-// Generate a Kaiser-Bessel Derived Window.
-#define BESSEL_I0_ITER 50 // default: 50 iterations of Bessel I0 approximation
-av_cold void ff_kbd_window_init(float *window, float alpha, int n)
-{
- int i, j;
- double sum = 0.0, bessel, tmp;
- double local_window[n];
- double alpha2 = (alpha * M_PI / n) * (alpha * M_PI / n);
-
- for (i = 0; i < n; i++) {
- tmp = i * (n - i) * alpha2;
- bessel = 1.0;
- for (j = BESSEL_I0_ITER; j > 0; j--)
- bessel = bessel * tmp / (j * j) + 1;
- sum += bessel;
- local_window[i] = sum;
- }
-
- sum++;
- for (i = 0; i < n; i++)
- window[i] = sqrt(local_window[i] / sum);
-}
-
-DECLARE_ALIGNED(16, float, ff_sine_128 [ 128]);
-DECLARE_ALIGNED(16, float, ff_sine_256 [ 256]);
-DECLARE_ALIGNED(16, float, ff_sine_512 [ 512]);
-DECLARE_ALIGNED(16, float, ff_sine_1024[1024]);
-DECLARE_ALIGNED(16, float, ff_sine_2048[2048]);
-DECLARE_ALIGNED(16, float, ff_sine_4096[4096]);
-float *ff_sine_windows[6] = {
- ff_sine_128, ff_sine_256, ff_sine_512, ff_sine_1024, ff_sine_2048, ff_sine_4096
-};
-
-// Generate a sine window.
-av_cold void ff_sine_window_init(float *window, int n) {
- int i;
- for(i = 0; i < n; i++)
- window[i] = sinf((i + 0.5) * (M_PI / (2.0 * n)));
-}