Merge commit 'cb45553f577f8e0ebfe05d3287e1b6fa5859b967'
[ffmpeg.git] / libavcodec / iirfilter.c
index e37fd81..610add1 100644 (file)
@@ -26,6 +26,7 @@
 
 #include "iirfilter.h"
 #include <math.h>
+#include "libavutil/common.h"
 
 /**
  * IIR filter global parameters
@@ -47,25 +48,25 @@ typedef struct FFIIRFilterState{
 /// maximum supported filter order
 #define MAXORDER 30
 
-av_cold struct FFIIRFilterCoeffs* ff_iir_filter_init_coeffs(enum IIRFilterType filt_type,
-                                                    enum IIRFilterMode filt_mode,
-                                                    int order, float cutoff_ratio,
-                                                    float stopband, float ripple)
+static int butterworth_init_coeffs(void *avc, struct FFIIRFilterCoeffs *c,
+                                   enum IIRFilterMode filt_mode,
+                                   int order, float cutoff_ratio,
+                                   float stopband)
 {
     int i, j;
-    FFIIRFilterCoeffs *c;
     double wa;
     double p[MAXORDER + 1][2];
 
-    if(filt_type != FF_FILTER_TYPE_BUTTERWORTH || filt_mode != FF_FILTER_MODE_LOWPASS)
-        return NULL;
-    if(order <= 1 || (order & 1) || order > MAXORDER || cutoff_ratio >= 1.0)
-        return NULL;
-
-    c = av_malloc(sizeof(FFIIRFilterCoeffs));
-    c->cx = av_malloc(sizeof(c->cx[0]) * ((order >> 1) + 1));
-    c->cy = av_malloc(sizeof(c->cy[0]) * order);
-    c->order = order;
+    if (filt_mode != FF_FILTER_MODE_LOWPASS) {
+        av_log(avc, AV_LOG_ERROR, "Butterworth filter currently only supports "
+               "low-pass filter mode\n");
+        return -1;
+    }
+    if (order & 1) {
+        av_log(avc, AV_LOG_ERROR, "Butterworth filter currently only supports "
+               "even filter orders\n");
+        return -1;
+    }
 
     wa = 2 * tan(M_PI * 0.5 * cutoff_ratio);
 
@@ -109,7 +110,92 @@ av_cold struct FFIIRFilterCoeffs* ff_iir_filter_init_coeffs(enum IIRFilterType f
     }
     c->gain /= 1 << order;
 
-    return c;
+    return 0;
+}
+
+static int biquad_init_coeffs(void *avc, struct FFIIRFilterCoeffs *c,
+                              enum IIRFilterMode filt_mode, int order,
+                              float cutoff_ratio, float stopband)
+{
+    double cos_w0, sin_w0;
+    double a0, x0, x1;
+
+    if (filt_mode != FF_FILTER_MODE_HIGHPASS &&
+        filt_mode != FF_FILTER_MODE_LOWPASS) {
+        av_log(avc, AV_LOG_ERROR, "Biquad filter currently only supports "
+               "high-pass and low-pass filter modes\n");
+        return -1;
+    }
+    if (order != 2) {
+        av_log(avc, AV_LOG_ERROR, "Biquad filter must have order of 2\n");
+        return -1;
+    }
+
+    cos_w0 = cos(M_PI * cutoff_ratio);
+    sin_w0 = sin(M_PI * cutoff_ratio);
+
+    a0 = 1.0 + (sin_w0 / 2.0);
+
+    if (filt_mode == FF_FILTER_MODE_HIGHPASS) {
+        c->gain  =  ((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) / 2.0)  / a0;
+        x1       =   (1.0 - cos_w0)         / 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
+    c->cx[0] = lrintf(x0 / c->gain);
+    c->cx[1] = lrintf(x1 / c->gain);
+
+    return 0;
+}
+
+av_cold struct FFIIRFilterCoeffs* ff_iir_filter_init_coeffs(void *avc,
+                                                enum IIRFilterType filt_type,
+                                                enum IIRFilterMode filt_mode,
+                                                int order, float cutoff_ratio,
+                                                float stopband, float ripple)
+{
+    FFIIRFilterCoeffs *c;
+    int ret = 0;
+
+    if (order <= 0 || order > MAXORDER || cutoff_ratio >= 1.0)
+        return NULL;
+
+    FF_ALLOCZ_OR_GOTO(avc, c,     sizeof(FFIIRFilterCoeffs),
+                      init_fail);
+    FF_ALLOC_OR_GOTO (avc, c->cx, sizeof(c->cx[0]) * ((order >> 1) + 1),
+                      init_fail);
+    FF_ALLOC_OR_GOTO (avc, c->cy, sizeof(c->cy[0]) * order,
+                      init_fail);
+    c->order = order;
+
+    switch (filt_type) {
+    case FF_FILTER_TYPE_BUTTERWORTH:
+        ret = butterworth_init_coeffs(avc, c, filt_mode, order, cutoff_ratio,
+                                      stopband);
+        break;
+    case FF_FILTER_TYPE_BIQUAD:
+        ret = biquad_init_coeffs(avc, c, filt_mode, order, cutoff_ratio,
+                                 stopband);
+        break;
+    default:
+        av_log(avc, AV_LOG_ERROR, "filter type is not currently implemented\n");
+        goto init_fail;
+    }
+
+    if (!ret)
+        return c;
+
+init_fail:
+    ff_iir_filter_free_coeffs(c);
+    return NULL;
 }
 
 av_cold struct FFIIRFilterState* ff_iir_filter_init_state(int order)
@@ -169,9 +255,29 @@ av_cold struct FFIIRFilterState* ff_iir_filter_init_state(int order)
     }                                                                       \
 }
 
-void ff_iir_filter(const struct FFIIRFilterCoeffs *c, struct FFIIRFilterState *s, int size, const int16_t *src, int sstep, int16_t *dst, int dstep)
+#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)
@@ -180,9 +286,11 @@ void ff_iir_filter(const struct FFIIRFilterCoeffs *c, struct FFIIRFilterState *s
 
 void ff_iir_filter_flt(const struct FFIIRFilterCoeffs *c,
                        struct FFIIRFilterState *s, int size,
-                       const float *src, int sstep, void *dst, int dstep)
+                       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)
@@ -204,6 +312,8 @@ av_cold void ff_iir_filter_free_coeffs(struct FFIIRFilterCoeffs *coeffs)
 }
 
 #ifdef TEST
+#include <stdio.h>
+
 #define FILT_ORDER 4
 #define SIZE 1024
 int main(void)
@@ -213,9 +323,8 @@ int main(void)
     float cutoff_coeff = 0.4;
     int16_t x[SIZE], y[SIZE];
     int i;
-    FILE* fd;
 
-    fcoeffs = ff_iir_filter_init_coeffs(FF_FILTER_TYPE_BUTTERWORTH,
+    fcoeffs = ff_iir_filter_init_coeffs(NULL, FF_FILTER_TYPE_BUTTERWORTH,
                                         FF_FILTER_MODE_LOWPASS, FILT_ORDER,
                                         cutoff_coeff, 0.0, 0.0);
     fstate  = ff_iir_filter_init_state(FILT_ORDER);
@@ -226,13 +335,8 @@ int main(void)
 
     ff_iir_filter(fcoeffs, fstate, SIZE, x, 1, y, 1);
 
-    fd = fopen("in.bin", "w");
-    fwrite(x, sizeof(x[0]), SIZE, fd);
-    fclose(fd);
-
-    fd = fopen("out.bin", "w");
-    fwrite(y, sizeof(y[0]), SIZE, fd);
-    fclose(fd);
+    for (i = 0; i < SIZE; i++)
+        printf("%6d %6d\n", x[i], y[i]);
 
     ff_iir_filter_free_coeffs(fcoeffs);
     ff_iir_filter_free_state(fstate);