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Split the last pulse out of the alg_quant() main loop.

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Jean-Marc Valin 2008-09-21 21:11:39 -04:00
parent 5ea2e7f267
commit 7bb339d9f9
1 changed files with 65 additions and 61 deletions
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126
libcelt/vq.c
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@ -135,11 +135,13 @@ void alg_quant(celt_norm_t *X, celt_mask_t *W, int N, int K, const celt_norm_t *
xy = yy = yp = 0; xy = yy = yp = 0;
pulsesLeft = K; pulsesLeft = K;
while (pulsesLeft > 0) while (pulsesLeft > 1)
{ {
int pulsesAtOnce=1; int pulsesAtOnce=1;
int best_id; int best_id;
celt_word16_t magnitude; celt_word16_t magnitude;
celt_word32_t best_num = -VERY_LARGE16;
celt_word16_t best_den = 0;
#ifdef FIXED_POINT #ifdef FIXED_POINT
int rshift; int rshift;
#endif #endif
@ -157,70 +159,30 @@ void alg_quant(celt_norm_t *X, celt_mask_t *W, int N, int K, const celt_norm_t *
add it outside the loop */ add it outside the loop */
yy = MAC16_16(yy, magnitude,magnitude); yy = MAC16_16(yy, magnitude,magnitude);
/* Choose between fast and accurate strategy depending on where we are in the search */ /* Choose between fast and accurate strategy depending on where we are in the search */
if (pulsesLeft>1)
{
/* This should ensure that anything we can process will have a better score */ /* This should ensure that anything we can process will have a better score */
celt_word32_t best_num = -VERY_LARGE16; j=0;
celt_word16_t best_den = 0; do {
j=0; celt_word16_t Rxy, Ryy;
do { /* Select sign based on X[j] alone */
celt_word16_t Rxy, Ryy; s = MULT16_16(signx[j],magnitude);
/* Select sign based on X[j] alone */ /* Temporary sums of the new pulse(s) */
s = MULT16_16(signx[j],magnitude); Rxy = EXTRACT16(SHR32(MAC16_16(xy, s,X[j]),rshift));
/* Temporary sums of the new pulse(s) */ /* We're multiplying y[j] by two so we don't have to do it here */
Rxy = EXTRACT16(SHR32(MAC16_16(xy, s,X[j]),rshift)); Ryy = EXTRACT16(SHR32(MAC16_16(yy, s,y[j]),rshift));
/* We're multiplying y[j] by two so we don't have to do it here */
Ryy = EXTRACT16(SHR32(MAC16_16(yy, s,y[j]),rshift));
/* Approximate score: we maximise Rxy/sqrt(Ryy) (we're guaranteed that /* Approximate score: we maximise Rxy/sqrt(Ryy) (we're guaranteed that
Rxy is positive because the sign is pre-computed) */ Rxy is positive because the sign is pre-computed) */
Rxy = MULT16_16_Q15(Rxy,Rxy); Rxy = MULT16_16_Q15(Rxy,Rxy);
/* The idea is to check for num/den >= best_num/best_den, but that way /* The idea is to check for num/den >= best_num/best_den, but that way
we can do it without any division */ we can do it without any division */
/* OPT: Make sure to use conditional moves here */ /* OPT: Make sure to use conditional moves here */
if (MULT16_16(best_den, Rxy) > MULT16_16(Ryy, best_num)) if (MULT16_16(best_den, Rxy) > MULT16_16(Ryy, best_num))
{ {
best_den = Ryy; best_den = Ryy;
best_num = Rxy; best_num = Rxy;
best_id = j; best_id = j;
} }
} while (++j<N); } while (++j<N);
} else {
celt_word16_t g;
celt_word16_t best_num = -VERY_LARGE16;
celt_word16_t best_den = 0;
j=0;
do {
celt_word16_t Rxy, Ryy, Ryp;
celt_word16_t num;
/* Select sign based on X[j] alone */
s = MULT16_16(signx[j],magnitude);
/* Temporary sums of the new pulse(s) */
Rxy = ROUND16(MAC16_16(xy, s,X[j]), 14);
/* We're multiplying y[j] by two so we don't have to do it here */
Ryy = ROUND16(MAC16_16(yy, s,y[j]), 14);
Ryp = ROUND16(MAC16_16(yp, s,P[j]), 14);
/* Compute the gain such that ||p + g*y|| = 1
...but instead, we compute g*Ryy to avoid dividing */
g = celt_psqrt(MULT16_16(Ryp,Ryp) + MULT16_16(Ryy,QCONST16(1.f,14)-Rpp)) - Ryp;
/* Knowing that gain, what's the error: (x-g*y)^2
(result is negated and we discard x^2 because it's constant) */
/* score = 2*g*Rxy - g*g*Ryy;*/
#ifdef FIXED_POINT
/* No need to multiply Rxy by 2 because we did it earlier */
num = MULT16_16_Q15(ADD16(SUB16(Rxy,g),Rxy),g);
#else
num = g*(2*Rxy-g);
#endif
if (MULT16_16(best_den, num) > MULT16_16(Ryy, best_num))
{
best_den = Ryy;
best_num = num;
best_id = j;
}
} while (++j<N);
}
j = best_id; j = best_id;
is = MULT16_16(signx[j],pulsesAtOnce); is = MULT16_16(signx[j],pulsesAtOnce);
@ -239,6 +201,48 @@ void alg_quant(celt_norm_t *X, celt_mask_t *W, int N, int K, const celt_norm_t *
pulsesLeft -= pulsesAtOnce; pulsesLeft -= pulsesAtOnce;
} }
{
celt_word16_t g;
celt_word16_t best_num = -VERY_LARGE16;
celt_word16_t best_den = 0;
int best_id = 0;
/* The squared magnitude term gets added anyway, so we might as well
add it outside the loop */
yy = MAC16_16(yy, 1,1);
j=0;
do {
celt_word16_t Rxy, Ryy, Ryp;
celt_word16_t num;
/* Select sign based on X[j] alone */
s = signx[j];
/* Temporary sums of the new pulse(s) */
Rxy = ROUND16(MAC16_16(xy, s,X[j]), 14);
/* We're multiplying y[j] by two so we don't have to do it here */
Ryy = ROUND16(MAC16_16(yy, s,y[j]), 14);
Ryp = ROUND16(MAC16_16(yp, s,P[j]), 14);
/* Compute the gain such that ||p + g*y|| = 1
...but instead, we compute g*Ryy to avoid dividing */
g = celt_psqrt(MULT16_16(Ryp,Ryp) + MULT16_16(Ryy,QCONST16(1.f,14)-Rpp)) - Ryp;
/* Knowing that gain, what's the error: (x-g*y)^2
(result is negated and we discard x^2 because it's constant) */
/* score = 2*g*Rxy - g*g*Ryy;*/
#ifdef FIXED_POINT
/* No need to multiply Rxy by 2 because we did it earlier */
num = MULT16_16_Q15(ADD16(SUB16(Rxy,g),Rxy),g);
#else
num = g*(2*Rxy-g);
#endif
if (MULT16_16(best_den, num) > MULT16_16(Ryy, best_num))
{
best_den = Ryy;
best_num = num;
best_id = j;
}
} while (++j<N);
iy[best_id] += signx[best_id];
}
encode_pulses(iy, N, K, enc); encode_pulses(iy, N, K, enc);
/* Recompute the gain in one pass to reduce the encoder-decoder mismatch /* Recompute the gain in one pass to reduce the encoder-decoder mismatch