/*
* Copyright (C) 2009, 2010 Hermann Meyer, James Warden, Andreas Degert
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
* --------------------------------------------------------------------------
*/
/* ------- This is the guitarix tuner, part of gx_engine_audio.cpp ------- */
#include <cstring>
#include <jack/jack.h>
#include "guitarix.h"
/****************************************************************
** Pitch Tracker
**
** some code and ideas taken from K4Guitune (William Spinelli)
**
*/
namespace gx_engine {
const int DOWNSAMPLE = 16; // downsampling factor
const int ZERO_PADDING_FACTOR = 64; // Number of times that the FFT is zero-padded to increase frequency resolution.
const float SIGNAL_THRESHOLD_ON = 0.001; // Value of the threshold above which the processing is activated.
const float SIGNAL_THRESHOLD_OFF = 0.0009; // Value of the threshold below which the input audio signal is deactivated.
const float TRACKER_PERIOD = 0.1; // Time between frequency estimates (in seconds)
void *PitchTracker::static_run(void *p)
{
((PitchTracker *)p)->run();
return NULL;
}
PitchTracker::PitchTracker():
error(false),
busy(false),
tick(0),
m_pthr(0),
m_buffer(new float[MAX_FFT_SIZE]),
m_bufferIndex(0),
m_audioLevel(false),
m_fftwPlanFFT(0),
m_fftwPlanIFFT(0)
{
const int fftw_buffer_size = MAX_FFT_SIZE * ZERO_PADDING_FACTOR;
m_fftwBufferTime = (float*)fftwf_malloc(fftw_buffer_size * sizeof(float));
m_fftwBufferFreq = (fftwf_complex*)fftwf_malloc(fftw_buffer_size * sizeof(fftwf_complex));
memset(m_buffer, 0, MAX_FFT_SIZE * sizeof(float));
memset(m_fftwBufferTime, 0, fftw_buffer_size * sizeof(float));
memset(m_fftwBufferFreq, 0, fftw_buffer_size * sizeof(fftwf_complex));
sem_init(&m_trig, 0, 0);
if (!m_buffer || !m_fftwBufferTime || !m_fftwBufferFreq) {
error = true;
}
}
PitchTracker::~PitchTracker()
{
fftwf_destroy_plan(m_fftwPlanFFT);
fftwf_destroy_plan(m_fftwPlanIFFT);
fftwf_free(m_fftwBufferTime);
fftwf_free(m_fftwBufferFreq);
delete[] m_buffer;
}
bool PitchTracker::setParameters(int sampleRate, int fftSize)
{
assert(fftSize <= MAX_FFT_SIZE);
if (error) {
return false;
}
m_sampleRate = sampleRate / DOWNSAMPLE;
resamp.setup(sampleRate, m_sampleRate, 1, 16); // 16 == least quality
if (m_fftSize != fftSize) {
m_fftSize = fftSize;
fftwf_destroy_plan(m_fftwPlanFFT);
fftwf_destroy_plan(m_fftwPlanIFFT);
m_fftwPlanFFT = fftwf_plan_dft_r2c_1d(
m_fftSize, m_fftwBufferTime, m_fftwBufferFreq, FFTW_ESTIMATE); // FFT
m_fftwPlanIFFT = fftwf_plan_dft_c2r_1d(
ZERO_PADDING_FACTOR * m_fftSize, m_fftwBufferFreq, m_fftwBufferTime, FFTW_ESTIMATE); // IFFT zero-padded
}
if (!m_fftwPlanFFT || !m_fftwPlanIFFT) {
error = true;
return false;
}
if (!m_pthr) {
start_thread();
}
pt_initialized = true;
return !error;
}
void PitchTracker::start_thread()
{
int min, max;
pthread_attr_t attr;
struct sched_param spar;
int priority, policy;
pthread_getschedparam(jack_client_thread_id(gx_jack::client), &policy, &spar);
priority = spar.sched_priority;
min = sched_get_priority_min(policy);
max = sched_get_priority_max(policy);
priority -= 6; // zita-convoler uses 5 levels
if (priority > max) priority = max;
if (priority < min) priority = min;
spar.sched_priority = priority;
pthread_attr_init (&attr);
pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
pthread_attr_setschedpolicy (&attr, policy);
pthread_attr_setschedparam (&attr, &spar);
pthread_attr_setscope (&attr, PTHREAD_SCOPE_SYSTEM);
pthread_attr_setinheritsched (&attr, PTHREAD_EXPLICIT_SCHED);
//pthread_attr_setstacksize (&attr, 0x10000);
if (pthread_create (&m_pthr, &attr, static_run, (void*)this)) {
error = true;
}
pthread_attr_destroy (&attr);
}
int PitchTracker::find_minimum()
{
const int peakwidth = 3;
float *p = &m_fftwBufferTime[peakwidth];
for ( ; p < &m_fftwBufferTime[ZERO_PADDING_FACTOR * m_fftSize / 2 + 1 - peakwidth]; p++) {
int i;
for (i = -peakwidth; i <= peakwidth; i++) {
if (*p > p[i]) {
break;
}
}
if (i > peakwidth) {
break;
}
}
return (int)(p - m_fftwBufferTime);
}
int PitchTracker::find_maximum(int l)
{
float maxAutocorr = 0.0;
int maxAutocorrIndex = 0;
while ( l < ZERO_PADDING_FACTOR * m_fftSize / 2 + 1) {
if (m_fftwBufferTime[l] > maxAutocorr) {
maxAutocorr = m_fftwBufferTime[l];
maxAutocorrIndex = l;
}
++l;
}
if (maxAutocorr == 0.0) {
return -1;
}
return maxAutocorrIndex;
}
float show_level(int n, float *buf)
{
float sum = 0.0;
for (int k = 0; k < n; ++k) {
sum += fabs(buf[k]);
}
return sum;
}
void PitchTracker::add(int count, float* input)
{
if (error) {
return;
}
resamp.inp_count = count;
resamp.inp_data = input;
for (;;) {
resamp.out_data = &m_buffer[m_bufferIndex];
int n = MAX_FFT_SIZE - m_bufferIndex;
resamp.out_count = n;
resamp.process();
n -= resamp.out_count; // n := number of output samples
if (!n) { // all soaked up by filter
return;
}
m_bufferIndex = (m_bufferIndex + n) % MAX_FFT_SIZE;
if (resamp.inp_count == 0) {
break;
}
}
if (++tick * count >= m_sampleRate * DOWNSAMPLE * TRACKER_PERIOD) {
if (busy) {
return;
}
tick = 0;
copy();
sem_post(&m_trig);
}
}
void PitchTracker::copy()
{
int start = (MAX_FFT_SIZE + m_bufferIndex - m_fftSize) % MAX_FFT_SIZE;
int end = (MAX_FFT_SIZE + m_bufferIndex) % MAX_FFT_SIZE;
int cnt = 0;
if (start >= end) {
cnt = MAX_FFT_SIZE - start;
memcpy(m_fftwBufferTime, &m_buffer[start], cnt * sizeof(float));
start = 0;
}
memcpy(&m_fftwBufferTime[cnt], &m_buffer[start], (end - start) * sizeof(float));
}
void PitchTracker::run()
{
for (;;) {
busy = false;
sem_wait(&m_trig);
busy = true;
if (error) {
continue;
}
float sum = 0.0;
for (int k = 0; k < m_fftSize; ++k) {
sum += fabs(m_fftwBufferTime[k]);
}
float threshold = (m_audioLevel ? SIGNAL_THRESHOLD_OFF : SIGNAL_THRESHOLD_ON);
m_audioLevel = (sum / m_fftSize >= threshold);
if ( m_audioLevel == false ) {
setEstimatedFrequency(0.0);
continue;
}
/* Compute the transform of the autocorrelation given in time domain by
* k=-N
* r[t] = sum( x[k] * x[t-k] )
* N
* or in the frequency domain (for a real signal) by
* R[f] = X[f] * X[f]' = |X[f]|^2 = Re(X[f])^2 + Im(X[f])^2
* When computing the FFT with fftwf_plan_dft_r2c_1d there are only N/2+1
* significant samples, so |.|^2 is computed for m_fftSize/2+1 samples only
*/
int fftRSize = m_fftSize/2 + 1;
fftwf_execute(m_fftwPlanFFT);
for (int k = 0; k < fftRSize; ++k) {
fftwf_complex& v = m_fftwBufferFreq[k];
v[0] = v[0]*v[0] + v[1]*v[1];
v[1] = 0.0;
}
// pad the FFT with zeros to increase resolution in time domain after IFFT
int size_with_padding = ZERO_PADDING_FACTOR * m_fftSize - fftRSize;
memset(&m_fftwBufferFreq[fftRSize][0], 0, size_with_padding * sizeof(fftwf_complex));
fftwf_execute(m_fftwPlanIFFT);
// search for a minimum and then for the next maximum to get the estimated frequency
int maxAutocorrIndex = find_maximum(find_minimum());
// compute the frequency of the maximum considering the padding factor
if (maxAutocorrIndex >= 0) {
setEstimatedFrequency(ZERO_PADDING_FACTOR * m_sampleRate / (float)maxAutocorrIndex);
} else {
setEstimatedFrequency(0.0);
}
busy = false;
}
}
void PitchTracker::setEstimatedFrequency(float freq)
{
midi.fConsta4 = freq;
audio.fConsta1t = (freq == 0.0 ? 1000.0 : 12 * log2f(2.272727e-03f * freq));
}
PitchTracker pitch_tracker;
}