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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 <assert.h>
12 #include <stdio.h>
13 #include <limits.h>
14 
15 #include "vpx/vpx_encoder.h"
16 #include "vpx_mem/vpx_mem.h"
17 #include "vpx_ports/mem_ops.h"
18 
19 #include "vp9/common/vp9_entropy.h"
20 #include "vp9/common/vp9_entropymode.h"
21 #include "vp9/common/vp9_entropymv.h"
22 #include "vp9/common/vp9_mvref_common.h"
23 #include "vp9/common/vp9_pragmas.h"
24 #include "vp9/common/vp9_pred_common.h"
25 #include "vp9/common/vp9_seg_common.h"
26 #include "vp9/common/vp9_systemdependent.h"
27 #include "vp9/common/vp9_tile_common.h"
28 
29 #include "vp9/encoder/vp9_cost.h"
30 #include "vp9/encoder/vp9_bitstream.h"
31 #include "vp9/encoder/vp9_encodemv.h"
32 #include "vp9/encoder/vp9_mcomp.h"
33 #include "vp9/encoder/vp9_segmentation.h"
34 #include "vp9/encoder/vp9_subexp.h"
35 #include "vp9/encoder/vp9_tokenize.h"
36 #include "vp9/encoder/vp9_write_bit_buffer.h"
37 
38 static struct vp9_token intra_mode_encodings[INTRA_MODES];
39 static struct vp9_token switchable_interp_encodings[SWITCHABLE_FILTERS];
40 static struct vp9_token partition_encodings[PARTITION_TYPES];
41 static struct vp9_token inter_mode_encodings[INTER_MODES];
42 
vp9_entropy_mode_init()43 void vp9_entropy_mode_init() {
44   vp9_tokens_from_tree(intra_mode_encodings, vp9_intra_mode_tree);
45   vp9_tokens_from_tree(switchable_interp_encodings, vp9_switchable_interp_tree);
46   vp9_tokens_from_tree(partition_encodings, vp9_partition_tree);
47   vp9_tokens_from_tree(inter_mode_encodings, vp9_inter_mode_tree);
48 }
49 
write_intra_mode(vp9_writer * w,MB_PREDICTION_MODE mode,const vp9_prob * probs)50 static void write_intra_mode(vp9_writer *w, MB_PREDICTION_MODE mode,
51                              const vp9_prob *probs) {
52   vp9_write_token(w, vp9_intra_mode_tree, probs, &intra_mode_encodings[mode]);
53 }
54 
write_inter_mode(vp9_writer * w,MB_PREDICTION_MODE mode,const vp9_prob * probs)55 static void write_inter_mode(vp9_writer *w, MB_PREDICTION_MODE mode,
56                              const vp9_prob *probs) {
57   assert(is_inter_mode(mode));
58   vp9_write_token(w, vp9_inter_mode_tree, probs,
59                   &inter_mode_encodings[INTER_OFFSET(mode)]);
60 }
61 
encode_unsigned_max(struct vp9_write_bit_buffer * wb,int data,int max)62 static void encode_unsigned_max(struct vp9_write_bit_buffer *wb,
63                                 int data, int max) {
64   vp9_wb_write_literal(wb, data, get_unsigned_bits(max));
65 }
66 
prob_diff_update(const vp9_tree_index * tree,vp9_prob probs[],const unsigned int counts[],int n,vp9_writer * w)67 static void prob_diff_update(const vp9_tree_index *tree,
68                              vp9_prob probs[/*n - 1*/],
69                              const unsigned int counts[/*n - 1*/],
70                              int n, vp9_writer *w) {
71   int i;
72   unsigned int branch_ct[32][2];
73 
74   // Assuming max number of probabilities <= 32
75   assert(n <= 32);
76 
77   vp9_tree_probs_from_distribution(tree, branch_ct, counts);
78   for (i = 0; i < n - 1; ++i)
79     vp9_cond_prob_diff_update(w, &probs[i], branch_ct[i]);
80 }
81 
write_selected_tx_size(const VP9_COMP * cpi,TX_SIZE tx_size,BLOCK_SIZE bsize,vp9_writer * w)82 static void write_selected_tx_size(const VP9_COMP *cpi,
83                                    TX_SIZE tx_size, BLOCK_SIZE bsize,
84                                    vp9_writer *w) {
85   const TX_SIZE max_tx_size = max_txsize_lookup[bsize];
86   const MACROBLOCKD *const xd = &cpi->mb.e_mbd;
87   const vp9_prob *const tx_probs = get_tx_probs2(max_tx_size, xd,
88                                                  &cpi->common.fc.tx_probs);
89   vp9_write(w, tx_size != TX_4X4, tx_probs[0]);
90   if (tx_size != TX_4X4 && max_tx_size >= TX_16X16) {
91     vp9_write(w, tx_size != TX_8X8, tx_probs[1]);
92     if (tx_size != TX_8X8 && max_tx_size >= TX_32X32)
93       vp9_write(w, tx_size != TX_16X16, tx_probs[2]);
94   }
95 }
96 
write_skip(const VP9_COMP * cpi,int segment_id,const MODE_INFO * mi,vp9_writer * w)97 static int write_skip(const VP9_COMP *cpi, int segment_id, const MODE_INFO *mi,
98                       vp9_writer *w) {
99   const MACROBLOCKD *const xd = &cpi->mb.e_mbd;
100   if (vp9_segfeature_active(&cpi->common.seg, segment_id, SEG_LVL_SKIP)) {
101     return 1;
102   } else {
103     const int skip = mi->mbmi.skip;
104     vp9_write(w, skip, vp9_get_skip_prob(&cpi->common, xd));
105     return skip;
106   }
107 }
108 
update_skip_probs(VP9_COMMON * cm,vp9_writer * w)109 static void update_skip_probs(VP9_COMMON *cm, vp9_writer *w) {
110   int k;
111 
112   for (k = 0; k < SKIP_CONTEXTS; ++k)
113     vp9_cond_prob_diff_update(w, &cm->fc.skip_probs[k], cm->counts.skip[k]);
114 }
115 
update_switchable_interp_probs(VP9_COMMON * cm,vp9_writer * w)116 static void update_switchable_interp_probs(VP9_COMMON *cm, vp9_writer *w) {
117   int j;
118   for (j = 0; j < SWITCHABLE_FILTER_CONTEXTS; ++j)
119     prob_diff_update(vp9_switchable_interp_tree,
120                      cm->fc.switchable_interp_prob[j],
121                      cm->counts.switchable_interp[j], SWITCHABLE_FILTERS, w);
122 }
123 
pack_mb_tokens(vp9_writer * w,TOKENEXTRA ** tp,const TOKENEXTRA * stop)124 static void pack_mb_tokens(vp9_writer *w,
125                            TOKENEXTRA **tp, const TOKENEXTRA *stop) {
126   TOKENEXTRA *p = *tp;
127 
128   while (p < stop && p->token != EOSB_TOKEN) {
129     const int t = p->token;
130     const struct vp9_token *const a = &vp9_coef_encodings[t];
131     const vp9_extra_bit *const b = &vp9_extra_bits[t];
132     int i = 0;
133     int v = a->value;
134     int n = a->len;
135 
136     /* skip one or two nodes */
137     if (p->skip_eob_node) {
138       n -= p->skip_eob_node;
139       i = 2 * p->skip_eob_node;
140     }
141 
142     // TODO(jbb): expanding this can lead to big gains.  It allows
143     // much better branch prediction and would enable us to avoid numerous
144     // lookups and compares.
145 
146     // If we have a token that's in the constrained set, the coefficient tree
147     // is split into two treed writes.  The first treed write takes care of the
148     // unconstrained nodes.  The second treed write takes care of the
149     // constrained nodes.
150     if (t >= TWO_TOKEN && t < EOB_TOKEN) {
151       int len = UNCONSTRAINED_NODES - p->skip_eob_node;
152       int bits = v >> (n - len);
153       vp9_write_tree(w, vp9_coef_tree, p->context_tree, bits, len, i);
154       vp9_write_tree(w, vp9_coef_con_tree,
155                      vp9_pareto8_full[p->context_tree[PIVOT_NODE] - 1],
156                      v, n - len, 0);
157     } else {
158       vp9_write_tree(w, vp9_coef_tree, p->context_tree, v, n, i);
159     }
160 
161     if (b->base_val) {
162       const int e = p->extra, l = b->len;
163 
164       if (l) {
165         const unsigned char *pb = b->prob;
166         int v = e >> 1;
167         int n = l;              /* number of bits in v, assumed nonzero */
168         int i = 0;
169 
170         do {
171           const int bb = (v >> --n) & 1;
172           vp9_write(w, bb, pb[i >> 1]);
173           i = b->tree[i + bb];
174         } while (n);
175       }
176 
177       vp9_write_bit(w, e & 1);
178     }
179     ++p;
180   }
181 
182   *tp = p + (p->token == EOSB_TOKEN);
183 }
184 
write_segment_id(vp9_writer * w,const struct segmentation * seg,int segment_id)185 static void write_segment_id(vp9_writer *w, const struct segmentation *seg,
186                              int segment_id) {
187   if (seg->enabled && seg->update_map)
188     vp9_write_tree(w, vp9_segment_tree, seg->tree_probs, segment_id, 3, 0);
189 }
190 
191 // This function encodes the reference frame
write_ref_frames(const VP9_COMP * cpi,vp9_writer * w)192 static void write_ref_frames(const VP9_COMP *cpi, vp9_writer *w) {
193   const VP9_COMMON *const cm = &cpi->common;
194   const MACROBLOCKD *const xd = &cpi->mb.e_mbd;
195   const MB_MODE_INFO *const mbmi = &xd->mi[0]->mbmi;
196   const int is_compound = has_second_ref(mbmi);
197   const int segment_id = mbmi->segment_id;
198 
199   // If segment level coding of this signal is disabled...
200   // or the segment allows multiple reference frame options
201   if (vp9_segfeature_active(&cm->seg, segment_id, SEG_LVL_REF_FRAME)) {
202     assert(!is_compound);
203     assert(mbmi->ref_frame[0] ==
204                vp9_get_segdata(&cm->seg, segment_id, SEG_LVL_REF_FRAME));
205   } else {
206     // does the feature use compound prediction or not
207     // (if not specified at the frame/segment level)
208     if (cm->reference_mode == REFERENCE_MODE_SELECT) {
209       vp9_write(w, is_compound, vp9_get_reference_mode_prob(cm, xd));
210     } else {
211       assert(!is_compound == (cm->reference_mode == SINGLE_REFERENCE));
212     }
213 
214     if (is_compound) {
215       vp9_write(w, mbmi->ref_frame[0] == GOLDEN_FRAME,
216                 vp9_get_pred_prob_comp_ref_p(cm, xd));
217     } else {
218       const int bit0 = mbmi->ref_frame[0] != LAST_FRAME;
219       vp9_write(w, bit0, vp9_get_pred_prob_single_ref_p1(cm, xd));
220       if (bit0) {
221         const int bit1 = mbmi->ref_frame[0] != GOLDEN_FRAME;
222         vp9_write(w, bit1, vp9_get_pred_prob_single_ref_p2(cm, xd));
223       }
224     }
225   }
226 }
227 
pack_inter_mode_mvs(VP9_COMP * cpi,const MODE_INFO * mi,vp9_writer * w)228 static void pack_inter_mode_mvs(VP9_COMP *cpi, const MODE_INFO *mi,
229                                 vp9_writer *w) {
230   VP9_COMMON *const cm = &cpi->common;
231   const nmv_context *nmvc = &cm->fc.nmvc;
232   const MACROBLOCK *const x = &cpi->mb;
233   const MACROBLOCKD *const xd = &x->e_mbd;
234   const struct segmentation *const seg = &cm->seg;
235   const MB_MODE_INFO *const mbmi = &mi->mbmi;
236   const MB_PREDICTION_MODE mode = mbmi->mode;
237   const int segment_id = mbmi->segment_id;
238   const BLOCK_SIZE bsize = mbmi->sb_type;
239   const int allow_hp = cm->allow_high_precision_mv;
240   const int is_inter = is_inter_block(mbmi);
241   const int is_compound = has_second_ref(mbmi);
242   int skip, ref;
243 
244   if (seg->update_map) {
245     if (seg->temporal_update) {
246       const int pred_flag = mbmi->seg_id_predicted;
247       vp9_prob pred_prob = vp9_get_pred_prob_seg_id(seg, xd);
248       vp9_write(w, pred_flag, pred_prob);
249       if (!pred_flag)
250         write_segment_id(w, seg, segment_id);
251     } else {
252       write_segment_id(w, seg, segment_id);
253     }
254   }
255 
256   skip = write_skip(cpi, segment_id, mi, w);
257 
258   if (!vp9_segfeature_active(seg, segment_id, SEG_LVL_REF_FRAME))
259     vp9_write(w, is_inter, vp9_get_intra_inter_prob(cm, xd));
260 
261   if (bsize >= BLOCK_8X8 && cm->tx_mode == TX_MODE_SELECT &&
262       !(is_inter &&
263         (skip || vp9_segfeature_active(seg, segment_id, SEG_LVL_SKIP)))) {
264     write_selected_tx_size(cpi, mbmi->tx_size, bsize, w);
265   }
266 
267   if (!is_inter) {
268     if (bsize >= BLOCK_8X8) {
269       write_intra_mode(w, mode, cm->fc.y_mode_prob[size_group_lookup[bsize]]);
270     } else {
271       int idx, idy;
272       const int num_4x4_w = num_4x4_blocks_wide_lookup[bsize];
273       const int num_4x4_h = num_4x4_blocks_high_lookup[bsize];
274       for (idy = 0; idy < 2; idy += num_4x4_h) {
275         for (idx = 0; idx < 2; idx += num_4x4_w) {
276           const MB_PREDICTION_MODE b_mode = mi->bmi[idy * 2 + idx].as_mode;
277           write_intra_mode(w, b_mode, cm->fc.y_mode_prob[0]);
278         }
279       }
280     }
281     write_intra_mode(w, mbmi->uv_mode, cm->fc.uv_mode_prob[mode]);
282   } else {
283     const int mode_ctx = mbmi->mode_context[mbmi->ref_frame[0]];
284     const vp9_prob *const inter_probs = cm->fc.inter_mode_probs[mode_ctx];
285     write_ref_frames(cpi, w);
286 
287     // If segment skip is not enabled code the mode.
288     if (!vp9_segfeature_active(seg, segment_id, SEG_LVL_SKIP)) {
289       if (bsize >= BLOCK_8X8) {
290         write_inter_mode(w, mode, inter_probs);
291         ++cm->counts.inter_mode[mode_ctx][INTER_OFFSET(mode)];
292       }
293     }
294 
295     if (cm->interp_filter == SWITCHABLE) {
296       const int ctx = vp9_get_pred_context_switchable_interp(xd);
297       vp9_write_token(w, vp9_switchable_interp_tree,
298                       cm->fc.switchable_interp_prob[ctx],
299                       &switchable_interp_encodings[mbmi->interp_filter]);
300     } else {
301       assert(mbmi->interp_filter == cm->interp_filter);
302     }
303 
304     if (bsize < BLOCK_8X8) {
305       const int num_4x4_w = num_4x4_blocks_wide_lookup[bsize];
306       const int num_4x4_h = num_4x4_blocks_high_lookup[bsize];
307       int idx, idy;
308       for (idy = 0; idy < 2; idy += num_4x4_h) {
309         for (idx = 0; idx < 2; idx += num_4x4_w) {
310           const int j = idy * 2 + idx;
311           const MB_PREDICTION_MODE b_mode = mi->bmi[j].as_mode;
312           write_inter_mode(w, b_mode, inter_probs);
313           ++cm->counts.inter_mode[mode_ctx][INTER_OFFSET(b_mode)];
314           if (b_mode == NEWMV) {
315             for (ref = 0; ref < 1 + is_compound; ++ref)
316               vp9_encode_mv(cpi, w, &mi->bmi[j].as_mv[ref].as_mv,
317                             &mbmi->ref_mvs[mbmi->ref_frame[ref]][0].as_mv,
318                             nmvc, allow_hp);
319           }
320         }
321       }
322     } else {
323       if (mode == NEWMV) {
324         for (ref = 0; ref < 1 + is_compound; ++ref)
325           vp9_encode_mv(cpi, w, &mbmi->mv[ref].as_mv,
326                         &mbmi->ref_mvs[mbmi->ref_frame[ref]][0].as_mv, nmvc,
327                         allow_hp);
328       }
329     }
330   }
331 }
332 
write_mb_modes_kf(const VP9_COMP * cpi,MODE_INFO ** mi_8x8,vp9_writer * w)333 static void write_mb_modes_kf(const VP9_COMP *cpi, MODE_INFO **mi_8x8,
334                               vp9_writer *w) {
335   const VP9_COMMON *const cm = &cpi->common;
336   const MACROBLOCKD *const xd = &cpi->mb.e_mbd;
337   const struct segmentation *const seg = &cm->seg;
338   const MODE_INFO *const mi = mi_8x8[0];
339   const MODE_INFO *const above_mi = mi_8x8[-xd->mi_stride];
340   const MODE_INFO *const left_mi = xd->left_available ? mi_8x8[-1] : NULL;
341   const MB_MODE_INFO *const mbmi = &mi->mbmi;
342   const BLOCK_SIZE bsize = mbmi->sb_type;
343 
344   if (seg->update_map)
345     write_segment_id(w, seg, mbmi->segment_id);
346 
347   write_skip(cpi, mbmi->segment_id, mi, w);
348 
349   if (bsize >= BLOCK_8X8 && cm->tx_mode == TX_MODE_SELECT)
350     write_selected_tx_size(cpi, mbmi->tx_size, bsize, w);
351 
352   if (bsize >= BLOCK_8X8) {
353     write_intra_mode(w, mbmi->mode, get_y_mode_probs(mi, above_mi, left_mi, 0));
354   } else {
355     const int num_4x4_w = num_4x4_blocks_wide_lookup[bsize];
356     const int num_4x4_h = num_4x4_blocks_high_lookup[bsize];
357     int idx, idy;
358 
359     for (idy = 0; idy < 2; idy += num_4x4_h) {
360       for (idx = 0; idx < 2; idx += num_4x4_w) {
361         const int block = idy * 2 + idx;
362         write_intra_mode(w, mi->bmi[block].as_mode,
363                          get_y_mode_probs(mi, above_mi, left_mi, block));
364       }
365     }
366   }
367 
368   write_intra_mode(w, mbmi->uv_mode, vp9_kf_uv_mode_prob[mbmi->mode]);
369 }
370 
write_modes_b(VP9_COMP * cpi,const TileInfo * const tile,vp9_writer * w,TOKENEXTRA ** tok,TOKENEXTRA * tok_end,int mi_row,int mi_col)371 static void write_modes_b(VP9_COMP *cpi, const TileInfo *const tile,
372                           vp9_writer *w, TOKENEXTRA **tok, TOKENEXTRA *tok_end,
373                           int mi_row, int mi_col) {
374   VP9_COMMON *const cm = &cpi->common;
375   MACROBLOCKD *const xd = &cpi->mb.e_mbd;
376   MODE_INFO *m;
377 
378   xd->mi = cm->mi_grid_visible + (mi_row * cm->mi_stride + mi_col);
379   m = xd->mi[0];
380 
381   set_mi_row_col(xd, tile,
382                  mi_row, num_8x8_blocks_high_lookup[m->mbmi.sb_type],
383                  mi_col, num_8x8_blocks_wide_lookup[m->mbmi.sb_type],
384                  cm->mi_rows, cm->mi_cols);
385   if (frame_is_intra_only(cm)) {
386     write_mb_modes_kf(cpi, xd->mi, w);
387   } else {
388     pack_inter_mode_mvs(cpi, m, w);
389   }
390 
391   assert(*tok < tok_end);
392   pack_mb_tokens(w, tok, tok_end);
393 }
394 
write_partition(VP9_COMMON * cm,MACROBLOCKD * xd,int hbs,int mi_row,int mi_col,PARTITION_TYPE p,BLOCK_SIZE bsize,vp9_writer * w)395 static void write_partition(VP9_COMMON *cm, MACROBLOCKD *xd,
396                             int hbs, int mi_row, int mi_col,
397                             PARTITION_TYPE p, BLOCK_SIZE bsize, vp9_writer *w) {
398   const int ctx = partition_plane_context(xd, mi_row, mi_col, bsize);
399   const vp9_prob *const probs = get_partition_probs(cm, ctx);
400   const int has_rows = (mi_row + hbs) < cm->mi_rows;
401   const int has_cols = (mi_col + hbs) < cm->mi_cols;
402 
403   if (has_rows && has_cols) {
404     vp9_write_token(w, vp9_partition_tree, probs, &partition_encodings[p]);
405   } else if (!has_rows && has_cols) {
406     assert(p == PARTITION_SPLIT || p == PARTITION_HORZ);
407     vp9_write(w, p == PARTITION_SPLIT, probs[1]);
408   } else if (has_rows && !has_cols) {
409     assert(p == PARTITION_SPLIT || p == PARTITION_VERT);
410     vp9_write(w, p == PARTITION_SPLIT, probs[2]);
411   } else {
412     assert(p == PARTITION_SPLIT);
413   }
414 }
415 
write_modes_sb(VP9_COMP * cpi,const TileInfo * const tile,vp9_writer * w,TOKENEXTRA ** tok,TOKENEXTRA * tok_end,int mi_row,int mi_col,BLOCK_SIZE bsize)416 static void write_modes_sb(VP9_COMP *cpi,
417                            const TileInfo *const tile,
418                            vp9_writer *w, TOKENEXTRA **tok, TOKENEXTRA *tok_end,
419                            int mi_row, int mi_col, BLOCK_SIZE bsize) {
420   VP9_COMMON *const cm = &cpi->common;
421   MACROBLOCKD *const xd = &cpi->mb.e_mbd;
422 
423   const int bsl = b_width_log2(bsize);
424   const int bs = (1 << bsl) / 4;
425   PARTITION_TYPE partition;
426   BLOCK_SIZE subsize;
427   MODE_INFO *m = cm->mi_grid_visible[mi_row * cm->mi_stride + mi_col];
428 
429   if (mi_row >= cm->mi_rows || mi_col >= cm->mi_cols)
430     return;
431 
432   partition = partition_lookup[bsl][m->mbmi.sb_type];
433   write_partition(cm, xd, bs, mi_row, mi_col, partition, bsize, w);
434   subsize = get_subsize(bsize, partition);
435   if (subsize < BLOCK_8X8) {
436     write_modes_b(cpi, tile, w, tok, tok_end, mi_row, mi_col);
437   } else {
438     switch (partition) {
439       case PARTITION_NONE:
440         write_modes_b(cpi, tile, w, tok, tok_end, mi_row, mi_col);
441         break;
442       case PARTITION_HORZ:
443         write_modes_b(cpi, tile, w, tok, tok_end, mi_row, mi_col);
444         if (mi_row + bs < cm->mi_rows)
445           write_modes_b(cpi, tile, w, tok, tok_end, mi_row + bs, mi_col);
446         break;
447       case PARTITION_VERT:
448         write_modes_b(cpi, tile, w, tok, tok_end, mi_row, mi_col);
449         if (mi_col + bs < cm->mi_cols)
450           write_modes_b(cpi, tile, w, tok, tok_end, mi_row, mi_col + bs);
451         break;
452       case PARTITION_SPLIT:
453         write_modes_sb(cpi, tile, w, tok, tok_end, mi_row, mi_col, subsize);
454         write_modes_sb(cpi, tile, w, tok, tok_end, mi_row, mi_col + bs,
455                        subsize);
456         write_modes_sb(cpi, tile, w, tok, tok_end, mi_row + bs, mi_col,
457                        subsize);
458         write_modes_sb(cpi, tile, w, tok, tok_end, mi_row + bs, mi_col + bs,
459                        subsize);
460         break;
461       default:
462         assert(0);
463     }
464   }
465 
466   // update partition context
467   if (bsize >= BLOCK_8X8 &&
468       (bsize == BLOCK_8X8 || partition != PARTITION_SPLIT))
469     update_partition_context(xd, mi_row, mi_col, subsize, bsize);
470 }
471 
write_modes(VP9_COMP * cpi,const TileInfo * const tile,vp9_writer * w,TOKENEXTRA ** tok,TOKENEXTRA * tok_end)472 static void write_modes(VP9_COMP *cpi,
473                         const TileInfo *const tile,
474                         vp9_writer *w, TOKENEXTRA **tok, TOKENEXTRA *tok_end) {
475   int mi_row, mi_col;
476 
477   for (mi_row = tile->mi_row_start; mi_row < tile->mi_row_end;
478        mi_row += MI_BLOCK_SIZE) {
479     vp9_zero(cpi->mb.e_mbd.left_seg_context);
480     for (mi_col = tile->mi_col_start; mi_col < tile->mi_col_end;
481          mi_col += MI_BLOCK_SIZE)
482       write_modes_sb(cpi, tile, w, tok, tok_end, mi_row, mi_col,
483                      BLOCK_64X64);
484   }
485 }
486 
build_tree_distribution(VP9_COMP * cpi,TX_SIZE tx_size,vp9_coeff_stats * coef_branch_ct)487 static void build_tree_distribution(VP9_COMP *cpi, TX_SIZE tx_size,
488                                     vp9_coeff_stats *coef_branch_ct) {
489   vp9_coeff_probs_model *coef_probs = cpi->frame_coef_probs[tx_size];
490   vp9_coeff_count *coef_counts = cpi->coef_counts[tx_size];
491   unsigned int (*eob_branch_ct)[REF_TYPES][COEF_BANDS][COEFF_CONTEXTS] =
492       cpi->common.counts.eob_branch[tx_size];
493   int i, j, k, l, m;
494 
495   for (i = 0; i < PLANE_TYPES; ++i) {
496     for (j = 0; j < REF_TYPES; ++j) {
497       for (k = 0; k < COEF_BANDS; ++k) {
498         for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
499           vp9_tree_probs_from_distribution(vp9_coef_tree,
500                                            coef_branch_ct[i][j][k][l],
501                                            coef_counts[i][j][k][l]);
502           coef_branch_ct[i][j][k][l][0][1] = eob_branch_ct[i][j][k][l] -
503                                              coef_branch_ct[i][j][k][l][0][0];
504           for (m = 0; m < UNCONSTRAINED_NODES; ++m)
505             coef_probs[i][j][k][l][m] = get_binary_prob(
506                                             coef_branch_ct[i][j][k][l][m][0],
507                                             coef_branch_ct[i][j][k][l][m][1]);
508         }
509       }
510     }
511   }
512 }
513 
update_coef_probs_common(vp9_writer * const bc,VP9_COMP * cpi,TX_SIZE tx_size,vp9_coeff_stats * frame_branch_ct)514 static void update_coef_probs_common(vp9_writer* const bc, VP9_COMP *cpi,
515                                      TX_SIZE tx_size,
516                                      vp9_coeff_stats *frame_branch_ct) {
517   vp9_coeff_probs_model *new_frame_coef_probs = cpi->frame_coef_probs[tx_size];
518   vp9_coeff_probs_model *old_frame_coef_probs =
519       cpi->common.fc.coef_probs[tx_size];
520   const vp9_prob upd = DIFF_UPDATE_PROB;
521   const int entropy_nodes_update = UNCONSTRAINED_NODES;
522   int i, j, k, l, t;
523   switch (cpi->sf.use_fast_coef_updates) {
524     case 0: {
525       /* dry run to see if there is any udpate at all needed */
526       int savings = 0;
527       int update[2] = {0, 0};
528       for (i = 0; i < PLANE_TYPES; ++i) {
529         for (j = 0; j < REF_TYPES; ++j) {
530           for (k = 0; k < COEF_BANDS; ++k) {
531             for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
532               for (t = 0; t < entropy_nodes_update; ++t) {
533                 vp9_prob newp = new_frame_coef_probs[i][j][k][l][t];
534                 const vp9_prob oldp = old_frame_coef_probs[i][j][k][l][t];
535                 int s;
536                 int u = 0;
537                 if (t == PIVOT_NODE)
538                   s = vp9_prob_diff_update_savings_search_model(
539                       frame_branch_ct[i][j][k][l][0],
540                       old_frame_coef_probs[i][j][k][l], &newp, upd);
541                 else
542                   s = vp9_prob_diff_update_savings_search(
543                       frame_branch_ct[i][j][k][l][t], oldp, &newp, upd);
544                 if (s > 0 && newp != oldp)
545                   u = 1;
546                 if (u)
547                   savings += s - (int)(vp9_cost_zero(upd));
548                 else
549                   savings -= (int)(vp9_cost_zero(upd));
550                 update[u]++;
551               }
552             }
553           }
554         }
555       }
556 
557       // printf("Update %d %d, savings %d\n", update[0], update[1], savings);
558       /* Is coef updated at all */
559       if (update[1] == 0 || savings < 0) {
560         vp9_write_bit(bc, 0);
561         return;
562       }
563       vp9_write_bit(bc, 1);
564       for (i = 0; i < PLANE_TYPES; ++i) {
565         for (j = 0; j < REF_TYPES; ++j) {
566           for (k = 0; k < COEF_BANDS; ++k) {
567             for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
568               // calc probs and branch cts for this frame only
569               for (t = 0; t < entropy_nodes_update; ++t) {
570                 vp9_prob newp = new_frame_coef_probs[i][j][k][l][t];
571                 vp9_prob *oldp = old_frame_coef_probs[i][j][k][l] + t;
572                 const vp9_prob upd = DIFF_UPDATE_PROB;
573                 int s;
574                 int u = 0;
575                 if (t == PIVOT_NODE)
576                   s = vp9_prob_diff_update_savings_search_model(
577                       frame_branch_ct[i][j][k][l][0],
578                       old_frame_coef_probs[i][j][k][l], &newp, upd);
579                 else
580                   s = vp9_prob_diff_update_savings_search(
581                       frame_branch_ct[i][j][k][l][t],
582                       *oldp, &newp, upd);
583                 if (s > 0 && newp != *oldp)
584                   u = 1;
585                 vp9_write(bc, u, upd);
586                 if (u) {
587                   /* send/use new probability */
588                   vp9_write_prob_diff_update(bc, newp, *oldp);
589                   *oldp = newp;
590                 }
591               }
592             }
593           }
594         }
595       }
596       return;
597     }
598 
599     case 1:
600     case 2: {
601       const int prev_coef_contexts_to_update =
602           cpi->sf.use_fast_coef_updates == 2 ? COEFF_CONTEXTS >> 1
603                                              : COEFF_CONTEXTS;
604       const int coef_band_to_update =
605           cpi->sf.use_fast_coef_updates == 2 ? COEF_BANDS >> 1
606                                              : COEF_BANDS;
607       int updates = 0;
608       int noupdates_before_first = 0;
609       for (i = 0; i < PLANE_TYPES; ++i) {
610         for (j = 0; j < REF_TYPES; ++j) {
611           for (k = 0; k < COEF_BANDS; ++k) {
612             for (l = 0; l < BAND_COEFF_CONTEXTS(k); ++l) {
613               // calc probs and branch cts for this frame only
614               for (t = 0; t < entropy_nodes_update; ++t) {
615                 vp9_prob newp = new_frame_coef_probs[i][j][k][l][t];
616                 vp9_prob *oldp = old_frame_coef_probs[i][j][k][l] + t;
617                 int s;
618                 int u = 0;
619                 if (l >= prev_coef_contexts_to_update ||
620                     k >= coef_band_to_update) {
621                   u = 0;
622                 } else {
623                   if (t == PIVOT_NODE)
624                     s = vp9_prob_diff_update_savings_search_model(
625                         frame_branch_ct[i][j][k][l][0],
626                         old_frame_coef_probs[i][j][k][l], &newp, upd);
627                   else
628                     s = vp9_prob_diff_update_savings_search(
629                         frame_branch_ct[i][j][k][l][t],
630                         *oldp, &newp, upd);
631                   if (s > 0 && newp != *oldp)
632                     u = 1;
633                 }
634                 updates += u;
635                 if (u == 0 && updates == 0) {
636                   noupdates_before_first++;
637                   continue;
638                 }
639                 if (u == 1 && updates == 1) {
640                   int v;
641                   // first update
642                   vp9_write_bit(bc, 1);
643                   for (v = 0; v < noupdates_before_first; ++v)
644                     vp9_write(bc, 0, upd);
645                 }
646                 vp9_write(bc, u, upd);
647                 if (u) {
648                   /* send/use new probability */
649                   vp9_write_prob_diff_update(bc, newp, *oldp);
650                   *oldp = newp;
651                 }
652               }
653             }
654           }
655         }
656       }
657       if (updates == 0) {
658         vp9_write_bit(bc, 0);  // no updates
659       }
660       return;
661     }
662 
663     default:
664       assert(0);
665   }
666 }
667 
update_coef_probs(VP9_COMP * cpi,vp9_writer * w)668 static void update_coef_probs(VP9_COMP *cpi, vp9_writer* w) {
669   const TX_MODE tx_mode = cpi->common.tx_mode;
670   const TX_SIZE max_tx_size = tx_mode_to_biggest_tx_size[tx_mode];
671   TX_SIZE tx_size;
672   vp9_coeff_stats frame_branch_ct[TX_SIZES][PLANE_TYPES];
673 
674   vp9_clear_system_state();
675 
676   for (tx_size = TX_4X4; tx_size <= TX_32X32; ++tx_size)
677     build_tree_distribution(cpi, tx_size, frame_branch_ct[tx_size]);
678 
679   for (tx_size = TX_4X4; tx_size <= max_tx_size; ++tx_size)
680     update_coef_probs_common(w, cpi, tx_size, frame_branch_ct[tx_size]);
681 }
682 
encode_loopfilter(struct loopfilter * lf,struct vp9_write_bit_buffer * wb)683 static void encode_loopfilter(struct loopfilter *lf,
684                               struct vp9_write_bit_buffer *wb) {
685   int i;
686 
687   // Encode the loop filter level and type
688   vp9_wb_write_literal(wb, lf->filter_level, 6);
689   vp9_wb_write_literal(wb, lf->sharpness_level, 3);
690 
691   // Write out loop filter deltas applied at the MB level based on mode or
692   // ref frame (if they are enabled).
693   vp9_wb_write_bit(wb, lf->mode_ref_delta_enabled);
694 
695   if (lf->mode_ref_delta_enabled) {
696     vp9_wb_write_bit(wb, lf->mode_ref_delta_update);
697     if (lf->mode_ref_delta_update) {
698       for (i = 0; i < MAX_REF_LF_DELTAS; i++) {
699         const int delta = lf->ref_deltas[i];
700         const int changed = delta != lf->last_ref_deltas[i];
701         vp9_wb_write_bit(wb, changed);
702         if (changed) {
703           lf->last_ref_deltas[i] = delta;
704           vp9_wb_write_literal(wb, abs(delta) & 0x3F, 6);
705           vp9_wb_write_bit(wb, delta < 0);
706         }
707       }
708 
709       for (i = 0; i < MAX_MODE_LF_DELTAS; i++) {
710         const int delta = lf->mode_deltas[i];
711         const int changed = delta != lf->last_mode_deltas[i];
712         vp9_wb_write_bit(wb, changed);
713         if (changed) {
714           lf->last_mode_deltas[i] = delta;
715           vp9_wb_write_literal(wb, abs(delta) & 0x3F, 6);
716           vp9_wb_write_bit(wb, delta < 0);
717         }
718       }
719     }
720   }
721 }
722 
write_delta_q(struct vp9_write_bit_buffer * wb,int delta_q)723 static void write_delta_q(struct vp9_write_bit_buffer *wb, int delta_q) {
724   if (delta_q != 0) {
725     vp9_wb_write_bit(wb, 1);
726     vp9_wb_write_literal(wb, abs(delta_q), 4);
727     vp9_wb_write_bit(wb, delta_q < 0);
728   } else {
729     vp9_wb_write_bit(wb, 0);
730   }
731 }
732 
encode_quantization(VP9_COMMON * cm,struct vp9_write_bit_buffer * wb)733 static void encode_quantization(VP9_COMMON *cm,
734                                 struct vp9_write_bit_buffer *wb) {
735   vp9_wb_write_literal(wb, cm->base_qindex, QINDEX_BITS);
736   write_delta_q(wb, cm->y_dc_delta_q);
737   write_delta_q(wb, cm->uv_dc_delta_q);
738   write_delta_q(wb, cm->uv_ac_delta_q);
739 }
740 
741 
encode_segmentation(VP9_COMP * cpi,struct vp9_write_bit_buffer * wb)742 static void encode_segmentation(VP9_COMP *cpi,
743                                 struct vp9_write_bit_buffer *wb) {
744   int i, j;
745 
746   struct segmentation *seg = &cpi->common.seg;
747 
748   vp9_wb_write_bit(wb, seg->enabled);
749   if (!seg->enabled)
750     return;
751 
752   // Segmentation map
753   vp9_wb_write_bit(wb, seg->update_map);
754   if (seg->update_map) {
755     // Select the coding strategy (temporal or spatial)
756     vp9_choose_segmap_coding_method(cpi);
757     // Write out probabilities used to decode unpredicted  macro-block segments
758     for (i = 0; i < SEG_TREE_PROBS; i++) {
759       const int prob = seg->tree_probs[i];
760       const int update = prob != MAX_PROB;
761       vp9_wb_write_bit(wb, update);
762       if (update)
763         vp9_wb_write_literal(wb, prob, 8);
764     }
765 
766     // Write out the chosen coding method.
767     vp9_wb_write_bit(wb, seg->temporal_update);
768     if (seg->temporal_update) {
769       for (i = 0; i < PREDICTION_PROBS; i++) {
770         const int prob = seg->pred_probs[i];
771         const int update = prob != MAX_PROB;
772         vp9_wb_write_bit(wb, update);
773         if (update)
774           vp9_wb_write_literal(wb, prob, 8);
775       }
776     }
777   }
778 
779   // Segmentation data
780   vp9_wb_write_bit(wb, seg->update_data);
781   if (seg->update_data) {
782     vp9_wb_write_bit(wb, seg->abs_delta);
783 
784     for (i = 0; i < MAX_SEGMENTS; i++) {
785       for (j = 0; j < SEG_LVL_MAX; j++) {
786         const int active = vp9_segfeature_active(seg, i, j);
787         vp9_wb_write_bit(wb, active);
788         if (active) {
789           const int data = vp9_get_segdata(seg, i, j);
790           const int data_max = vp9_seg_feature_data_max(j);
791 
792           if (vp9_is_segfeature_signed(j)) {
793             encode_unsigned_max(wb, abs(data), data_max);
794             vp9_wb_write_bit(wb, data < 0);
795           } else {
796             encode_unsigned_max(wb, data, data_max);
797           }
798         }
799       }
800     }
801   }
802 }
803 
804 
encode_txfm_probs(VP9_COMMON * cm,vp9_writer * w)805 static void encode_txfm_probs(VP9_COMMON *cm, vp9_writer *w) {
806   // Mode
807   vp9_write_literal(w, MIN(cm->tx_mode, ALLOW_32X32), 2);
808   if (cm->tx_mode >= ALLOW_32X32)
809     vp9_write_bit(w, cm->tx_mode == TX_MODE_SELECT);
810 
811   // Probabilities
812   if (cm->tx_mode == TX_MODE_SELECT) {
813     int i, j;
814     unsigned int ct_8x8p[TX_SIZES - 3][2];
815     unsigned int ct_16x16p[TX_SIZES - 2][2];
816     unsigned int ct_32x32p[TX_SIZES - 1][2];
817 
818 
819     for (i = 0; i < TX_SIZE_CONTEXTS; i++) {
820       tx_counts_to_branch_counts_8x8(cm->counts.tx.p8x8[i], ct_8x8p);
821       for (j = 0; j < TX_SIZES - 3; j++)
822         vp9_cond_prob_diff_update(w, &cm->fc.tx_probs.p8x8[i][j], ct_8x8p[j]);
823     }
824 
825     for (i = 0; i < TX_SIZE_CONTEXTS; i++) {
826       tx_counts_to_branch_counts_16x16(cm->counts.tx.p16x16[i], ct_16x16p);
827       for (j = 0; j < TX_SIZES - 2; j++)
828         vp9_cond_prob_diff_update(w, &cm->fc.tx_probs.p16x16[i][j],
829                                   ct_16x16p[j]);
830     }
831 
832     for (i = 0; i < TX_SIZE_CONTEXTS; i++) {
833       tx_counts_to_branch_counts_32x32(cm->counts.tx.p32x32[i], ct_32x32p);
834       for (j = 0; j < TX_SIZES - 1; j++)
835         vp9_cond_prob_diff_update(w, &cm->fc.tx_probs.p32x32[i][j],
836                                   ct_32x32p[j]);
837     }
838   }
839 }
840 
write_interp_filter(INTERP_FILTER filter,struct vp9_write_bit_buffer * wb)841 static void write_interp_filter(INTERP_FILTER filter,
842                                 struct vp9_write_bit_buffer *wb) {
843   const int filter_to_literal[] = { 1, 0, 2, 3 };
844 
845   vp9_wb_write_bit(wb, filter == SWITCHABLE);
846   if (filter != SWITCHABLE)
847     vp9_wb_write_literal(wb, filter_to_literal[filter], 2);
848 }
849 
fix_interp_filter(VP9_COMMON * cm)850 static void fix_interp_filter(VP9_COMMON *cm) {
851   if (cm->interp_filter == SWITCHABLE) {
852     // Check to see if only one of the filters is actually used
853     int count[SWITCHABLE_FILTERS];
854     int i, j, c = 0;
855     for (i = 0; i < SWITCHABLE_FILTERS; ++i) {
856       count[i] = 0;
857       for (j = 0; j < SWITCHABLE_FILTER_CONTEXTS; ++j)
858         count[i] += cm->counts.switchable_interp[j][i];
859       c += (count[i] > 0);
860     }
861     if (c == 1) {
862       // Only one filter is used. So set the filter at frame level
863       for (i = 0; i < SWITCHABLE_FILTERS; ++i) {
864         if (count[i]) {
865           cm->interp_filter = i;
866           break;
867         }
868       }
869     }
870   }
871 }
872 
write_tile_info(VP9_COMMON * cm,struct vp9_write_bit_buffer * wb)873 static void write_tile_info(VP9_COMMON *cm, struct vp9_write_bit_buffer *wb) {
874   int min_log2_tile_cols, max_log2_tile_cols, ones;
875   vp9_get_tile_n_bits(cm->mi_cols, &min_log2_tile_cols, &max_log2_tile_cols);
876 
877   // columns
878   ones = cm->log2_tile_cols - min_log2_tile_cols;
879   while (ones--)
880     vp9_wb_write_bit(wb, 1);
881 
882   if (cm->log2_tile_cols < max_log2_tile_cols)
883     vp9_wb_write_bit(wb, 0);
884 
885   // rows
886   vp9_wb_write_bit(wb, cm->log2_tile_rows != 0);
887   if (cm->log2_tile_rows != 0)
888     vp9_wb_write_bit(wb, cm->log2_tile_rows != 1);
889 }
890 
get_refresh_mask(VP9_COMP * cpi)891 static int get_refresh_mask(VP9_COMP *cpi) {
892     // Should the GF or ARF be updated using the transmitted frame or buffer
893 #if CONFIG_MULTIPLE_ARF
894     if (!cpi->multi_arf_enabled && cpi->refresh_golden_frame &&
895         !cpi->refresh_alt_ref_frame) {
896 #else
897     if (cpi->refresh_golden_frame && !cpi->refresh_alt_ref_frame &&
898         !cpi->use_svc) {
899 #endif
900       // Preserve the previously existing golden frame and update the frame in
901       // the alt ref slot instead. This is highly specific to the use of
902       // alt-ref as a forward reference, and this needs to be generalized as
903       // other uses are implemented (like RTC/temporal scaling)
904       //
905       // gld_fb_idx and alt_fb_idx need to be swapped for future frames, but
906       // that happens in vp9_onyx_if.c:update_reference_frames() so that it can
907       // be done outside of the recode loop.
908       return (cpi->refresh_last_frame << cpi->lst_fb_idx) |
909              (cpi->refresh_golden_frame << cpi->alt_fb_idx);
910     } else {
911       int arf_idx = cpi->alt_fb_idx;
912 #if CONFIG_MULTIPLE_ARF
913       // Determine which ARF buffer to use to encode this ARF frame.
914       if (cpi->multi_arf_enabled) {
915         int sn = cpi->sequence_number;
916         arf_idx = (cpi->frame_coding_order[sn] < 0) ?
917             cpi->arf_buffer_idx[sn + 1] :
918             cpi->arf_buffer_idx[sn];
919       }
920 #endif
921       return (cpi->refresh_last_frame << cpi->lst_fb_idx) |
922              (cpi->refresh_golden_frame << cpi->gld_fb_idx) |
923              (cpi->refresh_alt_ref_frame << arf_idx);
924     }
925 }
926 
927 static size_t encode_tiles(VP9_COMP *cpi, uint8_t *data_ptr) {
928   VP9_COMMON *const cm = &cpi->common;
929   vp9_writer residual_bc;
930 
931   int tile_row, tile_col;
932   TOKENEXTRA *tok[4][1 << 6], *tok_end;
933   size_t total_size = 0;
934   const int tile_cols = 1 << cm->log2_tile_cols;
935   const int tile_rows = 1 << cm->log2_tile_rows;
936 
937   vpx_memset(cm->above_seg_context, 0, sizeof(*cm->above_seg_context) *
938              mi_cols_aligned_to_sb(cm->mi_cols));
939 
940   tok[0][0] = cpi->tok;
941   for (tile_row = 0; tile_row < tile_rows; tile_row++) {
942     if (tile_row)
943       tok[tile_row][0] = tok[tile_row - 1][tile_cols - 1] +
944                          cpi->tok_count[tile_row - 1][tile_cols - 1];
945 
946     for (tile_col = 1; tile_col < tile_cols; tile_col++)
947       tok[tile_row][tile_col] = tok[tile_row][tile_col - 1] +
948                                 cpi->tok_count[tile_row][tile_col - 1];
949   }
950 
951   for (tile_row = 0; tile_row < tile_rows; tile_row++) {
952     for (tile_col = 0; tile_col < tile_cols; tile_col++) {
953       TileInfo tile;
954 
955       vp9_tile_init(&tile, cm, tile_row, tile_col);
956       tok_end = tok[tile_row][tile_col] + cpi->tok_count[tile_row][tile_col];
957 
958       if (tile_col < tile_cols - 1 || tile_row < tile_rows - 1)
959         vp9_start_encode(&residual_bc, data_ptr + total_size + 4);
960       else
961         vp9_start_encode(&residual_bc, data_ptr + total_size);
962 
963       write_modes(cpi, &tile, &residual_bc, &tok[tile_row][tile_col], tok_end);
964       assert(tok[tile_row][tile_col] == tok_end);
965       vp9_stop_encode(&residual_bc);
966       if (tile_col < tile_cols - 1 || tile_row < tile_rows - 1) {
967         // size of this tile
968         mem_put_be32(data_ptr + total_size, residual_bc.pos);
969         total_size += 4;
970       }
971 
972       total_size += residual_bc.pos;
973     }
974   }
975 
976   return total_size;
977 }
978 
979 static void write_display_size(const VP9_COMMON *cm,
980                                struct vp9_write_bit_buffer *wb) {
981   const int scaling_active = cm->width != cm->display_width ||
982                              cm->height != cm->display_height;
983   vp9_wb_write_bit(wb, scaling_active);
984   if (scaling_active) {
985     vp9_wb_write_literal(wb, cm->display_width - 1, 16);
986     vp9_wb_write_literal(wb, cm->display_height - 1, 16);
987   }
988 }
989 
990 static void write_frame_size(const VP9_COMMON *cm,
991                              struct vp9_write_bit_buffer *wb) {
992   vp9_wb_write_literal(wb, cm->width - 1, 16);
993   vp9_wb_write_literal(wb, cm->height - 1, 16);
994 
995   write_display_size(cm, wb);
996 }
997 
998 static void write_frame_size_with_refs(VP9_COMP *cpi,
999                                        struct vp9_write_bit_buffer *wb) {
1000   VP9_COMMON *const cm = &cpi->common;
1001   int found = 0;
1002 
1003   MV_REFERENCE_FRAME ref_frame;
1004   for (ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ++ref_frame) {
1005     YV12_BUFFER_CONFIG *cfg = get_ref_frame_buffer(cpi, ref_frame);
1006     found = cm->width == cfg->y_crop_width &&
1007             cm->height == cfg->y_crop_height;
1008 
1009     // TODO(ivan): This prevents a bug while more than 3 buffers are used. Do it
1010     // in a better way.
1011     if (cpi->use_svc) {
1012       found = 0;
1013     }
1014     vp9_wb_write_bit(wb, found);
1015     if (found) {
1016       break;
1017     }
1018   }
1019 
1020   if (!found) {
1021     vp9_wb_write_literal(wb, cm->width - 1, 16);
1022     vp9_wb_write_literal(wb, cm->height - 1, 16);
1023   }
1024 
1025   write_display_size(cm, wb);
1026 }
1027 
1028 static void write_sync_code(struct vp9_write_bit_buffer *wb) {
1029   vp9_wb_write_literal(wb, VP9_SYNC_CODE_0, 8);
1030   vp9_wb_write_literal(wb, VP9_SYNC_CODE_1, 8);
1031   vp9_wb_write_literal(wb, VP9_SYNC_CODE_2, 8);
1032 }
1033 
1034 static void write_uncompressed_header(VP9_COMP *cpi,
1035                                       struct vp9_write_bit_buffer *wb) {
1036   VP9_COMMON *const cm = &cpi->common;
1037 
1038   vp9_wb_write_literal(wb, VP9_FRAME_MARKER, 2);
1039 
1040   // bitstream version.
1041   // 00 - profile 0. 4:2:0 only
1042   // 10 - profile 1. adds 4:4:4, 4:2:2, alpha
1043   vp9_wb_write_bit(wb, cm->version);
1044   vp9_wb_write_bit(wb, 0);
1045 
1046   vp9_wb_write_bit(wb, 0);
1047   vp9_wb_write_bit(wb, cm->frame_type);
1048   vp9_wb_write_bit(wb, cm->show_frame);
1049   vp9_wb_write_bit(wb, cm->error_resilient_mode);
1050 
1051   if (cm->frame_type == KEY_FRAME) {
1052     const COLOR_SPACE cs = UNKNOWN;
1053     write_sync_code(wb);
1054     vp9_wb_write_literal(wb, cs, 3);
1055     if (cs != SRGB) {
1056       vp9_wb_write_bit(wb, 0);  // 0: [16, 235] (i.e. xvYCC), 1: [0, 255]
1057       if (cm->version == 1) {
1058         vp9_wb_write_bit(wb, cm->subsampling_x);
1059         vp9_wb_write_bit(wb, cm->subsampling_y);
1060         vp9_wb_write_bit(wb, 0);  // has extra plane
1061       }
1062     } else {
1063       assert(cm->version == 1);
1064       vp9_wb_write_bit(wb, 0);  // has extra plane
1065     }
1066 
1067     write_frame_size(cm, wb);
1068   } else {
1069     if (!cm->show_frame)
1070       vp9_wb_write_bit(wb, cm->intra_only);
1071 
1072     if (!cm->error_resilient_mode)
1073       vp9_wb_write_literal(wb, cm->reset_frame_context, 2);
1074 
1075     if (cm->intra_only) {
1076       write_sync_code(wb);
1077 
1078       vp9_wb_write_literal(wb, get_refresh_mask(cpi), REF_FRAMES);
1079       write_frame_size(cm, wb);
1080     } else {
1081       MV_REFERENCE_FRAME ref_frame;
1082       vp9_wb_write_literal(wb, get_refresh_mask(cpi), REF_FRAMES);
1083       for (ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ++ref_frame) {
1084         vp9_wb_write_literal(wb, get_ref_frame_idx(cpi, ref_frame),
1085                              REF_FRAMES_LOG2);
1086         vp9_wb_write_bit(wb, cm->ref_frame_sign_bias[ref_frame]);
1087       }
1088 
1089       write_frame_size_with_refs(cpi, wb);
1090 
1091       vp9_wb_write_bit(wb, cm->allow_high_precision_mv);
1092 
1093       fix_interp_filter(cm);
1094       write_interp_filter(cm->interp_filter, wb);
1095     }
1096   }
1097 
1098   if (!cm->error_resilient_mode) {
1099     vp9_wb_write_bit(wb, cm->refresh_frame_context);
1100     vp9_wb_write_bit(wb, cm->frame_parallel_decoding_mode);
1101   }
1102 
1103   vp9_wb_write_literal(wb, cm->frame_context_idx, FRAME_CONTEXTS_LOG2);
1104 
1105   encode_loopfilter(&cm->lf, wb);
1106   encode_quantization(cm, wb);
1107   encode_segmentation(cpi, wb);
1108 
1109   write_tile_info(cm, wb);
1110 }
1111 
1112 static size_t write_compressed_header(VP9_COMP *cpi, uint8_t *data) {
1113   VP9_COMMON *const cm = &cpi->common;
1114   MACROBLOCKD *const xd = &cpi->mb.e_mbd;
1115   FRAME_CONTEXT *const fc = &cm->fc;
1116   vp9_writer header_bc;
1117 
1118   vp9_start_encode(&header_bc, data);
1119 
1120   if (xd->lossless)
1121     cm->tx_mode = ONLY_4X4;
1122   else
1123     encode_txfm_probs(cm, &header_bc);
1124 
1125   update_coef_probs(cpi, &header_bc);
1126   update_skip_probs(cm, &header_bc);
1127 
1128   if (!frame_is_intra_only(cm)) {
1129     int i;
1130 
1131     for (i = 0; i < INTER_MODE_CONTEXTS; ++i)
1132       prob_diff_update(vp9_inter_mode_tree, cm->fc.inter_mode_probs[i],
1133                        cm->counts.inter_mode[i], INTER_MODES, &header_bc);
1134 
1135     vp9_zero(cm->counts.inter_mode);
1136 
1137     if (cm->interp_filter == SWITCHABLE)
1138       update_switchable_interp_probs(cm, &header_bc);
1139 
1140     for (i = 0; i < INTRA_INTER_CONTEXTS; i++)
1141       vp9_cond_prob_diff_update(&header_bc, &fc->intra_inter_prob[i],
1142                                 cm->counts.intra_inter[i]);
1143 
1144     if (cm->allow_comp_inter_inter) {
1145       const int use_compound_pred = cm->reference_mode != SINGLE_REFERENCE;
1146       const int use_hybrid_pred = cm->reference_mode == REFERENCE_MODE_SELECT;
1147 
1148       vp9_write_bit(&header_bc, use_compound_pred);
1149       if (use_compound_pred) {
1150         vp9_write_bit(&header_bc, use_hybrid_pred);
1151         if (use_hybrid_pred)
1152           for (i = 0; i < COMP_INTER_CONTEXTS; i++)
1153             vp9_cond_prob_diff_update(&header_bc, &fc->comp_inter_prob[i],
1154                                       cm->counts.comp_inter[i]);
1155       }
1156     }
1157 
1158     if (cm->reference_mode != COMPOUND_REFERENCE) {
1159       for (i = 0; i < REF_CONTEXTS; i++) {
1160         vp9_cond_prob_diff_update(&header_bc, &fc->single_ref_prob[i][0],
1161                                   cm->counts.single_ref[i][0]);
1162         vp9_cond_prob_diff_update(&header_bc, &fc->single_ref_prob[i][1],
1163                                   cm->counts.single_ref[i][1]);
1164       }
1165     }
1166 
1167     if (cm->reference_mode != SINGLE_REFERENCE)
1168       for (i = 0; i < REF_CONTEXTS; i++)
1169         vp9_cond_prob_diff_update(&header_bc, &fc->comp_ref_prob[i],
1170                                   cm->counts.comp_ref[i]);
1171 
1172     for (i = 0; i < BLOCK_SIZE_GROUPS; ++i)
1173       prob_diff_update(vp9_intra_mode_tree, cm->fc.y_mode_prob[i],
1174                        cm->counts.y_mode[i], INTRA_MODES, &header_bc);
1175 
1176     for (i = 0; i < PARTITION_CONTEXTS; ++i)
1177       prob_diff_update(vp9_partition_tree, fc->partition_prob[i],
1178                        cm->counts.partition[i], PARTITION_TYPES, &header_bc);
1179 
1180     vp9_write_nmv_probs(cm, cm->allow_high_precision_mv, &header_bc);
1181   }
1182 
1183   vp9_stop_encode(&header_bc);
1184   assert(header_bc.pos <= 0xffff);
1185 
1186   return header_bc.pos;
1187 }
1188 
1189 void vp9_pack_bitstream(VP9_COMP *cpi, uint8_t *dest, size_t *size) {
1190   uint8_t *data = dest;
1191   size_t first_part_size, uncompressed_hdr_size;
1192   struct vp9_write_bit_buffer wb = {data, 0};
1193   struct vp9_write_bit_buffer saved_wb;
1194 
1195   write_uncompressed_header(cpi, &wb);
1196   saved_wb = wb;
1197   vp9_wb_write_literal(&wb, 0, 16);  // don't know in advance first part. size
1198 
1199   uncompressed_hdr_size = vp9_rb_bytes_written(&wb);
1200   data += uncompressed_hdr_size;
1201 
1202   vp9_compute_update_table();
1203 
1204   vp9_clear_system_state();
1205 
1206   first_part_size = write_compressed_header(cpi, data);
1207   data += first_part_size;
1208   // TODO(jbb): Figure out what to do if first_part_size > 16 bits.
1209   vp9_wb_write_literal(&saved_wb, (int)first_part_size, 16);
1210 
1211   data += encode_tiles(cpi, data);
1212 
1213   *size = data - dest;
1214 }
1215 
1216