libavcodec/faanidct.c

   1 /*
   2  * Floating point AAN IDCT
   3  * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21 #include "faanidct.h"
  22
  23 /* To allow switching to double. */
  24 #define FLOAT float
  25
  26 #define B0 1.0000000000000000000000
  27 #define B1 1.3870398453221474618216 // cos(pi*1/16)sqrt(2)
  28 #define B2 1.3065629648763765278566 // cos(pi*2/16)sqrt(2)
  29 #define B3 1.1758756024193587169745 // cos(pi*3/16)sqrt(2)
  30 #define B4 1.0000000000000000000000 // cos(pi*4/16)sqrt(2)
  31 #define B5 0.7856949583871021812779 // cos(pi*5/16)sqrt(2)
  32 #define B6 0.5411961001461969843997 // cos(pi*6/16)sqrt(2)
  33 #define B7 0.2758993792829430123360 // cos(pi*7/16)sqrt(2)
  34
  35 #define A4 0.70710678118654752438 // cos(pi*4/16)
  36 #define A2 0.92387953251128675613 // cos(pi*2/16)
  37
  38 static const FLOAT prescale[64]={
  39 B0*B0/8, B0*B1/8, B0*B2/8, B0*B3/8, B0*B4/8, B0*B5/8, B0*B6/8, B0*B7/8,
  40 B1*B0/8, B1*B1/8, B1*B2/8, B1*B3/8, B1*B4/8, B1*B5/8, B1*B6/8, B1*B7/8,
  41 B2*B0/8, B2*B1/8, B2*B2/8, B2*B3/8, B2*B4/8, B2*B5/8, B2*B6/8, B2*B7/8,
  42 B3*B0/8, B3*B1/8, B3*B2/8, B3*B3/8, B3*B4/8, B3*B5/8, B3*B6/8, B3*B7/8,
  43 B4*B0/8, B4*B1/8, B4*B2/8, B4*B3/8, B4*B4/8, B4*B5/8, B4*B6/8, B4*B7/8,
  44 B5*B0/8, B5*B1/8, B5*B2/8, B5*B3/8, B5*B4/8, B5*B5/8, B5*B6/8, B5*B7/8,
  45 B6*B0/8, B6*B1/8, B6*B2/8, B6*B3/8, B6*B4/8, B6*B5/8, B6*B6/8, B6*B7/8,
  46 B7*B0/8, B7*B1/8, B7*B2/8, B7*B3/8, B7*B4/8, B7*B5/8, B7*B6/8, B7*B7/8,
  47 };
  48
  49 static inline void p8idct(DCTELEM data[64], FLOAT temp[64], uint8_t *dest, int stride, int x, int y, int type){
  50     int i;
  51     FLOAT av_unused tmp0;
  52     FLOAT s04, d04, s17, d17, s26, d26, s53, d53;
  53     FLOAT os07, os16, os25, os34;
  54     FLOAT od07, od16, od25, od34;
  55
  56     for(i=0; i<y*8; i+=y){
  57         s17= temp[1*x + i] + temp[7*x + i];
  58         d17= temp[1*x + i] - temp[7*x + i];
  59         s53= temp[5*x + i] + temp[3*x + i];
  60         d53= temp[5*x + i] - temp[3*x + i];
  61
  62         od07=  s17 + s53;
  63         od25= (s17 - s53)*(2*A4);
  64
  65 #if 0 //these 2 are equivalent
  66         tmp0= (d17 + d53)*(2*A2);
  67         od34=  d17*( 2*B6) - tmp0;
  68         od16=  d53*(-2*B2) + tmp0;
  69 #else
  70         od34=  d17*(2*(B6-A2)) - d53*(2*A2);
  71         od16=  d53*(2*(A2-B2)) + d17*(2*A2);
  72 #endif
  73
  74         od16 -= od07;
  75         od25 -= od16;
  76         od34 += od25;
  77
  78         s26 = temp[2*x + i] + temp[6*x + i];
  79         d26 = temp[2*x + i] - temp[6*x + i];
  80         d26*= 2*A4;
  81         d26-= s26;
  82
  83         s04= temp[0*x + i] + temp[4*x + i];
  84         d04= temp[0*x + i] - temp[4*x + i];
  85
  86         os07= s04 + s26;
  87         os34= s04 - s26;
  88         os16= d04 + d26;
  89         os25= d04 - d26;
  90
  91         if(type==0){
  92             temp[0*x + i]= os07 + od07;
  93             temp[7*x + i]= os07 - od07;
  94             temp[1*x + i]= os16 + od16;
  95             temp[6*x + i]= os16 - od16;
  96             temp[2*x + i]= os25 + od25;
  97             temp[5*x + i]= os25 - od25;
  98             temp[3*x + i]= os34 - od34;
  99             temp[4*x + i]= os34 + od34;
 100         }else if(type==1){
 101             data[0*x + i]= lrintf(os07 + od07);
 102             data[7*x + i]= lrintf(os07 - od07);
 103             data[1*x + i]= lrintf(os16 + od16);
 104             data[6*x + i]= lrintf(os16 - od16);
 105             data[2*x + i]= lrintf(os25 + od25);
 106             data[5*x + i]= lrintf(os25 - od25);
 107             data[3*x + i]= lrintf(os34 - od34);
 108             data[4*x + i]= lrintf(os34 + od34);
 109         }else if(type==2){
 110             dest[0*stride + i]= av_clip_uint8(((int)dest[0*stride + i]) + lrintf(os07 + od07));
 111             dest[7*stride + i]= av_clip_uint8(((int)dest[7*stride + i]) + lrintf(os07 - od07));
 112             dest[1*stride + i]= av_clip_uint8(((int)dest[1*stride + i]) + lrintf(os16 + od16));
 113             dest[6*stride + i]= av_clip_uint8(((int)dest[6*stride + i]) + lrintf(os16 - od16));
 114             dest[2*stride + i]= av_clip_uint8(((int)dest[2*stride + i]) + lrintf(os25 + od25));
 115             dest[5*stride + i]= av_clip_uint8(((int)dest[5*stride + i]) + lrintf(os25 - od25));
 116             dest[3*stride + i]= av_clip_uint8(((int)dest[3*stride + i]) + lrintf(os34 - od34));
 117             dest[4*stride + i]= av_clip_uint8(((int)dest[4*stride + i]) + lrintf(os34 + od34));
 118         }else{
 119             dest[0*stride + i]= av_clip_uint8(lrintf(os07 + od07));
 120             dest[7*stride + i]= av_clip_uint8(lrintf(os07 - od07));
 121             dest[1*stride + i]= av_clip_uint8(lrintf(os16 + od16));
 122             dest[6*stride + i]= av_clip_uint8(lrintf(os16 - od16));
 123             dest[2*stride + i]= av_clip_uint8(lrintf(os25 + od25));
 124             dest[5*stride + i]= av_clip_uint8(lrintf(os25 - od25));
 125             dest[3*stride + i]= av_clip_uint8(lrintf(os34 - od34));
 126             dest[4*stride + i]= av_clip_uint8(lrintf(os34 + od34));
 127         }
 128     }
 129 }
 130
 131 void ff_faanidct(DCTELEM block[64]){
 132     FLOAT temp[64];
 133     int i;
 134
 135     emms_c();
 136
 137     for(i=0; i<64; i++)
 138         temp[i] = block[i] * prescale[i];
 139
 140     p8idct(block, temp, NULL, 0, 1, 8, 0);
 141     p8idct(block, temp, NULL, 0, 8, 1, 1);
 142 }
 143
 144 void ff_faanidct_add(uint8_t *dest, int line_size, DCTELEM block[64]){
 145     FLOAT temp[64];
 146     int i;
 147
 148     emms_c();
 149
 150     for(i=0; i<64; i++)
 151         temp[i] = block[i] * prescale[i];
 152
 153     p8idct(block, temp, NULL,         0, 1, 8, 0);
 154     p8idct(NULL , temp, dest, line_size, 8, 1, 2);
 155 }
 156
 157 void ff_faanidct_put(uint8_t *dest, int line_size, DCTELEM block[64]){
 158     FLOAT temp[64];
 159     int i;
 160
 161     emms_c();
 162
 163     for(i=0; i<64; i++)
 164         temp[i] = block[i] * prescale[i];
 165
 166     p8idct(block, temp, NULL,         0, 1, 8, 0);
 167     p8idct(NULL , temp, dest, line_size, 8, 1, 3);
 168 }