330 lines
10 KiB
C
330 lines
10 KiB
C
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/*
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* Copyright (c) 2013-2014 Mozilla Corporation
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* Copyright (c) 2017 Rostislav Pehlivanov <atomnuker@gmail.com>
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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 "mdct15.h"
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#define FFT_FLOAT 1
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#include "fft-internal.h"
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#define CMUL3(c, a, b) CMUL((c).re, (c).im, (a).re, (a).im, (b).re, (b).im)
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av_cold void ff_mdct15_uninit(MDCT15Context **ps)
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{
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MDCT15Context *s = *ps;
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if (!s)
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return;
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ff_fft_end(&s->ptwo_fft);
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av_freep(&s->pfa_prereindex);
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av_freep(&s->pfa_postreindex);
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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 inline int init_pfa_reindex_tabs(MDCT15Context *s)
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{
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int i, j;
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const int b_ptwo = s->ptwo_fft.nbits; /* Bits for the power of two FFTs */
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const int l_ptwo = 1 << b_ptwo; /* Total length for the power of two FFTs */
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const int inv_1 = l_ptwo << ((4 - b_ptwo) & 3); /* (2^b_ptwo)^-1 mod 15 */
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const int inv_2 = 0xeeeeeeef & ((1U << b_ptwo) - 1); /* 15^-1 mod 2^b_ptwo */
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s->pfa_prereindex = av_malloc_array(15 * l_ptwo, sizeof(*s->pfa_prereindex));
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if (!s->pfa_prereindex)
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return 1;
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s->pfa_postreindex = av_malloc_array(15 * l_ptwo, sizeof(*s->pfa_postreindex));
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if (!s->pfa_postreindex)
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return 1;
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/* Pre/Post-reindex */
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for (i = 0; i < l_ptwo; i++) {
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for (j = 0; j < 15; j++) {
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const int q_pre = ((l_ptwo * j)/15 + i) >> b_ptwo;
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const int q_post = (((j*inv_1)/15) + (i*inv_2)) >> b_ptwo;
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const int k_pre = 15*i + (j - q_pre*15)*(1 << b_ptwo);
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const int k_post = i*inv_2*15 + j*inv_1 - 15*q_post*l_ptwo;
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s->pfa_prereindex[i*15 + j] = k_pre << 1;
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s->pfa_postreindex[k_post] = l_ptwo*j + i;
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}
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}
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return 0;
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}
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/* Stride is hardcoded to 3 */
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static inline void fft5(FFTComplex *out, FFTComplex *in, FFTComplex exptab[2])
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{
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FFTComplex z0[4], t[6];
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t[0].re = in[3].re + in[12].re;
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t[0].im = in[3].im + in[12].im;
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t[1].im = in[3].re - in[12].re;
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t[1].re = in[3].im - in[12].im;
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t[2].re = in[6].re + in[ 9].re;
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t[2].im = in[6].im + in[ 9].im;
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t[3].im = in[6].re - in[ 9].re;
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t[3].re = in[6].im - in[ 9].im;
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out[0].re = in[0].re + in[3].re + in[6].re + in[9].re + in[12].re;
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out[0].im = in[0].im + in[3].im + in[6].im + in[9].im + in[12].im;
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t[4].re = exptab[0].re * t[2].re - exptab[1].re * t[0].re;
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t[4].im = exptab[0].re * t[2].im - exptab[1].re * t[0].im;
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t[0].re = exptab[0].re * t[0].re - exptab[1].re * t[2].re;
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t[0].im = exptab[0].re * t[0].im - exptab[1].re * t[2].im;
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t[5].re = exptab[0].im * t[3].re - exptab[1].im * t[1].re;
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t[5].im = exptab[0].im * t[3].im - exptab[1].im * t[1].im;
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t[1].re = exptab[0].im * t[1].re + exptab[1].im * t[3].re;
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t[1].im = exptab[0].im * t[1].im + exptab[1].im * t[3].im;
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z0[0].re = t[0].re - t[1].re;
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z0[0].im = t[0].im - t[1].im;
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z0[1].re = t[4].re + t[5].re;
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z0[1].im = t[4].im + t[5].im;
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z0[2].re = t[4].re - t[5].re;
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z0[2].im = t[4].im - t[5].im;
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z0[3].re = t[0].re + t[1].re;
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z0[3].im = t[0].im + t[1].im;
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out[1].re = in[0].re + z0[3].re;
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out[1].im = in[0].im + z0[0].im;
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out[2].re = in[0].re + z0[2].re;
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out[2].im = in[0].im + z0[1].im;
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out[3].re = in[0].re + z0[1].re;
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out[3].im = in[0].im + z0[2].im;
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out[4].re = in[0].re + z0[0].re;
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out[4].im = in[0].im + z0[3].im;
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}
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static void fft15_c(FFTComplex *out, FFTComplex *in, FFTComplex *exptab, ptrdiff_t stride)
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{
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int k;
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FFTComplex tmp1[5], tmp2[5], tmp3[5];
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fft5(tmp1, in + 0, exptab + 19);
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fft5(tmp2, in + 1, exptab + 19);
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fft5(tmp3, in + 2, exptab + 19);
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for (k = 0; k < 5; k++) {
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FFTComplex t[2];
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CMUL3(t[0], tmp2[k], exptab[k]);
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CMUL3(t[1], tmp3[k], exptab[2 * k]);
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out[stride*k].re = tmp1[k].re + t[0].re + t[1].re;
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out[stride*k].im = tmp1[k].im + t[0].im + t[1].im;
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CMUL3(t[0], tmp2[k], exptab[k + 5]);
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CMUL3(t[1], tmp3[k], exptab[2 * (k + 5)]);
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out[stride*(k + 5)].re = tmp1[k].re + t[0].re + t[1].re;
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out[stride*(k + 5)].im = tmp1[k].im + t[0].im + t[1].im;
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CMUL3(t[0], tmp2[k], exptab[k + 10]);
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CMUL3(t[1], tmp3[k], exptab[2 * k + 5]);
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out[stride*(k + 10)].re = tmp1[k].re + t[0].re + t[1].re;
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out[stride*(k + 10)].im = tmp1[k].im + t[0].im + t[1].im;
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}
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}
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static void mdct15(MDCT15Context *s, float *dst, const float *src, ptrdiff_t stride)
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{
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int i, j;
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const int len4 = s->len4, len3 = len4 * 3, len8 = len4 >> 1;
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const int l_ptwo = 1 << s->ptwo_fft.nbits;
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FFTComplex fft15in[15];
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/* Folding and pre-reindexing */
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for (i = 0; i < l_ptwo; i++) {
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for (j = 0; j < 15; j++) {
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const int k = s->pfa_prereindex[i*15 + j];
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FFTComplex tmp, exp = s->twiddle_exptab[k >> 1];
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if (k < len4) {
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tmp.re = -src[ len4 + k] + src[1*len4 - 1 - k];
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tmp.im = -src[ len3 + k] - src[1*len3 - 1 - k];
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} else {
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tmp.re = -src[ len4 + k] - src[5*len4 - 1 - k];
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tmp.im = src[-len4 + k] - src[1*len3 - 1 - k];
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}
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CMUL(fft15in[j].im, fft15in[j].re, tmp.re, tmp.im, exp.re, exp.im);
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}
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s->fft15(s->tmp + s->ptwo_fft.revtab[i], fft15in, s->exptab, l_ptwo);
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}
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/* Then a 15xN FFT (where N is a power of two) */
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for (i = 0; i < 15; i++)
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s->ptwo_fft.fft_calc(&s->ptwo_fft, s->tmp + l_ptwo*i);
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/* Reindex again, apply twiddles and output */
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for (i = 0; i < len8; i++) {
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const int i0 = len8 + i, i1 = len8 - i - 1;
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const int s0 = s->pfa_postreindex[i0], s1 = s->pfa_postreindex[i1];
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CMUL(dst[2*i1*stride + stride], dst[2*i0*stride], s->tmp[s0].re, s->tmp[s0].im,
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s->twiddle_exptab[i0].im, s->twiddle_exptab[i0].re);
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CMUL(dst[2*i0*stride + stride], dst[2*i1*stride], s->tmp[s1].re, s->tmp[s1].im,
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s->twiddle_exptab[i1].im, s->twiddle_exptab[i1].re);
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}
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}
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static void imdct15_half(MDCT15Context *s, float *dst, const float *src,
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ptrdiff_t stride)
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{
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FFTComplex fft15in[15];
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FFTComplex *z = (FFTComplex *)dst;
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int i, j, len8 = s->len4 >> 1, l_ptwo = 1 << s->ptwo_fft.nbits;
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const float *in1 = src, *in2 = src + (s->len2 - 1) * stride;
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/* Reindex input, putting it into a buffer and doing an Nx15 FFT */
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for (i = 0; i < l_ptwo; i++) {
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for (j = 0; j < 15; j++) {
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const int k = s->pfa_prereindex[i*15 + j];
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FFTComplex tmp = { in2[-k*stride], in1[k*stride] };
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CMUL3(fft15in[j], tmp, s->twiddle_exptab[k >> 1]);
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}
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s->fft15(s->tmp + s->ptwo_fft.revtab[i], fft15in, s->exptab, l_ptwo);
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}
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/* Then a 15xN FFT (where N is a power of two) */
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for (i = 0; i < 15; i++)
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s->ptwo_fft.fft_calc(&s->ptwo_fft, s->tmp + l_ptwo*i);
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/* Reindex again, apply twiddles and output */
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s->postreindex(z, s->tmp, s->twiddle_exptab, s->pfa_postreindex, len8);
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}
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static void postrotate_c(FFTComplex *out, FFTComplex *in, FFTComplex *exp,
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int *lut, ptrdiff_t len8)
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{
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int i;
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/* Reindex again, apply twiddles and output */
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for (i = 0; i < len8; i++) {
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const int i0 = len8 + i, i1 = len8 - i - 1;
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const int s0 = lut[i0], s1 = lut[i1];
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CMUL(out[i1].re, out[i0].im, in[s1].im, in[s1].re, exp[i1].im, exp[i1].re);
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CMUL(out[i0].re, out[i1].im, in[s0].im, in[s0].re, exp[i0].im, exp[i0].re);
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}
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}
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av_cold int ff_mdct15_init(MDCT15Context **ps, int inverse, int N, double scale)
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{
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MDCT15Context *s;
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double alpha, theta;
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int len2 = 15 * (1 << N);
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int len = 2 * len2;
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int i;
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/* Tested and verified to work on everything in between */
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if ((N < 2) || (N > 13))
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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->inverse = inverse;
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s->fft15 = fft15_c;
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s->mdct = mdct15;
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s->imdct_half = imdct15_half;
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s->postreindex = postrotate_c;
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if (ff_fft_init(&s->ptwo_fft, N - 1, s->inverse) < 0)
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goto fail;
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if (init_pfa_reindex_tabs(s))
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goto fail;
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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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theta = 0.125f + (scale < 0 ? s->len4 : 0);
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scale = sqrt(fabs(scale));
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for (i = 0; i < s->len4; i++) {
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alpha = 2 * M_PI * (i + theta) / len;
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s->twiddle_exptab[i].re = cosf(alpha) * scale;
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s->twiddle_exptab[i].im = sinf(alpha) * scale;
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}
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/* 15-point FFT exptab */
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for (i = 0; i < 19; i++) {
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if (i < 15) {
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double theta = (2.0f * M_PI * i) / 15.0f;
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if (!s->inverse)
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theta *= -1;
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s->exptab[i].re = cosf(theta);
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s->exptab[i].im = sinf(theta);
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} else { /* Wrap around to simplify fft15 */
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s->exptab[i] = s->exptab[i - 15];
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}
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}
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/* 5-point FFT exptab */
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s->exptab[19].re = cosf(2.0f * M_PI / 5.0f);
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|
|
s->exptab[19].im = sinf(2.0f * M_PI / 5.0f);
|
||
|
|
s->exptab[20].re = cosf(1.0f * M_PI / 5.0f);
|
||
|
|
s->exptab[20].im = sinf(1.0f * M_PI / 5.0f);
|
||
|
|
|
||
|
|
/* Invert the phase for an inverse transform, do nothing for a forward transform */
|
||
|
|
if (s->inverse) {
|
||
|
|
s->exptab[19].im *= -1;
|
||
|
|
s->exptab[20].im *= -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (ARCH_X86)
|
||
|
|
ff_mdct15_init_x86(s);
|
||
|
|
|
||
|
|
*ps = s;
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
fail:
|
||
|
|
ff_mdct15_uninit(&s);
|
||
|
|
return AVERROR(ENOMEM);
|
||
|
|
}
|