dds: Fix enum declaration
[ffmpeg.git] / libavcodec / iirfilter.c
index 62c2a61..40a543d 100644 (file)
@@ -2,31 +2,32 @@
  * IIR filter
  * Copyright (c) 2008 Konstantin Shishkov
  *
- * This file is part of FFmpeg.
+ * This file is part of Libav.
  *
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
- * FFmpeg is distributed in the hope that it will be useful,
+ * Libav is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**
- * @file libavcodec/iirfilter.c
+ * @file
  * different IIR filters implementation
  */
 
 #include "iirfilter.h"
-#include <complex.h>
 #include <math.h>
+#include "libavutil/attributes.h"
+#include "libavutil/common.h"
 
 /**
  * IIR filter global parameters
@@ -48,25 +49,26 @@ typedef struct FFIIRFilterState{
 /// maximum supported filter order
 #define MAXORDER 30
 
-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 av_cold int butterworth_init_coeffs(void *avc,
+                                           struct FFIIRFilterCoeffs *c,
+                                           enum IIRFilterMode filt_mode,
+                                           int order, float cutoff_ratio,
+                                           float stopband)
 {
-    int i, j, size;
-    FFIIRFilterCoeffs *c;
+    int i, j;
     double wa;
-    complex p[MAXORDER + 1];
-
-    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;
+    double p[MAXORDER + 1][2];
 
-    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);
 
@@ -74,86 +76,235 @@ struct FFIIRFilterCoeffs* ff_iir_filter_init_coeffs(enum IIRFilterType filt_type
     for(i = 1; i < (order >> 1) + 1; i++)
         c->cx[i] = c->cx[i - 1] * (order - i + 1LL) / i;
 
-    p[0] = 1.0;
+    p[0][0] = 1.0;
+    p[0][1] = 0.0;
     for(i = 1; i <= order; i++)
-        p[i] = 0.0;
+        p[i][0] = p[i][1] = 0.0;
     for(i = 0; i < order; i++){
-        complex zp;
+        double zp[2];
         double th = (i + (order >> 1) + 0.5) * M_PI / order;
-        zp = cexp(I*th) * wa;
-        zp = (zp + 2.0) / (zp - 2.0);
+        double a_re, a_im, c_re, c_im;
+        zp[0] = cos(th) * wa;
+        zp[1] = sin(th) * wa;
+        a_re = zp[0] + 2.0;
+        c_re = zp[0] - 2.0;
+        a_im =
+        c_im = zp[1];
+        zp[0] = (a_re * c_re + a_im * c_im) / (c_re * c_re + c_im * c_im);
+        zp[1] = (a_im * c_re - a_re * c_im) / (c_re * c_re + c_im * c_im);
 
         for(j = order; j >= 1; j--)
-            p[j] = zp*p[j] + p[j - 1];
-        p[0] *= zp;
+        {
+            a_re = p[j][0];
+            a_im = p[j][1];
+            p[j][0] = a_re*zp[0] - a_im*zp[1] + p[j-1][0];
+            p[j][1] = a_re*zp[1] + a_im*zp[0] + p[j-1][1];
+        }
+        a_re    = p[0][0]*zp[0] - p[0][1]*zp[1];
+        p[0][1] = p[0][0]*zp[1] + p[0][1]*zp[0];
+        p[0][0] = a_re;
     }
-    c->gain = creal(p[order]);
+    c->gain = p[order][0];
     for(i = 0; i < order; i++){
-        c->gain += creal(p[i]);
-        c->cy[i] = creal(-p[i] / p[order]);
+        c->gain += p[i][0];
+        c->cy[i] = (-p[i][0] * p[order][0] + -p[i][1] * p[order][1]) /
+                   (p[order][0] * p[order][0] + p[order][1] * p[order][1]);
     }
     c->gain /= 1 << order;
 
-    return c;
+    return 0;
+}
+
+static av_cold 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;
 }
 
-struct FFIIRFilterState* ff_iir_filter_init_state(int order)
+av_cold struct FFIIRFilterState* ff_iir_filter_init_state(int order)
 {
     FFIIRFilterState* s = av_mallocz(sizeof(FFIIRFilterState) + sizeof(s->x[0]) * (order - 1));
     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;                                 \
-
-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;
+#define CONV_S16(dest, source) dest = av_clip_int16(lrintf(source));
 
-    if(c->order == 4){
-        for(i = 0; i < size; i += 4){
-            float in, res;
+#define CONV_FLT(dest, source) dest = source;
 
-            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 += sstep;
-        }
+#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;                                                      \
+    }                                                                       \
+}
+
+#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 == 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)
     }
 }
 
-void ff_iir_filter_free_state(struct FFIIRFilterState *state)
+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 == 2) {
+        FILTER_O2(float, FLT)
+    } else if (c->order == 4) {
+        FILTER_BW_O4(float, FLT)
+    } else {
+        FILTER_DIRECT_FORM_II(float, FLT)
+    }
+}
+
+av_cold void ff_iir_filter_free_state(struct FFIIRFilterState *state)
 {
     av_free(state);
 }
 
-void ff_iir_filter_free_coeffs(struct FFIIRFilterCoeffs *coeffs)
+av_cold void ff_iir_filter_free_coeffs(struct FFIIRFilterCoeffs *coeffs)
 {
     if(coeffs){
         av_free(coeffs->cx);
@@ -162,3 +313,35 @@ void ff_iir_filter_free_coeffs(struct FFIIRFilterCoeffs *coeffs)
     av_free(coeffs);
 }
 
+#ifdef TEST
+#include <stdio.h>
+
+#define FILT_ORDER 4
+#define SIZE 1024
+int main(void)
+{
+    struct FFIIRFilterCoeffs *fcoeffs = NULL;
+    struct FFIIRFilterState  *fstate  = NULL;
+    float cutoff_coeff = 0.4;
+    int16_t x[SIZE], y[SIZE];
+    int i;
+
+    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);
+
+    for (i = 0; i < SIZE; i++) {
+        x[i] = lrint(0.75 * INT16_MAX * sin(0.5*M_PI*i*i/SIZE));
+    }
+
+    ff_iir_filter(fcoeffs, fstate, SIZE, x, 1, y, 1);
+
+    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);
+    return 0;
+}
+#endif /* TEST */