gstreamer/ext/cog/generate_tables.c

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2009-09-21 18:33:50 +00:00
#include "config.h"
#include <glib.h>
#include <math.h>
#define SCALE 256
void
get_taps (double *taps, double x)
{
taps[3] = x * x * (x - 1);
taps[2] = x * (-x * x + x + 1);
x = 1 - x;
taps[1] = x * (-x * x + x + 1);
taps[0] = x * x * (x - 1);
}
int
main (int argc, char *argv[])
{
int i;
g_print ("/* This file is autogenerated. Do not edit.*/\n");
g_print ("#include <glib.h>\n");
g_print ("gint8 cog_resample_table_4tap[256][4] = {\n");
for (i = 0; i < 256; i++) {
double x = i / 256.0;
double taps[4];
int t[4];
int sum;
get_taps (taps, x);
taps[0] *= SCALE;
taps[1] *= SCALE;
taps[2] *= SCALE;
taps[3] *= SCALE;
t[0] = floor (taps[0]);
t[1] = floor (taps[1]);
t[2] = floor (taps[2]);
t[3] = floor (taps[3]);
sum = t[0] + t[1] + t[2] + t[3];
for (; sum < SCALE; sum++) {
int i;
double max = 0;
int max_i = -1;
for (i = 0; i < 4; i++) {
if (max_i == -1 || (t[i] < taps[i] && (taps[i] - t[i]) > max)) {
max_i = i;
max = taps[i] - t[i];
}
}
t[max_i]++;
}
sum = t[0] + t[1] + t[2] + t[3];
g_print (" { %d, %d, %d, %d }, /* %d %d */\n",
t[0], t[1], t[2], t[3], t[2] + t[0], t[1] + t[3]);
#if 0
g_print ("/* %.3f %.3f %.3f %.3f %d */\n",
taps[0] - t[0], taps[1] - t[1], taps[2] - t[2], taps[3] - t[3], sum);
#endif
}
g_print ("};\n");
g_print ("\n");
return 0;
}