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As extra safety, make sure not to use pitch prediction when it would make

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the "effective gain" too high (>10 dB).
This commit is contained in:
Jean-Marc Valin 2008-02-11 17:54:28 +11:00
parent 7e8a487ed2
commit 05686a5d6e
1 changed files with 38 additions and 23 deletions
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59
libcelt/celt.c
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@ -151,9 +151,10 @@ void celt_encoder_destroy(CELTEncoder *st)
} }
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; int i, c;
float E = 1e-15;
for (c=0;c<C;c++) for (c=0;c<C;c++)
{ {
for (i=0;i<B;i++) for (i=0;i<B;i++)
@ -162,13 +163,17 @@ static void compute_mdcts(mdct_lookup *mdct_lookup, float *window, float *in, fl
float x[2*N]; float x[2*N];
float tmp[N]; float tmp[N];
for (j=0;j<2*N;j++) for (j=0;j<2*N;j++)
{
x[j] = window[j]*in[C*i*N+C*j+c]; x[j] = window[j]*in[C*i*N+C*j+c];
E += x[j]*x[j];
}
mdct_forward(mdct_lookup, x, tmp); mdct_forward(mdct_lookup, x, tmp);
/* Interleaving the sub-frames */ /* Interleaving the sub-frames */
for (j=0;j<N;j++) for (j=0;j<N;j++)
out[C*B*j+C*i+c] = tmp[j]; 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) 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)
@ -213,6 +218,7 @@ int celt_encode(CELTEncoder *st, celt_int16_t *pcm, unsigned char *compressed, i
float bandE[st->mode->nbEBands*C]; float bandE[st->mode->nbEBands*C];
float gains[st->mode->nbPBands]; float gains[st->mode->nbPBands];
int pitch_index; int pitch_index;
float curr_power, pitch_power;
N4 = (N-st->overlap)/2; N4 = (N-st->overlap)/2;
@ -235,7 +241,7 @@ int celt_encode(CELTEncoder *st, celt_int16_t *pcm, unsigned char *compressed, i
} }
//for (i=0;i<(B+1)*C*N;i++) printf ("%f(%d) ", in[i], i); printf ("\n"); //for (i=0;i<(B+1)*C*N;i++) printf ("%f(%d) ", in[i], i); printf ("\n");
/* Compute MDCTs */ /* 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 */ #if 0 /* Mask disabled until it can be made to do something useful */
compute_mdct_masking(X, mask, B*C*N, st->Fs); compute_mdct_masking(X, mask, B*C*N, st->Fs);
@ -261,8 +267,9 @@ int celt_encode(CELTEncoder *st, celt_int16_t *pcm, unsigned char *compressed, i
find_spectral_pitch(st->fft, &st->psy, in, st->out_mem, MAX_PERIOD, (B+1)*N, C, &pitch_index); 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 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; /*int j;
for (j=0;j<B*N;j++) for (j=0;j<B*N;j++)
printf ("%f ", X[j]); printf ("%f ", X[j]);
@ -276,31 +283,39 @@ int celt_encode(CELTEncoder *st, celt_int16_t *pcm, unsigned char *compressed, i
//for (i=0;i<st->mode->nbEBands;i++)printf("%f ", bandE[i]);printf("\n"); //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"); //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]; float bandEp[st->mode->nbEBands*st->mode->nbChannels];
compute_band_energies(st->mode, P, bandEp); compute_band_energies(st->mode, P, bandEp);
normalise_bands(st->mode, P, bandEp); normalise_bands(st->mode, P, bandEp);
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;
/* 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;
} }
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;
/* 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); pitch_quant_bands(st->mode, X, P, gains);