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 **************************************************************************/
26 static const int cospi8sqrt2minus1 = 20091;
27 static const int sinpi8sqrt2 = 35468;
28
vp8_short_idct4x4llm_c(short * input,unsigned char * pred_ptr,int pred_stride,unsigned char * dst_ptr,int dst_stride)29 void vp8_short_idct4x4llm_c(short *input, unsigned char *pred_ptr,
30 int pred_stride, unsigned char *dst_ptr,
31 int dst_stride) {
32 int i;
33 int r, c;
34 int a1, b1, c1, d1;
35 short output[16];
36 short *ip = input;
37 short *op = output;
38 int temp1, temp2;
39 int shortpitch = 4;
40
41 for (i = 0; i < 4; ++i) {
42 a1 = ip[0] + ip[8];
43 b1 = ip[0] - ip[8];
44
45 temp1 = (ip[4] * sinpi8sqrt2) >> 16;
46 temp2 = ip[12] + ((ip[12] * cospi8sqrt2minus1) >> 16);
47 c1 = temp1 - temp2;
48
49 temp1 = ip[4] + ((ip[4] * cospi8sqrt2minus1) >> 16);
50 temp2 = (ip[12] * sinpi8sqrt2) >> 16;
51 d1 = temp1 + temp2;
52
53 op[shortpitch * 0] = a1 + d1;
54 op[shortpitch * 3] = a1 - d1;
55
56 op[shortpitch * 1] = b1 + c1;
57 op[shortpitch * 2] = b1 - c1;
58
59 ip++;
60 op++;
61 }
62
63 ip = output;
64 op = output;
65
66 for (i = 0; i < 4; ++i) {
67 a1 = ip[0] + ip[2];
68 b1 = ip[0] - ip[2];
69
70 temp1 = (ip[1] * sinpi8sqrt2) >> 16;
71 temp2 = ip[3] + ((ip[3] * cospi8sqrt2minus1) >> 16);
72 c1 = temp1 - temp2;
73
74 temp1 = ip[1] + ((ip[1] * cospi8sqrt2minus1) >> 16);
75 temp2 = (ip[3] * sinpi8sqrt2) >> 16;
76 d1 = temp1 + temp2;
77
78 op[0] = (a1 + d1 + 4) >> 3;
79 op[3] = (a1 - d1 + 4) >> 3;
80
81 op[1] = (b1 + c1 + 4) >> 3;
82 op[2] = (b1 - c1 + 4) >> 3;
83
84 ip += shortpitch;
85 op += shortpitch;
86 }
87
88 ip = output;
89 for (r = 0; r < 4; ++r) {
90 for (c = 0; c < 4; ++c) {
91 int a = ip[c] + pred_ptr[c];
92
93 if (a < 0) a = 0;
94
95 if (a > 255) a = 255;
96
97 dst_ptr[c] = (unsigned char)a;
98 }
99 ip += 4;
100 dst_ptr += dst_stride;
101 pred_ptr += pred_stride;
102 }
103 }
104
vp8_dc_only_idct_add_c(short input_dc,unsigned char * pred_ptr,int pred_stride,unsigned char * dst_ptr,int dst_stride)105 void vp8_dc_only_idct_add_c(short input_dc, unsigned char *pred_ptr,
106 int pred_stride, unsigned char *dst_ptr,
107 int dst_stride) {
108 int a1 = ((input_dc + 4) >> 3);
109 int r, c;
110
111 for (r = 0; r < 4; ++r) {
112 for (c = 0; c < 4; ++c) {
113 int a = a1 + pred_ptr[c];
114
115 if (a < 0) a = 0;
116
117 if (a > 255) a = 255;
118
119 dst_ptr[c] = (unsigned char)a;
120 }
121
122 dst_ptr += dst_stride;
123 pred_ptr += pred_stride;
124 }
125 }
126
vp8_short_inv_walsh4x4_c(short * input,short * mb_dqcoeff)127 void vp8_short_inv_walsh4x4_c(short *input, short *mb_dqcoeff) {
128 short output[16];
129 int i;
130 int a1, b1, c1, d1;
131 int a2, b2, c2, d2;
132 short *ip = input;
133 short *op = output;
134
135 for (i = 0; i < 4; ++i) {
136 a1 = ip[0] + ip[12];
137 b1 = ip[4] + ip[8];
138 c1 = ip[4] - ip[8];
139 d1 = ip[0] - ip[12];
140
141 op[0] = a1 + b1;
142 op[4] = c1 + d1;
143 op[8] = a1 - b1;
144 op[12] = d1 - c1;
145 ip++;
146 op++;
147 }
148
149 ip = output;
150 op = output;
151
152 for (i = 0; i < 4; ++i) {
153 a1 = ip[0] + ip[3];
154 b1 = ip[1] + ip[2];
155 c1 = ip[1] - ip[2];
156 d1 = ip[0] - ip[3];
157
158 a2 = a1 + b1;
159 b2 = c1 + d1;
160 c2 = a1 - b1;
161 d2 = d1 - c1;
162
163 op[0] = (a2 + 3) >> 3;
164 op[1] = (b2 + 3) >> 3;
165 op[2] = (c2 + 3) >> 3;
166 op[3] = (d2 + 3) >> 3;
167
168 ip += 4;
169 op += 4;
170 }
171
172 for (i = 0; i < 16; ++i) {
173 mb_dqcoeff[i * 16] = output[i];
174 }
175 }
176
vp8_short_inv_walsh4x4_1_c(short * input,short * mb_dqcoeff)177 void vp8_short_inv_walsh4x4_1_c(short *input, short *mb_dqcoeff) {
178 int i;
179 int a1;
180
181 a1 = ((input[0] + 3) >> 3);
182 for (i = 0; i < 16; ++i) {
183 mb_dqcoeff[i * 16] = a1;
184 }
185 }
186