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#include "./vp8_rtcd.h" 12 13/**************************************************************************** 14 * Notes: 15 * 16 * This implementation makes use of 16 bit fixed point verio of two multiply 17 * constants: 18 * 1. sqrt(2) * cos (pi/8) 19 * 2. sqrt(2) * sin (pi/8) 20 * Becuase the first constant is bigger than 1, to maintain the same 16 bit 21 * fixed point precision as the second one, we use a trick of 22 * x * a = x + x*(a-1) 23 * so 24 * x * sqrt(2) * cos (pi/8) = x + x * (sqrt(2) *cos(pi/8)-1). 25 **************************************************************************/ 26static const int cospi8sqrt2minus1 = 20091; 27static const int sinpi8sqrt2 = 35468; 28 29void vp8_short_idct4x4llm_c(short *input, unsigned char *pred_ptr, 30 int pred_stride, unsigned char *dst_ptr, 31 int dst_stride) 32{ 33 int i; 34 int r, c; 35 int a1, b1, c1, d1; 36 short output[16]; 37 short *ip = input; 38 short *op = output; 39 int temp1, temp2; 40 int shortpitch = 4; 41 42 for (i = 0; i < 4; i++) 43 { 44 a1 = ip[0] + ip[8]; 45 b1 = ip[0] - ip[8]; 46 47 temp1 = (ip[4] * sinpi8sqrt2) >> 16; 48 temp2 = ip[12] + ((ip[12] * cospi8sqrt2minus1) >> 16); 49 c1 = temp1 - temp2; 50 51 temp1 = ip[4] + ((ip[4] * cospi8sqrt2minus1) >> 16); 52 temp2 = (ip[12] * sinpi8sqrt2) >> 16; 53 d1 = temp1 + temp2; 54 55 op[shortpitch*0] = a1 + d1; 56 op[shortpitch*3] = a1 - d1; 57 58 op[shortpitch*1] = b1 + c1; 59 op[shortpitch*2] = b1 - c1; 60 61 ip++; 62 op++; 63 } 64 65 ip = output; 66 op = output; 67 68 for (i = 0; i < 4; i++) 69 { 70 a1 = ip[0] + ip[2]; 71 b1 = ip[0] - ip[2]; 72 73 temp1 = (ip[1] * sinpi8sqrt2) >> 16; 74 temp2 = ip[3] + ((ip[3] * cospi8sqrt2minus1) >> 16); 75 c1 = temp1 - temp2; 76 77 temp1 = ip[1] + ((ip[1] * cospi8sqrt2minus1) >> 16); 78 temp2 = (ip[3] * sinpi8sqrt2) >> 16; 79 d1 = temp1 + temp2; 80 81 82 op[0] = (a1 + d1 + 4) >> 3; 83 op[3] = (a1 - d1 + 4) >> 3; 84 85 op[1] = (b1 + c1 + 4) >> 3; 86 op[2] = (b1 - c1 + 4) >> 3; 87 88 ip += shortpitch; 89 op += shortpitch; 90 } 91 92 ip = output; 93 for (r = 0; r < 4; r++) 94 { 95 for (c = 0; c < 4; c++) 96 { 97 int a = ip[c] + pred_ptr[c] ; 98 99 if (a < 0) 100 a = 0; 101 102 if (a > 255) 103 a = 255; 104 105 dst_ptr[c] = (unsigned char) a ; 106 } 107 ip += 4; 108 dst_ptr += dst_stride; 109 pred_ptr += pred_stride; 110 } 111} 112 113void vp8_dc_only_idct_add_c(short input_dc, unsigned char *pred_ptr, 114 int pred_stride, unsigned char *dst_ptr, 115 int dst_stride) 116{ 117 int a1 = ((input_dc + 4) >> 3); 118 int r, c; 119 120 for (r = 0; r < 4; r++) 121 { 122 for (c = 0; c < 4; c++) 123 { 124 int a = a1 + pred_ptr[c] ; 125 126 if (a < 0) 127 a = 0; 128 129 if (a > 255) 130 a = 255; 131 132 dst_ptr[c] = (unsigned char) a ; 133 } 134 135 dst_ptr += dst_stride; 136 pred_ptr += pred_stride; 137 } 138 139} 140 141void vp8_short_inv_walsh4x4_c(short *input, short *mb_dqcoeff) 142{ 143 short output[16]; 144 int i; 145 int a1, b1, c1, d1; 146 int a2, b2, c2, d2; 147 short *ip = input; 148 short *op = output; 149 150 for (i = 0; i < 4; i++) 151 { 152 a1 = ip[0] + ip[12]; 153 b1 = ip[4] + ip[8]; 154 c1 = ip[4] - ip[8]; 155 d1 = ip[0] - ip[12]; 156 157 op[0] = a1 + b1; 158 op[4] = c1 + d1; 159 op[8] = a1 - b1; 160 op[12] = d1 - c1; 161 ip++; 162 op++; 163 } 164 165 ip = output; 166 op = output; 167 168 for (i = 0; i < 4; i++) 169 { 170 a1 = ip[0] + ip[3]; 171 b1 = ip[1] + ip[2]; 172 c1 = ip[1] - ip[2]; 173 d1 = ip[0] - ip[3]; 174 175 a2 = a1 + b1; 176 b2 = c1 + d1; 177 c2 = a1 - b1; 178 d2 = d1 - c1; 179 180 op[0] = (a2 + 3) >> 3; 181 op[1] = (b2 + 3) >> 3; 182 op[2] = (c2 + 3) >> 3; 183 op[3] = (d2 + 3) >> 3; 184 185 ip += 4; 186 op += 4; 187 } 188 189 for(i = 0; i < 16; i++) 190 { 191 mb_dqcoeff[i * 16] = output[i]; 192 } 193} 194 195void vp8_short_inv_walsh4x4_1_c(short *input, short *mb_dqcoeff) 196{ 197 int i; 198 int a1; 199 200 a1 = ((input[0] + 3) >> 3); 201 for(i = 0; i < 16; i++) 202 { 203 mb_dqcoeff[i * 16] = a1; 204 } 205} 206