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Diffstat (limited to 'chromium/third_party/ffmpeg/libavutil/tx.c')
| -rw-r--r-- | chromium/third_party/ffmpeg/libavutil/tx.c | 803 |
1 files changed, 803 insertions, 0 deletions
diff --git a/chromium/third_party/ffmpeg/libavutil/tx.c b/chromium/third_party/ffmpeg/libavutil/tx.c new file mode 100644 index 00000000000..93f6e489d36 --- /dev/null +++ b/chromium/third_party/ffmpeg/libavutil/tx.c @@ -0,0 +1,803 @@ +/* + * Copyright (c) 2019 Lynne <dev@lynne.ee> + * Power of two FFT: + * Copyright (c) 2008 Loren Merritt + * Copyright (c) 2002 Fabrice Bellard + * Partly based on libdjbfft by D. J. Bernstein + * + * 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 + */ + +#include <stddef.h> +#include "tx.h" +#include "thread.h" +#include "mem.h" +#include "avassert.h" + +typedef float FFTSample; +typedef AVComplexFloat FFTComplex; + +struct AVTXContext { + int n; /* Nptwo part */ + int m; /* Ptwo part */ + + FFTComplex *exptab; /* MDCT exptab */ + FFTComplex *tmp; /* Temporary buffer needed for all compound transforms */ + int *pfatab; /* Input/Output mapping for compound transforms */ + int *revtab; /* Input mapping for power of two transforms */ +}; + +#define FFT_NAME(x) x + +#define COSTABLE(size) \ + static DECLARE_ALIGNED(32, FFTSample, FFT_NAME(ff_cos_##size))[size/2] + +static FFTSample * const FFT_NAME(ff_cos_tabs)[18]; + +COSTABLE(16); +COSTABLE(32); +COSTABLE(64); +COSTABLE(128); +COSTABLE(256); +COSTABLE(512); +COSTABLE(1024); +COSTABLE(2048); +COSTABLE(4096); +COSTABLE(8192); +COSTABLE(16384); +COSTABLE(32768); +COSTABLE(65536); +COSTABLE(131072); + +static av_cold void init_ff_cos_tabs(int index) +{ + int m = 1 << index; + double freq = 2*M_PI/m; + FFTSample *tab = FFT_NAME(ff_cos_tabs)[index]; + for(int i = 0; i <= m/4; i++) + tab[i] = cos(i*freq); + for(int i = 1; i < m/4; i++) + tab[m/2 - i] = tab[i]; +} + +typedef struct CosTabsInitOnce { + void (*func)(void); + AVOnce control; +} CosTabsInitOnce; + +#define INIT_FF_COS_TABS_FUNC(index, size) \ +static av_cold void init_ff_cos_tabs_ ## size (void) \ +{ \ + init_ff_cos_tabs(index); \ +} + +INIT_FF_COS_TABS_FUNC(4, 16) +INIT_FF_COS_TABS_FUNC(5, 32) +INIT_FF_COS_TABS_FUNC(6, 64) +INIT_FF_COS_TABS_FUNC(7, 128) +INIT_FF_COS_TABS_FUNC(8, 256) +INIT_FF_COS_TABS_FUNC(9, 512) +INIT_FF_COS_TABS_FUNC(10, 1024) +INIT_FF_COS_TABS_FUNC(11, 2048) +INIT_FF_COS_TABS_FUNC(12, 4096) +INIT_FF_COS_TABS_FUNC(13, 8192) +INIT_FF_COS_TABS_FUNC(14, 16384) +INIT_FF_COS_TABS_FUNC(15, 32768) +INIT_FF_COS_TABS_FUNC(16, 65536) +INIT_FF_COS_TABS_FUNC(17, 131072) + +static CosTabsInitOnce cos_tabs_init_once[] = { + { NULL }, + { NULL }, + { NULL }, + { NULL }, + { init_ff_cos_tabs_16, AV_ONCE_INIT }, + { init_ff_cos_tabs_32, AV_ONCE_INIT }, + { init_ff_cos_tabs_64, AV_ONCE_INIT }, + { init_ff_cos_tabs_128, AV_ONCE_INIT }, + { init_ff_cos_tabs_256, AV_ONCE_INIT }, + { init_ff_cos_tabs_512, AV_ONCE_INIT }, + { init_ff_cos_tabs_1024, AV_ONCE_INIT }, + { init_ff_cos_tabs_2048, AV_ONCE_INIT }, + { init_ff_cos_tabs_4096, AV_ONCE_INIT }, + { init_ff_cos_tabs_8192, AV_ONCE_INIT }, + { init_ff_cos_tabs_16384, AV_ONCE_INIT }, + { init_ff_cos_tabs_32768, AV_ONCE_INIT }, + { init_ff_cos_tabs_65536, AV_ONCE_INIT }, + { init_ff_cos_tabs_131072, AV_ONCE_INIT }, +}; + +static FFTSample * const FFT_NAME(ff_cos_tabs)[] = { + NULL, NULL, NULL, NULL, + FFT_NAME(ff_cos_16), + FFT_NAME(ff_cos_32), + FFT_NAME(ff_cos_64), + FFT_NAME(ff_cos_128), + FFT_NAME(ff_cos_256), + FFT_NAME(ff_cos_512), + FFT_NAME(ff_cos_1024), + FFT_NAME(ff_cos_2048), + FFT_NAME(ff_cos_4096), + FFT_NAME(ff_cos_8192), + FFT_NAME(ff_cos_16384), + FFT_NAME(ff_cos_32768), + FFT_NAME(ff_cos_65536), + FFT_NAME(ff_cos_131072), +}; + +static av_cold void ff_init_ff_cos_tabs(int index) +{ + ff_thread_once(&cos_tabs_init_once[index].control, + cos_tabs_init_once[index].func); +} + +static AVOnce tabs_53_once = AV_ONCE_INIT; +static DECLARE_ALIGNED(32, FFTComplex, FFT_NAME(ff_53_tabs))[4]; + +static av_cold void ff_init_53_tabs(void) +{ + ff_53_tabs[0] = (FFTComplex){ cos(2 * M_PI / 12), cos(2 * M_PI / 12) }; + ff_53_tabs[1] = (FFTComplex){ 0.5, 0.5 }; + ff_53_tabs[2] = (FFTComplex){ cos(2 * M_PI / 5), sin(2 * M_PI / 5) }; + ff_53_tabs[3] = (FFTComplex){ cos(2 * M_PI / 10), sin(2 * M_PI / 10) }; +} + +#define BF(x, y, a, b) do { \ + x = (a) - (b); \ + y = (a) + (b); \ + } while (0) + +#define CMUL(dre, dim, are, aim, bre, bim) do { \ + (dre) = (are) * (bre) - (aim) * (bim); \ + (dim) = (are) * (bim) + (aim) * (bre); \ + } while (0) + +#define CMUL3(c, a, b) CMUL((c).re, (c).im, (a).re, (a).im, (b).re, (b).im) + +static av_always_inline void fft3(FFTComplex *out, FFTComplex *in, + ptrdiff_t stride) +{ + FFTComplex tmp[2]; + + tmp[0].re = in[1].im - in[2].im; + tmp[0].im = in[1].re - in[2].re; + tmp[1].re = in[1].re + in[2].re; + tmp[1].im = in[1].im + in[2].im; + + out[0*stride].re = in[0].re + tmp[1].re; + out[0*stride].im = in[0].im + tmp[1].im; + + tmp[0].re *= ff_53_tabs[0].re; + tmp[0].im *= ff_53_tabs[0].im; + tmp[1].re *= ff_53_tabs[1].re; + tmp[1].im *= ff_53_tabs[1].re; + + out[1*stride].re = in[0].re - tmp[1].re + tmp[0].re; + out[1*stride].im = in[0].im - tmp[1].im - tmp[0].im; + out[2*stride].re = in[0].re - tmp[1].re - tmp[0].re; + out[2*stride].im = in[0].im - tmp[1].im + tmp[0].im; +} + +#define DECL_FFT5(NAME, D0, D1, D2, D3, D4) \ +static av_always_inline void NAME(FFTComplex *out, FFTComplex *in, \ + ptrdiff_t stride) \ +{ \ + FFTComplex z0[4], t[6]; \ + \ + t[0].re = in[1].re + in[4].re; \ + t[0].im = in[1].im + in[4].im; \ + t[1].im = in[1].re - in[4].re; \ + t[1].re = in[1].im - in[4].im; \ + t[2].re = in[2].re + in[3].re; \ + t[2].im = in[2].im + in[3].im; \ + t[3].im = in[2].re - in[3].re; \ + t[3].re = in[2].im - in[3].im; \ + \ + out[D0*stride].re = in[0].re + in[1].re + in[2].re + \ + in[3].re + in[4].re; \ + out[D0*stride].im = in[0].im + in[1].im + in[2].im + \ + in[3].im + in[4].im; \ + \ + t[4].re = ff_53_tabs[2].re * t[2].re - ff_53_tabs[3].re * t[0].re; \ + t[4].im = ff_53_tabs[2].re * t[2].im - ff_53_tabs[3].re * t[0].im; \ + t[0].re = ff_53_tabs[2].re * t[0].re - ff_53_tabs[3].re * t[2].re; \ + t[0].im = ff_53_tabs[2].re * t[0].im - ff_53_tabs[3].re * t[2].im; \ + t[5].re = ff_53_tabs[2].im * t[3].re - ff_53_tabs[3].im * t[1].re; \ + t[5].im = ff_53_tabs[2].im * t[3].im - ff_53_tabs[3].im * t[1].im; \ + t[1].re = ff_53_tabs[2].im * t[1].re + ff_53_tabs[3].im * t[3].re; \ + t[1].im = ff_53_tabs[2].im * t[1].im + ff_53_tabs[3].im * t[3].im; \ + \ + z0[0].re = t[0].re - t[1].re; \ + z0[0].im = t[0].im - t[1].im; \ + z0[1].re = t[4].re + t[5].re; \ + z0[1].im = t[4].im + t[5].im; \ + \ + z0[2].re = t[4].re - t[5].re; \ + z0[2].im = t[4].im - t[5].im; \ + z0[3].re = t[0].re + t[1].re; \ + z0[3].im = t[0].im + t[1].im; \ + \ + out[D1*stride].re = in[0].re + z0[3].re; \ + out[D1*stride].im = in[0].im + z0[0].im; \ + out[D2*stride].re = in[0].re + z0[2].re; \ + out[D2*stride].im = in[0].im + z0[1].im; \ + out[D3*stride].re = in[0].re + z0[1].re; \ + out[D3*stride].im = in[0].im + z0[2].im; \ + out[D4*stride].re = in[0].re + z0[0].re; \ + out[D4*stride].im = in[0].im + z0[3].im; \ +} + +DECL_FFT5(fft5, 0, 1, 2, 3, 4) +DECL_FFT5(fft5_m1, 0, 6, 12, 3, 9) +DECL_FFT5(fft5_m2, 10, 1, 7, 13, 4) +DECL_FFT5(fft5_m3, 5, 11, 2, 8, 14) + +static av_always_inline void fft15(FFTComplex *out, FFTComplex *in, + ptrdiff_t stride) +{ + FFTComplex tmp[15]; + + for (int i = 0; i < 5; i++) + fft3(tmp + i, in + i*3, 5); + + fft5_m1(out, tmp + 0, stride); + fft5_m2(out, tmp + 5, stride); + fft5_m3(out, tmp + 10, stride); +} + +#define BUTTERFLIES(a0,a1,a2,a3) {\ + BF(t3, t5, t5, t1);\ + BF(a2.re, a0.re, a0.re, t5);\ + BF(a3.im, a1.im, a1.im, t3);\ + BF(t4, t6, t2, t6);\ + BF(a3.re, a1.re, a1.re, t4);\ + BF(a2.im, a0.im, a0.im, t6);\ +} + +// force loading all the inputs before storing any. +// this is slightly slower for small data, but avoids store->load aliasing +// for addresses separated by large powers of 2. +#define BUTTERFLIES_BIG(a0,a1,a2,a3) {\ + FFTSample r0=a0.re, i0=a0.im, r1=a1.re, i1=a1.im;\ + BF(t3, t5, t5, t1);\ + BF(a2.re, a0.re, r0, t5);\ + BF(a3.im, a1.im, i1, t3);\ + BF(t4, t6, t2, t6);\ + BF(a3.re, a1.re, r1, t4);\ + BF(a2.im, a0.im, i0, t6);\ +} + +#define TRANSFORM(a0,a1,a2,a3,wre,wim) {\ + CMUL(t1, t2, a2.re, a2.im, wre, -wim);\ + CMUL(t5, t6, a3.re, a3.im, wre, wim);\ + BUTTERFLIES(a0,a1,a2,a3)\ +} + +#define TRANSFORM_ZERO(a0,a1,a2,a3) {\ + t1 = a2.re;\ + t2 = a2.im;\ + t5 = a3.re;\ + t6 = a3.im;\ + BUTTERFLIES(a0,a1,a2,a3)\ +} + +/* z[0...8n-1], w[1...2n-1] */ +#define PASS(name)\ +static void name(FFTComplex *z, const FFTSample *wre, unsigned int n)\ +{\ + FFTSample t1, t2, t3, t4, t5, t6;\ + int o1 = 2*n;\ + int o2 = 4*n;\ + int o3 = 6*n;\ + const FFTSample *wim = wre+o1;\ + n--;\ +\ + TRANSFORM_ZERO(z[0],z[o1],z[o2],z[o3]);\ + TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\ + do {\ + z += 2;\ + wre += 2;\ + wim -= 2;\ + TRANSFORM(z[0],z[o1],z[o2],z[o3],wre[0],wim[0]);\ + TRANSFORM(z[1],z[o1+1],z[o2+1],z[o3+1],wre[1],wim[-1]);\ + } while(--n);\ +} + +PASS(pass) +#undef BUTTERFLIES +#define BUTTERFLIES BUTTERFLIES_BIG +PASS(pass_big) + +#define DECL_FFT(n,n2,n4)\ +static void fft##n(FFTComplex *z)\ +{\ + fft##n2(z);\ + fft##n4(z+n4*2);\ + fft##n4(z+n4*3);\ + pass(z,FFT_NAME(ff_cos_##n),n4/2);\ +} + +static void fft4(FFTComplex *z) +{ + FFTSample t1, t2, t3, t4, t5, t6, t7, t8; + + BF(t3, t1, z[0].re, z[1].re); + BF(t8, t6, z[3].re, z[2].re); + BF(z[2].re, z[0].re, t1, t6); + BF(t4, t2, z[0].im, z[1].im); + BF(t7, t5, z[2].im, z[3].im); + BF(z[3].im, z[1].im, t4, t8); + BF(z[3].re, z[1].re, t3, t7); + BF(z[2].im, z[0].im, t2, t5); +} + +static void fft8(FFTComplex *z) +{ + FFTSample t1, t2, t3, t4, t5, t6; + + fft4(z); + + BF(t1, z[5].re, z[4].re, -z[5].re); + BF(t2, z[5].im, z[4].im, -z[5].im); + BF(t5, z[7].re, z[6].re, -z[7].re); + BF(t6, z[7].im, z[6].im, -z[7].im); + + BUTTERFLIES(z[0],z[2],z[4],z[6]); + TRANSFORM(z[1],z[3],z[5],z[7],M_SQRT1_2,M_SQRT1_2); +} + +static void fft16(FFTComplex *z) +{ + FFTSample t1, t2, t3, t4, t5, t6; + FFTSample cos_16_1 = FFT_NAME(ff_cos_16)[1]; + FFTSample cos_16_3 = FFT_NAME(ff_cos_16)[3]; + + fft8(z); + fft4(z+8); + fft4(z+12); + + TRANSFORM_ZERO(z[0],z[4],z[8],z[12]); + TRANSFORM(z[2],z[6],z[10],z[14],M_SQRT1_2,M_SQRT1_2); + TRANSFORM(z[1],z[5],z[9],z[13],cos_16_1,cos_16_3); + TRANSFORM(z[3],z[7],z[11],z[15],cos_16_3,cos_16_1); +} + +DECL_FFT(32,16,8) +DECL_FFT(64,32,16) +DECL_FFT(128,64,32) +DECL_FFT(256,128,64) +DECL_FFT(512,256,128) +#define pass pass_big +DECL_FFT(1024,512,256) +DECL_FFT(2048,1024,512) +DECL_FFT(4096,2048,1024) +DECL_FFT(8192,4096,2048) +DECL_FFT(16384,8192,4096) +DECL_FFT(32768,16384,8192) +DECL_FFT(65536,32768,16384) +DECL_FFT(131072,65536,32768) + +static void (* const fft_dispatch[])(FFTComplex*) = { + fft4, fft8, fft16, fft32, fft64, fft128, fft256, fft512, fft1024, + fft2048, fft4096, fft8192, fft16384, fft32768, fft65536, fft131072 +}; + +#define DECL_COMP_FFT(N) \ +static void compound_fft_##N##xM(AVTXContext *s, void *_out, \ + void *_in, ptrdiff_t stride) \ +{ \ + const int m = s->m, *in_map = s->pfatab, *out_map = in_map + N*m; \ + FFTComplex *in = _in; \ + FFTComplex *out = _out; \ + FFTComplex fft##N##in[N]; \ + void (*fftp)(FFTComplex *z) = fft_dispatch[av_log2(m) - 2]; \ + \ + for (int i = 0; i < m; i++) { \ + for (int j = 0; j < N; j++) \ + fft##N##in[j] = in[in_map[i*N + j]]; \ + fft##N(s->tmp + s->revtab[i], fft##N##in, m); \ + } \ + \ + for (int i = 0; i < N; i++) \ + fftp(s->tmp + m*i); \ + \ + for (int i = 0; i < N*m; i++) \ + out[i] = s->tmp[out_map[i]]; \ +} + +DECL_COMP_FFT(3) +DECL_COMP_FFT(5) +DECL_COMP_FFT(15) + +static void monolithic_fft(AVTXContext *s, void *_out, void *_in, + ptrdiff_t stride) +{ + FFTComplex *in = _in; + FFTComplex *out = _out; + int m = s->m, mb = av_log2(m) - 2; + for (int i = 0; i < m; i++) + out[s->revtab[i]] = in[i]; + fft_dispatch[mb](out); +} + +#define DECL_COMP_IMDCT(N) \ +static void compound_imdct_##N##xM(AVTXContext *s, void *_dst, void *_src, \ + ptrdiff_t stride) \ +{ \ + FFTComplex fft##N##in[N]; \ + FFTComplex *z = _dst, *exp = s->exptab; \ + const int m = s->m, len8 = N*m >> 1; \ + const int *in_map = s->pfatab, *out_map = in_map + N*m; \ + const float *src = _src, *in1, *in2; \ + void (*fftp)(FFTComplex *) = fft_dispatch[av_log2(m) - 2]; \ + \ + stride /= sizeof(*src); /* To convert it from bytes */ \ + in1 = src; \ + in2 = src + ((N*m*2) - 1) * stride; \ + \ + for (int i = 0; i < m; i++) { \ + for (int j = 0; j < N; j++) { \ + const int k = in_map[i*N + j]; \ + FFTComplex tmp = { in2[-k*stride], in1[k*stride] }; \ + CMUL3(fft##N##in[j], tmp, exp[k >> 1]); \ + } \ + fft##N(s->tmp + s->revtab[i], fft##N##in, m); \ + } \ + \ + for (int i = 0; i < N; i++) \ + fftp(s->tmp + m*i); \ + \ + for (int i = 0; i < len8; i++) { \ + const int i0 = len8 + i, i1 = len8 - i - 1; \ + const int s0 = out_map[i0], s1 = out_map[i1]; \ + FFTComplex src1 = { s->tmp[s1].im, s->tmp[s1].re }; \ + FFTComplex src0 = { s->tmp[s0].im, s->tmp[s0].re }; \ + \ + CMUL(z[i1].re, z[i0].im, src1.re, src1.im, exp[i1].im, exp[i1].re); \ + CMUL(z[i0].re, z[i1].im, src0.re, src0.im, exp[i0].im, exp[i0].re); \ + } \ +} + +DECL_COMP_IMDCT(3) +DECL_COMP_IMDCT(5) +DECL_COMP_IMDCT(15) + +#define DECL_COMP_MDCT(N) \ +static void compound_mdct_##N##xM(AVTXContext *s, void *_dst, void *_src, \ + ptrdiff_t stride) \ +{ \ + float *src = _src, *dst = _dst; \ + FFTComplex *exp = s->exptab, tmp, fft##N##in[N]; \ + const int m = s->m, len4 = N*m, len3 = len4 * 3, len8 = len4 >> 1; \ + const int *in_map = s->pfatab, *out_map = in_map + N*m; \ + void (*fftp)(FFTComplex *) = fft_dispatch[av_log2(m) - 2]; \ + \ + stride /= sizeof(*dst); \ + \ + for (int i = 0; i < m; i++) { /* Folding and pre-reindexing */ \ + for (int j = 0; j < N; j++) { \ + const int k = in_map[i*N + j]; \ + if (k < len4) { \ + tmp.re = -src[ len4 + k] + src[1*len4 - 1 - k]; \ + tmp.im = -src[ len3 + k] - src[1*len3 - 1 - k]; \ + } else { \ + tmp.re = -src[ len4 + k] - src[5*len4 - 1 - k]; \ + tmp.im = src[-len4 + k] - src[1*len3 - 1 - k]; \ + } \ + CMUL(fft##N##in[j].im, fft##N##in[j].re, tmp.re, tmp.im, \ + exp[k >> 1].re, exp[k >> 1].im); \ + } \ + fft##N(s->tmp + s->revtab[i], fft##N##in, m); \ + } \ + \ + for (int i = 0; i < N; i++) \ + fftp(s->tmp + m*i); \ + \ + for (int i = 0; i < len8; i++) { \ + const int i0 = len8 + i, i1 = len8 - i - 1; \ + const int s0 = out_map[i0], s1 = out_map[i1]; \ + FFTComplex src1 = { s->tmp[s1].re, s->tmp[s1].im }; \ + FFTComplex src0 = { s->tmp[s0].re, s->tmp[s0].im }; \ + \ + CMUL(dst[2*i1*stride + stride], dst[2*i0*stride], src0.re, src0.im, \ + exp[i0].im, exp[i0].re); \ + CMUL(dst[2*i0*stride + stride], dst[2*i1*stride], src1.re, src1.im, \ + exp[i1].im, exp[i1].re); \ + } \ +} + +DECL_COMP_MDCT(3) +DECL_COMP_MDCT(5) +DECL_COMP_MDCT(15) + +static void monolithic_imdct(AVTXContext *s, void *_dst, void *_src, + ptrdiff_t stride) +{ + FFTComplex *z = _dst, *exp = s->exptab; + const int m = s->m, len8 = m >> 1; + const float *src = _src, *in1, *in2; + void (*fftp)(FFTComplex *) = fft_dispatch[av_log2(m) - 2]; + + stride /= sizeof(*src); + in1 = src; + in2 = src + ((m*2) - 1) * stride; + + for (int i = 0; i < m; i++) { + FFTComplex tmp = { in2[-2*i*stride], in1[2*i*stride] }; + CMUL3(z[s->revtab[i]], tmp, exp[i]); + } + + fftp(z); + + for (int i = 0; i < len8; i++) { + const int i0 = len8 + i, i1 = len8 - i - 1; + FFTComplex src1 = { z[i1].im, z[i1].re }; + FFTComplex src0 = { z[i0].im, z[i0].re }; + + CMUL(z[i1].re, z[i0].im, src1.re, src1.im, exp[i1].im, exp[i1].re); + CMUL(z[i0].re, z[i1].im, src0.re, src0.im, exp[i0].im, exp[i0].re); + } +} + +static void monolithic_mdct(AVTXContext *s, void *_dst, void *_src, + ptrdiff_t stride) +{ + float *src = _src, *dst = _dst; + FFTComplex *exp = s->exptab, tmp, *z = _dst; + const int m = s->m, len4 = m, len3 = len4 * 3, len8 = len4 >> 1; + void (*fftp)(FFTComplex *) = fft_dispatch[av_log2(m) - 2]; + + stride /= sizeof(*dst); + + for (int i = 0; i < m; i++) { /* Folding and pre-reindexing */ + const int k = 2*i; + if (k < len4) { + tmp.re = -src[ len4 + k] + src[1*len4 - 1 - k]; + tmp.im = -src[ len3 + k] - src[1*len3 - 1 - k]; + } else { + tmp.re = -src[ len4 + k] - src[5*len4 - 1 - k]; + tmp.im = src[-len4 + k] - src[1*len3 - 1 - k]; + } + CMUL(z[s->revtab[i]].im, z[s->revtab[i]].re, tmp.re, tmp.im, + exp[i].re, exp[i].im); + } + + fftp(z); + + for (int i = 0; i < len8; i++) { + const int i0 = len8 + i, i1 = len8 - i - 1; + FFTComplex src1 = { z[i1].re, z[i1].im }; + FFTComplex src0 = { z[i0].re, z[i0].im }; + + CMUL(dst[2*i1*stride + stride], dst[2*i0*stride], src0.re, src0.im, + exp[i0].im, exp[i0].re); + CMUL(dst[2*i0*stride + stride], dst[2*i1*stride], src1.re, src1.im, + exp[i1].im, exp[i1].re); + } +} + +/* Calculates the modular multiplicative inverse, not fast, replace */ +static int mulinv(int n, int m) +{ + n = n % m; + for (int x = 1; x < m; x++) + if (((n * x) % m) == 1) + return x; + av_assert0(0); /* Never reached */ +} + +/* Guaranteed to work for any n, m where gcd(n, m) == 1 */ +static int gen_compound_mapping(AVTXContext *s, int n, int m, int inv, + enum AVTXType type) +{ + int *in_map, *out_map; + const int len = n*m; + const int m_inv = mulinv(m, n); + const int n_inv = mulinv(n, m); + const int mdct = type == AV_TX_FLOAT_MDCT; + + if (!(s->pfatab = av_malloc(2*len*sizeof(*s->pfatab)))) + return AVERROR(ENOMEM); + + in_map = s->pfatab; + out_map = s->pfatab + n*m; + + /* Ruritanian map for input, CRT map for output, can be swapped */ + for (int j = 0; j < m; j++) { + for (int i = 0; i < n; i++) { + /* Shifted by 1 to simplify forward MDCTs */ + in_map[j*n + i] = ((i*m + j*n) % len) << mdct; + out_map[(i*m*m_inv + j*n*n_inv) % len] = i*m + j; + } + } + + /* Change transform direction by reversing all ACs */ + if (inv) { + for (int i = 0; i < m; i++) { + int *in = &in_map[i*n + 1]; /* Skip the DC */ + for (int j = 0; j < ((n - 1) >> 1); j++) + FFSWAP(int, in[j], in[n - j - 2]); + } + } + + /* Our 15-point transform is also a compound one, so embed its input map */ + if (n == 15) { + for (int k = 0; k < m; k++) { + int tmp[15]; + memcpy(tmp, &in_map[k*15], 15*sizeof(*tmp)); + for (int i = 0; i < 5; i++) { + for (int j = 0; j < 3; j++) + in_map[k*15 + i*3 + j] = tmp[(i*3 + j*5) % 15]; + } + } + } + + return 0; +} + +static int split_radix_permutation(int i, int n, int inverse) +{ + int m; + if (n <= 2) + return i & 1; + m = n >> 1; + if (!(i & m)) + return split_radix_permutation(i, m, inverse)*2; + m >>= 1; + if (inverse == !(i & m)) + return split_radix_permutation(i, m, inverse)*4 + 1; + else + return split_radix_permutation(i, m, inverse)*4 - 1; +} + +static int get_ptwo_revtab(AVTXContext *s, int m, int inv) +{ + if (!(s->revtab = av_malloc(m*sizeof(*s->revtab)))) + return AVERROR(ENOMEM); + + /* Default */ + for (int i = 0; i < m; i++) { + int k = -split_radix_permutation(i, m, inv) & (m - 1); + s->revtab[k] = i; + } + + return 0; +} + +static int gen_mdct_exptab(AVTXContext *s, int len4, double scale) +{ + const double theta = (scale < 0 ? len4 : 0) + 1.0/8.0; + + if (!(s->exptab = av_malloc_array(len4, sizeof(*s->exptab)))) + return AVERROR(ENOMEM); + + scale = sqrt(fabs(scale)); + for (int i = 0; i < len4; i++) { + const double alpha = M_PI_2 * (i + theta) / len4; + s->exptab[i].re = cos(alpha) * scale; + s->exptab[i].im = sin(alpha) * scale; + } + + return 0; +} + +av_cold void av_tx_uninit(AVTXContext **ctx) +{ + if (!(*ctx)) + return; + + av_free((*ctx)->pfatab); + av_free((*ctx)->exptab); + av_free((*ctx)->revtab); + av_free((*ctx)->tmp); + + av_freep(ctx); +} + +static int init_mdct_fft(AVTXContext *s, av_tx_fn *tx, enum AVTXType type, + int inv, int len, const void *scale, uint64_t flags) +{ + int err, n = 1, m = 1, max_ptwo = 1 << (FF_ARRAY_ELEMS(fft_dispatch) + 1); + + if (type == AV_TX_FLOAT_MDCT) + len >>= 1; + +#define CHECK_FACTOR(DST, FACTOR, SRC) \ + if (DST == 1 && !(SRC % FACTOR)) { \ + DST = FACTOR; \ + SRC /= FACTOR; \ + } + CHECK_FACTOR(n, 15, len) + CHECK_FACTOR(n, 5, len) + CHECK_FACTOR(n, 3, len) +#undef CHECK_NPTWO_FACTOR + + /* len must be a power of two now */ + if (!(len & (len - 1)) && len >= 4 && len <= max_ptwo) { + m = len; + len = 1; + } + + /* Filter out direct 3, 5 and 15 transforms, too niche */ + if (len > 1 || m == 1) { + av_log(NULL, AV_LOG_ERROR, "Unsupported transform size: n = %i, " + "m = %i, residual = %i!\n", n, m, len); + return AVERROR(EINVAL); + } else if (n > 1 && m > 1) { /* 2D transform case */ + if ((err = gen_compound_mapping(s, n, m, inv, type))) + return err; + if (!(s->tmp = av_malloc(n*m*sizeof(*s->tmp)))) + return AVERROR(ENOMEM); + *tx = n == 3 ? compound_fft_3xM : + n == 5 ? compound_fft_5xM : + compound_fft_15xM; + if (type == AV_TX_FLOAT_MDCT) + *tx = n == 3 ? inv ? compound_imdct_3xM : compound_mdct_3xM : + n == 5 ? inv ? compound_imdct_5xM : compound_mdct_5xM : + inv ? compound_imdct_15xM : compound_mdct_15xM; + } else { /* Direct transform case */ + *tx = monolithic_fft; + if (type == AV_TX_FLOAT_MDCT) + *tx = inv ? monolithic_imdct : monolithic_mdct; + } + + if (n != 1) + ff_thread_once(&tabs_53_once, ff_init_53_tabs); + if (m != 1) { + get_ptwo_revtab(s, m, inv); + for (int i = 4; i <= av_log2(m); i++) + ff_init_ff_cos_tabs(i); + } + + if (type == AV_TX_FLOAT_MDCT) + if ((err = gen_mdct_exptab(s, n*m, *((float *)scale)))) + return err; + + s->n = n; + s->m = m; + + return 0; +} + +av_cold int av_tx_init(AVTXContext **ctx, av_tx_fn *tx, enum AVTXType type, + int inv, int len, const void *scale, uint64_t flags) +{ + int err; + AVTXContext *s = av_mallocz(sizeof(*s)); + if (!s) + return AVERROR(ENOMEM); + + switch (type) { + case AV_TX_FLOAT_FFT: + case AV_TX_FLOAT_MDCT: + if ((err = init_mdct_fft(s, tx, type, inv, len, scale, flags))) + goto fail; + break; + default: + err = AVERROR(EINVAL); + goto fail; + } + + *ctx = s; + + return 0; + +fail: + av_tx_uninit(&s); + *tx = NULL; + return err; +} |