PROPERTY(PropertyInfo(Variant::REAL,"pitch_scale",PROPERTY_HINT_RANGE,"0.01,16,0.01"),_SCS("set_pitch_scale"),_SCS("get_pitch_scale"));
+
+}
+
+AudioEffectPitchShift::AudioEffectPitchShift() {
+	pitch_scale=1.0;
+
+}

servers/audio/effects/audio_effect_pitch_shift.h

@@ -0,0 +1,89 @@
+#ifndef AUDIO_EFFECT_PITCH_SHIFT_H
+#define AUDIO_EFFECT_PITCH_SHIFT_H
+
+
+#include "servers/audio/audio_effect.h"
+
+class SMBPitchShift {
+
+	enum {
+		MAX_FRAME_LENGTH=8192
+	};
+
+	float gInFIFO[MAX_FRAME_LENGTH];
+	float gOutFIFO[MAX_FRAME_LENGTH];
+	float gFFTworksp[2*MAX_FRAME_LENGTH];
+	float gLastPhase[MAX_FRAME_LENGTH/2+1];
+	float gSumPhase[MAX_FRAME_LENGTH/2+1];
+	float gOutputAccum[2*MAX_FRAME_LENGTH];
+	float gAnaFreq[MAX_FRAME_LENGTH];
+	float gAnaMagn[MAX_FRAME_LENGTH];
+	float gSynFreq[MAX_FRAME_LENGTH];
+	float gSynMagn[MAX_FRAME_LENGTH];
+	long gRover;
+
+	void smbFft(float *fftBuffer, long fftFrameSize, long sign);
+public:
+	void PitchShift(float pitchShift, long numSampsToProcess, long fftFrameSize, long osamp, float sampleRate, float *indata, float *outdata, int stride);
+
+	SMBPitchShift() {
+		gRover=0;
+		memset(gInFIFO, 0, MAX_FRAME_LENGTH*sizeof(float));
+		memset(gOutFIFO, 0, MAX_FRAME_LENGTH*sizeof(float));
+		memset(gFFTworksp, 0, 2*MAX_FRAME_LENGTH*sizeof(float));
+		memset(gLastPhase, 0, (MAX_FRAME_LENGTH/2+1)*sizeof(float));
+		memset(gSumPhase, 0, (MAX_FRAME_LENGTH/2+1)*sizeof(float));
+		memset(gOutputAccum, 0, 2*MAX_FRAME_LENGTH*sizeof(float));
+		memset(gAnaFreq, 0, MAX_FRAME_LENGTH*sizeof(float));
+		memset(gAnaMagn, 0, MAX_FRAME_LENGTH*sizeof(float));
+	}
+
+
+};
+
+
+class AudioEffectPitchShift;
+
+class AudioEffectPitchShiftInstance : public AudioEffectInstance {
+	GDCLASS(AudioEffectPitchShiftInstance,AudioEffectInstance)
+friend class AudioEffectPitchShift;
+	Ref<AudioEffectPitchShift> base;
+
+	SMBPitchShift shift_l;
+	SMBPitchShift shift_r;
+
+
+public:
+
+	virtual void process(const AudioFrame *p_src_frames,AudioFrame *p_dst_frames,int p_frame_count);
+
+};
+
+
+class AudioEffectPitchShift : public AudioEffect {
+	GDCLASS(AudioEffectPitchShift,AudioEffect)
+
+friend class AudioEffectPitchShiftInstance;
+
+	float pitch_scale;
+	int window_size;
+	float wet;
+	float dry;
+	bool filter;
+
+protected:
+
+	static void _bind_methods();
+public:
+
+
+	Ref<AudioEffectInstance> instance();
+
+	void set_pitch_scale(float p_adjust);
+	float get_pitch_scale() const;
+
+	AudioEffectPitchShift();
+};
+
+
+#endif // AUDIO_EFFECT_PITCH_SHIFT_H

servers/register_server_types.cpp

@@ -48,6 +48,7 @@
 #include "audio/effects/audio_effect_delay.h"
 #include "audio/effects/audio_effect_compressor.h"
 #include "audio/effects/audio_effect_limiter.h"
+#include "audio/effects/audio_effect_pitch_shift.h"
 
 static void _debugger_get_resource_usage(List<ScriptDebuggerRemote::ResourceUsage>* r_usage) {
 
@@ -111,6 +112,7 @@ void register_server_types() {
 		ClassDB::register_class<AudioEffectDelay>();
 		ClassDB::register_class<AudioEffectCompressor>();
 		ClassDB::register_class<AudioEffectLimiter>();
+		ClassDB::register_class<AudioEffectPitchShift>();
 	}