ref: 05686a5d6e366d3a067c39f1b8567def7baa450d
parent: 7e8a487ed2e31e24d679d437b569740d825009c2
author: Jean-Marc Valin <[email protected]>
date: Mon Feb 11 12:54:28 EST 2008
As extra safety, make sure not to use pitch prediction when it would make the "effective gain" too high (>10 dB).
--- a/libcelt/celt.c
+++ b/libcelt/celt.c
@@ -151,9 +151,10 @@
}
-static void compute_mdcts(mdct_lookup *mdct_lookup, float *window, float *in, float *out, int N, int B, int C)
+static float compute_mdcts(mdct_lookup *mdct_lookup, float *window, float *in, float *out, int N, int B, int C)
{int i, c;
+ float E = 1e-15;
for (c=0;c<C;c++)
{for (i=0;i<B;i++)
@@ -162,7 +163,10 @@
float x[2*N];
float tmp[N];
for (j=0;j<2*N;j++)
+ {x[j] = window[j]*in[C*i*N+C*j+c];
+ E += x[j]*x[j];
+ }
mdct_forward(mdct_lookup, x, tmp);
/* Interleaving the sub-frames */
for (j=0;j<N;j++)
@@ -169,6 +173,7 @@
out[C*B*j+C*i+c] = tmp[j];
}
}
+ return E;
}
static void compute_inv_mdcts(mdct_lookup *mdct_lookup, float *window, float *X, float *out_mem, float *mdct_overlap, int N, int overlap, int B, int C)
@@ -213,7 +218,8 @@
float bandE[st->mode->nbEBands*C];
float gains[st->mode->nbPBands];
int pitch_index;
-
+ float curr_power, pitch_power;
+
N4 = (N-st->overlap)/2;
for (c=0;c<C;c++)
@@ -235,7 +241,7 @@
}
//for (i=0;i<(B+1)*C*N;i++) printf ("%f(%d) ", in[i], i); printf ("\n");/* Compute MDCTs */
- compute_mdcts(&st->mdct_lookup, st->window, in, X, N, B, C);
+ curr_power = compute_mdcts(&st->mdct_lookup, st->window, in, X, N, B, C);
#if 0 /* Mask disabled until it can be made to do something useful */
compute_mdct_masking(X, mask, B*C*N, st->Fs);
@@ -261,8 +267,9 @@
find_spectral_pitch(st->fft, &st->psy, in, st->out_mem, MAX_PERIOD, (B+1)*N, C, &pitch_index);
/* Compute MDCTs of the pitch part */
- compute_mdcts(&st->mdct_lookup, st->window, st->out_mem+pitch_index*C, P, N, B, C);
+ pitch_power = compute_mdcts(&st->mdct_lookup, st->window, st->out_mem+pitch_index*C, P, N, B, C);
+ //printf ("%f %f\n", curr_power, pitch_power);/*int j;
for (j=0;j<B*N;j++)
printf ("%f ", X[j]);@@ -276,31 +283,39 @@
//for (i=0;i<st->mode->nbEBands;i++)printf("%f ", bandE[i]);printf("\n"); //for (i=0;i<N*B*C;i++)printf("%f ", X[i]);printf("\n");- /* Normalise the pitch vector as well (discard the energies) */
+ quant_energy(st->mode, bandE, st->oldBandE, &st->enc);
+
+ /* Check if we can safely use the pitch (i.e. effective gain isn't too high) */
+ if (curr_power + 1e5f < 10.f*pitch_power)
{+ /* Normalise the pitch vector as well (discard the energies) */
float bandEp[st->mode->nbEBands*st->mode->nbChannels];
compute_band_energies(st->mode, P, bandEp);
normalise_bands(st->mode, P, bandEp);
- }
- quant_energy(st->mode, bandE, st->oldBandE, &st->enc);
+ if (C==2)
+ {+ stereo_mix(st->mode, X, bandE, 1);
+ stereo_mix(st->mode, P, bandE, 1);
+ }
+ /* Simulates intensity stereo */
+ //for (i=30;i<N*B;i++)
+ // X[i*C+1] = P[i*C+1] = 0;
- if (C==2)
- {- stereo_mix(st->mode, X, bandE, 1);
- stereo_mix(st->mode, P, bandE, 1);
+ /* Pitch prediction */
+ compute_pitch_gain(st->mode, X, P, gains, bandE);
+ has_pitch = quant_pitch(gains, st->mode->nbPBands, &st->enc);
+ if (has_pitch)
+ ec_enc_uint(&st->enc, pitch_index, MAX_PERIOD-(B+1)*N);
+ } else {+ /* No pitch, so we just pretend we found a gain of zero */
+ for (i=0;i<st->mode->nbPBands;i++)
+ gains[i] = 0;
+ ec_enc_uint(&st->enc, 0, 128);
+ for (i=0;i<B*C*N;i++)
+ P[i] = 0;
}
- /* Simulates intensity stereo */
- //for (i=30;i<N*B;i++)
- // X[i*C+1] = P[i*C+1] = 0;
- /* Get a tiny bit more frequency resolution and prevent unstable energy when quantising */
-
- /* Pitch prediction */
- compute_pitch_gain(st->mode, X, P, gains, bandE);
- has_pitch = quant_pitch(gains, st->mode->nbPBands, &st->enc);
- if (has_pitch)
- ec_enc_uint(&st->enc, pitch_index, MAX_PERIOD-(B+1)*N);
pitch_quant_bands(st->mode, X, P, gains);