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FFmpeg/libavcodec/x86/mdct15_init.c
Rostislav Pehlivanov 70eb77b34e mdct15: add inverse transform postrotation SIMD
2.5ms frames:
Before   (c):  2638 decicycles in postrotate, 2097040 runs,    112 skips
After (sse3):  1467 decicycles in postrotate, 2097083 runs,     69 skips
After (avx2):  1244 decicycles in postrotate, 2097085 runs,     67 skips

5ms frames:
Before   (c):  4987 decicycles in postrotate, 1048371 runs,    205 skips
After (sse3):  2644 decicycles in postrotate, 1048509 runs,     67 skips
After (avx2):  2031 decicycles in postrotate, 1048523 runs,     53 skips

10ms frames:
Before   (c):  9153 decicycles in postrotate,  523575 runs,    713 skips
After (sse3):  5110 decicycles in postrotate,  523726 runs,    562 skips
After (avx2):  3738 decicycles in postrotate,  524223 runs,     65 skips

20ms frames:
Before   (c): 17857 decicycles in postrotate,  261866 runs,    278 skips
After (sse3): 10041 decicycles in postrotate,  261746 runs,    398 skips
After (avx2):  7050 decicycles in postrotate,  262116 runs,     28 skips

Improves total decoding performance for real world content by 9% with avx2.

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
2017-07-30 07:38:39 +01:00

105 lines
3.4 KiB
C

/*
* SIMD optimized non-power-of-two MDCT functions
*
* Copyright (C) 2017 Rostislav Pehlivanov <atomnuker@gmail.com>
*
* 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 "config.h"
#include "libavutil/x86/cpu.h"
#include "libavcodec/mdct15.h"
void ff_mdct15_postreindex_sse3(FFTComplex *out, FFTComplex *in, FFTComplex *exp, int *lut, ptrdiff_t len8);
void ff_mdct15_postreindex_avx2(FFTComplex *out, FFTComplex *in, FFTComplex *exp, int *lut, ptrdiff_t len8);
void ff_fft15_avx(FFTComplex *out, FFTComplex *in, FFTComplex *exptab, ptrdiff_t stride);
static void perm_twiddles(MDCT15Context *s)
{
int k;
FFTComplex exp_5point[4];
FFTComplex tmp[21], tmp2[30];
memcpy(tmp, s->exptab, sizeof(FFTComplex)*21);
/* 15-point FFT twiddles */
for (k = 0; k < 5; k++) {
tmp2[6*k + 0] = tmp[k + 0];
tmp2[6*k + 2] = tmp[k + 5];
tmp2[6*k + 4] = tmp[k + 10];
tmp2[6*k + 1] = tmp[2 * (k + 0)];
tmp2[6*k + 3] = tmp[2 * (k + 5)];
tmp2[6*k + 5] = tmp[2 * k + 5 ];
}
for (k = 0; k < 6; k++) {
FFTComplex ac_exp[] = {
{ tmp2[6*1 + k].re, tmp2[6*1 + k].re },
{ tmp2[6*2 + k].re, tmp2[6*2 + k].re },
{ tmp2[6*3 + k].re, tmp2[6*3 + k].re },
{ tmp2[6*4 + k].re, tmp2[6*4 + k].re },
{ tmp2[6*1 + k].im, -tmp2[6*1 + k].im },
{ tmp2[6*2 + k].im, -tmp2[6*2 + k].im },
{ tmp2[6*3 + k].im, -tmp2[6*3 + k].im },
{ tmp2[6*4 + k].im, -tmp2[6*4 + k].im },
};
memcpy(s->exptab + 8*k, ac_exp, 8*sizeof(FFTComplex));
}
/* Specialcase when k = 0 */
for (k = 0; k < 3; k++) {
FFTComplex dc_exp[] = {
{ tmp2[2*k + 0].re, -tmp2[2*k + 0].im },
{ tmp2[2*k + 0].im, tmp2[2*k + 0].re },
{ tmp2[2*k + 1].re, -tmp2[2*k + 1].im },
{ tmp2[2*k + 1].im, tmp2[2*k + 1].re },
};
memcpy(s->exptab + 8*6 + 4*k, dc_exp, 4*sizeof(FFTComplex));
}
/* 5-point FFT twiddles */
exp_5point[0].re = exp_5point[0].im = tmp[19].re;
exp_5point[1].re = exp_5point[1].im = tmp[19].im;
exp_5point[2].re = exp_5point[2].im = tmp[20].re;
exp_5point[3].re = exp_5point[3].im = tmp[20].im;
memcpy(s->exptab + 8*6 + 4*3, exp_5point, 4*sizeof(FFTComplex));
}
av_cold void ff_mdct15_init_x86(MDCT15Context *s)
{
int adjust_twiddles = 0;
int cpu_flags = av_get_cpu_flags();
if (EXTERNAL_SSE3(cpu_flags))
s->postreindex = ff_mdct15_postreindex_sse3;
if (ARCH_X86_64 && EXTERNAL_AVX(cpu_flags)) {
s->fft15 = ff_fft15_avx;
adjust_twiddles = 1;
}
if (ARCH_X86_64 && EXTERNAL_AVX2_FAST(cpu_flags))
s->postreindex = ff_mdct15_postreindex_avx2;
if (adjust_twiddles)
perm_twiddles(s);
}