[SCM] libav/experimental: Add function ff_iir_filter_flt() to accept floating-point input and output.
siretart at users.alioth.debian.org
siretart at users.alioth.debian.org
Sun Jun 30 17:22:17 UTC 2013
The following commit has been merged in the experimental branch:
commit 0a3d7697b4fcb62305cd4a893b621a406a029ff0
Author: Justin Ruggles <justin.ruggles at gmail.com>
Date: Thu Jan 20 17:24:06 2011 +0000
Add function ff_iir_filter_flt() to accept floating-point input and output.
Signed-off-by: Mans Rullgard <mans at mansr.com>
diff --git a/libavcodec/iirfilter.c b/libavcodec/iirfilter.c
index 65d9f89..e37fd81 100644
--- a/libavcodec/iirfilter.c
+++ b/libavcodec/iirfilter.c
@@ -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)
}
}
diff --git a/libavcodec/iirfilter.h b/libavcodec/iirfilter.h
index f660955..fd26166 100644
--- a/libavcodec/iirfilter.h
+++ b/libavcodec/iirfilter.h
@@ -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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