From 4be7fe795ea2ec8ccd3ba33b213e8c26492c3377 Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Tue, 23 Oct 2012 16:51:37 -0400
Subject: [PATCH] This should speed up deemphasis() quite a bit.
Removes the resampling branches from the main loop and no longer computes
the multiplications for coefs equal to one or zero.
---
celt/celt.c | 47 +++++++++++++++++++++++++++++------------------
1 file changed, 29 insertions(+), 18 deletions(-)
diff --git a/celt/celt.c b/celt/celt.c
index 06cc4cc5c..7caabf2dd 100644
--- a/celt/celt.c
+++ b/celt/celt.c
@@ -503,10 +503,11 @@ static void compute_inv_mdcts(const CELTMode *mode, int shortBlocks, celt_sig *X
RESTORE_STACK;
}
-static void deemphasis(celt_sig *in[], opus_val16 *pcm, int N, int C, int downsample, const opus_val16 *coef, celt_sig *mem)
+static void deemphasis(celt_sig *in[], opus_val16 *pcm, int N, int C, int downsample, const opus_val16 *coef, celt_sig *mem, celt_sig * OPUS_RESTRICT scratch)
{
int c;
- int count=0;
+ int Nd;
+ Nd = N/downsample;
c=0; do {
int j;
celt_sig * OPUS_RESTRICT x;
@@ -514,24 +515,30 @@ static void deemphasis(celt_sig *in[], opus_val16 *pcm, int N, int C, int downsa
celt_sig m = mem[c];
x =in[c];
y = pcm+c;
- for (j=0;j<N;j++)
+ /* Shortcut for the standard (non-custom modes) case */
+ if (coef[1] == 0)
{
- celt_sig tmp = *x + m;
- m = MULT16_32_Q15(coef[0], tmp)
- - MULT16_32_Q15(coef[1], *x);
- tmp = SHL32(MULT16_32_Q15(coef[3], tmp), 2);
- x++;
- /* Technically the store could be moved outside of the if because
- the stores we don't want will just be overwritten */
- if (count==0)
- *y = SCALEOUT(SIG2WORD16(tmp));
- if (++count==downsample)
+ for (j=0;j<N;j++)
{
- y+=C;
- count=0;
+ celt_sig tmp = x[j] + m;
+ m = MULT16_32_Q15(coef[0], tmp);
+ scratch[j] = tmp;
+ }
+ } else {
+ for (j=0;j<N;j++)
+ {
+ celt_sig tmp = x[j] + m;
+ m = MULT16_32_Q15(coef[0], tmp)
+ - MULT16_32_Q15(coef[1], x[j]);
+ tmp = SHL32(MULT16_32_Q15(coef[3], tmp), 2);
+ scratch[j] = tmp;
}
}
mem[c] = m;
+
+ /* Perform down-sampling */
+ for (j=0;j<Nd;j++)
+ y[j*C] = SCALEOUT(SIG2WORD16(scratch[j*downsample]));
} while (++c<C);
}
@@ -1920,7 +1927,8 @@ int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm,
st->mode->window, st->mode->overlap);
} while (++c<CC);
- deemphasis(out_mem, (opus_val16*)pcm, N, CC, st->upsample, st->mode->preemph, st->preemph_memD);
+ /* We reuse freq[] as scratch space for the de-emphasis */
+ deemphasis(out_mem, (opus_val16*)pcm, N, CC, st->upsample, st->mode->preemph, st->preemph_memD, freq);
st->prefilter_period_old = st->prefilter_period;
st->prefilter_gain_old = st->prefilter_gain;
st->prefilter_tapset_old = st->prefilter_tapset;
@@ -2360,6 +2368,7 @@ static void celt_decode_lost(CELTDecoder * OPUS_RESTRICT st, opus_val16 * OPUS_R
opus_val16 *lpc;
opus_val32 *out_syn[2];
opus_val16 *oldBandE, *oldLogE, *oldLogE2, *backgroundLogE;
+ VARDECL(celt_sig, scratch);
SAVE_STACK;
c=0; do {
@@ -2599,7 +2608,8 @@ static void celt_decode_lost(CELTDecoder * OPUS_RESTRICT st, opus_val16 * OPUS_R
} while (++c<C);
}
- deemphasis(out_syn, pcm, N, C, st->downsample, st->mode->preemph, st->preemph_memD);
+ ALLOC(scratch, N, celt_sig);
+ deemphasis(out_syn, pcm, N, C, st->downsample, st->mode->preemph, st->preemph_memD, scratch);
st->loss_count++;
@@ -2974,7 +2984,8 @@ int celt_decode_with_ec(CELTDecoder * OPUS_RESTRICT st, const unsigned char *dat
} while (++c<2);
st->rng = dec->rng;
- deemphasis(out_syn, pcm, N, CC, st->downsample, st->mode->preemph, st->preemph_memD);
+ /* We reuse freq[] as scratch space for the de-emphasis */
+ deemphasis(out_syn, pcm, N, CC, st->downsample, st->mode->preemph, st->preemph_memD, freq);
st->loss_count = 0;
RESTORE_STACK;
if (ec_tell(dec) > 8*len)
--
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