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 "treereader.h"
13 #include "vp8/common/entropymv.h"
14 #include "vp8/common/entropymode.h"
15 #include "onyxd_int.h"
16 #include "vp8/common/findnearmv.h"
17 
18 #if CONFIG_DEBUG
19 #include <assert.h>
20 #endif
read_bmode(vp8_reader * bc,const vp8_prob * p)21 static B_PREDICTION_MODE read_bmode(vp8_reader *bc, const vp8_prob *p)
22 {
23     const int i = vp8_treed_read(bc, vp8_bmode_tree, p);
24 
25     return (B_PREDICTION_MODE)i;
26 }
27 
read_ymode(vp8_reader * bc,const vp8_prob * p)28 static MB_PREDICTION_MODE read_ymode(vp8_reader *bc, const vp8_prob *p)
29 {
30     const int i = vp8_treed_read(bc, vp8_ymode_tree, p);
31 
32     return (MB_PREDICTION_MODE)i;
33 }
34 
read_kf_ymode(vp8_reader * bc,const vp8_prob * p)35 static MB_PREDICTION_MODE read_kf_ymode(vp8_reader *bc, const vp8_prob *p)
36 {
37     const int i = vp8_treed_read(bc, vp8_kf_ymode_tree, p);
38 
39     return (MB_PREDICTION_MODE)i;
40 }
41 
read_uv_mode(vp8_reader * bc,const vp8_prob * p)42 static MB_PREDICTION_MODE read_uv_mode(vp8_reader *bc, const vp8_prob *p)
43 {
44     const int i = vp8_treed_read(bc, vp8_uv_mode_tree, p);
45 
46     return (MB_PREDICTION_MODE)i;
47 }
48 
read_kf_modes(VP8D_COMP * pbi,MODE_INFO * mi)49 static void read_kf_modes(VP8D_COMP *pbi, MODE_INFO *mi)
50 {
51     vp8_reader *const bc = & pbi->mbc[8];
52     const int mis = pbi->common.mode_info_stride;
53 
54     mi->mbmi.ref_frame = INTRA_FRAME;
55     mi->mbmi.mode = read_kf_ymode(bc, vp8_kf_ymode_prob);
56 
57     if (mi->mbmi.mode == B_PRED)
58     {
59         int i = 0;
60         mi->mbmi.is_4x4 = 1;
61 
62         do
63         {
64             const B_PREDICTION_MODE A = above_block_mode(mi, i, mis);
65             const B_PREDICTION_MODE L = left_block_mode(mi, i);
66 
67             mi->bmi[i].as_mode =
68                 read_bmode(bc, vp8_kf_bmode_prob [A] [L]);
69         }
70         while (++i < 16);
71     }
72 
73     mi->mbmi.uv_mode = read_uv_mode(bc, vp8_kf_uv_mode_prob);
74 }
75 
read_mvcomponent(vp8_reader * r,const MV_CONTEXT * mvc)76 static int read_mvcomponent(vp8_reader *r, const MV_CONTEXT *mvc)
77 {
78     const vp8_prob *const p = (const vp8_prob *) mvc;
79     int x = 0;
80 
81     if (vp8_read(r, p [mvpis_short]))  /* Large */
82     {
83         int i = 0;
84 
85         do
86         {
87             x += vp8_read(r, p [MVPbits + i]) << i;
88         }
89         while (++i < 3);
90 
91         i = mvlong_width - 1;  /* Skip bit 3, which is sometimes implicit */
92 
93         do
94         {
95             x += vp8_read(r, p [MVPbits + i]) << i;
96         }
97         while (--i > 3);
98 
99         if (!(x & 0xFFF0)  ||  vp8_read(r, p [MVPbits + 3]))
100             x += 8;
101     }
102     else   /* small */
103         x = vp8_treed_read(r, vp8_small_mvtree, p + MVPshort);
104 
105     if (x  &&  vp8_read(r, p [MVPsign]))
106         x = -x;
107 
108     return x;
109 }
110 
read_mv(vp8_reader * r,MV * mv,const MV_CONTEXT * mvc)111 static void read_mv(vp8_reader *r, MV *mv, const MV_CONTEXT *mvc)
112 {
113     mv->row = (short)(read_mvcomponent(r,   mvc) * 2);
114     mv->col = (short)(read_mvcomponent(r, ++mvc) * 2);
115 }
116 
117 
read_mvcontexts(vp8_reader * bc,MV_CONTEXT * mvc)118 static void read_mvcontexts(vp8_reader *bc, MV_CONTEXT *mvc)
119 {
120     int i = 0;
121 
122     do
123     {
124         const vp8_prob *up = vp8_mv_update_probs[i].prob;
125         vp8_prob *p = (vp8_prob *)(mvc + i);
126         vp8_prob *const pstop = p + MVPcount;
127 
128         do
129         {
130             if (vp8_read(bc, *up++))
131             {
132                 const vp8_prob x = (vp8_prob)vp8_read_literal(bc, 7);
133 
134                 *p = x ? x << 1 : 1;
135             }
136         }
137         while (++p < pstop);
138     }
139     while (++i < 2);
140 }
141 
142 static const unsigned char mbsplit_fill_count[4] = {8, 8, 4, 1};
143 static const unsigned char mbsplit_fill_offset[4][16] = {
144     { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  10, 11, 12, 13, 14, 15},
145     { 0,  1,  4,  5,  8,  9, 12, 13,  2,  3,   6,  7, 10, 11, 14, 15},
146     { 0,  1,  4,  5,  2,  3,  6,  7,  8,  9,  12, 13, 10, 11, 14, 15},
147     { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  10, 11, 12, 13, 14, 15}
148 };
149 
150 
mb_mode_mv_init(VP8D_COMP * pbi)151 static void mb_mode_mv_init(VP8D_COMP *pbi)
152 {
153     vp8_reader *const bc = & pbi->mbc[8];
154     MV_CONTEXT *const mvc = pbi->common.fc.mvc;
155 
156 #if CONFIG_ERROR_CONCEALMENT
157     /* Default is that no macroblock is corrupt, therefore we initialize
158      * mvs_corrupt_from_mb to something very big, which we can be sure is
159      * outside the frame. */
160     pbi->mvs_corrupt_from_mb = UINT_MAX;
161 #endif
162     /* Read the mb_no_coeff_skip flag */
163     pbi->common.mb_no_coeff_skip = (int)vp8_read_bit(bc);
164 
165     pbi->prob_skip_false = 0;
166     if (pbi->common.mb_no_coeff_skip)
167         pbi->prob_skip_false = (vp8_prob)vp8_read_literal(bc, 8);
168 
169     if(pbi->common.frame_type != KEY_FRAME)
170     {
171         pbi->prob_intra = (vp8_prob)vp8_read_literal(bc, 8);
172         pbi->prob_last  = (vp8_prob)vp8_read_literal(bc, 8);
173         pbi->prob_gf    = (vp8_prob)vp8_read_literal(bc, 8);
174 
175         if (vp8_read_bit(bc))
176         {
177             int i = 0;
178 
179             do
180             {
181                 pbi->common.fc.ymode_prob[i] =
182                     (vp8_prob) vp8_read_literal(bc, 8);
183             }
184             while (++i < 4);
185         }
186 
187         if (vp8_read_bit(bc))
188         {
189             int i = 0;
190 
191             do
192             {
193                 pbi->common.fc.uv_mode_prob[i] =
194                     (vp8_prob) vp8_read_literal(bc, 8);
195             }
196             while (++i < 3);
197         }
198 
199         read_mvcontexts(bc, mvc);
200     }
201 }
202 
203 const vp8_prob vp8_sub_mv_ref_prob3 [8][VP8_SUBMVREFS-1] =
204 {
205     { 147, 136, 18 },   /* SUBMVREF_NORMAL          */
206     { 223, 1  , 34 },   /* SUBMVREF_LEFT_ABOVE_SAME */
207     { 106, 145, 1  },   /* SUBMVREF_LEFT_ZED        */
208     { 208, 1  , 1  },   /* SUBMVREF_LEFT_ABOVE_ZED  */
209     { 179, 121, 1  },   /* SUBMVREF_ABOVE_ZED       */
210     { 223, 1  , 34 },   /* SUBMVREF_LEFT_ABOVE_SAME */
211     { 179, 121, 1  },   /* SUBMVREF_ABOVE_ZED       */
212     { 208, 1  , 1  }    /* SUBMVREF_LEFT_ABOVE_ZED  */
213 };
214 
215 static
get_sub_mv_ref_prob(const int left,const int above)216 const vp8_prob * get_sub_mv_ref_prob(const int left, const int above)
217 {
218     int lez = (left == 0);
219     int aez = (above == 0);
220     int lea = (left == above);
221     const vp8_prob * prob;
222 
223     prob = vp8_sub_mv_ref_prob3[(aez << 2) |
224                                 (lez << 1) |
225                                 (lea)];
226 
227     return prob;
228 }
229 
decode_split_mv(vp8_reader * const bc,MODE_INFO * mi,const MODE_INFO * left_mb,const MODE_INFO * above_mb,MB_MODE_INFO * mbmi,int_mv best_mv,MV_CONTEXT * const mvc,int mb_to_left_edge,int mb_to_right_edge,int mb_to_top_edge,int mb_to_bottom_edge)230 static void decode_split_mv(vp8_reader *const bc, MODE_INFO *mi,
231                         const MODE_INFO *left_mb, const MODE_INFO *above_mb,
232                         MB_MODE_INFO *mbmi, int_mv best_mv,
233                         MV_CONTEXT *const mvc, int mb_to_left_edge,
234                         int mb_to_right_edge, int mb_to_top_edge,
235                         int mb_to_bottom_edge)
236 {
237     int s;      /* split configuration (16x8, 8x16, 8x8, 4x4) */
238     int num_p;  /* number of partitions in the split configuration
239                   (see vp8_mbsplit_count) */
240     int j = 0;
241 
242     s = 3;
243     num_p = 16;
244     if( vp8_read(bc, 110) )
245     {
246         s = 2;
247         num_p = 4;
248         if( vp8_read(bc, 111) )
249         {
250             s = vp8_read(bc, 150);
251             num_p = 2;
252         }
253     }
254 
255     do  /* for each subset j */
256     {
257         int_mv leftmv, abovemv;
258         int_mv blockmv;
259         int k;  /* first block in subset j */
260 
261         const vp8_prob *prob;
262         k = vp8_mbsplit_offset[s][j];
263 
264         if (!(k & 3))
265         {
266             /* On L edge, get from MB to left of us */
267             if(left_mb->mbmi.mode != SPLITMV)
268                 leftmv.as_int =  left_mb->mbmi.mv.as_int;
269             else
270                 leftmv.as_int =  (left_mb->bmi + k + 4 - 1)->mv.as_int;
271         }
272         else
273             leftmv.as_int =  (mi->bmi + k - 1)->mv.as_int;
274 
275         if (!(k >> 2))
276         {
277             /* On top edge, get from MB above us */
278             if(above_mb->mbmi.mode != SPLITMV)
279                 abovemv.as_int =  above_mb->mbmi.mv.as_int;
280             else
281                 abovemv.as_int =  (above_mb->bmi + k + 16 - 4)->mv.as_int;
282         }
283         else
284             abovemv.as_int = (mi->bmi + k - 4)->mv.as_int;
285 
286         prob = get_sub_mv_ref_prob(leftmv.as_int, abovemv.as_int);
287 
288         if( vp8_read(bc, prob[0]) )
289         {
290             if( vp8_read(bc, prob[1]) )
291             {
292                 blockmv.as_int = 0;
293                 if( vp8_read(bc, prob[2]) )
294                 {
295                     blockmv.as_mv.row = read_mvcomponent(bc, &mvc[0]) * 2;
296                     blockmv.as_mv.row += best_mv.as_mv.row;
297                     blockmv.as_mv.col = read_mvcomponent(bc, &mvc[1]) * 2;
298                     blockmv.as_mv.col += best_mv.as_mv.col;
299                 }
300             }
301             else
302             {
303                 blockmv.as_int = abovemv.as_int;
304             }
305         }
306         else
307         {
308             blockmv.as_int = leftmv.as_int;
309         }
310 
311         mbmi->need_to_clamp_mvs |= vp8_check_mv_bounds(&blockmv,
312                                                   mb_to_left_edge,
313                                                   mb_to_right_edge,
314                                                   mb_to_top_edge,
315                                                   mb_to_bottom_edge);
316 
317         {
318             /* Fill (uniform) modes, mvs of jth subset.
319              Must do it here because ensuing subsets can
320              refer back to us via "left" or "above". */
321             const unsigned char *fill_offset;
322             unsigned int fill_count = mbsplit_fill_count[s];
323 
324             fill_offset = &mbsplit_fill_offset[s]
325                              [(unsigned char)j * mbsplit_fill_count[s]];
326 
327             do {
328                 mi->bmi[ *fill_offset].mv.as_int = blockmv.as_int;
329                 fill_offset++;
330             }while (--fill_count);
331         }
332 
333     }
334     while (++j < num_p);
335 
336     mbmi->partitioning = s;
337 }
338 
read_mb_modes_mv(VP8D_COMP * pbi,MODE_INFO * mi,MB_MODE_INFO * mbmi)339 static void read_mb_modes_mv(VP8D_COMP *pbi, MODE_INFO *mi, MB_MODE_INFO *mbmi)
340 {
341     vp8_reader *const bc = & pbi->mbc[8];
342     mbmi->ref_frame = (MV_REFERENCE_FRAME) vp8_read(bc, pbi->prob_intra);
343     if (mbmi->ref_frame)    /* inter MB */
344     {
345         enum {CNT_INTRA, CNT_NEAREST, CNT_NEAR, CNT_SPLITMV};
346         int cnt[4];
347         int *cntx = cnt;
348         int_mv near_mvs[4];
349         int_mv *nmv = near_mvs;
350         const int mis = pbi->mb.mode_info_stride;
351         const MODE_INFO *above = mi - mis;
352         const MODE_INFO *left = mi - 1;
353         const MODE_INFO *aboveleft = above - 1;
354         int *ref_frame_sign_bias = pbi->common.ref_frame_sign_bias;
355 
356         mbmi->need_to_clamp_mvs = 0;
357 
358         if (vp8_read(bc, pbi->prob_last))
359         {
360             mbmi->ref_frame =
361                 (MV_REFERENCE_FRAME)((int)(2 + vp8_read(bc, pbi->prob_gf)));
362         }
363 
364         /* Zero accumulators */
365         nmv[0].as_int = nmv[1].as_int = nmv[2].as_int = 0;
366         cnt[0] = cnt[1] = cnt[2] = cnt[3] = 0;
367 
368         /* Process above */
369         if (above->mbmi.ref_frame != INTRA_FRAME)
370         {
371             if (above->mbmi.mv.as_int)
372             {
373                 (++nmv)->as_int = above->mbmi.mv.as_int;
374                 mv_bias(ref_frame_sign_bias[above->mbmi.ref_frame],
375                         mbmi->ref_frame, nmv, ref_frame_sign_bias);
376                 ++cntx;
377             }
378 
379             *cntx += 2;
380         }
381 
382         /* Process left */
383         if (left->mbmi.ref_frame != INTRA_FRAME)
384         {
385             if (left->mbmi.mv.as_int)
386             {
387                 int_mv this_mv;
388 
389                 this_mv.as_int = left->mbmi.mv.as_int;
390                 mv_bias(ref_frame_sign_bias[left->mbmi.ref_frame],
391                         mbmi->ref_frame, &this_mv, ref_frame_sign_bias);
392 
393                 if (this_mv.as_int != nmv->as_int)
394                 {
395                     (++nmv)->as_int = this_mv.as_int;
396                     ++cntx;
397                 }
398 
399                 *cntx += 2;
400             }
401             else
402                 cnt[CNT_INTRA] += 2;
403         }
404 
405         /* Process above left */
406         if (aboveleft->mbmi.ref_frame != INTRA_FRAME)
407         {
408             if (aboveleft->mbmi.mv.as_int)
409             {
410                 int_mv this_mv;
411 
412                 this_mv.as_int = aboveleft->mbmi.mv.as_int;
413                 mv_bias(ref_frame_sign_bias[aboveleft->mbmi.ref_frame],
414                         mbmi->ref_frame, &this_mv, ref_frame_sign_bias);
415 
416                 if (this_mv.as_int != nmv->as_int)
417                 {
418                     (++nmv)->as_int = this_mv.as_int;
419                     ++cntx;
420                 }
421 
422                 *cntx += 1;
423             }
424             else
425                 cnt[CNT_INTRA] += 1;
426         }
427 
428         if( vp8_read(bc, vp8_mode_contexts [cnt[CNT_INTRA]] [0]) )
429         {
430 
431             /* If we have three distinct MV's ... */
432             /* See if above-left MV can be merged with NEAREST */
433             cnt[CNT_NEAREST] += ( (cnt[CNT_SPLITMV] > 0) &
434                 (nmv->as_int == near_mvs[CNT_NEAREST].as_int));
435 
436             /* Swap near and nearest if necessary */
437             if (cnt[CNT_NEAR] > cnt[CNT_NEAREST])
438             {
439                 int tmp;
440                 tmp = cnt[CNT_NEAREST];
441                 cnt[CNT_NEAREST] = cnt[CNT_NEAR];
442                 cnt[CNT_NEAR] = tmp;
443                 tmp = near_mvs[CNT_NEAREST].as_int;
444                 near_mvs[CNT_NEAREST].as_int = near_mvs[CNT_NEAR].as_int;
445                 near_mvs[CNT_NEAR].as_int = tmp;
446             }
447 
448             if( vp8_read(bc, vp8_mode_contexts [cnt[CNT_NEAREST]] [1]) )
449             {
450 
451                 if( vp8_read(bc, vp8_mode_contexts [cnt[CNT_NEAR]] [2]) )
452                 {
453                     int mb_to_top_edge;
454                     int mb_to_bottom_edge;
455                     int mb_to_left_edge;
456                     int mb_to_right_edge;
457                     MV_CONTEXT *const mvc = pbi->common.fc.mvc;
458                     int near_index;
459 
460                     mb_to_top_edge = pbi->mb.mb_to_top_edge;
461                     mb_to_bottom_edge = pbi->mb.mb_to_bottom_edge;
462                     mb_to_top_edge -= LEFT_TOP_MARGIN;
463                     mb_to_bottom_edge += RIGHT_BOTTOM_MARGIN;
464                     mb_to_right_edge = pbi->mb.mb_to_right_edge;
465                     mb_to_right_edge += RIGHT_BOTTOM_MARGIN;
466                     mb_to_left_edge = pbi->mb.mb_to_left_edge;
467                     mb_to_left_edge -= LEFT_TOP_MARGIN;
468 
469                     /* Use near_mvs[0] to store the "best" MV */
470                     near_index = CNT_INTRA +
471                         (cnt[CNT_NEAREST] >= cnt[CNT_INTRA]);
472 
473                     vp8_clamp_mv2(&near_mvs[near_index], &pbi->mb);
474 
475                     cnt[CNT_SPLITMV] = ((above->mbmi.mode == SPLITMV)
476                                         + (left->mbmi.mode == SPLITMV)) * 2
477                                        + (aboveleft->mbmi.mode == SPLITMV);
478 
479                     if( vp8_read(bc, vp8_mode_contexts [cnt[CNT_SPLITMV]] [3]) )
480                     {
481                         decode_split_mv(bc, mi, left, above,
482                                                     mbmi,
483                                                     near_mvs[near_index],
484                                                     mvc, mb_to_left_edge,
485                                                     mb_to_right_edge,
486                                                     mb_to_top_edge,
487                                                     mb_to_bottom_edge);
488                         mbmi->mv.as_int = mi->bmi[15].mv.as_int;
489                         mbmi->mode =  SPLITMV;
490                         mbmi->is_4x4 = 1;
491                     }
492                     else
493                     {
494                         int_mv *const mbmi_mv = & mbmi->mv;
495                         read_mv(bc, &mbmi_mv->as_mv, (const MV_CONTEXT *) mvc);
496                         mbmi_mv->as_mv.row += near_mvs[near_index].as_mv.row;
497                         mbmi_mv->as_mv.col += near_mvs[near_index].as_mv.col;
498 
499                         /* Don't need to check this on NEARMV and NEARESTMV
500                          * modes since those modes clamp the MV. The NEWMV mode
501                          * does not, so signal to the prediction stage whether
502                          * special handling may be required.
503                          */
504                         mbmi->need_to_clamp_mvs =
505                             vp8_check_mv_bounds(mbmi_mv, mb_to_left_edge,
506                                                 mb_to_right_edge,
507                                                 mb_to_top_edge,
508                                                 mb_to_bottom_edge);
509                         mbmi->mode =  NEWMV;
510                     }
511                 }
512                 else
513                 {
514                     mbmi->mode =  NEARMV;
515                     mbmi->mv.as_int = near_mvs[CNT_NEAR].as_int;
516                     vp8_clamp_mv2(&mbmi->mv, &pbi->mb);
517                 }
518             }
519             else
520             {
521                 mbmi->mode =  NEARESTMV;
522                 mbmi->mv.as_int = near_mvs[CNT_NEAREST].as_int;
523                 vp8_clamp_mv2(&mbmi->mv, &pbi->mb);
524             }
525         }
526         else
527         {
528             mbmi->mode =  ZEROMV;
529             mbmi->mv.as_int = 0;
530         }
531 
532 #if CONFIG_ERROR_CONCEALMENT
533         if(pbi->ec_enabled && (mbmi->mode != SPLITMV))
534         {
535             mi->bmi[ 0].mv.as_int =
536             mi->bmi[ 1].mv.as_int =
537             mi->bmi[ 2].mv.as_int =
538             mi->bmi[ 3].mv.as_int =
539             mi->bmi[ 4].mv.as_int =
540             mi->bmi[ 5].mv.as_int =
541             mi->bmi[ 6].mv.as_int =
542             mi->bmi[ 7].mv.as_int =
543             mi->bmi[ 8].mv.as_int =
544             mi->bmi[ 9].mv.as_int =
545             mi->bmi[10].mv.as_int =
546             mi->bmi[11].mv.as_int =
547             mi->bmi[12].mv.as_int =
548             mi->bmi[13].mv.as_int =
549             mi->bmi[14].mv.as_int =
550             mi->bmi[15].mv.as_int = mbmi->mv.as_int;
551         }
552 #endif
553     }
554     else
555     {
556         /* required for left and above block mv */
557         mbmi->mv.as_int = 0;
558 
559         /* MB is intra coded */
560         if ((mbmi->mode = read_ymode(bc, pbi->common.fc.ymode_prob)) == B_PRED)
561         {
562             int j = 0;
563             mbmi->is_4x4 = 1;
564             do
565             {
566                 mi->bmi[j].as_mode = read_bmode(bc, pbi->common.fc.bmode_prob);
567             }
568             while (++j < 16);
569         }
570 
571         mbmi->uv_mode = read_uv_mode(bc, pbi->common.fc.uv_mode_prob);
572     }
573 
574 }
575 
read_mb_features(vp8_reader * r,MB_MODE_INFO * mi,MACROBLOCKD * x)576 static void read_mb_features(vp8_reader *r, MB_MODE_INFO *mi, MACROBLOCKD *x)
577 {
578     /* Is segmentation enabled */
579     if (x->segmentation_enabled && x->update_mb_segmentation_map)
580     {
581         /* If so then read the segment id. */
582         if (vp8_read(r, x->mb_segment_tree_probs[0]))
583             mi->segment_id =
584                 (unsigned char)(2 + vp8_read(r, x->mb_segment_tree_probs[2]));
585         else
586             mi->segment_id =
587                 (unsigned char)(vp8_read(r, x->mb_segment_tree_probs[1]));
588     }
589 }
590 
decode_mb_mode_mvs(VP8D_COMP * pbi,MODE_INFO * mi)591 static void decode_mb_mode_mvs(VP8D_COMP *pbi, MODE_INFO *mi)
592 {
593     /* Read the Macroblock segmentation map if it is being updated explicitly
594      * this frame (reset to 0 above by default)
595      * By default on a key frame reset all MBs to segment 0
596      */
597     if (pbi->mb.update_mb_segmentation_map)
598         read_mb_features(&pbi->mbc[8], &mi->mbmi, &pbi->mb);
599     else if(pbi->common.frame_type == KEY_FRAME)
600         mi->mbmi.segment_id = 0;
601 
602     /* Read the macroblock coeff skip flag if this feature is in use,
603      * else default to 0 */
604     if (pbi->common.mb_no_coeff_skip)
605         mi->mbmi.mb_skip_coeff = vp8_read(&pbi->mbc[8], pbi->prob_skip_false);
606     else
607         mi->mbmi.mb_skip_coeff = 0;
608 
609     mi->mbmi.is_4x4 = 0;
610     if(pbi->common.frame_type == KEY_FRAME)
611         read_kf_modes(pbi, mi);
612     else
613         read_mb_modes_mv(pbi, mi, &mi->mbmi);
614 
615 }
616 
vp8_decode_mode_mvs(VP8D_COMP * pbi)617 void vp8_decode_mode_mvs(VP8D_COMP *pbi)
618 {
619     MODE_INFO *mi = pbi->common.mi;
620     int mb_row = -1;
621     int mb_to_right_edge_start;
622 
623     mb_mode_mv_init(pbi);
624 
625     pbi->mb.mb_to_top_edge = 0;
626     pbi->mb.mb_to_bottom_edge = ((pbi->common.mb_rows - 1) * 16) << 3;
627     mb_to_right_edge_start = ((pbi->common.mb_cols - 1) * 16) << 3;
628 
629     while (++mb_row < pbi->common.mb_rows)
630     {
631         int mb_col = -1;
632 
633         pbi->mb.mb_to_left_edge =  0;
634         pbi->mb.mb_to_right_edge = mb_to_right_edge_start;
635 
636         while (++mb_col < pbi->common.mb_cols)
637         {
638 #if CONFIG_ERROR_CONCEALMENT
639             int mb_num = mb_row * pbi->common.mb_cols + mb_col;
640 #endif
641 
642             decode_mb_mode_mvs(pbi, mi);
643 
644 #if CONFIG_ERROR_CONCEALMENT
645             /* look for corruption. set mvs_corrupt_from_mb to the current
646              * mb_num if the frame is corrupt from this macroblock. */
647             if (vp8dx_bool_error(&pbi->mbc[8]) && mb_num <
648                 (int)pbi->mvs_corrupt_from_mb)
649             {
650                 pbi->mvs_corrupt_from_mb = mb_num;
651                 /* no need to continue since the partition is corrupt from
652                  * here on.
653                  */
654                 return;
655             }
656 #endif
657 
658             pbi->mb.mb_to_left_edge -= (16 << 3);
659             pbi->mb.mb_to_right_edge -= (16 << 3);
660             mi++;       /* next macroblock */
661         }
662         pbi->mb.mb_to_top_edge -= (16 << 3);
663         pbi->mb.mb_to_bottom_edge -= (16 << 3);
664 
665         mi++;           /* skip left predictor each row */
666     }
667 }
668