avfilter: move window function generation into separate file

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavfilter/Makefile

@@ -284,7 +284,7 @@ OBJS-$(CONFIG_APHASEMETER_FILTER)            += avf_aphasemeter.o
 OBJS-$(CONFIG_AVECTORSCOPE_FILTER)           += avf_avectorscope.o
 OBJS-$(CONFIG_CONCAT_FILTER)                 += avf_concat.o
 OBJS-$(CONFIG_SHOWCQT_FILTER)                += avf_showcqt.o lswsutils.o lavfutils.o
-OBJS-$(CONFIG_SHOWFREQS_FILTER)              += avf_showfreqs.o
+OBJS-$(CONFIG_SHOWFREQS_FILTER)              += avf_showfreqs.o window_func.o
 OBJS-$(CONFIG_SHOWSPECTRUM_FILTER)           += avf_showspectrum.o
 OBJS-$(CONFIG_SHOWVOLUME_FILTER)             += avf_showvolume.o
 OBJS-$(CONFIG_SHOWWAVES_FILTER)              += avf_showwaves.o

libavfilter/avf_showfreqs.c

@@ -32,15 +32,12 @@
 #include "video.h"
 #include "avfilter.h"
 #include "internal.h"
+#include "window_func.h"
 
 enum DisplayMode    { LINE, BAR, DOT, NB_MODES };
 enum ChannelMode    { COMBINED, SEPARATE, NB_CMODES };
 enum FrequencyScale { FS_LINEAR, FS_LOG, FS_RLOG, NB_FSCALES };
 enum AmplitudeScale { AS_LINEAR, AS_SQRT, AS_CBRT, AS_LOG, NB_ASCALES };
-enum WindowFunc     { WFUNC_RECT, WFUNC_HANNING, WFUNC_HAMMING, WFUNC_BLACKMAN,
-                      WFUNC_BARTLETT, WFUNC_WELCH, WFUNC_FLATTOP,
-                      WFUNC_BHARRIS, WFUNC_BNUTTALL, WFUNC_SINE, WFUNC_NUTTALL,
-                      WFUNC_BHANN, WFUNC_LANCZOS, WFUNC_GAUSS, NB_WFUNC };
 
 typedef struct ShowFreqsContext {
     const AVClass *class;
@@ -156,92 +153,6 @@ static int query_formats(AVFilterContext *ctx)
     return 0;
 }
 
-static void generate_window_func(float *lut, int N, int win_func, float *overlap)
-{
-    int n;
-
-    switch (win_func) {
-    case WFUNC_RECT:
-        for (n = 0; n < N; n++)
-            lut[n] = 1.;
-        *overlap = 0.;
-        break;
-    case WFUNC_BARTLETT:
-        for (n = 0; n < N; n++)
-            lut[n] = 1.-fabs((n-(N-1)/2.)/((N-1)/2.));
-        *overlap = 0.5;
-        break;
-    case WFUNC_HANNING:
-        for (n = 0; n < N; n++)
-            lut[n] = .5*(1-cos(2*M_PI*n/(N-1)));
-        *overlap = 0.5;
-        break;
-    case WFUNC_HAMMING:
-        for (n = 0; n < N; n++)
-            lut[n] = .54-.46*cos(2*M_PI*n/(N-1));
-        *overlap = 0.5;
-        break;
-    case WFUNC_BLACKMAN:
-        for (n = 0; n < N; n++)
-            lut[n] = .42659-.49656*cos(2*M_PI*n/(N-1))+.076849*cos(4*M_PI*n/(N-1));
-        *overlap = 0.661;
-        break;
-    case WFUNC_WELCH:
-        for (n = 0; n < N; n++)
-            lut[n] = 1.-(n-(N-1)/2.)/((N-1)/2.)*(n-(N-1)/2.)/((N-1)/2.);
-        *overlap = 0.293;
-        break;
-    case WFUNC_FLATTOP:
-        for (n = 0; n < N; n++)
-            lut[n] = 1.-1.985844164102*cos( 2*M_PI*n/(N-1))+1.791176438506*cos( 4*M_PI*n/(N-1))-
-                        1.282075284005*cos( 6*M_PI*n/(N-1))+0.667777530266*cos( 8*M_PI*n/(N-1))-
-                        0.240160796576*cos(10*M_PI*n/(N-1))+0.056656381764*cos(12*M_PI*n/(N-1))-
-                        0.008134974479*cos(14*M_PI*n/(N-1))+0.000624544650*cos(16*M_PI*n/(N-1))-
-                        0.000019808998*cos(18*M_PI*n/(N-1))+0.000000132974*cos(20*M_PI*n/(N-1));
-        *overlap = 0.841;
-        break;
-    case WFUNC_BHARRIS:
-        for (n = 0; n < N; n++)
-            lut[n] = 0.35875-0.48829*cos(2*M_PI*n/(N-1))+0.14128*cos(4*M_PI*n/(N-1))-0.01168*cos(6*M_PI*n/(N-1));
-        *overlap = 0.661;
-        break;
-    case WFUNC_BNUTTALL:
-        for (n = 0; n < N; n++)
-            lut[n] = 0.3635819-0.4891775*cos(2*M_PI*n/(N-1))+0.1365995*cos(4*M_PI*n/(N-1))-0.0106411*cos(6*M_PI*n/(N-1));
-        *overlap = 0.661;
-        break;
-    case WFUNC_BHANN:
-        for (n = 0; n < N; n++)
-            lut[n] = 0.62-0.48*fabs(n/(double)(N-1)-.5)-0.38*cos(2*M_PI*n/(N-1));
-        *overlap = 0.5;
-        break;
-    case WFUNC_SINE:
-        for (n = 0; n < N; n++)
-            lut[n] = sin(M_PI*n/(N-1));
-        *overlap = 0.75;
-        break;
-    case WFUNC_NUTTALL:
-        for (n = 0; n < N; n++)
-            lut[n] = 0.355768-0.487396*cos(2*M_PI*n/(N-1))+0.144232*cos(4*M_PI*n/(N-1))-0.012604*cos(6*M_PI*n/(N-1));
-        *overlap = 0.663;
-        break;
-    case WFUNC_LANCZOS:
-#define SINC(x) (!(x)) ? 1 : sin(M_PI * (x))/(M_PI * (x));
-        for (n = 0; n < N; n++)
-            lut[n] = SINC((2.*n)/(N-1)-1);
-        *overlap = 0.75;
-        break;
-    case WFUNC_GAUSS:
-#define SQR(x) ((x)*(x))
-        for (n = 0; n < N; n++)
-            lut[n] = exp(-0.5 * SQR((n-(N-1)/2)/(0.4*(N-1)/2.f)));
-        *overlap = 0.75;
-        break;
-    default:
-        av_assert0(0);
-    }
-}
-
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
@@ -290,7 +201,7 @@ static int config_output(AVFilterLink *outlink)
                                       sizeof(*s->window_func_lut));
     if (!s->window_func_lut)
         return AVERROR(ENOMEM);
-    generate_window_func(s->window_func_lut, s->win_size, s->win_func, &overlap);
+    ff_generate_window_func(s->window_func_lut, s->win_size, s->win_func, &overlap);
     if (s->overlap == 1.)
         s->overlap = overlap;
     s->skip_samples = (1. - s->overlap) * s->win_size;

libavfilter/window_func.c

@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2015 Paul B Mahol
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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,
+ * 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
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <math.h>
+
+#include "libavutil/avassert.h"
+#include "window_func.h"
+
+void ff_generate_window_func(float *lut, int N, int win_func, float *overlap)
+{
+    int n;
+
+    switch (win_func) {
+    case WFUNC_RECT:
+        for (n = 0; n < N; n++)
+            lut[n] = 1.;
+        *overlap = 0.;
+        break;
+    case WFUNC_BARTLETT:
+        for (n = 0; n < N; n++)
+            lut[n] = 1.-fabs((n-(N-1)/2.)/((N-1)/2.));
+        *overlap = 0.5;
+        break;
+    case WFUNC_HANNING:
+        for (n = 0; n < N; n++)
+            lut[n] = .5*(1-cos(2*M_PI*n/(N-1)));
+        *overlap = 0.5;
+        break;
+    case WFUNC_HAMMING:
+        for (n = 0; n < N; n++)
+            lut[n] = .54-.46*cos(2*M_PI*n/(N-1));
+        *overlap = 0.5;
+        break;
+    case WFUNC_BLACKMAN:
+        for (n = 0; n < N; n++)
+            lut[n] = .42659-.49656*cos(2*M_PI*n/(N-1))+.076849*cos(4*M_PI*n/(N-1));
+        *overlap = 0.661;
+        break;
+    case WFUNC_WELCH:
+        for (n = 0; n < N; n++)
+            lut[n] = 1.-(n-(N-1)/2.)/((N-1)/2.)*(n-(N-1)/2.)/((N-1)/2.);
+        *overlap = 0.293;
+        break;
+    case WFUNC_FLATTOP:
+        for (n = 0; n < N; n++)
+            lut[n] = 1.-1.985844164102*cos( 2*M_PI*n/(N-1))+1.791176438506*cos( 4*M_PI*n/(N-1))-
+                        1.282075284005*cos( 6*M_PI*n/(N-1))+0.667777530266*cos( 8*M_PI*n/(N-1))-
+                        0.240160796576*cos(10*M_PI*n/(N-1))+0.056656381764*cos(12*M_PI*n/(N-1))-
+                        0.008134974479*cos(14*M_PI*n/(N-1))+0.000624544650*cos(16*M_PI*n/(N-1))-
+                        0.000019808998*cos(18*M_PI*n/(N-1))+0.000000132974*cos(20*M_PI*n/(N-1));
+        *overlap = 0.841;
+        break;
+    case WFUNC_BHARRIS:
+        for (n = 0; n < N; n++)
+            lut[n] = 0.35875-0.48829*cos(2*M_PI*n/(N-1))+0.14128*cos(4*M_PI*n/(N-1))-0.01168*cos(6*M_PI*n/(N-1));
+        *overlap = 0.661;
+        break;
+    case WFUNC_BNUTTALL:
+        for (n = 0; n < N; n++)
+            lut[n] = 0.3635819-0.4891775*cos(2*M_PI*n/(N-1))+0.1365995*cos(4*M_PI*n/(N-1))-0.0106411*cos(6*M_PI*n/(N-1));
+        *overlap = 0.661;
+        break;
+    case WFUNC_BHANN:
+        for (n = 0; n < N; n++)
+            lut[n] = 0.62-0.48*fabs(n/(double)(N-1)-.5)-0.38*cos(2*M_PI*n/(N-1));
+        *overlap = 0.5;
+        break;
+    case WFUNC_SINE:
+        for (n = 0; n < N; n++)
+            lut[n] = sin(M_PI*n/(N-1));
+        *overlap = 0.75;
+        break;
+    case WFUNC_NUTTALL:
+        for (n = 0; n < N; n++)
+            lut[n] = 0.355768-0.487396*cos(2*M_PI*n/(N-1))+0.144232*cos(4*M_PI*n/(N-1))-0.012604*cos(6*M_PI*n/(N-1));
+        *overlap = 0.663;
+        break;
+    case WFUNC_LANCZOS:
+#define SINC(x) (!(x)) ? 1 : sin(M_PI * (x))/(M_PI * (x));
+        for (n = 0; n < N; n++)
+            lut[n] = SINC((2.*n)/(N-1)-1);
+        *overlap = 0.75;
+        break;
+    case WFUNC_GAUSS:
+#define SQR(x) ((x)*(x))
+        for (n = 0; n < N; n++)
+            lut[n] = exp(-0.5 * SQR((n-(N-1)/2)/(0.4*(N-1)/2.f)));
+        *overlap = 0.75;
+        break;
+    default:
+        av_assert0(0);
+    }
+}

libavfilter/window_func.h

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2015 Paul B Mahol
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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,
+ * 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
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+
+#ifndef AVFILTER_WINDOW_FUNC_H
+#define AVFILTER_WINDOW_FUNC_H
+
+enum WindowFunc     { WFUNC_RECT, WFUNC_HANNING, WFUNC_HAMMING, WFUNC_BLACKMAN,
+                      WFUNC_BARTLETT, WFUNC_WELCH, WFUNC_FLATTOP,
+                      WFUNC_BHARRIS, WFUNC_BNUTTALL, WFUNC_SINE, WFUNC_NUTTALL,
+                      WFUNC_BHANN, WFUNC_LANCZOS, WFUNC_GAUSS, NB_WFUNC };
+
+void ff_generate_window_func(float *lut, int N, int win_func, float *overlap);
+
+#endif /* AVFILTER_WINDOW_FUNC_H */