ref: dff7d36a88df376a035b922dd6fb7648d5d24f4f
parent: 991c0f0254426e67f2f7938876001acca31cb5dd
author: Jean-Marc Valin <[email protected]>
date: Fri Nov 30 11:57:43 EST 2007
Some pitch prediction work.
--- a/libcelt/bands.c
+++ b/libcelt/bands.c
@@ -33,7 +33,11 @@
#include "bands.h"
const int qbank[NBANDS+2] = {0, 2, 4, 6, 8, 12, 16, 20, 24, 28, 36, 44, 52, 68, 84, 116, 128};+int qpulses[] = {4, 5, 4, 4, 3, 3, 3, 3, 3, 4, 4, 4, 0, 0, 0}; //c: 134 bits+#define WAVEFORM_END 52
+/* Start frequency of each band */
+int pbank[] = {0, 4, 8, 12, 20, WAVEFORM_END, 128};/* Compute the energy in each of the bands */
void compute_bands(float *X, int B, float *bank)
@@ -56,7 +60,7 @@
for (i=0;i<NBANDS;i++)
{int j;
- float x = 1.f/bank[i];
+ float x = 1.f/(1e-10+bank[i]);
for (j=B*qbank[i];j<B*qbank[i+1];j++)
X[j] *= x;
}
@@ -80,6 +84,61 @@
}
+/* Compute the best gain for each "pitch band" */
+void compute_pitch_gain(float *X, int B, float *P, float *gains, float *bank)
+{+ int i;
+ float w[B*qbank[NBANDS]];
+ for (i=0;i<NBANDS;i++)
+ {+ int j;
+ for (j=B*qbank[i];j<B*qbank[i+1];j++)
+ w[j] = bank[i];
+ }
+
+
+ for (i=0;i<PBANDS;i++)
+ {+ float Sxy=0;
+ float Sxx = 0;
+ int j;
+ float gain;
+ for (j=B*pbank[i];j<B*pbank[i+1];j++)
+ {+ Sxy += X[j]*P[j]*w[j];
+ Sxx += X[j]*X[j]*w[j];
+ }
+ gain = Sxy/(1e-10+Sxx);
+ //gain = Sxy/(2*(pbank[i+1]-pbank[i]));
+ //if (i<3)
+ //gain *= 1+.02*gain;
+ if (gain > .90)
+ gain = .90;
+ if (gain < 0.0)
+ gain = 0.0;
+
+ gains[i] = gain;
+ }
+ for (i=B*pbank[PBANDS];i<B*pbank[PBANDS+1];i++)
+ P[i] = 0;
+}
+
+/* Apply the (quantised) gain to each "pitch band" */
+void pitch_quant_bands(float *X, int B, float *P, float *gains)
+{+ int i;
+ for (i=0;i<PBANDS;i++)
+ {+ int j;
+ for (j=B*pbank[i];j<B*pbank[i+1];j++)
+ P[j] *= gains[i];
+ //printf ("%f ", gain);+ }
+ for (i=B*pbank[PBANDS];i<B*pbank[PBANDS+1];i++)
+ P[i] = 0;
+}
+
+
/* Scales the pulse-codebook entry in each band such that unit-energy is conserved when
adding the pitch */
void pitch_renormalise_bands(float *X, int B, float *P)
@@ -105,7 +164,7 @@
Rxx = 0;
for (j=B*qbank[i];j<B*qbank[i+1];j++)
{- X[j*2-1] = P[j]+gain1*X[j];
+ X[j] = P[j]+gain1*X[j];
Rxx += X[j]*X[j];
}
}
--- a/libcelt/bands.h
+++ b/libcelt/bands.h
@@ -32,7 +32,10 @@
#ifndef BANDS_H
#define BANDS_H
+/* Number of constant-energy bands */
#define NBANDS 15
+/* Number of bands only for the pitch prediction */
+#define PBANDS 5
void compute_bands(float *X, int B, float *bands);
@@ -39,6 +42,10 @@
void normalise_bands(float *X, int B, float *bands);
void denormalise_bands(float *X, int B, float *bands);
+
+void compute_pitch_gain(float *X, int B, float *P, float *gains, float *bank);
+
+void pitch_quant_bands(float *X, int B, float *P, float *gains);
void pitch_renormalise_bands(float *X, int B, float *P);
--- a/libcelt/celt.c
+++ b/libcelt/celt.c
@@ -55,8 +55,6 @@
float *mdct_overlap;
float *out_mem;
- float *bandE;
-
};
@@ -78,7 +76,6 @@
st->in_mem = celt_alloc(N*sizeof(float));
st->mdct_overlap = celt_alloc(N*sizeof(float));
st->out_mem = celt_alloc(MAX_PERIOD*sizeof(float));
- st->bandE = celt_alloc(NBANDS*sizeof(float));
for (i=0;i<N;i++)
st->window[i] = st->window[2*N-i-1] = sin(.5*M_PI* sin(.5*M_PI*(i+.5)/N) * sin(.5*M_PI*(i+.5)/N));
return st;
@@ -99,8 +96,6 @@
celt_free(st->mdct_overlap);
celt_free(st->out_mem);
- celt_free(st->bandE);
-
celt_free(st);
}
@@ -131,6 +126,9 @@
float X[B*N]; /**< Interleaved signal MDCTs */
float P[B*N]; /**< Interleaved pitch MDCTs*/
+ float bandEp[NBANDS];
+ float bandE[NBANDS];
+ float gains[PBANDS];
int pitch_index;
/* FIXME: Add preemphasis */
@@ -164,18 +162,34 @@
printf ("\n");*//* Band normalisation */
- compute_bands(X, B, st->bandE);
- normalise_bands(X, B, st->bandE);
+ compute_bands(X, B, bandE);
+ //for (i=0;i<NBANDS;i++) printf("%f ",bandE[i]);printf("\n"); + normalise_bands(X, B, bandE);
- compute_bands(P, B, st->bandE);
- normalise_bands(P, B, st->bandE);
+ compute_bands(P, B, bandEp);
+ normalise_bands(P, B, bandEp);
/* Pitch prediction */
+ compute_pitch_gain(X, B, P, gains, bandE);
+ //quantise_pitch(gains, PBANDS);
+ pitch_quant_bands(X, B, P, gains);
+
+ for (i=0;i<B*N;i++) printf("%f ",P[i]);printf("\n");+ /* Subtract the pitch prediction from the signal to encode */
+ for (i=0;i<B*N;i++)
+ X[i] -= P[i];
/* Residual quantisation */
+ if (1) {+ float tmpE[NBANDS];
+ compute_bands(X, B, tmpE);
+ normalise_bands(X, B, tmpE);
+ pitch_renormalise_bands(X, B, P);
+ }
+ //quant_bands(X, P);
/* Synthesis */
- denormalise_bands(X, B, st->bandE);
+ denormalise_bands(X, B, bandE);
CELT_MOVE(st->out_mem, st->out_mem+B*N, MAX_PERIOD-B*N);
/* Compute inverse MDCTs */