if (filt_mode == FF_FILTER_MODE_HIGHPASS) {
c->gain = ((1.0 + cos_w0) / 2.0) / a0;
- x0 = (-(1.0 + cos_w0)) / a0;
- x1 = ((1.0 + cos_w0) / 2.0) / a0;
+ x0 = ((1.0 + cos_w0) / 2.0) / a0;
+ x1 = (-(1.0 + cos_w0)) / a0;
} else { // FF_FILTER_MODE_LOWPASS
c->gain = ((1.0 - cos_w0) / 2.0) / a0;
- x0 = (1.0 - cos_w0) / a0;
- x1 = ((1.0 - cos_w0) / 2.0) / a0;
+ x0 = ((1.0 - cos_w0) / 2.0) / a0;
+ x1 = (1.0 - cos_w0) / a0;
}
- c->cy[0] = (2.0 * cos_w0) / a0;
- c->cy[1] = (-1.0 + (sin_w0 / 2.0)) / a0;
+ c->cy[0] = (-1.0 + (sin_w0 / 2.0)) / a0;
+ c->cy[1] = (2.0 * cos_w0) / a0;
// divide by gain to make the x coeffs integers.
// during filtering, the delay state will include the gain multiplication
} \
}
+#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)
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)