1/* 2 * Copyright (c) 2013-2014 Mozilla Corporation 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21/** 22 * @file 23 * Celt non-power of 2 iMDCT 24 */ 25 26#include <float.h> 27#include <math.h> 28#include <stddef.h> 29 30#include "config.h" 31 32#include "libavutil/attributes.h" 33#include "libavutil/common.h" 34 35#include "avfft.h" 36#include "opus.h" 37#include "opus_imdct.h" 38 39// minimal iMDCT size to make SIMD opts easier 40#define CELT_MIN_IMDCT_SIZE 120 41 42// complex c = a * b 43#define CMUL3(cre, cim, are, aim, bre, bim) \ 44do { \ 45 cre = are * bre - aim * bim; \ 46 cim = are * bim + aim * bre; \ 47} while (0) 48 49#define CMUL(c, a, b) CMUL3((c).re, (c).im, (a).re, (a).im, (b).re, (b).im) 50 51// complex c = a * b 52// d = a * conjugate(b) 53#define CMUL2(c, d, a, b) \ 54do { \ 55 float are = (a).re; \ 56 float aim = (a).im; \ 57 float bre = (b).re; \ 58 float bim = (b).im; \ 59 float rr = are * bre; \ 60 float ri = are * bim; \ 61 float ir = aim * bre; \ 62 float ii = aim * bim; \ 63 (c).re = rr - ii; \ 64 (c).im = ri + ir; \ 65 (d).re = rr + ii; \ 66 (d).im = -ri + ir; \ 67} while (0) 68 69av_cold void ff_celt_imdct_uninit(CeltIMDCTContext **ps) 70{ 71 CeltIMDCTContext *s = *ps; 72 int i; 73 74 if (!s) 75 return; 76 77 for (i = 0; i < FF_ARRAY_ELEMS(s->exptab); i++) 78 av_freep(&s->exptab[i]); 79 80 av_freep(&s->twiddle_exptab); 81 82 av_freep(&s->tmp); 83 84 av_freep(ps); 85} 86 87static void celt_imdct_half(CeltIMDCTContext *s, float *dst, const float *src, 88 ptrdiff_t stride, float scale); 89 90av_cold int ff_celt_imdct_init(CeltIMDCTContext **ps, int N) 91{ 92 CeltIMDCTContext *s; 93 int len2 = 15 * (1 << N); 94 int len = 2 * len2; 95 int i, j; 96 97 if (len2 > CELT_MAX_FRAME_SIZE || len2 < CELT_MIN_IMDCT_SIZE) 98 return AVERROR(EINVAL); 99 100 s = av_mallocz(sizeof(*s)); 101 if (!s) 102 return AVERROR(ENOMEM); 103 104 s->fft_n = N - 1; 105 s->len4 = len2 / 2; 106 s->len2 = len2; 107 108 s->tmp = av_malloc(len * 2 * sizeof(*s->tmp)); 109 if (!s->tmp) 110 goto fail; 111 112 s->twiddle_exptab = av_malloc(s->len4 * sizeof(*s->twiddle_exptab)); 113 if (!s->twiddle_exptab) 114 goto fail; 115 116 for (i = 0; i < s->len4; i++) { 117 s->twiddle_exptab[i].re = cos(2 * M_PI * (i + 0.125 + s->len4) / len); 118 s->twiddle_exptab[i].im = sin(2 * M_PI * (i + 0.125 + s->len4) / len); 119 } 120 121 for (i = 0; i < FF_ARRAY_ELEMS(s->exptab); i++) { 122 int N = 15 * (1 << i); 123 s->exptab[i] = av_malloc(sizeof(*s->exptab[i]) * FFMAX(N, 19)); 124 if (!s->exptab[i]) 125 goto fail; 126 127 for (j = 0; j < N; j++) { 128 s->exptab[i][j].re = cos(2 * M_PI * j / N); 129 s->exptab[i][j].im = sin(2 * M_PI * j / N); 130 } 131 } 132 133 // wrap around to simplify fft15 134 for (j = 15; j < 19; j++) 135 s->exptab[0][j] = s->exptab[0][j - 15]; 136 137 s->imdct_half = celt_imdct_half; 138 139 if (ARCH_AARCH64) 140 ff_celt_imdct_init_aarch64(s); 141 142 *ps = s; 143 144 return 0; 145fail: 146 ff_celt_imdct_uninit(&s); 147 return AVERROR(ENOMEM); 148} 149 150static void fft5(FFTComplex *out, const FFTComplex *in, ptrdiff_t stride) 151{ 152 // [0] = exp(2 * i * pi / 5), [1] = exp(2 * i * pi * 2 / 5) 153 static const FFTComplex fact[] = { { 0.30901699437494745, 0.95105651629515353 }, 154 { -0.80901699437494734, 0.58778525229247325 } }; 155 156 FFTComplex z[4][4]; 157 158 CMUL2(z[0][0], z[0][3], in[1 * stride], fact[0]); 159 CMUL2(z[0][1], z[0][2], in[1 * stride], fact[1]); 160 CMUL2(z[1][0], z[1][3], in[2 * stride], fact[0]); 161 CMUL2(z[1][1], z[1][2], in[2 * stride], fact[1]); 162 CMUL2(z[2][0], z[2][3], in[3 * stride], fact[0]); 163 CMUL2(z[2][1], z[2][2], in[3 * stride], fact[1]); 164 CMUL2(z[3][0], z[3][3], in[4 * stride], fact[0]); 165 CMUL2(z[3][1], z[3][2], in[4 * stride], fact[1]); 166 167 out[0].re = in[0].re + in[stride].re + in[2 * stride].re + in[3 * stride].re + in[4 * stride].re; 168 out[0].im = in[0].im + in[stride].im + in[2 * stride].im + in[3 * stride].im + in[4 * stride].im; 169 170 out[1].re = in[0].re + z[0][0].re + z[1][1].re + z[2][2].re + z[3][3].re; 171 out[1].im = in[0].im + z[0][0].im + z[1][1].im + z[2][2].im + z[3][3].im; 172 173 out[2].re = in[0].re + z[0][1].re + z[1][3].re + z[2][0].re + z[3][2].re; 174 out[2].im = in[0].im + z[0][1].im + z[1][3].im + z[2][0].im + z[3][2].im; 175 176 out[3].re = in[0].re + z[0][2].re + z[1][0].re + z[2][3].re + z[3][1].re; 177 out[3].im = in[0].im + z[0][2].im + z[1][0].im + z[2][3].im + z[3][1].im; 178 179 out[4].re = in[0].re + z[0][3].re + z[1][2].re + z[2][1].re + z[3][0].re; 180 out[4].im = in[0].im + z[0][3].im + z[1][2].im + z[2][1].im + z[3][0].im; 181} 182 183static void fft15(CeltIMDCTContext *s, FFTComplex *out, const FFTComplex *in, ptrdiff_t stride) 184{ 185 const FFTComplex *exptab = s->exptab[0]; 186 FFTComplex tmp[5]; 187 FFTComplex tmp1[5]; 188 FFTComplex tmp2[5]; 189 int k; 190 191 fft5(tmp, in, stride * 3); 192 fft5(tmp1, in + stride, stride * 3); 193 fft5(tmp2, in + 2 * stride, stride * 3); 194 195 for (k = 0; k < 5; k++) { 196 FFTComplex t1, t2; 197 198 CMUL(t1, tmp1[k], exptab[k]); 199 CMUL(t2, tmp2[k], exptab[2 * k]); 200 out[k].re = tmp[k].re + t1.re + t2.re; 201 out[k].im = tmp[k].im + t1.im + t2.im; 202 203 CMUL(t1, tmp1[k], exptab[k + 5]); 204 CMUL(t2, tmp2[k], exptab[2 * (k + 5)]); 205 out[k + 5].re = tmp[k].re + t1.re + t2.re; 206 out[k + 5].im = tmp[k].im + t1.im + t2.im; 207 208 CMUL(t1, tmp1[k], exptab[k + 10]); 209 CMUL(t2, tmp2[k], exptab[2 * k + 5]); 210 out[k + 10].re = tmp[k].re + t1.re + t2.re; 211 out[k + 10].im = tmp[k].im + t1.im + t2.im; 212 } 213} 214 215/* 216 * FFT of the length 15 * (2^N) 217 */ 218static void fft_calc(CeltIMDCTContext *s, FFTComplex *out, const FFTComplex *in, 219 int N, ptrdiff_t stride) 220{ 221 if (N) { 222 const FFTComplex *exptab = s->exptab[N]; 223 const int len2 = 15 * (1 << (N - 1)); 224 int k; 225 226 fft_calc(s, out, in, N - 1, stride * 2); 227 fft_calc(s, out + len2, in + stride, N - 1, stride * 2); 228 229 for (k = 0; k < len2; k++) { 230 FFTComplex t; 231 232 CMUL(t, out[len2 + k], exptab[k]); 233 234 out[len2 + k].re = out[k].re - t.re; 235 out[len2 + k].im = out[k].im - t.im; 236 237 out[k].re += t.re; 238 out[k].im += t.im; 239 } 240 } else 241 fft15(s, out, in, stride); 242} 243 244static void celt_imdct_half(CeltIMDCTContext *s, float *dst, const float *src, 245 ptrdiff_t stride, float scale) 246{ 247 FFTComplex *z = (FFTComplex *)dst; 248 const int len8 = s->len4 / 2; 249 const float *in1 = src; 250 const float *in2 = src + (s->len2 - 1) * stride; 251 int i; 252 253 for (i = 0; i < s->len4; i++) { 254 FFTComplex tmp = { *in2, *in1 }; 255 CMUL(s->tmp[i], tmp, s->twiddle_exptab[i]); 256 in1 += 2 * stride; 257 in2 -= 2 * stride; 258 } 259 260 fft_calc(s, z, s->tmp, s->fft_n, 1); 261 262 for (i = 0; i < len8; i++) { 263 float r0, i0, r1, i1; 264 265 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); 266 CMUL3(r1, i0, z[len8 + i].im, z[len8 + i].re, s->twiddle_exptab[len8 + i].im, s->twiddle_exptab[len8 + i].re); 267 z[len8 - i - 1].re = scale * r0; 268 z[len8 - i - 1].im = scale * i0; 269 z[len8 + i].re = scale * r1; 270 z[len8 + i].im = scale * i1; 271 } 272} 273