avfilter/window_func: use a constant instead of acosh()
authorJames Almer <jamrial@gmail.com>
Sat, 20 Aug 2016 04:03:00 +0000 (01:03 -0300)
committerJames Almer <jamrial@gmail.com>
Sat, 20 Aug 2016 14:50:58 +0000 (11:50 -0300)
Should fix compilation with non C99 compilers like msvc 2012, where
acosh() is not available.

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
libavfilter/window_func.c

index fcdf6ea..acf1b20 100644 (file)
@@ -117,7 +117,7 @@ void ff_generate_window_func(float *lut, int N, int win_func, float *overlap)
         *overlap = 0.33;
         break;
     case WFUNC_DOLPH: {
-        double b = cosh(acosh(pow(10., 3)) / (N-1)), sum, t, c, norm = 0;
+        double b = cosh(7.6009022095419887 / (N-1)), sum, t, c, norm = 0;
         int j;
         for (c = 1 - 1 / (b*b), n = (N-1) / 2; n >= 0; --n) {
             for (sum = !n, b = t = j = 1; j <= n && sum != t; b *= (n-j) * (1./j), ++j)