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Add special case for 2nd-order IIR filter. 

40% faster in ff_iir_filter_flt() when c->order == 2.
This commit is contained in:
Justin Ruggles 2011-01-27 23:58:27 +00:00 committed by Mans Rullgard
parent d1b6f33bf2
commit 37cb3eb534
1 changed files with 22 additions and 2 deletions
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24
libavcodec/iirfilter.c
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@ -256,11 +256,29 @@ av_cold struct FFIIRFilterState* ff_iir_filter_init_state(int order)
} \
}
#define FILTER_O2(type, fmt) { \
int i; \
const type *src0 = src; \
type *dst0 = dst; \
for (i = 0; i < size; i++) { \
float in = *src0 * c->gain + \
s->x[0] * c->cy[0] + \
s->x[1] * c->cy[1]; \
CONV_##fmt(*dst0, s->x[0] + in + s->x[1] * c->cx[1]) \
s->x[0] = s->x[1]; \
s->x[1] = in; \
src0 += sstep; \
dst0 += dstep; \
} \
}
void ff_iir_filter(const struct FFIIRFilterCoeffs *c,
struct FFIIRFilterState *s, int size,
const int16_t *src, int sstep, int16_t *dst, int dstep)
{
if (c->order == 4) {
if (c->order == 2) {
FILTER_O2(int16_t, S16)
} else if (c->order == 4) {
FILTER_BW_O4(int16_t, S16)
} else {
FILTER_DIRECT_FORM_II(int16_t, S16)
@ -271,7 +289,9 @@ void ff_iir_filter_flt(const struct FFIIRFilterCoeffs *c,
struct FFIIRFilterState *s, int size,
const float *src, int sstep, float *dst, int dstep)
{
if (c->order == 4) {
if (c->order == 2) {
FILTER_O2(float, FLT)
} else if (c->order == 4) {
FILTER_BW_O4(float, FLT)
} else {
FILTER_DIRECT_FORM_II(float, FLT)