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avcodec/kbdwin: Support arbitrary sized windows

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Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2023-06-14 17:22:55 +02:00
parent 94d44dbe21
commit cf00f60bab
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GPG Key ID: B18E8928B3948D64
2 changed files with 19 additions and 11 deletions
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22
libavcodec/kbdwin.c
View File

@ -19,20 +19,23 @@
#include "libavutil/avassert.h" #include "libavutil/avassert.h"
#include "libavutil/mathematics.h" #include "libavutil/mathematics.h"
#include "libavutil/attributes.h" #include "libavutil/attributes.h"
#include "libavutil/mem.h"
#include "kbdwin.h" #include "kbdwin.h"
av_cold static void kbd_window_init(float *float_window, int *int_window, float alpha, int n) av_cold static int kbd_window_init(float *float_window, int *int_window, float alpha, int n)
{ {
int i; int i;
double sum = 0.0, tmp; double sum = 0.0, tmp;
double scale = 0.0; double scale = 0.0;
double temp[FF_KBD_WINDOW_MAX / 2 + 1]; double temp_small[FF_KBD_WINDOW_MAX / 2 + 1];
double *temp= n<=FF_KBD_WINDOW_MAX ? temp_small : av_malloc((n/2+1) * sizeof(*temp));
double alpha2 = 4 * (alpha * M_PI / n) * (alpha * M_PI / n); double alpha2 = 4 * (alpha * M_PI / n) * (alpha * M_PI / n);
av_assert0(n <= FF_KBD_WINDOW_MAX); if (!temp)
return AVERROR(ENOMEM);
for (i = 0; i <= n / 2; i++) { for (i = 0; i <= n / 2; i++) {
tmp = i * (n - i) * alpha2; tmp = alpha2 * i * (n - i);
temp[i] = av_bessel_i0(sqrt(tmp)); temp[i] = av_bessel_i0(sqrt(tmp));
scale += temp[i] * (1 + (i && i<n/2)); scale += temp[i] * (1 + (i && i<n/2));
} }
@ -48,14 +51,17 @@ av_cold static void kbd_window_init(float *float_window, int *int_window, float
if (float_window) float_window[i] = sqrt(sum * scale); if (float_window) float_window[i] = sqrt(sum * scale);
else int_window[i] = lrint(2147483647 * sqrt(sum * scale)); else int_window[i] = lrint(2147483647 * sqrt(sum * scale));
} }
if (temp != temp_small)
av_free(temp);
return 0;
} }
av_cold void ff_kbd_window_init(float *window, float alpha, int n) av_cold int ff_kbd_window_init(float *window, float alpha, int n)
{ {
kbd_window_init(window, NULL, alpha, n); return kbd_window_init(window, NULL, alpha, n);
} }
av_cold void ff_kbd_window_init_fixed(int32_t *window, float alpha, int n) av_cold int ff_kbd_window_init_fixed(int32_t *window, float alpha, int n)
{ {
kbd_window_init(NULL, window, alpha, n); return kbd_window_init(NULL, window, alpha, n);
} }

8
libavcodec/kbdwin.h
View File

@ -30,9 +30,11 @@
* Generate a Kaiser-Bessel Derived Window. * Generate a Kaiser-Bessel Derived Window.
* @param window pointer to half window * @param window pointer to half window
* @param alpha determines window shape * @param alpha determines window shape
* @param n size of half window, max FF_KBD_WINDOW_MAX * @param n size of half window
*
* @return if n is larger than FF_KBD_WINDOW_MAX then AVERROR(ENOMEM) is possible
*/ */
void ff_kbd_window_init(float *window, float alpha, int n); int ff_kbd_window_init(float *window, float alpha, int n);
void ff_kbd_window_init_fixed(int32_t *window, float alpha, int n); int ff_kbd_window_init_fixed(int32_t *window, float alpha, int n);
#endif /* AVCODEC_KBDWIN_H */ #endif /* AVCODEC_KBDWIN_H */