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1 : Isibaar 1.1 /**************************************************************************
2 :     *
3 :     * XVID MPEG-4 VIDEO CODEC
4 :     * mpeg-4 quantization/dequantization
5 :     *
6 :     * This program is an implementation of a part of one or more MPEG-4
7 :     * Video tools as specified in ISO/IEC 14496-2 standard. Those intending
8 :     * to use this software module in hardware or software products are
9 :     * advised that its use may infringe existing patents or copyrights, and
10 :     * any such use would be at such party's own risk. The original
11 :     * developer of this software module and his/her company, and subsequent
12 :     * editors and their companies, will have no liability for use of this
13 :     * software or modifications or derivatives thereof.
14 :     *
15 :     * This program is free software; you can redistribute it and/or modify
16 :     * it under the terms of the GNU General Public License as published by
17 :     * the Free Software Foundation; either version 2 of the License, or
18 :     * (at your option) any later version.
19 :     *
20 :     * This program is distributed in the hope that it will be useful,
21 :     * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 :     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 :     * GNU General Public License for more details.
24 :     *
25 :     * You should have received a copy of the GNU General Public License
26 :     * along with this program; if not, write to the Free Software
27 :     * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28 :     *
29 :     *************************************************************************/
30 :    
31 :     /**************************************************************************
32 :     *
33 :     * History:
34 :     *
35 :     * 26.01.2002 fixed quant4_intra dcscalar signed/unsigned error
36 :     * 20.01.2002 increased accuracy of >> divide
37 :     * 26.12.2001 divide-by-multiplication optimization
38 :     * 22.12.2001 [-127,127] clamping removed; minor tweaks
39 :     * 19.11.2001 inital version <pross@cs.rmit.edu.au>
40 :     *
41 :     *************************************************************************/
42 :    
43 : suxen_drol 1.3.2.1 #include "../global.h"
44 : Isibaar 1.1 #include "quant_mpeg4.h"
45 : Isibaar 1.2 #include "quant_matrix.h"
46 : Isibaar 1.1
47 :     // function pointers
48 :     quant_intraFuncPtr quant4_intra;
49 :     quant_intraFuncPtr dequant4_intra;
50 :     dequant_interFuncPtr dequant4_inter;
51 :     quant_interFuncPtr quant4_inter;
52 :    
53 :    
54 :     #define VM18P 3
55 :     #define VM18Q 4
56 :    
57 :    
58 :     // divide-by-multiply table
59 :     // need 17 bit shift (16 causes slight errors when q > 19)
60 :    
61 :     #define SCALEBITS 17
62 :     #define FIX(X) ((1UL << SCALEBITS) / (X) + 1)
63 :    
64 : edgomez 1.3 static const uint32_t multipliers[32] = {
65 :     0, FIX(2), FIX(4), FIX(6),
66 :     FIX(8), FIX(10), FIX(12), FIX(14),
67 :     FIX(16), FIX(18), FIX(20), FIX(22),
68 :     FIX(24), FIX(26), FIX(28), FIX(30),
69 :     FIX(32), FIX(34), FIX(36), FIX(38),
70 :     FIX(40), FIX(42), FIX(44), FIX(46),
71 :     FIX(48), FIX(50), FIX(52), FIX(54),
72 :     FIX(56), FIX(58), FIX(60), FIX(62)
73 :     };
74 : Isibaar 1.1
75 :     /* quantize intra-block
76 :    
77 :     // const int32_t quantd = DIV_DIV(VM18P*quant, VM18Q);
78 :     //
79 :     // level = DIV_DIV(16 * data[i], default_intra_matrix[i]);
80 :     // coeff[i] = (level + quantd) / quant2;
81 :     */
82 :    
83 : edgomez 1.3 void
84 :     quant4_intra_c(int16_t * coeff,
85 :     const int16_t * data,
86 :     const uint32_t quant,
87 :     const uint32_t dcscalar)
88 : Isibaar 1.1 {
89 : edgomez 1.3 const uint32_t quantd = ((VM18P * quant) + (VM18Q / 2)) / VM18Q;
90 :     const uint32_t mult = multipliers[quant];
91 :     uint32_t i;
92 : Isibaar 1.2 int16_t *intra_matrix;
93 :    
94 :     intra_matrix = get_intra_matrix();
95 : Isibaar 1.1
96 : edgomez 1.3 coeff[0] = DIV_DIV(data[0], (int32_t) dcscalar);
97 : Isibaar 1.1
98 : edgomez 1.3 for (i = 1; i < 64; i++) {
99 :     if (data[i] < 0) {
100 :     uint32_t level = -data[i];
101 :    
102 :     level = ((level << 4) + (intra_matrix[i] >> 1)) / intra_matrix[i];
103 :     level = ((level + quantd) * mult) >> 17;
104 :     coeff[i] = -(int16_t) level;
105 :     } else if (data[i] > 0) {
106 :     uint32_t level = data[i];
107 :    
108 :     level = ((level << 4) + (intra_matrix[i] >> 1)) / intra_matrix[i];
109 :     level = ((level + quantd) * mult) >> 17;
110 :     coeff[i] = level;
111 :     } else {
112 :     coeff[i] = 0;
113 :     }
114 :     }
115 : Isibaar 1.1 }
116 :    
117 :    
118 :    
119 :     /* dequantize intra-block & clamp to [-2048,2047]
120 :     // data[i] = (coeff[i] * default_intra_matrix[i] * quant2) >> 4;
121 :     */
122 :    
123 : edgomez 1.3 void
124 :     dequant4_intra_c(int16_t * data,
125 :     const int16_t * coeff,
126 :     const uint32_t quant,
127 :     const uint32_t dcscalar)
128 : Isibaar 1.1 {
129 : edgomez 1.3 uint32_t i;
130 : Isibaar 1.2 int16_t *intra_matrix;
131 :    
132 :     intra_matrix = get_intra_matrix();
133 : edgomez 1.3
134 :     data[0] = coeff[0] * dcscalar;
135 :     if (data[0] < -2048) {
136 :     data[0] = -2048;
137 :     } else if (data[0] > 2047) {
138 :     data[0] = 2047;
139 :     }
140 :    
141 :     for (i = 1; i < 64; i++) {
142 :     if (coeff[i] == 0) {
143 :     data[i] = 0;
144 :     } else if (coeff[i] < 0) {
145 :     uint32_t level = -coeff[i];
146 :    
147 :     level = (level * intra_matrix[i] * quant) >> 3;
148 :     data[i] = (level <= 2048 ? -(int16_t) level : -2048);
149 :     } else // if (coeff[i] > 0)
150 :     {
151 :     uint32_t level = coeff[i];
152 :    
153 :     level = (level * intra_matrix[i] * quant) >> 3;
154 :     data[i] = (level <= 2047 ? level : 2047);
155 :     }
156 :     }
157 : Isibaar 1.1 }
158 :    
159 :    
160 :    
161 :     /* quantize inter-block
162 :    
163 :     // level = DIV_DIV(16 * data[i], default_intra_matrix[i]);
164 :     // coeff[i] = (level + quantd) / quant2;
165 :     // sum += abs(level);
166 :     */
167 :    
168 : edgomez 1.3 uint32_t
169 :     quant4_inter_c(int16_t * coeff,
170 :     const int16_t * data,
171 :     const uint32_t quant)
172 : Isibaar 1.1 {
173 : edgomez 1.3 const uint32_t mult = multipliers[quant];
174 :     uint32_t sum = 0;
175 :     uint32_t i;
176 : Isibaar 1.2 int16_t *inter_matrix;
177 :    
178 :     inter_matrix = get_inter_matrix();
179 : edgomez 1.3
180 :     for (i = 0; i < 64; i++) {
181 :     if (data[i] < 0) {
182 :     uint32_t level = -data[i];
183 :    
184 :     level = ((level << 4) + (inter_matrix[i] >> 1)) / inter_matrix[i];
185 :     level = (level * mult) >> 17;
186 :     sum += level;
187 :     coeff[i] = -(int16_t) level;
188 :     } else if (data[i] > 0) {
189 :     uint32_t level = data[i];
190 :    
191 :     level = ((level << 4) + (inter_matrix[i] >> 1)) / inter_matrix[i];
192 :     level = (level * mult) >> 17;
193 :     sum += level;
194 :     coeff[i] = level;
195 :     } else {
196 :     coeff[i] = 0;
197 :     }
198 :     }
199 :     return sum;
200 : Isibaar 1.1 }
201 :    
202 :    
203 :    
204 :     /* dequantize inter-block & clamp to [-2048,2047]
205 :     data = ((2 * coeff + SIGN(coeff)) * inter_matrix[i] * quant) / 16
206 :     */
207 :    
208 : edgomez 1.3 void
209 :     dequant4_inter_c(int16_t * data,
210 :     const int16_t * coeff,
211 :     const uint32_t quant)
212 : Isibaar 1.1 {
213 : edgomez 1.3 uint32_t sum = 0;
214 :     uint32_t i;
215 : Isibaar 1.2 int16_t *inter_matrix;
216 :    
217 :     inter_matrix = get_inter_matrix();
218 : edgomez 1.3
219 :     for (i = 0; i < 64; i++) {
220 :     if (coeff[i] == 0) {
221 :     data[i] = 0;
222 :     } else if (coeff[i] < 0) {
223 :     int32_t level = -coeff[i];
224 :    
225 :     level = ((2 * level + 1) * inter_matrix[i] * quant) >> 4;
226 :     data[i] = (level <= 2048 ? -level : -2048);
227 :     } else // if (coeff[i] > 0)
228 :     {
229 :     uint32_t level = coeff[i];
230 :    
231 :     level = ((2 * level + 1) * inter_matrix[i] * quant) >> 4;
232 :     data[i] = (level <= 2047 ? level : 2047);
233 :     }
234 :    
235 :     sum ^= data[i];
236 :     }
237 :    
238 :     // mismatch control
239 :    
240 :     if ((sum & 1) == 0) {
241 :     data[63] ^= 1;
242 :     }
243 : Isibaar 1.1 }

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