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Add function ff_iir_filter_flt() to accept floating-point input and output.

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Signed-off-by: Mans Rullgard <mans@mansr.com>
(cherry picked from commit 0a3d7697b4)
oldabi
Justin Ruggles 14 years ago committed by Michael Niedermayer
parent 236bb68d76
commit b3b8b930fc
2 changed files with 80 additions and 39 deletions
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  1. 102
      libavcodec/iirfilter.c
  2. 17
      libavcodec/iirfilter.h

102
libavcodec/iirfilter.c
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@ -118,48 +118,74 @@ av_cold struct FFIIRFilterState* ff_iir_filter_init_state(int order)
return s;
}
#define FILTER(i0, i1, i2, i3) \
in = *src * c->gain \
+ c->cy[0]*s->x[i0] + c->cy[1]*s->x[i1] \
+ c->cy[2]*s->x[i2] + c->cy[3]*s->x[i3]; \
res = (s->x[i0] + in )*1 \
+ (s->x[i1] + s->x[i3])*4 \
+ s->x[i2] *6; \
*dst = av_clip_int16(lrintf(res)); \
s->x[i0] = in; \
src += sstep; \
dst += dstep; \
#define CONV_S16(dest, source) dest = av_clip_int16(lrintf(source));
#define CONV_FLT(dest, source) dest = source;
#define FILTER_BW_O4_1(i0, i1, i2, i3, fmt) \
in = *src0 * c->gain \
+ c->cy[0]*s->x[i0] + c->cy[1]*s->x[i1] \
+ c->cy[2]*s->x[i2] + c->cy[3]*s->x[i3]; \
res = (s->x[i0] + in )*1 \
+ (s->x[i1] + s->x[i3])*4 \
+ s->x[i2] *6; \
CONV_##fmt(*dst0, res) \
s->x[i0] = in; \
src0 += sstep; \
dst0 += dstep;
#define FILTER_BW_O4(type, fmt) { \
int i; \
const type *src0 = src; \
type *dst0 = dst; \
for (i = 0; i < size; i += 4) { \
float in, res; \
FILTER_BW_O4_1(0, 1, 2, 3, fmt); \
FILTER_BW_O4_1(1, 2, 3, 0, fmt); \
FILTER_BW_O4_1(2, 3, 0, 1, fmt); \
FILTER_BW_O4_1(3, 0, 1, 2, fmt); \
} \
}
#define FILTER_DIRECT_FORM_II(type, fmt) { \
int i; \
const type *src0 = src; \
type *dst0 = dst; \
for (i = 0; i < size; i++) { \
int j; \
float in, res; \
in = *src0 * c->gain; \
for(j = 0; j < c->order; j++) \
in += c->cy[j] * s->x[j]; \
res = s->x[0] + in + s->x[c->order >> 1] * c->cx[c->order >> 1]; \
for(j = 1; j < c->order >> 1; j++) \
res += (s->x[j] + s->x[c->order - j]) * c->cx[j]; \
for(j = 0; j < c->order - 1; j++) \
s->x[j] = s->x[j + 1]; \
CONV_##fmt(*dst0, res) \
s->x[c->order - 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)
{
int i;
if(c->order == 4){
for(i = 0; i < size; i += 4){
float in, res;
if (c->order == 4) {
FILTER_BW_O4(int16_t, S16)
} else {
FILTER_DIRECT_FORM_II(int16_t, S16)
}
}
FILTER(0, 1, 2, 3);
FILTER(1, 2, 3, 0);
FILTER(2, 3, 0, 1);
FILTER(3, 0, 1, 2);
}
}else{
for(i = 0; i < size; i++){
int j;
float in, res;
in = *src * c->gain;
for(j = 0; j < c->order; j++)
in += c->cy[j] * s->x[j];
res = s->x[0] + in + s->x[c->order >> 1] * c->cx[c->order >> 1];
for(j = 1; j < c->order >> 1; j++)
res += (s->x[j] + s->x[c->order - j]) * c->cx[j];
for(j = 0; j < c->order - 1; j++)
s->x[j] = s->x[j + 1];
*dst = av_clip_int16(lrintf(res));
s->x[c->order - 1] = in;
src += sstep;
dst += dstep;
}
void ff_iir_filter_flt(const struct FFIIRFilterCoeffs *c,
struct FFIIRFilterState *s, int size,
const float *src, int sstep, void *dst, int dstep)
{
if (c->order == 4) {
FILTER_BW_O4(float, FLT)
} else {
FILTER_DIRECT_FORM_II(float, FLT)
}
}

17
libavcodec/iirfilter.h
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@ -87,7 +87,7 @@ void ff_iir_filter_free_coeffs(struct FFIIRFilterCoeffs *coeffs);
void ff_iir_filter_free_state(struct FFIIRFilterState *state);
/**
* Perform lowpass filtering on input samples.
* Perform IIR filtering on signed 16-bit input samples.
*
* @param coeffs pointer to filter coefficients
* @param state pointer to filter state
@ -100,4 +100,19 @@ void ff_iir_filter_free_state(struct FFIIRFilterState *state);
void ff_iir_filter(const struct FFIIRFilterCoeffs *coeffs, struct FFIIRFilterState *state,
int size, const int16_t *src, int sstep, int16_t *dst, int dstep);
/**
* Perform IIR filtering on floating-point input samples.
*
* @param coeffs pointer to filter coefficients
* @param state pointer to filter state
* @param size input length
* @param src source samples
* @param sstep source stride
* @param dst filtered samples (destination may be the same as input)
* @param dstep destination stride
*/
void ff_iir_filter_flt(const struct FFIIRFilterCoeffs *coeffs,
struct FFIIRFilterState *state, int size,
const float *src, int sstep, void *dst, int dstep);
#endif /* AVCODEC_IIRFILTER_H */

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