/* * Copyright (c) 2013-2014 Mozilla Corporation * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * Celt non-power of 2 iMDCT */ #include <float.h> #include <math.h> #include <stddef.h> #include "config.h" #include "libavutil/attributes.h" #include "libavutil/common.h" #include "avfft.h" #include "imdct15.h" #include "opus.h" // minimal iMDCT size to make SIMD opts easier #define CELT_MIN_IMDCT_SIZE 120 // complex c = a * b #define CMUL3(cre, cim, are, aim, bre, bim) \ do { \ cre = are * bre - aim * bim; \ cim = are * bim + aim * bre; \ } while (0) #define CMUL(c, a, b) CMUL3((c).re, (c).im, (a).re, (a).im, (b).re, (b).im) // complex c = a * b // d = a * conjugate(b) #define CMUL2(c, d, a, b) \ do { \ float are = (a).re; \ float aim = (a).im; \ float bre = (b).re; \ float bim = (b).im; \ float rr = are * bre; \ float ri = are * bim; \ float ir = aim * bre; \ float ii = aim * bim; \ (c).re = rr - ii; \ (c).im = ri + ir; \ (d).re = rr + ii; \ (d).im = -ri + ir; \ } while (0) av_cold void ff_imdct15_uninit(IMDCT15Context **ps) { IMDCT15Context *s = *ps; int i; if (!s) return; for (i = 0; i < FF_ARRAY_ELEMS(s->exptab); i++) av_freep(&s->exptab[i]); av_freep(&s->twiddle_exptab); av_freep(&s->tmp); av_freep(ps); } static void imdct15_half(IMDCT15Context *s, float *dst, const float *src, ptrdiff_t stride, float scale); av_cold int ff_imdct15_init(IMDCT15Context **ps, int N) { IMDCT15Context *s; int len2 = 15 * (1 << N); int len = 2 * len2; int i, j; if (len2 > CELT_MAX_FRAME_SIZE || len2 < CELT_MIN_IMDCT_SIZE) return AVERROR(EINVAL); s = av_mallocz(sizeof(*s)); if (!s) return AVERROR(ENOMEM); s->fft_n = N - 1; s->len4 = len2 / 2; s->len2 = len2; s->tmp = av_malloc_array(len, 2 * sizeof(*s->tmp)); if (!s->tmp) goto fail; s->twiddle_exptab = av_malloc_array(s->len4, sizeof(*s->twiddle_exptab)); if (!s->twiddle_exptab) goto fail; for (i = 0; i < s->len4; i++) { s->twiddle_exptab[i].re = cos(2 * M_PI * (i + 0.125 + s->len4) / len); s->twiddle_exptab[i].im = sin(2 * M_PI * (i + 0.125 + s->len4) / len); } for (i = 0; i < FF_ARRAY_ELEMS(s->exptab); i++) { int N = 15 * (1 << i); s->exptab[i] = av_malloc(sizeof(*s->exptab[i]) * FFMAX(N, 19)); if (!s->exptab[i]) goto fail; for (j = 0; j < N; j++) { s->exptab[i][j].re = cos(2 * M_PI * j / N); s->exptab[i][j].im = sin(2 * M_PI * j / N); } } // wrap around to simplify fft15 for (j = 15; j < 19; j++) s->exptab[0][j] = s->exptab[0][j - 15]; s->imdct_half = imdct15_half; if (ARCH_AARCH64) ff_imdct15_init_aarch64(s); *ps = s; return 0; fail: ff_imdct15_uninit(&s); return AVERROR(ENOMEM); } static void fft5(FFTComplex *out, const FFTComplex *in, ptrdiff_t stride) { // [0] = exp(2 * i * pi / 5), [1] = exp(2 * i * pi * 2 / 5) static const FFTComplex fact[] = { { 0.30901699437494745, 0.95105651629515353 }, { -0.80901699437494734, 0.58778525229247325 } }; FFTComplex z[4][4]; CMUL2(z[0][0], z[0][3], in[1 * stride], fact[0]); CMUL2(z[0][1], z[0][2], in[1 * stride], fact[1]); CMUL2(z[1][0], z[1][3], in[2 * stride], fact[0]); CMUL2(z[1][1], z[1][2], in[2 * stride], fact[1]); CMUL2(z[2][0], z[2][3], in[3 * stride], fact[0]); CMUL2(z[2][1], z[2][2], in[3 * stride], fact[1]); CMUL2(z[3][0], z[3][3], in[4 * stride], fact[0]); CMUL2(z[3][1], z[3][2], in[4 * stride], fact[1]); out[0].re = in[0].re + in[stride].re + in[2 * stride].re + in[3 * stride].re + in[4 * stride].re; out[0].im = in[0].im + in[stride].im + in[2 * stride].im + in[3 * stride].im + in[4 * stride].im; out[1].re = in[0].re + z[0][0].re + z[1][1].re + z[2][2].re + z[3][3].re; out[1].im = in[0].im + z[0][0].im + z[1][1].im + z[2][2].im + z[3][3].im; out[2].re = in[0].re + z[0][1].re + z[1][3].re + z[2][0].re + z[3][2].re; out[2].im = in[0].im + z[0][1].im + z[1][3].im + z[2][0].im + z[3][2].im; out[3].re = in[0].re + z[0][2].re + z[1][0].re + z[2][3].re + z[3][1].re; out[3].im = in[0].im + z[0][2].im + z[1][0].im + z[2][3].im + z[3][1].im; out[4].re = in[0].re + z[0][3].re + z[1][2].re + z[2][1].re + z[3][0].re; out[4].im = in[0].im + z[0][3].im + z[1][2].im + z[2][1].im + z[3][0].im; } static void fft15(IMDCT15Context *s, FFTComplex *out, const FFTComplex *in, ptrdiff_t stride) { const FFTComplex *exptab = s->exptab[0]; FFTComplex tmp[5]; FFTComplex tmp1[5]; FFTComplex tmp2[5]; int k; fft5(tmp, in, stride * 3); fft5(tmp1, in + stride, stride * 3); fft5(tmp2, in + 2 * stride, stride * 3); for (k = 0; k < 5; k++) { FFTComplex t1, t2; CMUL(t1, tmp1[k], exptab[k]); CMUL(t2, tmp2[k], exptab[2 * k]); out[k].re = tmp[k].re + t1.re + t2.re; out[k].im = tmp[k].im + t1.im + t2.im; CMUL(t1, tmp1[k], exptab[k + 5]); CMUL(t2, tmp2[k], exptab[2 * (k + 5)]); out[k + 5].re = tmp[k].re + t1.re + t2.re; out[k + 5].im = tmp[k].im + t1.im + t2.im; CMUL(t1, tmp1[k], exptab[k + 10]); CMUL(t2, tmp2[k], exptab[2 * k + 5]); out[k + 10].re = tmp[k].re + t1.re + t2.re; out[k + 10].im = tmp[k].im + t1.im + t2.im; } } /* * FFT of the length 15 * (2^N) */ static void fft_calc(IMDCT15Context *s, FFTComplex *out, const FFTComplex *in, int N, ptrdiff_t stride) { if (N) { const FFTComplex *exptab = s->exptab[N]; const int len2 = 15 * (1 << (N - 1)); int k; fft_calc(s, out, in, N - 1, stride * 2); fft_calc(s, out + len2, in + stride, N - 1, stride * 2); for (k = 0; k < len2; k++) { FFTComplex t; CMUL(t, out[len2 + k], exptab[k]); out[len2 + k].re = out[k].re - t.re; out[len2 + k].im = out[k].im - t.im; out[k].re += t.re; out[k].im += t.im; } } else fft15(s, out, in, stride); } static void imdct15_half(IMDCT15Context *s, float *dst, const float *src, ptrdiff_t stride, float scale) { FFTComplex *z = (FFTComplex *)dst; const int len8 = s->len4 / 2; const float *in1 = src; const float *in2 = src + (s->len2 - 1) * stride; int i; for (i = 0; i < s->len4; i++) { FFTComplex tmp = { *in2, *in1 }; CMUL(s->tmp[i], tmp, s->twiddle_exptab[i]); in1 += 2 * stride; in2 -= 2 * stride; } fft_calc(s, z, s->tmp, s->fft_n, 1); for (i = 0; i < len8; i++) { float r0, i0, r1, i1; 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); CMUL3(r1, i0, z[len8 + i].im, z[len8 + i].re, s->twiddle_exptab[len8 + i].im, s->twiddle_exptab[len8 + i].re); z[len8 - i - 1].re = scale * r0; z[len8 - i - 1].im = scale * i0; z[len8 + i].re = scale * r1; z[len8 + i].im = scale * i1; } }