mirror of https://git.ffmpeg.org/ffmpeg.git
83 lines
2.5 KiB
C
83 lines
2.5 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 <stdint.h>
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#include "libavutil/avassert.h"
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#include "avfilter.h"
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#include "generate_wave_table.h"
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void ff_generate_wave_table(enum WaveType wave_type,
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enum AVSampleFormat sample_fmt,
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void *table, int table_size,
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double min, double max, double phase)
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{
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uint32_t i, phase_offset = phase / M_PI / 2 * table_size + 0.5;
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for (i = 0; i < table_size; i++) {
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uint32_t point = (i + phase_offset) % table_size;
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double d;
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switch (wave_type) {
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case WAVE_SIN:
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d = (sin((double)point / table_size * 2 * M_PI) + 1) / 2;
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break;
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case WAVE_TRI:
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d = (double)point * 2 / table_size;
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switch (4 * point / table_size) {
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case 0: d = d + 0.5; break;
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case 1:
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case 2: d = 1.5 - d; break;
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case 3: d = d - 1.5; break;
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}
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break;
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default:
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av_assert0(0);
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}
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d = d * (max - min) + min;
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switch (sample_fmt) {
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case AV_SAMPLE_FMT_FLT: {
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float *fp = (float *)table;
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*fp++ = (float)d;
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table = fp;
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continue; }
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case AV_SAMPLE_FMT_DBL: {
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double *dp = (double *)table;
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*dp++ = d;
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table = dp;
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continue; }
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}
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d += d < 0 ? -0.5 : 0.5;
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switch (sample_fmt) {
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case AV_SAMPLE_FMT_S16: {
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int16_t *sp = table;
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*sp++ = (int16_t)d;
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table = sp;
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continue; }
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case AV_SAMPLE_FMT_S32: {
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int32_t *ip = table;
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*ip++ = (int32_t)d;
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table = ip;
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continue; }
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default:
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av_assert0(0);
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}
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}
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}
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