From 2efdfbb5cc8b9c76dec861fea8396a8f011df1c2 Mon Sep 17 00:00:00 2001
From: Johnathan Corgan
Date: Mon, 18 Jul 2011 16:39:20 -0700
Subject: gr-vocoder: removed gr-codec2-vocoder

---
 gr-codec2-vocoder/src/lib/codec2/phase.c | 262 -------------------------------
 1 file changed, 262 deletions(-)
 delete mode 100644 gr-codec2-vocoder/src/lib/codec2/phase.c

(limited to 'gr-codec2-vocoder/src/lib/codec2/phase.c')

diff --git a/gr-codec2-vocoder/src/lib/codec2/phase.c b/gr-codec2-vocoder/src/lib/codec2/phase.c
deleted file mode 100644
index 0e1a14a60..000000000
--- a/gr-codec2-vocoder/src/lib/codec2/phase.c
+++ /dev/null
@@ -1,262 +0,0 @@
-/*---------------------------------------------------------------------------*\
-                                                                             
-  FILE........: phase.c                                           
-  AUTHOR......: David Rowe                                             
-  DATE CREATED: 1/2/09                                                 
-                                                                             
-  Functions for modelling and synthesising phase.
-                                                                             
-\*---------------------------------------------------------------------------*/
-
-/*
-  Copyright (C) 2009 David Rowe
-
-  All rights reserved.
-
-  This program is free software; you can redistribute it and/or modify
-  it under the terms of the GNU Lesser General Public License version 2.1, as
-  published by the Free Software Foundation.  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 Lesser General Public License
-  along with this program; if not,see <http://www.gnu.org/licenses/>. 
-*/
-
-#include "defines.h"
-#include "phase.h"
-#include "fft.h"
-#include "comp.h"
-#include "glottal.c"
-
-#include <assert.h>
-#include <math.h>
-#include <string.h>
-#include <stdlib.h>
-
-#define GLOTTAL_FFT_SIZE 512
-
-/*---------------------------------------------------------------------------*\
-
-  aks_to_H()
-
-  Samples the complex LPC synthesis filter spectrum at the harmonic
-  frequencies.
-
-\*---------------------------------------------------------------------------*/
-
-void aks_to_H(
-	      MODEL *model,	/* model parameters */
-	      float  aks[],	/* LPC's */
-	      float  G,	        /* energy term */
-	      COMP   H[],	/* complex LPC spectral samples */
-	      int    order
-)
-{
-  COMP  Pw[FFT_DEC];	/* power spectrum */
-  int   i,m;		/* loop variables */
-  int   am,bm;		/* limits of current band */
-  float r;		/* no. rads/bin */
-  float Em;		/* energy in band */
-  float Am;		/* spectral amplitude sample */
-  int   b;		/* centre bin of harmonic */
-  float phi_;		/* phase of LPC spectra */
-
-  r = TWO_PI/(FFT_DEC);
-
-  /* Determine DFT of A(exp(jw)) ------------------------------------------*/
-
-  for(i=0; i<FFT_DEC; i++) {
-    Pw[i].real = 0.0;
-    Pw[i].imag = 0.0;
-  }
-
-  for(i=0; i<=order; i++)
-    Pw[i].real = aks[i];
-
-  fft(&Pw[0].real,FFT_DEC,-1);
-
-  /* Sample magnitude and phase at harmonics */
-
-  for(m=1; m<=model->L; m++) {
-    am = floor((m - 0.5)*model->Wo/r + 0.5);
-    bm = floor((m + 0.5)*model->Wo/r + 0.5);
-    b = floor(m*model->Wo/r + 0.5);
-
-    Em = 0.0;
-    for(i=am; i<bm; i++)
-      Em += G/(Pw[i].real*Pw[i].real + Pw[i].imag*Pw[i].imag);
-    Am = sqrt(fabs(Em/(bm-am)));
-
-    phi_ = -atan2(Pw[b].imag,Pw[b].real);
-    H[m].real = Am*cos(phi_);
-    H[m].imag = Am*sin(phi_);
-  }
-}
-
-
-/*---------------------------------------------------------------------------*\
-
-   phase_synth_zero_order()
-
-   Synthesises phases based on SNR and a rule based approach.  No phase 
-   parameters are required apart from the SNR (which can be reduced to a
-   1 bit V/UV decision per frame).
-
-   The phase of each harmonic is modelled as the phase of a LPC
-   synthesis filter excited by an impulse.  Unlike the first order
-   model the position of the impulse is not transmitted, so we create
-   an excitation pulse train using a rule based approach.  
-
-   Consider a pulse train with a pulse starting time n=0, with pulses
-   repeated at a rate of Wo, the fundamental frequency.  A pulse train
-   in the time domain is equivalent to harmonics in the frequency
-   domain.  We can make an excitation pulse train using a sum of
-   sinsusoids:
-
-     for(m=1; m<=L; m++)
-       ex[n] = cos(m*Wo*n)
-
-   Note: the Octave script ../octave/phase.m is an example of this if
-   you would like to try making a pulse train.
-
-   The phase of each excitation harmonic is:
-
-     arg(E[m]) = mWo
-
-   where E[m] are the complex excitation (freq domain) samples,
-   arg(x), just returns the phase of a complex sample x.
-
-   As we don't transmit the pulse position for this model, we need to
-   synthesise it.  Now the excitation pulses occur at a rate of Wo.
-   This means the phase of the first harmonic advances by N samples
-   over a synthesis frame of N samples.  For example if Wo is pi/20
-   (200 Hz), then over a 10ms frame (N=80 samples), the phase of the
-   first harmonic would advance (pi/20)*80 = 4*pi or two complete
-   cycles.
-
-   We generate the excitation phase of the fundamental (first
-   harmonic):
-
-     arg[E[1]] = Wo*N;
-
-   We then relate the phase of the m-th excitation harmonic to the
-   phase of the fundamental as:
-
-     arg(E[m]) = m*arg(E[1])
-
-   This E[m] then gets passed through the LPC synthesis filter to
-   determine the final harmonic phase.
-     
-   Comparing to speech synthesised using original phases:
-
-   - Through headphones speech synthesised with this model is not as 
-     good. Through a loudspeaker it is very close to original phases.
-
-   - If there are voicing errors, the speech can sound clicky or
-     staticy.  If V speech is mistakenly declared UV, this model tends to
-     synthesise impulses or clicks, as there is usually very little shift or
-     dispersion through the LPC filter.
-
-   - When combined with LPC amplitude modelling there is an additional
-     drop in quality.  I am not sure why, theory is interformant energy
-     is raised making any phase errors more obvious.
-
-   NOTES:
-
-     1/ This synthesis model is effectively the same as a simple LPC-10
-     vocoders, and yet sounds much better.  Why? Conventional wisdom
-     (AMBE, MELP) says mixed voicing is required for high quality
-     speech.
-
-     2/ I am pretty sure the Lincoln Lab sinusoidal coding guys (like xMBE
-     also from MIT) first described this zero phase model, I need to look
-     up the paper.
-
-     3/ Note that this approach could cause some discontinuities in
-     the phase at the edge of synthesis frames, as no attempt is made
-     to make sure that the phase tracks are continuous (the excitation
-     phases are continuous, but not the final phases after filtering
-     by the LPC spectra).  Technically this is a bad thing.  However
-     this may actually be a good thing, disturbing the phase tracks a
-     bit.  More research needed, e.g. test a synthesis model that adds
-     a small delta-W to make phase tracks line up for voiced
-     harmonics.
-
-\*---------------------------------------------------------------------------*/
-
-void phase_synth_zero_order(
-    MODEL *model,
-    float  aks[],
-    float *ex_phase,            /* excitation phase of fundamental */
-    int    order
-)
-{
-  int   m;
-  float new_phi;
-  COMP  Ex[MAX_AMP];		/* excitation samples */
-  COMP  A_[MAX_AMP];		/* synthesised harmonic samples */
-  COMP  H[MAX_AMP];             /* LPC freq domain samples */
-  float G;
-  float jitter = 0.0;
-  float r;
-  int   b;
-
-  G = 1.0;
-  aks_to_H(model, aks, G, H, order);
-
-  /* 
-     Update excitation fundamental phase track, this sets the position
-     of each pitch pulse during voiced speech.  After much experiment
-     I found that using just this frame's Wo improved quality for UV
-     sounds compared to interpolating two frames Wo like this:
-     
-     ex_phase[0] += (*prev_Wo+mode->Wo)*N/2;
-  */
-  
-  ex_phase[0] += (model->Wo)*N;
-  ex_phase[0] -= TWO_PI*floor(ex_phase[0]/TWO_PI + 0.5);
-  r = TWO_PI/GLOTTAL_FFT_SIZE;
-
-  for(m=1; m<=model->L; m++) {
-	  
-      /* generate excitation */
-
-      if (model->voiced) {
-	  /* I think adding a little jitter helps improve low pitch
-	     males like hts1a. This moves the onset of each harmonic
-	     over at +/- 0.25 of a sample.
-	  */
-	  jitter = 0.25*(1.0 - 2.0*rand()/RAND_MAX);
-	  b = floor(m*model->Wo/r + 0.5);
-	  if (b > ((GLOTTAL_FFT_SIZE/2)-1)) {
-	      b = (GLOTTAL_FFT_SIZE/2)-1;
-	  }
-	  Ex[m].real = cos(ex_phase[0]*m - jitter*model->Wo*m + glottal[b]);
-	  Ex[m].imag = sin(ex_phase[0]*m - jitter*model->Wo*m + glottal[b]);
-      }
-      else {
-
-	  /* When a few samples were tested I found that LPC filter
-	     phase is not needed in the unvoiced case, but no harm in
-	     keeping it.
-	  */
-	  float phi = TWO_PI*(float)rand()/RAND_MAX;
-	  Ex[m].real = cos(phi);
-	  Ex[m].imag = sin(phi);
-      }
-
-      /* filter using LPC filter */
-
-      A_[m].real = H[m].real*Ex[m].real - H[m].imag*Ex[m].imag;
-      A_[m].imag = H[m].imag*Ex[m].real + H[m].real*Ex[m].imag;
-
-      /* modify sinusoidal phase */
-   
-      new_phi = atan2(A_[m].imag, A_[m].real+1E-12);
-      model->phi[m] = new_phi;
-  }
-
-}
-- 
cgit