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bb81c60927
This reverts commitsfd5aa93a37andcf00f60bab("avcodec/kbdwin: Support arbitrary sized windows"). The change in question has only been made for libavradio. in anticipation of merging it into the main tree. This has not happened, so this commit reverts the changes to kbdwin that are not used for anything else. In particular, these functions are no longer exported (as avpriv functions); notice that the fixed-point function has been exported despite having never been used outside of lavc. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
63 lines
2.0 KiB
C
63 lines
2.0 KiB
C
/*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/avassert.h"
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#include "libavutil/libm.h"
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#include "libavutil/mathematics.h"
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#include "libavutil/attributes.h"
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#include "kbdwin.h"
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av_cold static void kbd_window_init(float *float_window, int *int_window, float alpha, int n)
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{
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int i;
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double sum = 0.0, tmp;
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double scale = 0.0;
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double temp[FF_KBD_WINDOW_MAX / 2 + 1];
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double alpha2 = 4 * (alpha * M_PI / n) * (alpha * M_PI / n);
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av_assert0(n <= FF_KBD_WINDOW_MAX);
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for (i = 0; i <= n / 2; i++) {
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tmp = i * (n - i) * alpha2;
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temp[i] = av_bessel_i0(sqrt(tmp));
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scale += temp[i] * (1 + (i && i<n/2));
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}
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scale = 1.0/(scale + 1);
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for (i = 0; i <= n / 2; i++) {
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sum += temp[i];
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if (float_window) float_window[i] = sqrt(sum * scale);
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else int_window[i] = lrint(2147483647 * sqrt(sum * scale));
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}
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for (; i < n; i++) {
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sum += temp[n - i];
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if (float_window) float_window[i] = sqrt(sum * scale);
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else int_window[i] = lrint(2147483647 * sqrt(sum * scale));
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}
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}
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av_cold void ff_kbd_window_init(float *window, float alpha, int n)
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{
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kbd_window_init(window, NULL, alpha, n);
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}
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av_cold void ff_kbd_window_init_fixed(int32_t *window, float alpha, int n)
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{
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kbd_window_init(NULL, window, alpha, n);
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}
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