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1 // Copyright 2010 Google Inc. All Rights Reserved.
2 //
3 // Use of this source code is governed by a BSD-style license
4 // that can be found in the COPYING file in the root of the source
5 // tree. An additional intellectual property rights grant can be found
6 // in the file PATENTS. All contributing project authors may
7 // be found in the AUTHORS file in the root of the source tree.
8 // -----------------------------------------------------------------------------
9 //
10 // Coding trees and probas
11 //
12 // Author: Skal (pascal.massimino@gmail.com)
13 
14 #include "src/dec/vp8i_dec.h"
15 #include "src/dsp/cpu.h"
16 #include "src/utils/bit_reader_inl_utils.h"
17 
18 #if !defined(USE_GENERIC_TREE)
19 #if !defined(__arm__) && !defined(_M_ARM) && !WEBP_AARCH64 && \
20     !defined(__wasm__)
21 // using a table is ~1-2% slower on ARM. Prefer the coded-tree approach then.
22 #define USE_GENERIC_TREE 1   // ALTERNATE_CODE
23 #else
24 #define USE_GENERIC_TREE 0
25 #endif
26 #endif  // USE_GENERIC_TREE
27 
28 #if (USE_GENERIC_TREE == 1)
29 static const int8_t kYModesIntra4[18] = {
30   -B_DC_PRED, 1,
31     -B_TM_PRED, 2,
32       -B_VE_PRED, 3,
33         4, 6,
34           -B_HE_PRED, 5,
35             -B_RD_PRED, -B_VR_PRED,
36         -B_LD_PRED, 7,
37           -B_VL_PRED, 8,
38             -B_HD_PRED, -B_HU_PRED
39 };
40 #endif
41 
42 //------------------------------------------------------------------------------
43 // Default probabilities
44 
45 // Paragraph 13.5
46 static const uint8_t
47   CoeffsProba0[NUM_TYPES][NUM_BANDS][NUM_CTX][NUM_PROBAS] = {
48   { { { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 },
49       { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 },
50       { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 }
51     },
52     { { 253, 136, 254, 255, 228, 219, 128, 128, 128, 128, 128 },
53       { 189, 129, 242, 255, 227, 213, 255, 219, 128, 128, 128 },
54       { 106, 126, 227, 252, 214, 209, 255, 255, 128, 128, 128 }
55     },
56     { { 1, 98, 248, 255, 236, 226, 255, 255, 128, 128, 128 },
57       { 181, 133, 238, 254, 221, 234, 255, 154, 128, 128, 128 },
58       { 78, 134, 202, 247, 198, 180, 255, 219, 128, 128, 128 },
59     },
60     { { 1, 185, 249, 255, 243, 255, 128, 128, 128, 128, 128 },
61       { 184, 150, 247, 255, 236, 224, 128, 128, 128, 128, 128 },
62       { 77, 110, 216, 255, 236, 230, 128, 128, 128, 128, 128 },
63     },
64     { { 1, 101, 251, 255, 241, 255, 128, 128, 128, 128, 128 },
65       { 170, 139, 241, 252, 236, 209, 255, 255, 128, 128, 128 },
66       { 37, 116, 196, 243, 228, 255, 255, 255, 128, 128, 128 }
67     },
68     { { 1, 204, 254, 255, 245, 255, 128, 128, 128, 128, 128 },
69       { 207, 160, 250, 255, 238, 128, 128, 128, 128, 128, 128 },
70       { 102, 103, 231, 255, 211, 171, 128, 128, 128, 128, 128 }
71     },
72     { { 1, 152, 252, 255, 240, 255, 128, 128, 128, 128, 128 },
73       { 177, 135, 243, 255, 234, 225, 128, 128, 128, 128, 128 },
74       { 80, 129, 211, 255, 194, 224, 128, 128, 128, 128, 128 }
75     },
76     { { 1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
77       { 246, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
78       { 255, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 }
79     }
80   },
81   { { { 198, 35, 237, 223, 193, 187, 162, 160, 145, 155, 62 },
82       { 131, 45, 198, 221, 172, 176, 220, 157, 252, 221, 1 },
83       { 68, 47, 146, 208, 149, 167, 221, 162, 255, 223, 128 }
84     },
85     { { 1, 149, 241, 255, 221, 224, 255, 255, 128, 128, 128 },
86       { 184, 141, 234, 253, 222, 220, 255, 199, 128, 128, 128 },
87       { 81, 99, 181, 242, 176, 190, 249, 202, 255, 255, 128 }
88     },
89     { { 1, 129, 232, 253, 214, 197, 242, 196, 255, 255, 128 },
90       { 99, 121, 210, 250, 201, 198, 255, 202, 128, 128, 128 },
91       { 23, 91, 163, 242, 170, 187, 247, 210, 255, 255, 128 }
92     },
93     { { 1, 200, 246, 255, 234, 255, 128, 128, 128, 128, 128 },
94       { 109, 178, 241, 255, 231, 245, 255, 255, 128, 128, 128 },
95       { 44, 130, 201, 253, 205, 192, 255, 255, 128, 128, 128 }
96     },
97     { { 1, 132, 239, 251, 219, 209, 255, 165, 128, 128, 128 },
98       { 94, 136, 225, 251, 218, 190, 255, 255, 128, 128, 128 },
99       { 22, 100, 174, 245, 186, 161, 255, 199, 128, 128, 128 }
100     },
101     { { 1, 182, 249, 255, 232, 235, 128, 128, 128, 128, 128 },
102       { 124, 143, 241, 255, 227, 234, 128, 128, 128, 128, 128 },
103       { 35, 77, 181, 251, 193, 211, 255, 205, 128, 128, 128 }
104     },
105     { { 1, 157, 247, 255, 236, 231, 255, 255, 128, 128, 128 },
106       { 121, 141, 235, 255, 225, 227, 255, 255, 128, 128, 128 },
107       { 45, 99, 188, 251, 195, 217, 255, 224, 128, 128, 128 }
108     },
109     { { 1, 1, 251, 255, 213, 255, 128, 128, 128, 128, 128 },
110       { 203, 1, 248, 255, 255, 128, 128, 128, 128, 128, 128 },
111       { 137, 1, 177, 255, 224, 255, 128, 128, 128, 128, 128 }
112     }
113   },
114   { { { 253, 9, 248, 251, 207, 208, 255, 192, 128, 128, 128 },
115       { 175, 13, 224, 243, 193, 185, 249, 198, 255, 255, 128 },
116       { 73, 17, 171, 221, 161, 179, 236, 167, 255, 234, 128 }
117     },
118     { { 1, 95, 247, 253, 212, 183, 255, 255, 128, 128, 128 },
119       { 239, 90, 244, 250, 211, 209, 255, 255, 128, 128, 128 },
120       { 155, 77, 195, 248, 188, 195, 255, 255, 128, 128, 128 }
121     },
122     { { 1, 24, 239, 251, 218, 219, 255, 205, 128, 128, 128 },
123       { 201, 51, 219, 255, 196, 186, 128, 128, 128, 128, 128 },
124       { 69, 46, 190, 239, 201, 218, 255, 228, 128, 128, 128 }
125     },
126     { { 1, 191, 251, 255, 255, 128, 128, 128, 128, 128, 128 },
127       { 223, 165, 249, 255, 213, 255, 128, 128, 128, 128, 128 },
128       { 141, 124, 248, 255, 255, 128, 128, 128, 128, 128, 128 }
129     },
130     { { 1, 16, 248, 255, 255, 128, 128, 128, 128, 128, 128 },
131       { 190, 36, 230, 255, 236, 255, 128, 128, 128, 128, 128 },
132       { 149, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 }
133     },
134     { { 1, 226, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
135       { 247, 192, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
136       { 240, 128, 255, 128, 128, 128, 128, 128, 128, 128, 128 }
137     },
138     { { 1, 134, 252, 255, 255, 128, 128, 128, 128, 128, 128 },
139       { 213, 62, 250, 255, 255, 128, 128, 128, 128, 128, 128 },
140       { 55, 93, 255, 128, 128, 128, 128, 128, 128, 128, 128 }
141     },
142     { { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 },
143       { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 },
144       { 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128 }
145     }
146   },
147   { { { 202, 24, 213, 235, 186, 191, 220, 160, 240, 175, 255 },
148       { 126, 38, 182, 232, 169, 184, 228, 174, 255, 187, 128 },
149       { 61, 46, 138, 219, 151, 178, 240, 170, 255, 216, 128 }
150     },
151     { { 1, 112, 230, 250, 199, 191, 247, 159, 255, 255, 128 },
152       { 166, 109, 228, 252, 211, 215, 255, 174, 128, 128, 128 },
153       { 39, 77, 162, 232, 172, 180, 245, 178, 255, 255, 128 }
154     },
155     { { 1, 52, 220, 246, 198, 199, 249, 220, 255, 255, 128 },
156       { 124, 74, 191, 243, 183, 193, 250, 221, 255, 255, 128 },
157       { 24, 71, 130, 219, 154, 170, 243, 182, 255, 255, 128 }
158     },
159     { { 1, 182, 225, 249, 219, 240, 255, 224, 128, 128, 128 },
160       { 149, 150, 226, 252, 216, 205, 255, 171, 128, 128, 128 },
161       { 28, 108, 170, 242, 183, 194, 254, 223, 255, 255, 128 }
162     },
163     { { 1, 81, 230, 252, 204, 203, 255, 192, 128, 128, 128 },
164       { 123, 102, 209, 247, 188, 196, 255, 233, 128, 128, 128 },
165       { 20, 95, 153, 243, 164, 173, 255, 203, 128, 128, 128 }
166     },
167     { { 1, 222, 248, 255, 216, 213, 128, 128, 128, 128, 128 },
168       { 168, 175, 246, 252, 235, 205, 255, 255, 128, 128, 128 },
169       { 47, 116, 215, 255, 211, 212, 255, 255, 128, 128, 128 }
170     },
171     { { 1, 121, 236, 253, 212, 214, 255, 255, 128, 128, 128 },
172       { 141, 84, 213, 252, 201, 202, 255, 219, 128, 128, 128 },
173       { 42, 80, 160, 240, 162, 185, 255, 205, 128, 128, 128 }
174     },
175     { { 1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
176       { 244, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 },
177       { 238, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128 }
178     }
179   }
180 };
181 
182 // Paragraph 11.5
183 static const uint8_t kBModesProba[NUM_BMODES][NUM_BMODES][NUM_BMODES - 1] = {
184   { { 231, 120, 48, 89, 115, 113, 120, 152, 112 },
185     { 152, 179, 64, 126, 170, 118, 46, 70, 95 },
186     { 175, 69, 143, 80, 85, 82, 72, 155, 103 },
187     { 56, 58, 10, 171, 218, 189, 17, 13, 152 },
188     { 114, 26, 17, 163, 44, 195, 21, 10, 173 },
189     { 121, 24, 80, 195, 26, 62, 44, 64, 85 },
190     { 144, 71, 10, 38, 171, 213, 144, 34, 26 },
191     { 170, 46, 55, 19, 136, 160, 33, 206, 71 },
192     { 63, 20, 8, 114, 114, 208, 12, 9, 226 },
193     { 81, 40, 11, 96, 182, 84, 29, 16, 36 } },
194   { { 134, 183, 89, 137, 98, 101, 106, 165, 148 },
195     { 72, 187, 100, 130, 157, 111, 32, 75, 80 },
196     { 66, 102, 167, 99, 74, 62, 40, 234, 128 },
197     { 41, 53, 9, 178, 241, 141, 26, 8, 107 },
198     { 74, 43, 26, 146, 73, 166, 49, 23, 157 },
199     { 65, 38, 105, 160, 51, 52, 31, 115, 128 },
200     { 104, 79, 12, 27, 217, 255, 87, 17, 7 },
201     { 87, 68, 71, 44, 114, 51, 15, 186, 23 },
202     { 47, 41, 14, 110, 182, 183, 21, 17, 194 },
203     { 66, 45, 25, 102, 197, 189, 23, 18, 22 } },
204   { { 88, 88, 147, 150, 42, 46, 45, 196, 205 },
205     { 43, 97, 183, 117, 85, 38, 35, 179, 61 },
206     { 39, 53, 200, 87, 26, 21, 43, 232, 171 },
207     { 56, 34, 51, 104, 114, 102, 29, 93, 77 },
208     { 39, 28, 85, 171, 58, 165, 90, 98, 64 },
209     { 34, 22, 116, 206, 23, 34, 43, 166, 73 },
210     { 107, 54, 32, 26, 51, 1, 81, 43, 31 },
211     { 68, 25, 106, 22, 64, 171, 36, 225, 114 },
212     { 34, 19, 21, 102, 132, 188, 16, 76, 124 },
213     { 62, 18, 78, 95, 85, 57, 50, 48, 51 } },
214   { { 193, 101, 35, 159, 215, 111, 89, 46, 111 },
215     { 60, 148, 31, 172, 219, 228, 21, 18, 111 },
216     { 112, 113, 77, 85, 179, 255, 38, 120, 114 },
217     { 40, 42, 1, 196, 245, 209, 10, 25, 109 },
218     { 88, 43, 29, 140, 166, 213, 37, 43, 154 },
219     { 61, 63, 30, 155, 67, 45, 68, 1, 209 },
220     { 100, 80, 8, 43, 154, 1, 51, 26, 71 },
221     { 142, 78, 78, 16, 255, 128, 34, 197, 171 },
222     { 41, 40, 5, 102, 211, 183, 4, 1, 221 },
223     { 51, 50, 17, 168, 209, 192, 23, 25, 82 } },
224   { { 138, 31, 36, 171, 27, 166, 38, 44, 229 },
225     { 67, 87, 58, 169, 82, 115, 26, 59, 179 },
226     { 63, 59, 90, 180, 59, 166, 93, 73, 154 },
227     { 40, 40, 21, 116, 143, 209, 34, 39, 175 },
228     { 47, 15, 16, 183, 34, 223, 49, 45, 183 },
229     { 46, 17, 33, 183, 6, 98, 15, 32, 183 },
230     { 57, 46, 22, 24, 128, 1, 54, 17, 37 },
231     { 65, 32, 73, 115, 28, 128, 23, 128, 205 },
232     { 40, 3, 9, 115, 51, 192, 18, 6, 223 },
233     { 87, 37, 9, 115, 59, 77, 64, 21, 47 } },
234   { { 104, 55, 44, 218, 9, 54, 53, 130, 226 },
235     { 64, 90, 70, 205, 40, 41, 23, 26, 57 },
236     { 54, 57, 112, 184, 5, 41, 38, 166, 213 },
237     { 30, 34, 26, 133, 152, 116, 10, 32, 134 },
238     { 39, 19, 53, 221, 26, 114, 32, 73, 255 },
239     { 31, 9, 65, 234, 2, 15, 1, 118, 73 },
240     { 75, 32, 12, 51, 192, 255, 160, 43, 51 },
241     { 88, 31, 35, 67, 102, 85, 55, 186, 85 },
242     { 56, 21, 23, 111, 59, 205, 45, 37, 192 },
243     { 55, 38, 70, 124, 73, 102, 1, 34, 98 } },
244   { { 125, 98, 42, 88, 104, 85, 117, 175, 82 },
245     { 95, 84, 53, 89, 128, 100, 113, 101, 45 },
246     { 75, 79, 123, 47, 51, 128, 81, 171, 1 },
247     { 57, 17, 5, 71, 102, 57, 53, 41, 49 },
248     { 38, 33, 13, 121, 57, 73, 26, 1, 85 },
249     { 41, 10, 67, 138, 77, 110, 90, 47, 114 },
250     { 115, 21, 2, 10, 102, 255, 166, 23, 6 },
251     { 101, 29, 16, 10, 85, 128, 101, 196, 26 },
252     { 57, 18, 10, 102, 102, 213, 34, 20, 43 },
253     { 117, 20, 15, 36, 163, 128, 68, 1, 26 } },
254   { { 102, 61, 71, 37, 34, 53, 31, 243, 192 },
255     { 69, 60, 71, 38, 73, 119, 28, 222, 37 },
256     { 68, 45, 128, 34, 1, 47, 11, 245, 171 },
257     { 62, 17, 19, 70, 146, 85, 55, 62, 70 },
258     { 37, 43, 37, 154, 100, 163, 85, 160, 1 },
259     { 63, 9, 92, 136, 28, 64, 32, 201, 85 },
260     { 75, 15, 9, 9, 64, 255, 184, 119, 16 },
261     { 86, 6, 28, 5, 64, 255, 25, 248, 1 },
262     { 56, 8, 17, 132, 137, 255, 55, 116, 128 },
263     { 58, 15, 20, 82, 135, 57, 26, 121, 40 } },
264   { { 164, 50, 31, 137, 154, 133, 25, 35, 218 },
265     { 51, 103, 44, 131, 131, 123, 31, 6, 158 },
266     { 86, 40, 64, 135, 148, 224, 45, 183, 128 },
267     { 22, 26, 17, 131, 240, 154, 14, 1, 209 },
268     { 45, 16, 21, 91, 64, 222, 7, 1, 197 },
269     { 56, 21, 39, 155, 60, 138, 23, 102, 213 },
270     { 83, 12, 13, 54, 192, 255, 68, 47, 28 },
271     { 85, 26, 85, 85, 128, 128, 32, 146, 171 },
272     { 18, 11, 7, 63, 144, 171, 4, 4, 246 },
273     { 35, 27, 10, 146, 174, 171, 12, 26, 128 } },
274   { { 190, 80, 35, 99, 180, 80, 126, 54, 45 },
275     { 85, 126, 47, 87, 176, 51, 41, 20, 32 },
276     { 101, 75, 128, 139, 118, 146, 116, 128, 85 },
277     { 56, 41, 15, 176, 236, 85, 37, 9, 62 },
278     { 71, 30, 17, 119, 118, 255, 17, 18, 138 },
279     { 101, 38, 60, 138, 55, 70, 43, 26, 142 },
280     { 146, 36, 19, 30, 171, 255, 97, 27, 20 },
281     { 138, 45, 61, 62, 219, 1, 81, 188, 64 },
282     { 32, 41, 20, 117, 151, 142, 20, 21, 163 },
283     { 112, 19, 12, 61, 195, 128, 48, 4, 24 } }
284 };
285 
VP8ResetProba(VP8Proba * const proba)286 void VP8ResetProba(VP8Proba* const proba) {
287   memset(proba->segments_, 255u, sizeof(proba->segments_));
288   // proba->bands_[][] is initialized later
289 }
290 
ParseIntraMode(VP8BitReader * const br,VP8Decoder * const dec,int mb_x)291 static void ParseIntraMode(VP8BitReader* const br,
292                            VP8Decoder* const dec, int mb_x) {
293   uint8_t* const top = dec->intra_t_ + 4 * mb_x;
294   uint8_t* const left = dec->intra_l_;
295   VP8MBData* const block = dec->mb_data_ + mb_x;
296 
297   // Note: we don't save segment map (yet), as we don't expect
298   // to decode more than 1 keyframe.
299   if (dec->segment_hdr_.update_map_) {
300     // Hardcoded tree parsing
301     block->segment_ = !VP8GetBit(br, dec->proba_.segments_[0], "segments")
302                     ?  VP8GetBit(br, dec->proba_.segments_[1], "segments")
303                     :  VP8GetBit(br, dec->proba_.segments_[2], "segments") + 2;
304   } else {
305     block->segment_ = 0;  // default for intra
306   }
307   if (dec->use_skip_proba_) block->skip_ = VP8GetBit(br, dec->skip_p_, "skip");
308 
309   block->is_i4x4_ = !VP8GetBit(br, 145, "block-size");
310   if (!block->is_i4x4_) {
311     // Hardcoded 16x16 intra-mode decision tree.
312     const int ymode =
313         VP8GetBit(br, 156, "pred-modes") ?
314             (VP8GetBit(br, 128, "pred-modes") ? TM_PRED : H_PRED) :
315             (VP8GetBit(br, 163, "pred-modes") ? V_PRED : DC_PRED);
316     block->imodes_[0] = ymode;
317     memset(top, ymode, 4 * sizeof(*top));
318     memset(left, ymode, 4 * sizeof(*left));
319   } else {
320     uint8_t* modes = block->imodes_;
321     int y;
322     for (y = 0; y < 4; ++y) {
323       int ymode = left[y];
324       int x;
325       for (x = 0; x < 4; ++x) {
326         const uint8_t* const prob = kBModesProba[top[x]][ymode];
327 #if (USE_GENERIC_TREE == 1)
328         // Generic tree-parsing
329         int i = kYModesIntra4[VP8GetBit(br, prob[0], "pred-modes")];
330         while (i > 0) {
331           i = kYModesIntra4[2 * i + VP8GetBit(br, prob[i], "pred-modes")];
332         }
333         ymode = -i;
334 #else
335         // Hardcoded tree parsing
336         ymode = !VP8GetBit(br, prob[0], "pred-modes") ? B_DC_PRED :
337                   !VP8GetBit(br, prob[1], "pred-modes") ? B_TM_PRED :
338                     !VP8GetBit(br, prob[2], "pred-modes") ? B_VE_PRED :
339                       !VP8GetBit(br, prob[3], "pred-modes") ?
340                         (!VP8GetBit(br, prob[4], "pred-modes") ? B_HE_PRED :
341                           (!VP8GetBit(br, prob[5], "pred-modes") ? B_RD_PRED
342                                                                  : B_VR_PRED)) :
343                         (!VP8GetBit(br, prob[6], "pred-modes") ? B_LD_PRED :
344                           (!VP8GetBit(br, prob[7], "pred-modes") ? B_VL_PRED :
345                             (!VP8GetBit(br, prob[8], "pred-modes") ? B_HD_PRED
346                                                                    : B_HU_PRED))
347                         );
348 #endif  // USE_GENERIC_TREE
349         top[x] = ymode;
350       }
351       memcpy(modes, top, 4 * sizeof(*top));
352       modes += 4;
353       left[y] = ymode;
354     }
355   }
356   // Hardcoded UVMode decision tree
357   block->uvmode_ = !VP8GetBit(br, 142, "pred-modes-uv") ? DC_PRED
358                  : !VP8GetBit(br, 114, "pred-modes-uv") ? V_PRED
359                  : VP8GetBit(br, 183, "pred-modes-uv") ? TM_PRED : H_PRED;
360 }
361 
VP8ParseIntraModeRow(VP8BitReader * const br,VP8Decoder * const dec)362 int VP8ParseIntraModeRow(VP8BitReader* const br, VP8Decoder* const dec) {
363   int mb_x;
364   for (mb_x = 0; mb_x < dec->mb_w_; ++mb_x) {
365     ParseIntraMode(br, dec, mb_x);
366   }
367   return !dec->br_.eof_;
368 }
369 
370 //------------------------------------------------------------------------------
371 // Paragraph 13
372 
373 static const uint8_t
374     CoeffsUpdateProba[NUM_TYPES][NUM_BANDS][NUM_CTX][NUM_PROBAS] = {
375   { { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
376       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
377       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
378     },
379     { { 176, 246, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
380       { 223, 241, 252, 255, 255, 255, 255, 255, 255, 255, 255 },
381       { 249, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255 }
382     },
383     { { 255, 244, 252, 255, 255, 255, 255, 255, 255, 255, 255 },
384       { 234, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
385       { 253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
386     },
387     { { 255, 246, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
388       { 239, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
389       { 254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 }
390     },
391     { { 255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
392       { 251, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
393       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
394     },
395     { { 255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
396       { 251, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
397       { 254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 }
398     },
399     { { 255, 254, 253, 255, 254, 255, 255, 255, 255, 255, 255 },
400       { 250, 255, 254, 255, 254, 255, 255, 255, 255, 255, 255 },
401       { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
402     },
403     { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
404       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
405       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
406     }
407   },
408   { { { 217, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
409       { 225, 252, 241, 253, 255, 255, 254, 255, 255, 255, 255 },
410       { 234, 250, 241, 250, 253, 255, 253, 254, 255, 255, 255 }
411     },
412     { { 255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
413       { 223, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
414       { 238, 253, 254, 254, 255, 255, 255, 255, 255, 255, 255 }
415     },
416     { { 255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
417       { 249, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
418       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
419     },
420     { { 255, 253, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
421       { 247, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
422       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
423     },
424     { { 255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
425       { 252, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
426       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
427     },
428     { { 255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
429       { 253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
430       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
431     },
432     { { 255, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
433       { 250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
434       { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
435     },
436     { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
437       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
438       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
439     }
440   },
441   { { { 186, 251, 250, 255, 255, 255, 255, 255, 255, 255, 255 },
442       { 234, 251, 244, 254, 255, 255, 255, 255, 255, 255, 255 },
443       { 251, 251, 243, 253, 254, 255, 254, 255, 255, 255, 255 }
444     },
445     { { 255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
446       { 236, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
447       { 251, 253, 253, 254, 254, 255, 255, 255, 255, 255, 255 }
448     },
449     { { 255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
450       { 254, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
451       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
452     },
453     { { 255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
454       { 254, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
455       { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
456     },
457     { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
458       { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
459       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
460     },
461     { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
462       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
463       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
464     },
465     { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
466       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
467       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
468     },
469     { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
470       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
471       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
472     }
473   },
474   { { { 248, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
475       { 250, 254, 252, 254, 255, 255, 255, 255, 255, 255, 255 },
476       { 248, 254, 249, 253, 255, 255, 255, 255, 255, 255, 255 }
477     },
478     { { 255, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
479       { 246, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
480       { 252, 254, 251, 254, 254, 255, 255, 255, 255, 255, 255 }
481     },
482     { { 255, 254, 252, 255, 255, 255, 255, 255, 255, 255, 255 },
483       { 248, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
484       { 253, 255, 254, 254, 255, 255, 255, 255, 255, 255, 255 }
485     },
486     { { 255, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
487       { 245, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
488       { 253, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 }
489     },
490     { { 255, 251, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
491       { 252, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
492       { 255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
493     },
494     { { 255, 252, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
495       { 249, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 },
496       { 255, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255 }
497     },
498     { { 255, 255, 253, 255, 255, 255, 255, 255, 255, 255, 255 },
499       { 250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
500       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
501     },
502     { { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
503       { 254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 },
504       { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }
505     }
506   }
507 };
508 
509 // Paragraph 9.9
510 
511 static const uint8_t kBands[16 + 1] = {
512   0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7,
513   0  // extra entry as sentinel
514 };
515 
VP8ParseProba(VP8BitReader * const br,VP8Decoder * const dec)516 void VP8ParseProba(VP8BitReader* const br, VP8Decoder* const dec) {
517   VP8Proba* const proba = &dec->proba_;
518   int t, b, c, p;
519   for (t = 0; t < NUM_TYPES; ++t) {
520     for (b = 0; b < NUM_BANDS; ++b) {
521       for (c = 0; c < NUM_CTX; ++c) {
522         for (p = 0; p < NUM_PROBAS; ++p) {
523           const int v =
524               VP8GetBit(br, CoeffsUpdateProba[t][b][c][p], "global-header") ?
525                         VP8GetValue(br, 8, "global-header") :
526                         CoeffsProba0[t][b][c][p];
527           proba->bands_[t][b].probas_[c][p] = v;
528         }
529       }
530     }
531     for (b = 0; b < 16 + 1; ++b) {
532       proba->bands_ptr_[t][b] = &proba->bands_[t][kBands[b]];
533     }
534   }
535   dec->use_skip_proba_ = VP8Get(br, "global-header");
536   if (dec->use_skip_proba_) {
537     dec->skip_p_ = VP8GetValue(br, 8, "global-header");
538   }
539 }
540