ref: a7750b90cc0b03623115de572a4726b7939f7fc9
parent: 0f0da999ae82a2b73974cc73a1a19d79a23ba8cd
author: Jean-Marc Valin <jean-marc.valin@usherbrooke.ca>
date: Sat Aug 29 18:52:03 EDT 2009
Re-introducing the successive rotations as a way to control low-bitrate tonal artefacts. This replaces folding for all cases where we have at least one pulse.
--- a/libcelt/bands.c
+++ b/libcelt/bands.c
@@ -45,6 +45,8 @@
const celt_word16_t sqrtC_1[2] = {QCONST16(1.f, 14), QCONST16(1.414214f, 14)};+
+
#ifdef FIXED_POINT
/* Compute the amplitude (sqrt energy) in each of the bands */
void compute_band_energies(const CELTMode *m, const celt_sig_t *X, celt_ener_t *bank)
@@ -469,7 +471,8 @@
if (q > 0)
{- alg_quant(X+eBands[i], W+eBands[i], eBands[i+1]-eBands[i], q, P+eBands[i], enc);
+ int spread = (eBands[i] >= m->pitchEnd && fold) ? B : 0;
+ alg_quant(X+eBands[i], W+eBands[i], eBands[i+1]-eBands[i], q, spread, P+eBands[i], enc);
} else {for (j=eBands[i];j<eBands[i+1];j++)
X[j] = P[j];
@@ -634,8 +637,10 @@
}
if (q1 > 0)
- alg_quant(v, W+C*eBands[i], N, q1, P+C*eBands[i]+c*N, enc);
- else {+ {+ int spread = (eBands[i] >= m->pitchEnd && fold) ? B : 0;
+ alg_quant(v, W+C*eBands[i], N, q1, spread, P+C*eBands[i]+c*N, enc);
+ } else {v[0] = QCONST16(1.f, 14);
v[1] = 0;
}
@@ -709,14 +714,16 @@
P[j] = 0;
}
deinterleave(X+C*eBands[i], C*N);
- if (q1 > 0)
- alg_quant(X+C*eBands[i], W+C*eBands[i], N, q1, P+C*eBands[i], enc);
- else
+ if (q1 > 0) {+ int spread = (eBands[i] >= m->pitchEnd && fold) ? B : 0;
+ alg_quant(X+C*eBands[i], W+C*eBands[i], N, q1, spread, P+C*eBands[i], enc);
+ } else
for (j=C*eBands[i];j<C*eBands[i]+N;j++)
X[j] = P[j];
- if (q2 > 0)
- alg_quant(X+C*eBands[i]+N, W+C*eBands[i], N, q2, P+C*eBands[i]+N, enc);
- else
+ if (q2 > 0) {+ int spread = (eBands[i] >= m->pitchEnd && fold) ? B : 0;
+ alg_quant(X+C*eBands[i]+N, W+C*eBands[i], N, q2, spread, P+C*eBands[i]+N, enc);
+ } else
for (j=C*eBands[i]+N;j<C*eBands[i+1];j++)
X[j] = 0;
}
@@ -831,7 +838,8 @@
if (q > 0)
{- alg_unquant(X+eBands[i], eBands[i+1]-eBands[i], q, P+eBands[i], dec);
+ int spread = (eBands[i] >= m->pitchEnd && fold) ? B : 0;
+ alg_unquant(X+eBands[i], eBands[i+1]-eBands[i], q, spread, P+eBands[i], dec);
} else {for (j=eBands[i];j<eBands[i+1];j++)
X[j] = P[j];
@@ -984,8 +992,10 @@
}
if (q1 > 0)
- alg_unquant(v, N, q1, P+C*eBands[i]+c*N, dec);
- else {+ {+ int spread = (eBands[i] >= m->pitchEnd && fold) ? B : 0;
+ alg_unquant(v, N, q1, spread, P+C*eBands[i]+c*N, dec);
+ } else {v[0] = QCONST16(1.f, 14);
v[1] = 0;
}
@@ -1055,13 +1065,17 @@
}
deinterleave(X+C*eBands[i], C*N);
if (q1 > 0)
- alg_unquant(X+C*eBands[i], N, q1, P+C*eBands[i], dec);
- else
+ {+ int spread = (eBands[i] >= m->pitchEnd && fold) ? B : 0;
+ alg_unquant(X+C*eBands[i], N, q1, spread, P+C*eBands[i], dec);
+ } else
for (j=C*eBands[i];j<C*eBands[i]+N;j++)
X[j] = P[j];
if (q2 > 0)
- alg_unquant(X+C*eBands[i]+N, N, q2, P+C*eBands[i]+N, dec);
- else
+ {+ int spread = (eBands[i] >= m->pitchEnd && fold) ? B : 0;
+ alg_unquant(X+C*eBands[i]+N, N, q2, spread, P+C*eBands[i]+N, dec);
+ } else
for (j=C*eBands[i]+N;j<C*eBands[i+1];j++)
X[j] = 0;
/*orthogonalize(X+C*eBands[i], X+C*eBands[i]+N, N);*/
--- a/libcelt/vq.c
+++ b/libcelt/vq.c
@@ -40,6 +40,59 @@
#include "os_support.h"
#include "rate.h"
+static void exp_rotation(celt_norm_t *X, int len, int dir, int stride, int K)
+{+ int i, k, iter;
+ celt_word16_t c, s;
+ celt_word16_t gain, theta;
+ celt_norm_t *Xptr;
+ gain = celt_div((celt_word32_t)MULT16_16(Q15_ONE,len),(celt_word32_t)(len+2*K*((K>>1)+1)));
+ /* FIXME: Make that HALF16 instead of HALF32 */
+ theta = SUB16(Q15ONE, HALF32(MULT16_16_Q15(gain,gain)));
+ /*if (len==30)
+ {+ for (i=0;i<len;i++)
+ X[i] = 0;
+ X[14] = 1;
+}*/
+ c = celt_cos_norm(EXTEND32(theta));
+ s = dir*celt_cos_norm(EXTEND32(SUB16(Q15ONE,theta))); /* sin(theta) */
+ if (stride == 1)
+ stride = 2;
+ iter = 1;
+ for (k=0;k<iter;k++)
+ {+ /* We could use MULT16_16_P15 instead of MULT16_16_Q15 for more accuracy,
+ but at this point, I really don't think it's necessary */
+ Xptr = X;
+ for (i=0;i<len-stride;i++)
+ {+ celt_norm_t x1, x2;
+ x1 = Xptr[0];
+ x2 = Xptr[stride];
+ Xptr[stride] = MULT16_16_Q15(c,x2) + MULT16_16_Q15(s,x1);
+ *Xptr++ = MULT16_16_Q15(c,x1) - MULT16_16_Q15(s,x2);
+ }
+ Xptr = &X[len-2*stride-1];
+ for (i=len-2*stride-1;i>=0;i--)
+ {+ celt_norm_t x1, x2;
+ x1 = Xptr[0];
+ x2 = Xptr[stride];
+ Xptr[stride] = MULT16_16_Q15(c,x2) + MULT16_16_Q15(s,x1);
+ *Xptr-- = MULT16_16_Q15(c,x1) - MULT16_16_Q15(s,x2);
+ }
+ }
+ /*if (len==30)
+ {+ for (i=0;i<len;i++)
+ printf ("%f ", X[i]);+ printf ("\n");+ exit(0);
+}*/
+}
+
+
/** Takes the pitch vector and the decoded residual vector, computes the gain
that will give ||p+g*y||=1 and mixes the residual with the pitch. */
static void mix_pitch_and_residual(int * restrict iy, celt_norm_t * restrict X, int N, int K, const celt_norm_t * restrict P)
@@ -90,7 +143,7 @@
}
-void alg_quant(celt_norm_t *X, celt_mask_t *W, int N, int K, celt_norm_t *P, ec_enc *enc)
+void alg_quant(celt_norm_t *X, celt_mask_t *W, int N, int K, int spread, celt_norm_t *P, ec_enc *enc)
{VARDECL(celt_norm_t, y);
VARDECL(int, iy);
@@ -116,6 +169,9 @@
ALLOC(iy, N, int);
ALLOC(signx, N, celt_word16_t);
N_1 = 512/N;
+
+ if (spread)
+ exp_rotation(X, N, 1, spread, K);
sum = 0;
j=0; do {@@ -301,6 +357,8 @@
/* Recompute the gain in one pass to reduce the encoder-decoder mismatch
due to the recursive computation used in quantisation. */
mix_pitch_and_residual(iy, X, N, K, P);
+ if (spread)
+ exp_rotation(X, N, -1, spread, K);
RESTORE_STACK;
}
@@ -307,7 +365,7 @@
/** Decode pulse vector and combine the result with the pitch vector to produce
the final normalised signal in the current band. */
-void alg_unquant(celt_norm_t *X, int N, int K, celt_norm_t *P, ec_dec *dec)
+void alg_unquant(celt_norm_t *X, int N, int K, int spread, celt_norm_t *P, ec_dec *dec)
{VARDECL(int, iy);
SAVE_STACK;
@@ -315,6 +373,8 @@
ALLOC(iy, N, int);
decode_pulses(iy, N, K, dec);
mix_pitch_and_residual(iy, X, N, K, P);
+ if (spread)
+ exp_rotation(X, N, -1, spread, K);
RESTORE_STACK;
}
@@ -376,7 +436,6 @@
void intra_fold(const CELTMode *m, celt_norm_t * restrict x, int N, int *pulses, celt_norm_t *Y, celt_norm_t * restrict P, int N0, int B)
{int c;
- celt_word16_t pred_gain;
const int C = CHANNELS(m);
fold(m, N, Y, P, N0, B);
@@ -383,12 +442,7 @@
c=0;
do {int K = get_pulses(pulses[c]);
- if (K==0)
- pred_gain = Q15ONE;
- else
- pred_gain = celt_div((celt_word32_t)MULT16_16(Q15_ONE,N),(celt_word32_t)(N+2*K*(K+1)));
-
- renormalise_vector(P+c, pred_gain, N, C);
+ renormalise_vector(P+c, K==0 ? Q15ONE : 0, N, C);
} while (++c < C);
}
--- a/libcelt/vq.h
+++ b/libcelt/vq.h
@@ -50,7 +50,7 @@
* @param p Pitch vector (it is assumed that p+x is a unit vector)
* @param enc Entropy encoder state
*/
-void alg_quant(celt_norm_t *X, celt_mask_t *W, int N, int K, celt_norm_t *P, ec_enc *enc);
+void alg_quant(celt_norm_t *X, celt_mask_t *W, int N, int K, int spread, celt_norm_t *P, ec_enc *enc);
/** Algebraic pulse decoder
* @param x Decoded normalised spectrum (returned)
@@ -59,7 +59,7 @@
* @param p Pitch vector (automatically added to x)
* @param dec Entropy decoder state
*/
-void alg_unquant(celt_norm_t *X, int N, int K, celt_norm_t *P, ec_dec *dec);
+void alg_unquant(celt_norm_t *X, int N, int K, int spread, celt_norm_t *P, ec_dec *dec);
celt_word16_t renormalise_vector(celt_norm_t *X, celt_word16_t value, int N, int stride);
--
⑨