ref: 7bb339d9f92a466673ce49aa5bfda8847a7534e0
parent: 5ea2e7f2671c601ab9cfe79efe287d44553fd1c2
author: Jean-Marc Valin <[email protected]>
date: Sun Sep 21 17:11:39 EDT 2008
Split the last pulse out of the alg_quant() main loop.
--- a/libcelt/vq.c
+++ b/libcelt/vq.c
@@ -135,11 +135,13 @@
xy = yy = yp = 0;
pulsesLeft = K;
- while (pulsesLeft > 0)
+ while (pulsesLeft > 1)
{int pulsesAtOnce=1;
int best_id;
celt_word16_t magnitude;
+ celt_word32_t best_num = -VERY_LARGE16;
+ celt_word16_t best_den = 0;
#ifdef FIXED_POINT
int rshift;
#endif
@@ -157,70 +159,30 @@
add it outside the loop */
yy = MAC16_16(yy, magnitude,magnitude);
/* 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 */
- celt_word32_t best_num = -VERY_LARGE16;
- celt_word16_t best_den = 0;
- j=0;
- do {- celt_word16_t Rxy, Ryy;
- /* Select sign based on X[j] alone */
- s = MULT16_16(signx[j],magnitude);
- /* Temporary sums of the new pulse(s) */
- Rxy = EXTRACT16(SHR32(MAC16_16(xy, s,X[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));
+ j=0;
+ do {+ celt_word16_t Rxy, Ryy;
+ /* Select sign based on X[j] alone */
+ s = MULT16_16(signx[j],magnitude);
+ /* Temporary sums of the new pulse(s) */
+ Rxy = EXTRACT16(SHR32(MAC16_16(xy, s,X[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
- Rxy is positive because the sign is pre-computed) */
- Rxy = MULT16_16_Q15(Rxy,Rxy);
+ Rxy is positive because the sign is pre-computed) */
+ Rxy = MULT16_16_Q15(Rxy,Rxy);
/* The idea is to check for num/den >= best_num/best_den, but that way
- we can do it without any division */
- /* OPT: Make sure to use conditional moves here */
- if (MULT16_16(best_den, Rxy) > MULT16_16(Ryy, best_num))
- {- best_den = Ryy;
- best_num = Rxy;
- best_id = j;
- }
- } 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);
- }
+ we can do it without any division */
+ /* OPT: Make sure to use conditional moves here */
+ if (MULT16_16(best_den, Rxy) > MULT16_16(Ryy, best_num))
+ {+ best_den = Ryy;
+ best_num = Rxy;
+ best_id = j;
+ }
+ } while (++j<N);
j = best_id;
is = MULT16_16(signx[j],pulsesAtOnce);
@@ -239,6 +201,48 @@
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);
/* Recompute the gain in one pass to reduce the encoder-decoder mismatch