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opus: speed up comb_filter

Skip expensive multiply-accumulate loop when gains are 0 and
just copy using memcpy if soure and destination are not the same

Speeds up decoding of a 64kbps test file by 6MHz on h300 (cf)
7MHz on c200 (pp) and 6MHz on fuzev1 (amsv1)

Change-Id: Ibbc9ddfd45a9ac661467b1327b8c67761924fb8b
Signed-off-by: Nils Wallménius <nils@rockbox.org>
This commit is contained in:
Andree Buschmann 2012-10-06 14:17:30 +02:00 committed by Nils Wallménius
parent 78ca74a56f
commit dceec09092

View file

@ -497,9 +497,12 @@ static void comb_filter(opus_val32 *y, opus_val32 *x, int T0, int T1, int N,
opus_val16 g0, opus_val16 g1, int tapset0, int tapset1, opus_val16 g0, opus_val16 g1, int tapset0, int tapset1,
const opus_val16 *window, int overlap) const opus_val16 *window, int overlap)
{ {
/* Multiply-adds are only needed if g0 or g1 are non-zero. In all other cases a simple
* copy of vector x to y is possible. */
if (g0!=0 || g1!=0)
{
int i; int i;
/* printf ("%d %d %f %f\n", T0, T1, g0, g1); */ opus_val16 g00, g01, g02, g10, g11, g12, idx0, idx1;
opus_val16 g00, g01, g02, g10, g11, g12;
static const opus_val16 gains[3][3] = { static const opus_val16 gains[3][3] = {
{QCONST16(0.3066406250f, 15), QCONST16(0.2170410156f, 15), QCONST16(0.1296386719f, 15)}, {QCONST16(0.3066406250f, 15), QCONST16(0.2170410156f, 15), QCONST16(0.1296386719f, 15)},
{QCONST16(0.4638671875f, 15), QCONST16(0.2680664062f, 15), QCONST16(0.f, 15)}, {QCONST16(0.4638671875f, 15), QCONST16(0.2680664062f, 15), QCONST16(0.f, 15)},
@ -510,30 +513,53 @@ static void comb_filter(opus_val32 *y, opus_val32 *x, int T0, int T1, int N,
g10 = MULT16_16_Q15(g1, gains[tapset1][0]); g10 = MULT16_16_Q15(g1, gains[tapset1][0]);
g11 = MULT16_16_Q15(g1, gains[tapset1][1]); g11 = MULT16_16_Q15(g1, gains[tapset1][1]);
g12 = MULT16_16_Q15(g1, gains[tapset1][2]); g12 = MULT16_16_Q15(g1, gains[tapset1][2]);
for (i=0;i<overlap;i++) /* printf("g0 %d g1 %d\n", g0,g1); */
idx0 = -T0;
idx1 = -T1;
for (i=0;i<overlap;i++,idx0++,idx1++)
{ {
opus_val16 f; opus_val16 f0, f1;
f = MULT16_16_Q15(window[i],window[i]); f1 = MULT16_16_Q15(window[i],window[i]);
f0 = Q15ONE - f1;
y[i] = x[i] y[i] = x[i]
+ MULT16_32_Q15(MULT16_16_Q15((Q15ONE-f),g00),x[i-T0]) + MULT16_32_Q15(MULT16_16_Q15(f0,g02), x[idx0-2])
+ MULT16_32_Q15(MULT16_16_Q15((Q15ONE-f),g01),x[i-T0-1]) + MULT16_32_Q15(MULT16_16_Q15(f0,g01), x[idx0-1])
+ MULT16_32_Q15(MULT16_16_Q15((Q15ONE-f),g01),x[i-T0+1]) + MULT16_32_Q15(MULT16_16_Q15(f0,g00), x[idx0 ])
+ MULT16_32_Q15(MULT16_16_Q15((Q15ONE-f),g02),x[i-T0-2]) + MULT16_32_Q15(MULT16_16_Q15(f0,g01), x[idx0+1])
+ MULT16_32_Q15(MULT16_16_Q15((Q15ONE-f),g02),x[i-T0+2]) + MULT16_32_Q15(MULT16_16_Q15(f0,g02), x[idx0+2])
+ MULT16_32_Q15(MULT16_16_Q15(f,g10),x[i-T1]) + MULT16_32_Q15(MULT16_16_Q15(f1,g12), x[idx1-2])
+ MULT16_32_Q15(MULT16_16_Q15(f,g11),x[i-T1-1]) + MULT16_32_Q15(MULT16_16_Q15(f1,g11), x[idx1-1])
+ MULT16_32_Q15(MULT16_16_Q15(f,g11),x[i-T1+1]) + MULT16_32_Q15(MULT16_16_Q15(f1,g10), x[idx1 ])
+ MULT16_32_Q15(MULT16_16_Q15(f,g12),x[i-T1-2]) + MULT16_32_Q15(MULT16_16_Q15(f1,g11), x[idx1+1])
+ MULT16_32_Q15(MULT16_16_Q15(f,g12),x[i-T1+2]); + MULT16_32_Q15(MULT16_16_Q15(f1,g12), x[idx1+2]);
} }
for (i=overlap;i<N;i++) /* No multiply-add required if g1=0 as all multiplicants are =0. */
if (g1!=0)
{
idx1 = overlap-T1;
for (i=overlap;i<N;i++,idx1++)
{
y[i] = x[i] y[i] = x[i]
+ MULT16_32_Q15(g10,x[i-T1]) + MULT16_32_Q15(g12, x[idx1-2])
+ MULT16_32_Q15(g11,x[i-T1-1]) + MULT16_32_Q15(g11, x[idx1-1])
+ MULT16_32_Q15(g11,x[i-T1+1]) + MULT16_32_Q15(g10, x[idx1 ])
+ MULT16_32_Q15(g12,x[i-T1-2]) + MULT16_32_Q15(g11, x[idx1+1])
+ MULT16_32_Q15(g12,x[i-T1+2]); + MULT16_32_Q15(g12, x[idx1+2]);
}
}
/* Only perform vector copy if source and destination are not same. */
else if (x != y)
{
/* Copy part of vector from x[overlap..N] to y[overlap..N] */
OPUS_COPY(y+overlap, x+overlap, N-overlap);
}
}
/* Only perform vector copy if source and destination are not same. */
else if (x != y)
{
/* Copy full vector from x[0..N] to y[0..N] */
OPUS_COPY(y, x, N);
}
} }
static const signed char tf_select_table[4][8] = { static const signed char tf_select_table[4][8] = {