From 26f1412188900199b63e187fcb0bd04db53c898a Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jean-marc.valin@octasic.com>
Date: Mon, 1 Nov 2010 10:39:25 -0400
Subject: [PATCH] Fixed-point version of the pitch gain calculation code
---
libcelt/pitch.c | 35 ++++++++++++++++++++++++++++-------
1 file changed, 28 insertions(+), 7 deletions(-)
diff --git a/libcelt/pitch.c b/libcelt/pitch.c
index d903ede2..91c44db2 100644
--- a/libcelt/pitch.c
+++ b/libcelt/pitch.c
@@ -272,7 +272,18 @@ celt_word16 remove_doubling(celt_word16 *x, int maxperiod, int minperiod,
}
best_xy = xy;
best_yy = yy;
- g0 = xy/sqrt(1+xx*1.f*yy);
+#ifdef FIXED_POINT
+ {
+ celt_word32 x2y2;
+ int sh, t;
+ x2y2 = HALF32(MULT32_32_Q31(xx,yy));
+ sh = celt_ilog2(x2y2)>>1;
+ t = VSHR32(x2y2, 2*(sh-7));
+ g = g0 = VSHR32(MULT16_32_Q15(celt_rsqrt_norm(t), xy),sh+1);
+ }
+#else
+ g = g0 = xy/sqrt(1+xx*yy);
+#endif
k0 = 1;
/* Look for any pitch at T/k */
for (k=2;k<=15;k++)
@@ -303,22 +314,32 @@ celt_word16 remove_doubling(celt_word16 *x, int maxperiod, int minperiod,
xy = MAC16_16(xy, x[i], x[i-T1b]);
yy = MAC16_16(yy, x[i-T1b], x[i-T1b]);
}
+#ifdef FIXED_POINT
+ {
+ celt_word32 x2y2;
+ int sh, t;
+ x2y2 = MULT32_32_Q31(xx,yy);
+ sh = celt_ilog2(x2y2)>>1;
+ t = VSHR32(x2y2, 2*(sh-7));
+ g1 = VSHR32(MULT16_32_Q15(celt_rsqrt_norm(t), xy),sh+1);
+ }
+#else
g1 = xy/sqrt(1+2.f*xx*1.f*yy);
+#endif
if (abs(T1-prev_period)<=2)
- cont += prev_gain*(1.f/Q15ONE);
+ cont += prev_gain;
else if (abs(T1-prev_period)<=4)
- cont += .5*prev_gain*(1.f/Q15ONE);
- if (g1+cont > .85*g0 || g1+cont > .5)
+ cont += .5*prev_gain;
+ if (g1+cont > .85*g0 || g1+cont > QCONST16(.5f,15))
{
best_xy = xy;
best_yy = yy;
T = T1;
+ g = g1;
}
}
pg = best_xy/(1.f+best_yy);
- if (T != T0)
- xx = 2*xx;
- g = best_xy/sqrt(1+xx*1.f*best_yy);
+ g /= Q15ONE;
/* FIXME: Handle the case where T = maxperiod */
for (k=0;k<3;k++)
--
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