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ffmpeg-4.2.2/libavcodec/x86/mdct15_init.c 3.32 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * 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 tmp[30];
  
      /* 5-point FFT twiddles */
      s->exptab[60].re = s->exptab[60].im = s->exptab[19].re;
      s->exptab[61].re = s->exptab[61].im = s->exptab[19].im;
      s->exptab[62].re = s->exptab[62].im = s->exptab[20].re;
      s->exptab[63].re = s->exptab[63].im = s->exptab[20].im;
  
      /* 15-point FFT twiddles */
      for (k = 0; k < 5; k++) {
          tmp[6*k + 0] = s->exptab[k +  0];
          tmp[6*k + 2] = s->exptab[k +  5];
          tmp[6*k + 4] = s->exptab[k + 10];
  
          tmp[6*k + 1] = s->exptab[2 * (k + 0)];
          tmp[6*k + 3] = s->exptab[2 * (k + 5)];
          tmp[6*k + 5] = s->exptab[2 *  k + 5 ];
      }
  
      for (k = 0; k < 6; k++) {
          FFTComplex ac_exp[] = {
              { tmp[6*1 + k].re,  tmp[6*1 + k].re },
              { tmp[6*2 + k].re,  tmp[6*2 + k].re },
              { tmp[6*3 + k].re,  tmp[6*3 + k].re },
              { tmp[6*4 + k].re,  tmp[6*4 + k].re },
              { tmp[6*1 + k].im, -tmp[6*1 + k].im },
              { tmp[6*2 + k].im, -tmp[6*2 + k].im },
              { tmp[6*3 + k].im, -tmp[6*3 + k].im },
              { tmp[6*4 + k].im, -tmp[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[] = {
              { tmp[2*k + 0].re, -tmp[2*k + 0].im },
              { tmp[2*k + 0].im,  tmp[2*k + 0].re },
              { tmp[2*k + 1].re, -tmp[2*k + 1].im },
              { tmp[2*k + 1].im,  tmp[2*k + 1].re },
          };
          memcpy(s->exptab + 8*6 + 4*k, dc_exp, 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);
  }