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spectrogram.cc
/*************************************************************************/
/* */
/* Centre for Speech Technology Research */
/* University of Edinburgh, UK */
/* Copyright (c) 1994,1995,1996 */
/* All Rights Reserved. */
/* */
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/* the following conditions: */
/* 1. The code must retain the above copyright notice, this list of */
/* conditions and the following disclaimer. */
/* 2. Any modifications must be clearly marked as such. */
/* 3. Original authors' names are not deleted. */
/* 4. The authors' names are not used to endorse or promote products */
/* derived from this software without specific prior written */
/* permission. */
/* */
/* THE UNIVERSITY OF EDINBURGH AND THE CONTRIBUTORS TO THIS WORK */
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/* ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT */
/* SHALL THE UNIVERSITY OF EDINBURGH NOR THE CONTRIBUTORS BE LIABLE */
/* FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES */
/* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN */
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/* THIS SOFTWARE. */
/* */
/*************************************************************************/
/* Author : Paul Taylor */
/* Date : December 96 */
/*-----------------------------------------------------------------------*/
/* Spectrogram Generation */
/* */
/*=======================================================================*/
#include <cmath>
#include <climits>
#include <cfloat> /* needed for FLT_MAX */
#include "EST_error.h"
#include "EST_Track.h"
#include "EST_Wave.h"
#include "sigpr/EST_Window.h"
#include "EST_Option.h"
#include "sigpr/EST_fft.h"
#include "sigpr/EST_spectrogram.h"
#include "sigpr/EST_misc_sigpr.h"
void make_spectrogram(EST_Wave &sig, EST_Track &sp, EST_Features &op)
{
EST_Wave psig;
EST_pre_emphasis(sig, psig, op.F("preemph"));
// calculate raw spectrogram
raw_spectrogram(sp, psig, op.F("frame_length"), op.F("frame_shift"),
op.I("frame_order"), op.present("slow_fft"));
if (op.present("raw"))
{
cout << "no scaling\n";
return;
}
// coerce the values so as to emphasis important features
if (op.present("sp_range") || op.present("sp_wcut") || op.present("sp_bcut"))
{
if (!op.present("sp_range"))
op.set("sp_range", 1.0);
if (!op.present("sp_wcut"))
op.set("sp_wcut", 1.0);
if (!op.present("sp_bcut"))
op.set("sp_bcut", 0.0);
scale_spectrogram(sp, op.F("sp_range"),op.F("sp_wcut"),op.F("sp_bcut"));
}
}
void scale_spectrogram(EST_Track &sp, float range, float wcut, float bcut)
{
float max, min, scale, v;
int i, j;
max = -FLT_MIN;
min = FLT_MAX;
// find min and max values
for (i = 0; i < sp.num_frames(); ++i)
for (j = 0; j < sp.num_channels(); ++j)
{
float vv = sp.a_no_check(i, j);
if (vv > max)
max = vv;
if (vv < min)
min = vv;
}
scale = (max - min);
// for every value:
// 1. Effectively scale in range 0 to 1
// 2. Impose white and black cut offs
// 3. Rescale to 0 and 1
// 4. scale to fit in "range"
// this can obviously be done more efficiently
float mag = (float)range / (float)(bcut - wcut);
for (i = 0; i < sp.num_frames(); ++i)
for (j = 0; j < sp.num_channels(); ++j)
{
v = (((sp.a_no_check(i, j) - min) / scale) - wcut) * mag;
if (v > range) v = range;
if (v < 0.0) v = 0.0;
sp.a_no_check(i, j) = v;
}
}
void raw_spectrogram(EST_Track &sp, EST_Wave &sig,
float length,
float shift,
int order,
bool slow)
{
int frame_length = (int) (length * (float) sig.sample_rate() +0.5);
int frame_shift = (int) (shift * (float) sig.sample_rate() +0.5);
EST_WindowFunc *make_window = EST_Window::creator("hamming");
// sanity check, we can't analyse more signal than order allows.
if (frame_length > order)
{
EST_warning("frame_length reduced to %f (%d samples) to fit order\n",
(float)order/(float) sig.sample_rate(), order);
frame_length=order;
}
// enough frames to cover the entire signal
int num_frames= (int)ceil(sig.num_samples()/(float)frame_shift);
// spectrogram gets order/2 powers, the moduli of order/2
// complex numbers
sp.resize(num_frames, order/2, FALSE);
EST_FVector real(order);
EST_FVector imag(order);
// create the window shape
EST_TBuffer<float> window_vals(frame_length);
make_window(frame_length, window_vals,-1);
for (int k = 0 ; k < num_frames ; k++)
{
int pos = frame_shift * k;
int window_start = pos - frame_length/2;
real.empty();
// imag not used in old FFT code
if (slow)
imag.empty();
EST_Window::window_signal(sig,
window_vals,
window_start,
frame_length,
real, FALSE);
int state = slow?power_spectrum_slow(real, imag):power_spectrum(real, imag);
if (state != 0)
{
fprintf(stderr, "FFT Failed for frame %d\n", k);
for (int i = 0; i < order /2; ++i)
sp.a_no_check(k, i) = 0;
}
else
sp.copy_frame_in(k, real);
}
sp.fill_time(shift);
}
EST_FVector
Definition EST_FMatrix.h:114
EST_Features
Definition EST_Features.h:62
EST_Features::set
void set(const EST_String &name, int ival)
Definition EST_Features.h:185
EST_Features::F
const float F(const EST_String &path) const
Definition EST_Features.h:135
EST_Features::present
int present(const EST_String &name) const
Definition EST_Features.cc:147
EST_Features::I
const int I(const EST_String &path) const
Definition EST_Features.h:146
EST_TBuffer
Definition EST_TBuffer.h:86
EST_Track
Definition EST_Track.h:89
EST_Track::copy_frame_in
void copy_frame_in(int n, const float *buf, int offset=0, int num=EST_ALL)
Definition EST_Track.h:345
EST_Track::num_channels
int num_channels() const
return number of channels in track
Definition EST_Track.h:656
EST_Track::num_frames
int num_frames() const
return number of frames in track
Definition EST_Track.h:650
EST_Track::a_no_check
float & a_no_check(int i, int c=0)
Definition EST_Track.h:419
EST_Track::resize
void resize(int num_frames, int num_channels, bool preserve=1)
Definition EST_Track.cc:211
EST_Track::fill_time
void fill_time(float t, int start=1)
Definition EST_Track.cc:786
EST_Wave
Definition EST_Wave.h:65
EST_Wave::sample_rate
int sample_rate() const
return the sampling rate (frequency)
Definition EST_Wave.h:147
EST_Wave::num_samples
int num_samples() const
return the number of samples in the waveform
Definition EST_Wave.h:143
EST_Window::window_signal
static void window_signal(const EST_Wave &sig, EST_WindowFunc *make_window, int start, int size, EST_TBuffer< float > &frame)
Definition EST_Window.cc:275
EST_Window::creator
static Func * creator(const char *name, bool report_error=false)
Return the creation function for the given window type.
Definition EST_Window.cc:216