vp8/encoder/dct.c

   1 /*
   2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license
   5  *  that can be found in the LICENSE file in the root of the source
   6  *  tree. An additional intellectual property rights grant can be found
   7  *  in the file PATENTS.  All contributing project authors may
   8  *  be found in the AUTHORS file in the root of the source tree.
   9  */
  10
  11
  12 #include <math.h>
  13
  14 #include "./vp8_rtcd.h"
  15
  16 void vp8_short_fdct4x4_c(short *input, short *output, int pitch)
  17 {
  18     int i;
  19     int a1, b1, c1, d1;
  20     short *ip = input;
  21     short *op = output;
  22
  23     for (i = 0; i < 4; i++)
  24     {
  25         a1 = ((ip[0] + ip[3]) * 8);
  26         b1 = ((ip[1] + ip[2]) * 8);
  27         c1 = ((ip[1] - ip[2]) * 8);
  28         d1 = ((ip[0] - ip[3]) * 8);
  29
  30         op[0] = a1 + b1;
  31         op[2] = a1 - b1;
  32
  33         op[1] = (c1 * 2217 + d1 * 5352 +  14500)>>12;
  34         op[3] = (d1 * 2217 - c1 * 5352 +   7500)>>12;
  35
  36         ip += pitch / 2;
  37         op += 4;
  38
  39     }
  40     ip = output;
  41     op = output;
  42     for (i = 0; i < 4; i++)
  43     {
  44         a1 = ip[0] + ip[12];
  45         b1 = ip[4] + ip[8];
  46         c1 = ip[4] - ip[8];
  47         d1 = ip[0] - ip[12];
  48
  49         op[0]  = ( a1 + b1 + 7)>>4;
  50         op[8]  = ( a1 - b1 + 7)>>4;
  51
  52         op[4]  =((c1 * 2217 + d1 * 5352 +  12000)>>16) + (d1!=0);
  53         op[12] = (d1 * 2217 - c1 * 5352 +  51000)>>16;
  54
  55         ip++;
  56         op++;
  57     }
  58 }
  59
  60 void vp8_short_fdct8x4_c(short *input, short *output, int pitch)
  61 {
  62     vp8_short_fdct4x4_c(input,   output,    pitch);
  63     vp8_short_fdct4x4_c(input + 4, output + 16, pitch);
  64 }
  65
  66 void vp8_short_walsh4x4_c(short *input, short *output, int pitch)
  67 {
  68     int i;
  69     int a1, b1, c1, d1;
  70     int a2, b2, c2, d2;
  71     short *ip = input;
  72     short *op = output;
  73
  74
  75     for (i = 0; i < 4; i++)
  76     {
  77         a1 = ((ip[0] + ip[2]) * 4);
  78         d1 = ((ip[1] + ip[3]) * 4);
  79         c1 = ((ip[1] - ip[3]) * 4);
  80         b1 = ((ip[0] - ip[2]) * 4);
  81
  82         op[0] = a1 + d1 + (a1!=0);
  83         op[1] = b1 + c1;
  84         op[2] = b1 - c1;
  85         op[3] = a1 - d1;
  86         ip += pitch / 2;
  87         op += 4;
  88     }
  89
  90     ip = output;
  91     op = output;
  92
  93     for (i = 0; i < 4; i++)
  94     {
  95         a1 = ip[0] + ip[8];
  96         d1 = ip[4] + ip[12];
  97         c1 = ip[4] - ip[12];
  98         b1 = ip[0] - ip[8];
  99
 100         a2 = a1 + d1;
 101         b2 = b1 + c1;
 102         c2 = b1 - c1;
 103         d2 = a1 - d1;
 104
 105         a2 += a2<0;
 106         b2 += b2<0;
 107         c2 += c2<0;
 108         d2 += d2<0;
 109
 110         op[0] = (a2+3) >> 3;
 111         op[4] = (b2+3) >> 3;
 112         op[8] = (c2+3) >> 3;
 113         op[12]= (d2+3) >> 3;
 114
 115         ip++;
 116         op++;
 117     }
 118 }