273 lines
8.4 KiB
C
273 lines
8.4 KiB
C
/*
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* Copyright (c) 2013-2014 Mozilla Corporation
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*
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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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/**
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* @file
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* Celt non-power of 2 iMDCT
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*/
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#include <float.h>
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#include <math.h>
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#include <stddef.h>
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#include "config.h"
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#include "libavutil/attributes.h"
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#include "libavutil/common.h"
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#include "avfft.h"
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#include "opus.h"
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#include "opus_imdct.h"
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// minimal iMDCT size to make SIMD opts easier
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#define CELT_MIN_IMDCT_SIZE 120
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// complex c = a * b
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#define CMUL3(cre, cim, are, aim, bre, bim) \
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do { \
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cre = are * bre - aim * bim; \
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cim = are * bim + aim * bre; \
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} while (0)
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#define CMUL(c, a, b) CMUL3((c).re, (c).im, (a).re, (a).im, (b).re, (b).im)
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// complex c = a * b
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// d = a * conjugate(b)
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#define CMUL2(c, d, a, b) \
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do { \
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float are = (a).re; \
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float aim = (a).im; \
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float bre = (b).re; \
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float bim = (b).im; \
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float rr = are * bre; \
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float ri = are * bim; \
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float ir = aim * bre; \
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float ii = aim * bim; \
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(c).re = rr - ii; \
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(c).im = ri + ir; \
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(d).re = rr + ii; \
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(d).im = -ri + ir; \
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} while (0)
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av_cold void ff_celt_imdct_uninit(CeltIMDCTContext **ps)
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{
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CeltIMDCTContext *s = *ps;
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int i;
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if (!s)
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return;
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for (i = 0; i < FF_ARRAY_ELEMS(s->exptab); i++)
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av_freep(&s->exptab[i]);
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av_freep(&s->twiddle_exptab);
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av_freep(&s->tmp);
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av_freep(ps);
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}
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static void celt_imdct_half(CeltIMDCTContext *s, float *dst, const float *src,
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ptrdiff_t stride, float scale);
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av_cold int ff_celt_imdct_init(CeltIMDCTContext **ps, int N)
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{
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CeltIMDCTContext *s;
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int len2 = 15 * (1 << N);
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int len = 2 * len2;
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int i, j;
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if (len2 > CELT_MAX_FRAME_SIZE || len2 < CELT_MIN_IMDCT_SIZE)
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return AVERROR(EINVAL);
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s = av_mallocz(sizeof(*s));
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if (!s)
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return AVERROR(ENOMEM);
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s->fft_n = N - 1;
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s->len4 = len2 / 2;
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s->len2 = len2;
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s->tmp = av_malloc_array(len, 2 * sizeof(*s->tmp));
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if (!s->tmp)
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goto fail;
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s->twiddle_exptab = av_malloc_array(s->len4, sizeof(*s->twiddle_exptab));
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if (!s->twiddle_exptab)
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goto fail;
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for (i = 0; i < s->len4; i++) {
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s->twiddle_exptab[i].re = cos(2 * M_PI * (i + 0.125 + s->len4) / len);
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s->twiddle_exptab[i].im = sin(2 * M_PI * (i + 0.125 + s->len4) / len);
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}
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for (i = 0; i < FF_ARRAY_ELEMS(s->exptab); i++) {
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int N = 15 * (1 << i);
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s->exptab[i] = av_malloc(sizeof(*s->exptab[i]) * FFMAX(N, 19));
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if (!s->exptab[i])
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goto fail;
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for (j = 0; j < N; j++) {
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s->exptab[i][j].re = cos(2 * M_PI * j / N);
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s->exptab[i][j].im = sin(2 * M_PI * j / N);
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}
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}
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// wrap around to simplify fft15
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for (j = 15; j < 19; j++)
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s->exptab[0][j] = s->exptab[0][j - 15];
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s->imdct_half = celt_imdct_half;
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if (ARCH_AARCH64)
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ff_celt_imdct_init_aarch64(s);
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*ps = s;
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return 0;
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fail:
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ff_celt_imdct_uninit(&s);
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return AVERROR(ENOMEM);
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}
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static void fft5(FFTComplex *out, const FFTComplex *in, ptrdiff_t stride)
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{
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// [0] = exp(2 * i * pi / 5), [1] = exp(2 * i * pi * 2 / 5)
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static const FFTComplex fact[] = { { 0.30901699437494745, 0.95105651629515353 },
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{ -0.80901699437494734, 0.58778525229247325 } };
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FFTComplex z[4][4];
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CMUL2(z[0][0], z[0][3], in[1 * stride], fact[0]);
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CMUL2(z[0][1], z[0][2], in[1 * stride], fact[1]);
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CMUL2(z[1][0], z[1][3], in[2 * stride], fact[0]);
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CMUL2(z[1][1], z[1][2], in[2 * stride], fact[1]);
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CMUL2(z[2][0], z[2][3], in[3 * stride], fact[0]);
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CMUL2(z[2][1], z[2][2], in[3 * stride], fact[1]);
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CMUL2(z[3][0], z[3][3], in[4 * stride], fact[0]);
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CMUL2(z[3][1], z[3][2], in[4 * stride], fact[1]);
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out[0].re = in[0].re + in[stride].re + in[2 * stride].re + in[3 * stride].re + in[4 * stride].re;
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out[0].im = in[0].im + in[stride].im + in[2 * stride].im + in[3 * stride].im + in[4 * stride].im;
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out[1].re = in[0].re + z[0][0].re + z[1][1].re + z[2][2].re + z[3][3].re;
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out[1].im = in[0].im + z[0][0].im + z[1][1].im + z[2][2].im + z[3][3].im;
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out[2].re = in[0].re + z[0][1].re + z[1][3].re + z[2][0].re + z[3][2].re;
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out[2].im = in[0].im + z[0][1].im + z[1][3].im + z[2][0].im + z[3][2].im;
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out[3].re = in[0].re + z[0][2].re + z[1][0].re + z[2][3].re + z[3][1].re;
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out[3].im = in[0].im + z[0][2].im + z[1][0].im + z[2][3].im + z[3][1].im;
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out[4].re = in[0].re + z[0][3].re + z[1][2].re + z[2][1].re + z[3][0].re;
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out[4].im = in[0].im + z[0][3].im + z[1][2].im + z[2][1].im + z[3][0].im;
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}
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static void fft15(CeltIMDCTContext *s, FFTComplex *out, const FFTComplex *in, ptrdiff_t stride)
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{
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const FFTComplex *exptab = s->exptab[0];
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FFTComplex tmp[5];
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FFTComplex tmp1[5];
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FFTComplex tmp2[5];
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int k;
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fft5(tmp, in, stride * 3);
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fft5(tmp1, in + stride, stride * 3);
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fft5(tmp2, in + 2 * stride, stride * 3);
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for (k = 0; k < 5; k++) {
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FFTComplex t1, t2;
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CMUL(t1, tmp1[k], exptab[k]);
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CMUL(t2, tmp2[k], exptab[2 * k]);
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out[k].re = tmp[k].re + t1.re + t2.re;
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out[k].im = tmp[k].im + t1.im + t2.im;
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CMUL(t1, tmp1[k], exptab[k + 5]);
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CMUL(t2, tmp2[k], exptab[2 * (k + 5)]);
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out[k + 5].re = tmp[k].re + t1.re + t2.re;
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out[k + 5].im = tmp[k].im + t1.im + t2.im;
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CMUL(t1, tmp1[k], exptab[k + 10]);
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CMUL(t2, tmp2[k], exptab[2 * k + 5]);
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out[k + 10].re = tmp[k].re + t1.re + t2.re;
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out[k + 10].im = tmp[k].im + t1.im + t2.im;
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}
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}
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/*
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* FFT of the length 15 * (2^N)
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*/
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static void fft_calc(CeltIMDCTContext *s, FFTComplex *out, const FFTComplex *in,
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int N, ptrdiff_t stride)
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{
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if (N) {
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const FFTComplex *exptab = s->exptab[N];
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const int len2 = 15 * (1 << (N - 1));
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int k;
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fft_calc(s, out, in, N - 1, stride * 2);
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fft_calc(s, out + len2, in + stride, N - 1, stride * 2);
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for (k = 0; k < len2; k++) {
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FFTComplex t;
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CMUL(t, out[len2 + k], exptab[k]);
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out[len2 + k].re = out[k].re - t.re;
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out[len2 + k].im = out[k].im - t.im;
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out[k].re += t.re;
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out[k].im += t.im;
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}
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} else
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fft15(s, out, in, stride);
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}
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static void celt_imdct_half(CeltIMDCTContext *s, float *dst, const float *src,
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ptrdiff_t stride, float scale)
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{
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FFTComplex *z = (FFTComplex *)dst;
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const int len8 = s->len4 / 2;
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const float *in1 = src;
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const float *in2 = src + (s->len2 - 1) * stride;
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int i;
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for (i = 0; i < s->len4; i++) {
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FFTComplex tmp = { *in2, *in1 };
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CMUL(s->tmp[i], tmp, s->twiddle_exptab[i]);
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in1 += 2 * stride;
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in2 -= 2 * stride;
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}
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fft_calc(s, z, s->tmp, s->fft_n, 1);
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for (i = 0; i < len8; i++) {
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float r0, i0, r1, i1;
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CMUL3(r0, i1, z[len8 - i - 1].im, z[len8 - i - 1].re, s->twiddle_exptab[len8 - i - 1].im, s->twiddle_exptab[len8 - i - 1].re);
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CMUL3(r1, i0, z[len8 + i].im, z[len8 + i].re, s->twiddle_exptab[len8 + i].im, s->twiddle_exptab[len8 + i].re);
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z[len8 - i - 1].re = scale * r0;
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z[len8 - i - 1].im = scale * i0;
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z[len8 + i].re = scale * r1;
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z[len8 + i].im = scale * i1;
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}
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}
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