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ppsspp/ext/ffmpeg/libavcodec/fft_template.c
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Henrik RydgårdandClaude Opus 5.5 d0e3141f43 FFmpeg: Vendor what PPSSPP uses into ext/ffmpeg, drop the submodule 
The ffmpeg submodule held prebuilt libraries for every platform next to the
sources (about 1.5 GB checked out), and nothing uses those any more. Only the
needed sources are copied in, from the submodule's commit, along with every
header and template they include. The path is new, so checking out commits on
either side of this works.

It's also cut down to what PPSSPP uses: the H.264, AAC, MP3, ATRAC3 and ATRAC3+
decoders, the H.264 parser, the demuxers as before, and the FFV1 encoder, AVI
muxer and file protocol for AVI dumping. config.h takes its CONFIG_ values from
FFmpeg 3.0.2's own configure run with just those enabled. The raw H.264 demuxer
stays even though nothing opens raw H.264: probing PSMF data uses it to identify
the video stream's codec, which otherwise comes out as none.

On top of that:
- The files nothing links (configure would build them, but they're never pulled
  out of the static library, going by the GCC link map) are left out: mostly
  libavutil's crypto and hashing and the alternative DCT/IDCT/FFT versions.
- libswresample isn't built, now that nothing uses it.
- The H.264 decoder only does 8-bit video, which is all the PSP has. The SPS
  parser rejects any other bit depth, and the DSP files no longer build their 9-
  to 16-bit variants, which the linker kept because the init functions pick one
  by bit depth at run time.

That's 160 files to compile instead of 277, and 391 of FFmpeg's vendored, about
5.8 MB. The README in ext/ffmpeg has what was done, the PPSSPP patches in the
copy, how to add a component, and the tradeoffs.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
2026-10-25 22:27:54 +01:00

529 lines
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/*
* FFT/IFFT transforms
* 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
*/
/**
* @file
* FFT/IFFT transforms.
*/
#include <stdlib.h>
#include <string.h>
#include "libavutil/mathematics.h"
#include "fft.h"
#include "fft-internal.h"
#if FFT_FIXED_32
#include "fft_table.h"
#else /* FFT_FIXED_32 */
/* cos(2*pi*x/n) for 0<=x<=n/4, followed by its reverse */
#if !CONFIG_HARDCODED_TABLES
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);
#endif
COSTABLE_CONST 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),
};
#endif /* FFT_FIXED_32 */
static void fft_permute_c(FFTContext *s, FFTComplex *z);
static void fft_calc_c(FFTContext *s, FFTComplex *z);
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;
}
av_cold void ff_init_ff_cos_tabs(int index)
{
#if (!CONFIG_HARDCODED_TABLES) && (!FFT_FIXED_32)
int i;
int m = 1<<index;
double freq = 2*M_PI/m;
FFTSample *tab = FFT_NAME(ff_cos_tabs)[index];
for(i=0; i<=m/4; i++)
tab[i] = FIX15(cos(i*freq));
for(i=1; i<m/4; i++)
tab[m/2-i] = tab[i];
#endif
}
static const int avx_tab[] = {
0, 4, 1, 5, 8, 12, 9, 13, 2, 6, 3, 7, 10, 14, 11, 15
};
static int is_second_half_of_fft32(int i, int n)
{
if (n <= 32)
return i >= 16;
else if (i < n/2)
return is_second_half_of_fft32(i, n/2);
else if (i < 3*n/4)
return is_second_half_of_fft32(i - n/2, n/4);
else
return is_second_half_of_fft32(i - 3*n/4, n/4);
}
static av_cold void fft_perm_avx(FFTContext *s)
{
int i;
int n = 1 << s->nbits;
for (i = 0; i < n; i += 16) {
int k;
if (is_second_half_of_fft32(i, n)) {
for (k = 0; k < 16; k++)
s->revtab[-split_radix_permutation(i + k, n, s->inverse) & (n - 1)] =
i + avx_tab[k];
} else {
for (k = 0; k < 16; k++) {
int j = i + k;
j = (j & ~7) | ((j >> 1) & 3) | ((j << 2) & 4);
s->revtab[-split_radix_permutation(i + k, n, s->inverse) & (n - 1)] = j;
}
}
}
}
av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse)
{
int i, j, n;
if (nbits < 2 || nbits > 16)
goto fail;
s->nbits = nbits;
n = 1 << nbits;
s->revtab = av_malloc(n * sizeof(uint16_t));
if (!s->revtab)
goto fail;
s->tmp_buf = av_malloc(n * sizeof(FFTComplex));
if (!s->tmp_buf)
goto fail;
s->inverse = inverse;
s->fft_permutation = FF_FFT_PERM_DEFAULT;
s->fft_permute = fft_permute_c;
s->fft_calc = fft_calc_c;
#if CONFIG_MDCT
s->imdct_calc = ff_imdct_calc_c;
s->imdct_half = ff_imdct_half_c;
s->mdct_calc = ff_mdct_calc_c;
#endif
#if FFT_FIXED_32
{
int n=0;
ff_fft_lut_init(ff_fft_offsets_lut, 0, 1 << 16, &n);
}
#else /* FFT_FIXED_32 */
#if FFT_FLOAT
if (ARCH_AARCH64) ff_fft_init_aarch64(s);
if (ARCH_ARM) ff_fft_init_arm(s);
if (ARCH_PPC) ff_fft_init_ppc(s);
if (ARCH_X86) ff_fft_init_x86(s);
if (CONFIG_MDCT) s->mdct_calcw = s->mdct_calc;
if (HAVE_MIPSFPU) ff_fft_init_mips(s);
#else
if (CONFIG_MDCT) s->mdct_calcw = ff_mdct_calcw_c;
if (ARCH_ARM) ff_fft_fixed_init_arm(s);
#endif
for(j=4; j<=nbits; j++) {
ff_init_ff_cos_tabs(j);
}
#endif /* FFT_FIXED_32 */
if (s->fft_permutation == FF_FFT_PERM_AVX) {
fft_perm_avx(s);
} else {
for(i=0; i<n; i++) {
j = i;
if (s->fft_permutation == FF_FFT_PERM_SWAP_LSBS)
j = (j&~3) | ((j>>1)&1) | ((j<<1)&2);
s->revtab[-split_radix_permutation(i, n, s->inverse) & (n-1)] = j;
}
}
return 0;
fail:
av_freep(&s->revtab);
av_freep(&s->tmp_buf);
return -1;
}
static void fft_permute_c(FFTContext *s, FFTComplex *z)
{
int j, np;
const uint16_t *revtab = s->revtab;
np = 1 << s->nbits;
/* TODO: handle split-radix permute in a more optimal way, probably in-place */
for(j=0;j<np;j++) s->tmp_buf[revtab[j]] = z[j];
memcpy(z, s->tmp_buf, np * sizeof(FFTComplex));
}
av_cold void ff_fft_end(FFTContext *s)
{
av_freep(&s->revtab);
av_freep(&s->tmp_buf);
}
#if FFT_FIXED_32
static void fft_calc_c(FFTContext *s, FFTComplex *z) {
int nbits, i, n, num_transforms, offset, step;
int n4, n2, n34;
FFTSample tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp8;
FFTComplex *tmpz;
const int fft_size = (1 << s->nbits);
int64_t accu;
num_transforms = (0x2aab >> (16 - s->nbits)) | 1;
for (n=0; n<num_transforms; n++){
offset = ff_fft_offsets_lut[n] << 2;
tmpz = z + offset;
tmp1 = tmpz[0].re + tmpz[1].re;
tmp5 = tmpz[2].re + tmpz[3].re;
tmp2 = tmpz[0].im + tmpz[1].im;
tmp6 = tmpz[2].im + tmpz[3].im;
tmp3 = tmpz[0].re - tmpz[1].re;
tmp8 = tmpz[2].im - tmpz[3].im;
tmp4 = tmpz[0].im - tmpz[1].im;
tmp7 = tmpz[2].re - tmpz[3].re;
tmpz[0].re = tmp1 + tmp5;
tmpz[2].re = tmp1 - tmp5;
tmpz[0].im = tmp2 + tmp6;
tmpz[2].im = tmp2 - tmp6;
tmpz[1].re = tmp3 + tmp8;
tmpz[3].re = tmp3 - tmp8;
tmpz[1].im = tmp4 - tmp7;
tmpz[3].im = tmp4 + tmp7;
}
if (fft_size < 8)
return;
num_transforms = (num_transforms >> 1) | 1;
for (n=0; n<num_transforms; n++){
offset = ff_fft_offsets_lut[n] << 3;
tmpz = z + offset;
tmp1 = tmpz[4].re + tmpz[5].re;
tmp3 = tmpz[6].re + tmpz[7].re;
tmp2 = tmpz[4].im + tmpz[5].im;
tmp4 = tmpz[6].im + tmpz[7].im;
tmp5 = tmp1 + tmp3;
tmp7 = tmp1 - tmp3;
tmp6 = tmp2 + tmp4;
tmp8 = tmp2 - tmp4;
tmp1 = tmpz[4].re - tmpz[5].re;
tmp2 = tmpz[4].im - tmpz[5].im;
tmp3 = tmpz[6].re - tmpz[7].re;
tmp4 = tmpz[6].im - tmpz[7].im;
tmpz[4].re = tmpz[0].re - tmp5;
tmpz[0].re = tmpz[0].re + tmp5;
tmpz[4].im = tmpz[0].im - tmp6;
tmpz[0].im = tmpz[0].im + tmp6;
tmpz[6].re = tmpz[2].re - tmp8;
tmpz[2].re = tmpz[2].re + tmp8;
tmpz[6].im = tmpz[2].im + tmp7;
tmpz[2].im = tmpz[2].im - tmp7;
accu = (int64_t)Q31(M_SQRT1_2)*(tmp1 + tmp2);
tmp5 = (int32_t)((accu + 0x40000000) >> 31);
accu = (int64_t)Q31(M_SQRT1_2)*(tmp3 - tmp4);
tmp7 = (int32_t)((accu + 0x40000000) >> 31);
accu = (int64_t)Q31(M_SQRT1_2)*(tmp2 - tmp1);
tmp6 = (int32_t)((accu + 0x40000000) >> 31);
accu = (int64_t)Q31(M_SQRT1_2)*(tmp3 + tmp4);
tmp8 = (int32_t)((accu + 0x40000000) >> 31);
tmp1 = tmp5 + tmp7;
tmp3 = tmp5 - tmp7;
tmp2 = tmp6 + tmp8;
tmp4 = tmp6 - tmp8;
tmpz[5].re = tmpz[1].re - tmp1;
tmpz[1].re = tmpz[1].re + tmp1;
tmpz[5].im = tmpz[1].im - tmp2;
tmpz[1].im = tmpz[1].im + tmp2;
tmpz[7].re = tmpz[3].re - tmp4;
tmpz[3].re = tmpz[3].re + tmp4;
tmpz[7].im = tmpz[3].im + tmp3;
tmpz[3].im = tmpz[3].im - tmp3;
}
step = 1 << ((MAX_LOG2_NFFT-4) - 4);
n4 = 4;
for (nbits=4; nbits<=s->nbits; nbits++){
n2 = 2*n4;
n34 = 3*n4;
num_transforms = (num_transforms >> 1) | 1;
for (n=0; n<num_transforms; n++){
const FFTSample *w_re_ptr = ff_w_tab_sr + step;
const FFTSample *w_im_ptr = ff_w_tab_sr + MAX_FFT_SIZE/(4*16) - step;
offset = ff_fft_offsets_lut[n] << nbits;
tmpz = z + offset;
tmp5 = tmpz[ n2].re + tmpz[n34].re;
tmp1 = tmpz[ n2].re - tmpz[n34].re;
tmp6 = tmpz[ n2].im + tmpz[n34].im;
tmp2 = tmpz[ n2].im - tmpz[n34].im;
tmpz[ n2].re = tmpz[ 0].re - tmp5;
tmpz[ 0].re = tmpz[ 0].re + tmp5;
tmpz[ n2].im = tmpz[ 0].im - tmp6;
tmpz[ 0].im = tmpz[ 0].im + tmp6;
tmpz[n34].re = tmpz[n4].re - tmp2;
tmpz[ n4].re = tmpz[n4].re + tmp2;
tmpz[n34].im = tmpz[n4].im + tmp1;
tmpz[ n4].im = tmpz[n4].im - tmp1;
for (i=1; i<n4; i++){
FFTSample w_re = w_re_ptr[0];
FFTSample w_im = w_im_ptr[0];
accu = (int64_t)w_re*tmpz[ n2+i].re;
accu += (int64_t)w_im*tmpz[ n2+i].im;
tmp1 = (int32_t)((accu + 0x40000000) >> 31);
accu = (int64_t)w_re*tmpz[ n2+i].im;
accu -= (int64_t)w_im*tmpz[ n2+i].re;
tmp2 = (int32_t)((accu + 0x40000000) >> 31);
accu = (int64_t)w_re*tmpz[n34+i].re;
accu -= (int64_t)w_im*tmpz[n34+i].im;
tmp3 = (int32_t)((accu + 0x40000000) >> 31);
accu = (int64_t)w_re*tmpz[n34+i].im;
accu += (int64_t)w_im*tmpz[n34+i].re;
tmp4 = (int32_t)((accu + 0x40000000) >> 31);
tmp5 = tmp1 + tmp3;
tmp1 = tmp1 - tmp3;
tmp6 = tmp2 + tmp4;
tmp2 = tmp2 - tmp4;
tmpz[ n2+i].re = tmpz[ i].re - tmp5;
tmpz[ i].re = tmpz[ i].re + tmp5;
tmpz[ n2+i].im = tmpz[ i].im - tmp6;
tmpz[ i].im = tmpz[ i].im + tmp6;
tmpz[n34+i].re = tmpz[n4+i].re - tmp2;
tmpz[ n4+i].re = tmpz[n4+i].re + tmp2;
tmpz[n34+i].im = tmpz[n4+i].im + tmp1;
tmpz[ n4+i].im = tmpz[n4+i].im - tmp1;
w_re_ptr += step;
w_im_ptr -= step;
}
}
step >>= 1;
n4 <<= 1;
}
}
#else /* FFT_FIXED_32 */
#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)\
{\
FFTDouble 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)
{
FFTDouble 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)
{
FFTDouble 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],sqrthalf,sqrthalf);
}
#if !CONFIG_SMALL
static void fft16(FFTComplex *z)
{
FFTDouble 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],sqrthalf,sqrthalf);
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);
}
#else
DECL_FFT(16,8,4)
#endif
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)
#if !CONFIG_SMALL
#define pass pass_big
#endif
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)
static void (* const fft_dispatch[])(FFTComplex*) = {
fft4, fft8, fft16, fft32, fft64, fft128, fft256, fft512, fft1024,
fft2048, fft4096, fft8192, fft16384, fft32768, fft65536,
};
static void fft_calc_c(FFTContext *s, FFTComplex *z)
{
fft_dispatch[s->nbits-2](z);
}
#endif /* FFT_FIXED_32 */
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