Merge commit 'e48746deec48e9ff195841bc3266b4e153a878cd'

[ffmpeg] / libavfilter / window_func.c

diff --git a/libavfilter/window_func.c b/libavfilter/window_func.c
index 9c6202aa187b7221aef952acb7ac8f3471a8c05f..acf1b20847ca26ad96ec470ee16042eb0238aa1f 100644 (file)
--- a/libavfilter/window_func.c
+++ b/libavfilter/window_func.c
@@ -116,6 +116,62 @@ void ff_generate_window_func(float *lut, int N, int win_func, float *overlap)
         }
         *overlap = 0.33;
         break;
+    case WFUNC_DOLPH: {
+        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)
+                t = sum, sum += (b *= c * (N - n - j) * (1./j));
+            sum /= (N - 1 - n), sum /= (norm = norm ? norm : sum);
+            lut[n] = sum;
+            lut[N - 1 - n] = sum;
+        }
+        *overlap = 0.5;}
+        break;
+    case WFUNC_CAUCHY:
+        for (n = 0; n < N; n++) {
+            double x = 2 * ((n / (double)(N - 1)) - .5);
+
+            if (x <= -.5 || x >= .5) {
+                lut[n] = 0;
+            } else {
+                lut[n] = FFMIN(1, fabs(1/(1+4*16*x*x)));
+            }
+        }
+        *overlap = 0.75;
+        break;
+    case WFUNC_PARZEN:
+        for (n = 0; n < N; n++) {
+            double x = 2 * ((n / (double)(N - 1)) - .5);
+
+            if (x > 0.25 && x <= 0.5) {
+                lut[n] = -2 * powf(-1 + 2 * x, 3);
+            } else if (x >= -.5 && x < -.25) {
+                lut[n] = 2 * powf(1 + 2 * x, 3);
+            } else if (x >= -.25 && x < 0) {
+                lut[n] = 1 - 24 * x * x - 48 * x * x * x;
+            } else if (x >= 0 && x <= .25) {
+                lut[n] = 1 - 24 * x * x + 48 * x * x * x;
+            } else {
+                lut[n] = 0;
+            }
+        }
+        *overlap = 0.75;
+        break;
+    case WFUNC_POISSON:
+        for (n = 0; n < N; n++) {
+            double x = 2 * ((n / (double)(N - 1)) - .5);
+
+            if (x >= 0 && x <= .5) {
+                lut[n] = exp(-6*x);
+            } else if (x < 0 && x >= -.5) {
+                lut[n] = exp(6*x);
+            } else {
+                lut[n] = 0;
+            }
+        }
+        *overlap = 0.75;
+        break;
     default:
         av_assert0(0);
     }