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1 /*
2  * Copyright (c) 2016, Alliance for Open Media. All rights reserved.
3  *
4  * This source code is subject to the terms of the BSD 2 Clause License and
5  * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
6  * was not distributed with this source code in the LICENSE file, you can
7  * obtain it at www.aomedia.org/license/software. If the Alliance for Open
8  * Media Patent License 1.0 was not distributed with this source code in the
9  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
10  */
11 
12 #include <stdlib.h>
13 
14 #include "av1/common/mvref_common.h"
15 #include "av1/common/warped_motion.h"
16 
17 // Although we assign 32 bit integers, all the values are strictly under 14
18 // bits.
19 static const int div_mult[32] = { 0,    16384, 8192, 5461, 4096, 3276, 2730,
20                                   2340, 2048,  1820, 1638, 1489, 1365, 1260,
21                                   1170, 1092,  1024, 963,  910,  862,  819,
22                                   780,  744,   712,  682,  655,  630,  606,
23                                   585,  564,   546,  528 };
24 
25 // TODO(jingning): Consider the use of lookup table for (num / den)
26 // altogether.
get_mv_projection(MV * output,MV ref,int num,int den)27 static inline void get_mv_projection(MV *output, MV ref, int num, int den) {
28   den = AOMMIN(den, MAX_FRAME_DISTANCE);
29   num = num > 0 ? AOMMIN(num, MAX_FRAME_DISTANCE)
30                 : AOMMAX(num, -MAX_FRAME_DISTANCE);
31   const int mv_row =
32       ROUND_POWER_OF_TWO_SIGNED(ref.row * num * div_mult[den], 14);
33   const int mv_col =
34       ROUND_POWER_OF_TWO_SIGNED(ref.col * num * div_mult[den], 14);
35   const int clamp_max = MV_UPP - 1;
36   const int clamp_min = MV_LOW + 1;
37   output->row = (int16_t)clamp(mv_row, clamp_min, clamp_max);
38   output->col = (int16_t)clamp(mv_col, clamp_min, clamp_max);
39 }
40 
av1_copy_frame_mvs(const AV1_COMMON * const cm,const MB_MODE_INFO * const mi,int mi_row,int mi_col,int x_mis,int y_mis)41 void av1_copy_frame_mvs(const AV1_COMMON *const cm,
42                         const MB_MODE_INFO *const mi, int mi_row, int mi_col,
43                         int x_mis, int y_mis) {
44   const int frame_mvs_stride = ROUND_POWER_OF_TWO(cm->mi_params.mi_cols, 1);
45   MV_REF *frame_mvs =
46       cm->cur_frame->mvs + (mi_row >> 1) * frame_mvs_stride + (mi_col >> 1);
47   x_mis = ROUND_POWER_OF_TWO(x_mis, 1);
48   y_mis = ROUND_POWER_OF_TWO(y_mis, 1);
49   int w, h;
50 
51   for (h = 0; h < y_mis; h++) {
52     MV_REF *mv = frame_mvs;
53     for (w = 0; w < x_mis; w++) {
54       mv->ref_frame = NONE_FRAME;
55       mv->mv.as_int = 0;
56 
57       for (int idx = 0; idx < 2; ++idx) {
58         MV_REFERENCE_FRAME ref_frame = mi->ref_frame[idx];
59         if (ref_frame > INTRA_FRAME) {
60           int8_t ref_idx = cm->ref_frame_side[ref_frame];
61           if (ref_idx) continue;
62           if ((abs(mi->mv[idx].as_mv.row) > REFMVS_LIMIT) ||
63               (abs(mi->mv[idx].as_mv.col) > REFMVS_LIMIT))
64             continue;
65           mv->ref_frame = ref_frame;
66           mv->mv.as_int = mi->mv[idx].as_int;
67         }
68       }
69       mv++;
70     }
71     frame_mvs += frame_mvs_stride;
72   }
73 }
74 
add_ref_mv_candidate(const MB_MODE_INFO * const candidate,const MV_REFERENCE_FRAME rf[2],uint8_t * refmv_count,uint8_t * ref_match_count,uint8_t * newmv_count,CANDIDATE_MV * ref_mv_stack,uint16_t * ref_mv_weight,int_mv * gm_mv_candidates,const WarpedMotionParams * gm_params,uint16_t weight)75 static inline void add_ref_mv_candidate(
76     const MB_MODE_INFO *const candidate, const MV_REFERENCE_FRAME rf[2],
77     uint8_t *refmv_count, uint8_t *ref_match_count, uint8_t *newmv_count,
78     CANDIDATE_MV *ref_mv_stack, uint16_t *ref_mv_weight,
79     int_mv *gm_mv_candidates, const WarpedMotionParams *gm_params,
80     uint16_t weight) {
81   if (!is_inter_block(candidate)) return;
82   assert(weight % 2 == 0);
83   int index, ref;
84 
85   if (rf[1] == NONE_FRAME) {
86     // single reference frame
87     for (ref = 0; ref < 2; ++ref) {
88       if (candidate->ref_frame[ref] == rf[0]) {
89         const int is_gm_block =
90             is_global_mv_block(candidate, gm_params[rf[0]].wmtype);
91         const int_mv this_refmv =
92             is_gm_block ? gm_mv_candidates[0] : get_block_mv(candidate, ref);
93         for (index = 0; index < *refmv_count; ++index) {
94           if (ref_mv_stack[index].this_mv.as_int == this_refmv.as_int) {
95             ref_mv_weight[index] += weight;
96             break;
97           }
98         }
99 
100         // Add a new item to the list.
101         if (index == *refmv_count && *refmv_count < MAX_REF_MV_STACK_SIZE) {
102           ref_mv_stack[index].this_mv = this_refmv;
103           ref_mv_weight[index] = weight;
104           ++(*refmv_count);
105         }
106         if (have_newmv_in_inter_mode(candidate->mode)) ++*newmv_count;
107         ++*ref_match_count;
108       }
109     }
110   } else {
111     // compound reference frame
112     if (candidate->ref_frame[0] == rf[0] && candidate->ref_frame[1] == rf[1]) {
113       int_mv this_refmv[2];
114 
115       for (ref = 0; ref < 2; ++ref) {
116         if (is_global_mv_block(candidate, gm_params[rf[ref]].wmtype))
117           this_refmv[ref] = gm_mv_candidates[ref];
118         else
119           this_refmv[ref] = get_block_mv(candidate, ref);
120       }
121 
122       for (index = 0; index < *refmv_count; ++index) {
123         if ((ref_mv_stack[index].this_mv.as_int == this_refmv[0].as_int) &&
124             (ref_mv_stack[index].comp_mv.as_int == this_refmv[1].as_int)) {
125           ref_mv_weight[index] += weight;
126           break;
127         }
128       }
129 
130       // Add a new item to the list.
131       if (index == *refmv_count && *refmv_count < MAX_REF_MV_STACK_SIZE) {
132         ref_mv_stack[index].this_mv = this_refmv[0];
133         ref_mv_stack[index].comp_mv = this_refmv[1];
134         ref_mv_weight[index] = weight;
135         ++(*refmv_count);
136       }
137       if (have_newmv_in_inter_mode(candidate->mode)) ++*newmv_count;
138       ++*ref_match_count;
139     }
140   }
141 }
142 
scan_row_mbmi(const AV1_COMMON * cm,const MACROBLOCKD * xd,int mi_col,const MV_REFERENCE_FRAME rf[2],int row_offset,CANDIDATE_MV * ref_mv_stack,uint16_t * ref_mv_weight,uint8_t * refmv_count,uint8_t * ref_match_count,uint8_t * newmv_count,int_mv * gm_mv_candidates,int max_row_offset,int * processed_rows)143 static inline void scan_row_mbmi(const AV1_COMMON *cm, const MACROBLOCKD *xd,
144                                  int mi_col, const MV_REFERENCE_FRAME rf[2],
145                                  int row_offset, CANDIDATE_MV *ref_mv_stack,
146                                  uint16_t *ref_mv_weight, uint8_t *refmv_count,
147                                  uint8_t *ref_match_count, uint8_t *newmv_count,
148                                  int_mv *gm_mv_candidates, int max_row_offset,
149                                  int *processed_rows) {
150   int end_mi = AOMMIN(xd->width, cm->mi_params.mi_cols - mi_col);
151   end_mi = AOMMIN(end_mi, mi_size_wide[BLOCK_64X64]);
152   const int width_8x8 = mi_size_wide[BLOCK_8X8];
153   const int width_16x16 = mi_size_wide[BLOCK_16X16];
154   int col_offset = 0;
155   // TODO(jingning): Revisit this part after cb4x4 is stable.
156   if (abs(row_offset) > 1) {
157     col_offset = 1;
158     if ((mi_col & 0x01) && xd->width < width_8x8) --col_offset;
159   }
160   const int use_step_16 = (xd->width >= 16);
161   MB_MODE_INFO **const candidate_mi0 = xd->mi + row_offset * xd->mi_stride;
162 
163   for (int i = 0; i < end_mi;) {
164     const MB_MODE_INFO *const candidate = candidate_mi0[col_offset + i];
165     const int candidate_bsize = candidate->bsize;
166     const int n4_w = mi_size_wide[candidate_bsize];
167     int len = AOMMIN(xd->width, n4_w);
168     if (use_step_16)
169       len = AOMMAX(width_16x16, len);
170     else if (abs(row_offset) > 1)
171       len = AOMMAX(len, width_8x8);
172 
173     uint16_t weight = 2;
174     if (xd->width >= width_8x8 && xd->width <= n4_w) {
175       uint16_t inc = AOMMIN(-max_row_offset + row_offset + 1,
176                             mi_size_high[candidate_bsize]);
177       // Obtain range used in weight calculation.
178       weight = AOMMAX(weight, inc);
179       // Update processed rows.
180       *processed_rows = inc - row_offset - 1;
181     }
182 
183     add_ref_mv_candidate(candidate, rf, refmv_count, ref_match_count,
184                          newmv_count, ref_mv_stack, ref_mv_weight,
185                          gm_mv_candidates, cm->global_motion, len * weight);
186 
187     i += len;
188   }
189 }
190 
scan_col_mbmi(const AV1_COMMON * cm,const MACROBLOCKD * xd,int mi_row,const MV_REFERENCE_FRAME rf[2],int col_offset,CANDIDATE_MV * ref_mv_stack,uint16_t * ref_mv_weight,uint8_t * refmv_count,uint8_t * ref_match_count,uint8_t * newmv_count,int_mv * gm_mv_candidates,int max_col_offset,int * processed_cols)191 static inline void scan_col_mbmi(const AV1_COMMON *cm, const MACROBLOCKD *xd,
192                                  int mi_row, const MV_REFERENCE_FRAME rf[2],
193                                  int col_offset, CANDIDATE_MV *ref_mv_stack,
194                                  uint16_t *ref_mv_weight, uint8_t *refmv_count,
195                                  uint8_t *ref_match_count, uint8_t *newmv_count,
196                                  int_mv *gm_mv_candidates, int max_col_offset,
197                                  int *processed_cols) {
198   int end_mi = AOMMIN(xd->height, cm->mi_params.mi_rows - mi_row);
199   end_mi = AOMMIN(end_mi, mi_size_high[BLOCK_64X64]);
200   const int n8_h_8 = mi_size_high[BLOCK_8X8];
201   const int n8_h_16 = mi_size_high[BLOCK_16X16];
202   int i;
203   int row_offset = 0;
204   if (abs(col_offset) > 1) {
205     row_offset = 1;
206     if ((mi_row & 0x01) && xd->height < n8_h_8) --row_offset;
207   }
208   const int use_step_16 = (xd->height >= 16);
209 
210   for (i = 0; i < end_mi;) {
211     const MB_MODE_INFO *const candidate =
212         xd->mi[(row_offset + i) * xd->mi_stride + col_offset];
213     const int candidate_bsize = candidate->bsize;
214     const int n4_h = mi_size_high[candidate_bsize];
215     int len = AOMMIN(xd->height, n4_h);
216     if (use_step_16)
217       len = AOMMAX(n8_h_16, len);
218     else if (abs(col_offset) > 1)
219       len = AOMMAX(len, n8_h_8);
220 
221     int weight = 2;
222     if (xd->height >= n8_h_8 && xd->height <= n4_h) {
223       int inc = AOMMIN(-max_col_offset + col_offset + 1,
224                        mi_size_wide[candidate_bsize]);
225       // Obtain range used in weight calculation.
226       weight = AOMMAX(weight, inc);
227       // Update processed cols.
228       *processed_cols = inc - col_offset - 1;
229     }
230 
231     add_ref_mv_candidate(candidate, rf, refmv_count, ref_match_count,
232                          newmv_count, ref_mv_stack, ref_mv_weight,
233                          gm_mv_candidates, cm->global_motion, len * weight);
234 
235     i += len;
236   }
237 }
238 
scan_blk_mbmi(const AV1_COMMON * cm,const MACROBLOCKD * xd,const int mi_row,const int mi_col,const MV_REFERENCE_FRAME rf[2],int row_offset,int col_offset,CANDIDATE_MV * ref_mv_stack,uint16_t * ref_mv_weight,uint8_t * ref_match_count,uint8_t * newmv_count,int_mv * gm_mv_candidates,uint8_t * refmv_count)239 static inline void scan_blk_mbmi(const AV1_COMMON *cm, const MACROBLOCKD *xd,
240                                  const int mi_row, const int mi_col,
241                                  const MV_REFERENCE_FRAME rf[2], int row_offset,
242                                  int col_offset, CANDIDATE_MV *ref_mv_stack,
243                                  uint16_t *ref_mv_weight,
244                                  uint8_t *ref_match_count, uint8_t *newmv_count,
245                                  int_mv *gm_mv_candidates,
246                                  uint8_t *refmv_count) {
247   const TileInfo *const tile = &xd->tile;
248   POSITION mi_pos;
249 
250   mi_pos.row = row_offset;
251   mi_pos.col = col_offset;
252 
253   if (is_inside(tile, mi_col, mi_row, &mi_pos)) {
254     const MB_MODE_INFO *const candidate =
255         xd->mi[mi_pos.row * xd->mi_stride + mi_pos.col];
256     const int len = mi_size_wide[BLOCK_8X8];
257 
258     add_ref_mv_candidate(candidate, rf, refmv_count, ref_match_count,
259                          newmv_count, ref_mv_stack, ref_mv_weight,
260                          gm_mv_candidates, cm->global_motion, 2 * len);
261   }  // Analyze a single 8x8 block motion information.
262 }
263 
has_top_right(const AV1_COMMON * cm,const MACROBLOCKD * xd,int mi_row,int mi_col,int bs)264 static int has_top_right(const AV1_COMMON *cm, const MACROBLOCKD *xd,
265                          int mi_row, int mi_col, int bs) {
266   const int sb_mi_size = mi_size_wide[cm->seq_params->sb_size];
267   const int mask_row = mi_row & (sb_mi_size - 1);
268   const int mask_col = mi_col & (sb_mi_size - 1);
269 
270   if (bs > mi_size_wide[BLOCK_64X64]) return 0;
271 
272   // In a split partition all apart from the bottom right has a top right
273   int has_tr = !((mask_row & bs) && (mask_col & bs));
274 
275   // bs > 0 and bs is a power of 2
276   assert(bs > 0 && !(bs & (bs - 1)));
277 
278   // For each 4x4 group of blocks, when the bottom right is decoded the blocks
279   // to the right have not been decoded therefore the bottom right does
280   // not have a top right
281   while (bs < sb_mi_size) {
282     if (mask_col & bs) {
283       if ((mask_col & (2 * bs)) && (mask_row & (2 * bs))) {
284         has_tr = 0;
285         break;
286       }
287     } else {
288       break;
289     }
290     bs <<= 1;
291   }
292 
293   // In a VERTICAL or VERTICAL_4 partition, all partition before the last one
294   // always have a top right (as the block above will have been decoded).
295   if (xd->width < xd->height) {
296     if (!xd->is_last_vertical_rect) has_tr = 1;
297   }
298 
299   // In a HORIZONTAL or HORIZONTAL_4 partition, partitions after the first one
300   // never have a top right (as the block to the right won't have been decoded).
301   if (xd->width > xd->height) {
302     if (!xd->is_first_horizontal_rect) has_tr = 0;
303   }
304 
305   // The bottom left square of a Vertical A (in the old format) does
306   // not have a top right as it is decoded before the right hand
307   // rectangle of the partition
308   if (xd->mi[0]->partition == PARTITION_VERT_A) {
309     if (xd->width == xd->height)
310       if (mask_row & bs) has_tr = 0;
311   }
312 
313   return has_tr;
314 }
315 
check_sb_border(const int mi_row,const int mi_col,const int row_offset,const int col_offset)316 static int check_sb_border(const int mi_row, const int mi_col,
317                            const int row_offset, const int col_offset) {
318   const int sb_mi_size = mi_size_wide[BLOCK_64X64];
319   const int row = mi_row & (sb_mi_size - 1);
320   const int col = mi_col & (sb_mi_size - 1);
321 
322   if (row + row_offset < 0 || row + row_offset >= sb_mi_size ||
323       col + col_offset < 0 || col + col_offset >= sb_mi_size)
324     return 0;
325 
326   return 1;
327 }
328 
add_tpl_ref_mv(const AV1_COMMON * cm,const MACROBLOCKD * xd,int mi_row,int mi_col,MV_REFERENCE_FRAME ref_frame,int blk_row,int blk_col,int_mv * gm_mv_candidates,uint8_t * const refmv_count,CANDIDATE_MV ref_mv_stack[MAX_REF_MV_STACK_SIZE],uint16_t ref_mv_weight[MAX_REF_MV_STACK_SIZE],int16_t * mode_context)329 static int add_tpl_ref_mv(const AV1_COMMON *cm, const MACROBLOCKD *xd,
330                           int mi_row, int mi_col, MV_REFERENCE_FRAME ref_frame,
331                           int blk_row, int blk_col, int_mv *gm_mv_candidates,
332                           uint8_t *const refmv_count,
333                           CANDIDATE_MV ref_mv_stack[MAX_REF_MV_STACK_SIZE],
334                           uint16_t ref_mv_weight[MAX_REF_MV_STACK_SIZE],
335                           int16_t *mode_context) {
336   POSITION mi_pos;
337   mi_pos.row = (mi_row & 0x01) ? blk_row : blk_row + 1;
338   mi_pos.col = (mi_col & 0x01) ? blk_col : blk_col + 1;
339 
340   if (!is_inside(&xd->tile, mi_col, mi_row, &mi_pos)) return 0;
341 
342   const TPL_MV_REF *prev_frame_mvs =
343       cm->tpl_mvs +
344       ((mi_row + mi_pos.row) >> 1) * (cm->mi_params.mi_stride >> 1) +
345       ((mi_col + mi_pos.col) >> 1);
346   if (prev_frame_mvs->mfmv0.as_int == INVALID_MV) return 0;
347 
348   MV_REFERENCE_FRAME rf[2];
349   av1_set_ref_frame(rf, ref_frame);
350 
351   const uint16_t weight_unit = 1;  // mi_size_wide[BLOCK_8X8];
352   const int cur_frame_index = cm->cur_frame->order_hint;
353   const RefCntBuffer *const buf_0 = get_ref_frame_buf(cm, rf[0]);
354   const int frame0_index = buf_0->order_hint;
355   const int cur_offset_0 = get_relative_dist(&cm->seq_params->order_hint_info,
356                                              cur_frame_index, frame0_index);
357   int idx;
358   const int allow_high_precision_mv = cm->features.allow_high_precision_mv;
359   const int force_integer_mv = cm->features.cur_frame_force_integer_mv;
360 
361   int_mv this_refmv;
362   get_mv_projection(&this_refmv.as_mv, prev_frame_mvs->mfmv0.as_mv,
363                     cur_offset_0, prev_frame_mvs->ref_frame_offset);
364   lower_mv_precision(&this_refmv.as_mv, allow_high_precision_mv,
365                      force_integer_mv);
366 
367   if (rf[1] == NONE_FRAME) {
368     if (blk_row == 0 && blk_col == 0) {
369       if (abs(this_refmv.as_mv.row - gm_mv_candidates[0].as_mv.row) >= 16 ||
370           abs(this_refmv.as_mv.col - gm_mv_candidates[0].as_mv.col) >= 16)
371         mode_context[ref_frame] |= (1 << GLOBALMV_OFFSET);
372     }
373 
374     for (idx = 0; idx < *refmv_count; ++idx)
375       if (this_refmv.as_int == ref_mv_stack[idx].this_mv.as_int) break;
376 
377     if (idx < *refmv_count) ref_mv_weight[idx] += 2 * weight_unit;
378 
379     if (idx == *refmv_count && *refmv_count < MAX_REF_MV_STACK_SIZE) {
380       ref_mv_stack[idx].this_mv.as_int = this_refmv.as_int;
381       ref_mv_weight[idx] = 2 * weight_unit;
382       ++(*refmv_count);
383     }
384   } else {
385     // Process compound inter mode
386     const RefCntBuffer *const buf_1 = get_ref_frame_buf(cm, rf[1]);
387     const int frame1_index = buf_1->order_hint;
388     const int cur_offset_1 = get_relative_dist(&cm->seq_params->order_hint_info,
389                                                cur_frame_index, frame1_index);
390     int_mv comp_refmv;
391     get_mv_projection(&comp_refmv.as_mv, prev_frame_mvs->mfmv0.as_mv,
392                       cur_offset_1, prev_frame_mvs->ref_frame_offset);
393     lower_mv_precision(&comp_refmv.as_mv, allow_high_precision_mv,
394                        force_integer_mv);
395 
396     if (blk_row == 0 && blk_col == 0) {
397       if (abs(this_refmv.as_mv.row - gm_mv_candidates[0].as_mv.row) >= 16 ||
398           abs(this_refmv.as_mv.col - gm_mv_candidates[0].as_mv.col) >= 16 ||
399           abs(comp_refmv.as_mv.row - gm_mv_candidates[1].as_mv.row) >= 16 ||
400           abs(comp_refmv.as_mv.col - gm_mv_candidates[1].as_mv.col) >= 16)
401         mode_context[ref_frame] |= (1 << GLOBALMV_OFFSET);
402     }
403 
404     for (idx = 0; idx < *refmv_count; ++idx) {
405       if (this_refmv.as_int == ref_mv_stack[idx].this_mv.as_int &&
406           comp_refmv.as_int == ref_mv_stack[idx].comp_mv.as_int)
407         break;
408     }
409 
410     if (idx < *refmv_count) ref_mv_weight[idx] += 2 * weight_unit;
411 
412     if (idx == *refmv_count && *refmv_count < MAX_REF_MV_STACK_SIZE) {
413       ref_mv_stack[idx].this_mv.as_int = this_refmv.as_int;
414       ref_mv_stack[idx].comp_mv.as_int = comp_refmv.as_int;
415       ref_mv_weight[idx] = 2 * weight_unit;
416       ++(*refmv_count);
417     }
418   }
419 
420   return 1;
421 }
422 
process_compound_ref_mv_candidate(const MB_MODE_INFO * const candidate,const AV1_COMMON * const cm,const MV_REFERENCE_FRAME * const rf,int_mv ref_id[2][2],int ref_id_count[2],int_mv ref_diff[2][2],int ref_diff_count[2])423 static inline void process_compound_ref_mv_candidate(
424     const MB_MODE_INFO *const candidate, const AV1_COMMON *const cm,
425     const MV_REFERENCE_FRAME *const rf, int_mv ref_id[2][2],
426     int ref_id_count[2], int_mv ref_diff[2][2], int ref_diff_count[2]) {
427   for (int rf_idx = 0; rf_idx < 2; ++rf_idx) {
428     MV_REFERENCE_FRAME can_rf = candidate->ref_frame[rf_idx];
429 
430     for (int cmp_idx = 0; cmp_idx < 2; ++cmp_idx) {
431       if (can_rf == rf[cmp_idx] && ref_id_count[cmp_idx] < 2) {
432         ref_id[cmp_idx][ref_id_count[cmp_idx]] = candidate->mv[rf_idx];
433         ++ref_id_count[cmp_idx];
434       } else if (can_rf > INTRA_FRAME && ref_diff_count[cmp_idx] < 2) {
435         int_mv this_mv = candidate->mv[rf_idx];
436         if (cm->ref_frame_sign_bias[can_rf] !=
437             cm->ref_frame_sign_bias[rf[cmp_idx]]) {
438           this_mv.as_mv.row = -this_mv.as_mv.row;
439           this_mv.as_mv.col = -this_mv.as_mv.col;
440         }
441         ref_diff[cmp_idx][ref_diff_count[cmp_idx]] = this_mv;
442         ++ref_diff_count[cmp_idx];
443       }
444     }
445   }
446 }
447 
process_single_ref_mv_candidate(const MB_MODE_INFO * const candidate,const AV1_COMMON * const cm,MV_REFERENCE_FRAME ref_frame,uint8_t * const refmv_count,CANDIDATE_MV ref_mv_stack[MAX_REF_MV_STACK_SIZE],uint16_t ref_mv_weight[MAX_REF_MV_STACK_SIZE])448 static inline void process_single_ref_mv_candidate(
449     const MB_MODE_INFO *const candidate, const AV1_COMMON *const cm,
450     MV_REFERENCE_FRAME ref_frame, uint8_t *const refmv_count,
451     CANDIDATE_MV ref_mv_stack[MAX_REF_MV_STACK_SIZE],
452     uint16_t ref_mv_weight[MAX_REF_MV_STACK_SIZE]) {
453   for (int rf_idx = 0; rf_idx < 2; ++rf_idx) {
454     if (candidate->ref_frame[rf_idx] > INTRA_FRAME) {
455       int_mv this_mv = candidate->mv[rf_idx];
456       if (cm->ref_frame_sign_bias[candidate->ref_frame[rf_idx]] !=
457           cm->ref_frame_sign_bias[ref_frame]) {
458         this_mv.as_mv.row = -this_mv.as_mv.row;
459         this_mv.as_mv.col = -this_mv.as_mv.col;
460       }
461       int stack_idx;
462       for (stack_idx = 0; stack_idx < *refmv_count; ++stack_idx) {
463         const int_mv stack_mv = ref_mv_stack[stack_idx].this_mv;
464         if (this_mv.as_int == stack_mv.as_int) break;
465       }
466 
467       if (stack_idx == *refmv_count) {
468         ref_mv_stack[stack_idx].this_mv = this_mv;
469 
470         // TODO(jingning): Set an arbitrary small number here. The weight
471         // doesn't matter as long as it is properly initialized.
472         ref_mv_weight[stack_idx] = 2;
473         ++(*refmv_count);
474       }
475     }
476   }
477 }
478 
setup_ref_mv_list(const AV1_COMMON * cm,const MACROBLOCKD * xd,MV_REFERENCE_FRAME ref_frame,uint8_t * const refmv_count,CANDIDATE_MV ref_mv_stack[MAX_REF_MV_STACK_SIZE],uint16_t ref_mv_weight[MAX_REF_MV_STACK_SIZE],int_mv mv_ref_list[MAX_MV_REF_CANDIDATES],int_mv * gm_mv_candidates,int mi_row,int mi_col,int16_t * mode_context)479 static inline void setup_ref_mv_list(
480     const AV1_COMMON *cm, const MACROBLOCKD *xd, MV_REFERENCE_FRAME ref_frame,
481     uint8_t *const refmv_count,
482     CANDIDATE_MV ref_mv_stack[MAX_REF_MV_STACK_SIZE],
483     uint16_t ref_mv_weight[MAX_REF_MV_STACK_SIZE],
484     int_mv mv_ref_list[MAX_MV_REF_CANDIDATES], int_mv *gm_mv_candidates,
485     int mi_row, int mi_col, int16_t *mode_context) {
486   const int bs = AOMMAX(xd->width, xd->height);
487   const int has_tr = has_top_right(cm, xd, mi_row, mi_col, bs);
488   MV_REFERENCE_FRAME rf[2];
489 
490   const TileInfo *const tile = &xd->tile;
491   int max_row_offset = 0, max_col_offset = 0;
492   const int row_adj = (xd->height < mi_size_high[BLOCK_8X8]) && (mi_row & 0x01);
493   const int col_adj = (xd->width < mi_size_wide[BLOCK_8X8]) && (mi_col & 0x01);
494   int processed_rows = 0;
495   int processed_cols = 0;
496 
497   av1_set_ref_frame(rf, ref_frame);
498   mode_context[ref_frame] = 0;
499   *refmv_count = 0;
500 
501   // Find valid maximum row/col offset.
502   if (xd->up_available) {
503     max_row_offset = -(MVREF_ROW_COLS << 1) + row_adj;
504 
505     if (xd->height < mi_size_high[BLOCK_8X8])
506       max_row_offset = -(2 << 1) + row_adj;
507 
508     max_row_offset = find_valid_row_offset(tile, mi_row, max_row_offset);
509   }
510 
511   if (xd->left_available) {
512     max_col_offset = -(MVREF_ROW_COLS << 1) + col_adj;
513 
514     if (xd->width < mi_size_wide[BLOCK_8X8])
515       max_col_offset = -(2 << 1) + col_adj;
516 
517     max_col_offset = find_valid_col_offset(tile, mi_col, max_col_offset);
518   }
519 
520   uint8_t col_match_count = 0;
521   uint8_t row_match_count = 0;
522   uint8_t newmv_count = 0;
523 
524   // Scan the first above row mode info. row_offset = -1;
525   if (abs(max_row_offset) >= 1)
526     scan_row_mbmi(cm, xd, mi_col, rf, -1, ref_mv_stack, ref_mv_weight,
527                   refmv_count, &row_match_count, &newmv_count, gm_mv_candidates,
528                   max_row_offset, &processed_rows);
529   // Scan the first left column mode info. col_offset = -1;
530   if (abs(max_col_offset) >= 1)
531     scan_col_mbmi(cm, xd, mi_row, rf, -1, ref_mv_stack, ref_mv_weight,
532                   refmv_count, &col_match_count, &newmv_count, gm_mv_candidates,
533                   max_col_offset, &processed_cols);
534   // Check top-right boundary
535   if (has_tr)
536     scan_blk_mbmi(cm, xd, mi_row, mi_col, rf, -1, xd->width, ref_mv_stack,
537                   ref_mv_weight, &row_match_count, &newmv_count,
538                   gm_mv_candidates, refmv_count);
539 
540   const uint8_t nearest_match = (row_match_count > 0) + (col_match_count > 0);
541   const uint8_t nearest_refmv_count = *refmv_count;
542 
543   // TODO(yunqing): for comp_search, do it for all 3 cases.
544   for (int idx = 0; idx < nearest_refmv_count; ++idx)
545     ref_mv_weight[idx] += REF_CAT_LEVEL;
546 
547   if (cm->features.allow_ref_frame_mvs) {
548     int is_available = 0;
549     const int voffset = AOMMAX(mi_size_high[BLOCK_8X8], xd->height);
550     const int hoffset = AOMMAX(mi_size_wide[BLOCK_8X8], xd->width);
551     const int blk_row_end = AOMMIN(xd->height, mi_size_high[BLOCK_64X64]);
552     const int blk_col_end = AOMMIN(xd->width, mi_size_wide[BLOCK_64X64]);
553 
554     const int tpl_sample_pos[3][2] = {
555       { voffset, -2 },
556       { voffset, hoffset },
557       { voffset - 2, hoffset },
558     };
559     const int allow_extension = (xd->height >= mi_size_high[BLOCK_8X8]) &&
560                                 (xd->height < mi_size_high[BLOCK_64X64]) &&
561                                 (xd->width >= mi_size_wide[BLOCK_8X8]) &&
562                                 (xd->width < mi_size_wide[BLOCK_64X64]);
563 
564     const int step_h = (xd->height >= mi_size_high[BLOCK_64X64])
565                            ? mi_size_high[BLOCK_16X16]
566                            : mi_size_high[BLOCK_8X8];
567     const int step_w = (xd->width >= mi_size_wide[BLOCK_64X64])
568                            ? mi_size_wide[BLOCK_16X16]
569                            : mi_size_wide[BLOCK_8X8];
570 
571     for (int blk_row = 0; blk_row < blk_row_end; blk_row += step_h) {
572       for (int blk_col = 0; blk_col < blk_col_end; blk_col += step_w) {
573         int ret = add_tpl_ref_mv(cm, xd, mi_row, mi_col, ref_frame, blk_row,
574                                  blk_col, gm_mv_candidates, refmv_count,
575                                  ref_mv_stack, ref_mv_weight, mode_context);
576         if (blk_row == 0 && blk_col == 0) is_available = ret;
577       }
578     }
579 
580     if (is_available == 0) mode_context[ref_frame] |= (1 << GLOBALMV_OFFSET);
581 
582     for (int i = 0; i < 3 && allow_extension; ++i) {
583       const int blk_row = tpl_sample_pos[i][0];
584       const int blk_col = tpl_sample_pos[i][1];
585 
586       if (!check_sb_border(mi_row, mi_col, blk_row, blk_col)) continue;
587       add_tpl_ref_mv(cm, xd, mi_row, mi_col, ref_frame, blk_row, blk_col,
588                      gm_mv_candidates, refmv_count, ref_mv_stack, ref_mv_weight,
589                      mode_context);
590     }
591   }
592 
593   uint8_t dummy_newmv_count = 0;
594 
595   // Scan the second outer area.
596   scan_blk_mbmi(cm, xd, mi_row, mi_col, rf, -1, -1, ref_mv_stack, ref_mv_weight,
597                 &row_match_count, &dummy_newmv_count, gm_mv_candidates,
598                 refmv_count);
599 
600   for (int idx = 2; idx <= MVREF_ROW_COLS; ++idx) {
601     const int row_offset = -(idx << 1) + 1 + row_adj;
602     const int col_offset = -(idx << 1) + 1 + col_adj;
603 
604     if (abs(row_offset) <= abs(max_row_offset) &&
605         abs(row_offset) > processed_rows)
606       scan_row_mbmi(cm, xd, mi_col, rf, row_offset, ref_mv_stack, ref_mv_weight,
607                     refmv_count, &row_match_count, &dummy_newmv_count,
608                     gm_mv_candidates, max_row_offset, &processed_rows);
609 
610     if (abs(col_offset) <= abs(max_col_offset) &&
611         abs(col_offset) > processed_cols)
612       scan_col_mbmi(cm, xd, mi_row, rf, col_offset, ref_mv_stack, ref_mv_weight,
613                     refmv_count, &col_match_count, &dummy_newmv_count,
614                     gm_mv_candidates, max_col_offset, &processed_cols);
615   }
616 
617   const uint8_t ref_match_count = (row_match_count > 0) + (col_match_count > 0);
618 
619   switch (nearest_match) {
620     case 0:
621       if (ref_match_count >= 1) mode_context[ref_frame] |= 1;
622       if (ref_match_count == 1)
623         mode_context[ref_frame] |= (1 << REFMV_OFFSET);
624       else if (ref_match_count >= 2)
625         mode_context[ref_frame] |= (2 << REFMV_OFFSET);
626       break;
627     case 1:
628       mode_context[ref_frame] |= (newmv_count > 0) ? 2 : 3;
629       if (ref_match_count == 1)
630         mode_context[ref_frame] |= (3 << REFMV_OFFSET);
631       else if (ref_match_count >= 2)
632         mode_context[ref_frame] |= (4 << REFMV_OFFSET);
633       break;
634     case 2:
635     default:
636       if (newmv_count >= 1)
637         mode_context[ref_frame] |= 4;
638       else
639         mode_context[ref_frame] |= 5;
640 
641       mode_context[ref_frame] |= (5 << REFMV_OFFSET);
642       break;
643   }
644 
645   // Rank the likelihood and assign nearest and near mvs.
646   int len = nearest_refmv_count;
647   while (len > 0) {
648     int nr_len = 0;
649     for (int idx = 1; idx < len; ++idx) {
650       if (ref_mv_weight[idx - 1] < ref_mv_weight[idx]) {
651         const CANDIDATE_MV tmp_mv = ref_mv_stack[idx - 1];
652         const uint16_t tmp_ref_mv_weight = ref_mv_weight[idx - 1];
653         ref_mv_stack[idx - 1] = ref_mv_stack[idx];
654         ref_mv_stack[idx] = tmp_mv;
655         ref_mv_weight[idx - 1] = ref_mv_weight[idx];
656         ref_mv_weight[idx] = tmp_ref_mv_weight;
657         nr_len = idx;
658       }
659     }
660     len = nr_len;
661   }
662 
663   len = *refmv_count;
664   while (len > nearest_refmv_count) {
665     int nr_len = nearest_refmv_count;
666     for (int idx = nearest_refmv_count + 1; idx < len; ++idx) {
667       if (ref_mv_weight[idx - 1] < ref_mv_weight[idx]) {
668         const CANDIDATE_MV tmp_mv = ref_mv_stack[idx - 1];
669         const uint16_t tmp_ref_mv_weight = ref_mv_weight[idx - 1];
670         ref_mv_stack[idx - 1] = ref_mv_stack[idx];
671         ref_mv_stack[idx] = tmp_mv;
672         ref_mv_weight[idx - 1] = ref_mv_weight[idx];
673         ref_mv_weight[idx] = tmp_ref_mv_weight;
674         nr_len = idx;
675       }
676     }
677     len = nr_len;
678   }
679 
680   int mi_width = AOMMIN(mi_size_wide[BLOCK_64X64], xd->width);
681   mi_width = AOMMIN(mi_width, cm->mi_params.mi_cols - mi_col);
682   int mi_height = AOMMIN(mi_size_high[BLOCK_64X64], xd->height);
683   mi_height = AOMMIN(mi_height, cm->mi_params.mi_rows - mi_row);
684   const int mi_size = AOMMIN(mi_width, mi_height);
685   if (rf[1] > NONE_FRAME) {
686     // TODO(jingning, yunqing): Refactor and consolidate the compound and
687     // single reference frame modes. Reduce unnecessary redundancy.
688     if (*refmv_count < MAX_MV_REF_CANDIDATES) {
689       int_mv ref_id[2][2], ref_diff[2][2];
690       int ref_id_count[2] = { 0 }, ref_diff_count[2] = { 0 };
691 
692       for (int idx = 0; abs(max_row_offset) >= 1 && idx < mi_size;) {
693         const MB_MODE_INFO *const candidate = xd->mi[-xd->mi_stride + idx];
694         process_compound_ref_mv_candidate(
695             candidate, cm, rf, ref_id, ref_id_count, ref_diff, ref_diff_count);
696         idx += mi_size_wide[candidate->bsize];
697       }
698 
699       for (int idx = 0; abs(max_col_offset) >= 1 && idx < mi_size;) {
700         const MB_MODE_INFO *const candidate = xd->mi[idx * xd->mi_stride - 1];
701         process_compound_ref_mv_candidate(
702             candidate, cm, rf, ref_id, ref_id_count, ref_diff, ref_diff_count);
703         idx += mi_size_high[candidate->bsize];
704       }
705 
706       // Build up the compound mv predictor
707       int_mv comp_list[MAX_MV_REF_CANDIDATES][2];
708 
709       for (int idx = 0; idx < 2; ++idx) {
710         int comp_idx = 0;
711         for (int list_idx = 0;
712              list_idx < ref_id_count[idx] && comp_idx < MAX_MV_REF_CANDIDATES;
713              ++list_idx, ++comp_idx)
714           comp_list[comp_idx][idx] = ref_id[idx][list_idx];
715         for (int list_idx = 0;
716              list_idx < ref_diff_count[idx] && comp_idx < MAX_MV_REF_CANDIDATES;
717              ++list_idx, ++comp_idx)
718           comp_list[comp_idx][idx] = ref_diff[idx][list_idx];
719         for (; comp_idx < MAX_MV_REF_CANDIDATES; ++comp_idx)
720           comp_list[comp_idx][idx] = gm_mv_candidates[idx];
721       }
722 
723       if (*refmv_count) {
724         assert(*refmv_count == 1);
725         if (comp_list[0][0].as_int == ref_mv_stack[0].this_mv.as_int &&
726             comp_list[0][1].as_int == ref_mv_stack[0].comp_mv.as_int) {
727           ref_mv_stack[*refmv_count].this_mv = comp_list[1][0];
728           ref_mv_stack[*refmv_count].comp_mv = comp_list[1][1];
729         } else {
730           ref_mv_stack[*refmv_count].this_mv = comp_list[0][0];
731           ref_mv_stack[*refmv_count].comp_mv = comp_list[0][1];
732         }
733         ref_mv_weight[*refmv_count] = 2;
734         ++*refmv_count;
735       } else {
736         for (int idx = 0; idx < MAX_MV_REF_CANDIDATES; ++idx) {
737           ref_mv_stack[*refmv_count].this_mv = comp_list[idx][0];
738           ref_mv_stack[*refmv_count].comp_mv = comp_list[idx][1];
739           ref_mv_weight[*refmv_count] = 2;
740           ++*refmv_count;
741         }
742       }
743     }
744 
745     assert(*refmv_count >= 2);
746 
747     for (int idx = 0; idx < *refmv_count; ++idx) {
748       clamp_mv_ref(&ref_mv_stack[idx].this_mv.as_mv, xd->width << MI_SIZE_LOG2,
749                    xd->height << MI_SIZE_LOG2, xd);
750       clamp_mv_ref(&ref_mv_stack[idx].comp_mv.as_mv, xd->width << MI_SIZE_LOG2,
751                    xd->height << MI_SIZE_LOG2, xd);
752     }
753   } else {
754     // Handle single reference frame extension
755     for (int idx = 0; abs(max_row_offset) >= 1 && idx < mi_size &&
756                       *refmv_count < MAX_MV_REF_CANDIDATES;) {
757       const MB_MODE_INFO *const candidate = xd->mi[-xd->mi_stride + idx];
758       process_single_ref_mv_candidate(candidate, cm, ref_frame, refmv_count,
759                                       ref_mv_stack, ref_mv_weight);
760       idx += mi_size_wide[candidate->bsize];
761     }
762 
763     for (int idx = 0; abs(max_col_offset) >= 1 && idx < mi_size &&
764                       *refmv_count < MAX_MV_REF_CANDIDATES;) {
765       const MB_MODE_INFO *const candidate = xd->mi[idx * xd->mi_stride - 1];
766       process_single_ref_mv_candidate(candidate, cm, ref_frame, refmv_count,
767                                       ref_mv_stack, ref_mv_weight);
768       idx += mi_size_high[candidate->bsize];
769     }
770 
771     for (int idx = 0; idx < *refmv_count; ++idx) {
772       clamp_mv_ref(&ref_mv_stack[idx].this_mv.as_mv, xd->width << MI_SIZE_LOG2,
773                    xd->height << MI_SIZE_LOG2, xd);
774     }
775 
776     if (mv_ref_list != NULL) {
777       for (int idx = *refmv_count; idx < MAX_MV_REF_CANDIDATES; ++idx)
778         mv_ref_list[idx].as_int = gm_mv_candidates[0].as_int;
779 
780       for (int idx = 0; idx < AOMMIN(MAX_MV_REF_CANDIDATES, *refmv_count);
781            ++idx) {
782         mv_ref_list[idx].as_int = ref_mv_stack[idx].this_mv.as_int;
783       }
784     }
785   }
786 }
787 
av1_find_mv_refs(const AV1_COMMON * cm,const MACROBLOCKD * xd,MB_MODE_INFO * mi,MV_REFERENCE_FRAME ref_frame,uint8_t ref_mv_count[MODE_CTX_REF_FRAMES],CANDIDATE_MV ref_mv_stack[][MAX_REF_MV_STACK_SIZE],uint16_t ref_mv_weight[][MAX_REF_MV_STACK_SIZE],int_mv mv_ref_list[][MAX_MV_REF_CANDIDATES],int_mv * global_mvs,int16_t * mode_context)788 void av1_find_mv_refs(const AV1_COMMON *cm, const MACROBLOCKD *xd,
789                       MB_MODE_INFO *mi, MV_REFERENCE_FRAME ref_frame,
790                       uint8_t ref_mv_count[MODE_CTX_REF_FRAMES],
791                       CANDIDATE_MV ref_mv_stack[][MAX_REF_MV_STACK_SIZE],
792                       uint16_t ref_mv_weight[][MAX_REF_MV_STACK_SIZE],
793                       int_mv mv_ref_list[][MAX_MV_REF_CANDIDATES],
794                       int_mv *global_mvs, int16_t *mode_context) {
795   const int mi_row = xd->mi_row;
796   const int mi_col = xd->mi_col;
797   int_mv gm_mv[2];
798 
799   if (ref_frame == INTRA_FRAME) {
800     gm_mv[0].as_int = gm_mv[1].as_int = 0;
801     if (global_mvs != NULL) {
802       global_mvs[ref_frame].as_int = INVALID_MV;
803     }
804   } else {
805     const BLOCK_SIZE bsize = mi->bsize;
806     const int allow_high_precision_mv = cm->features.allow_high_precision_mv;
807     const int force_integer_mv = cm->features.cur_frame_force_integer_mv;
808     if (ref_frame < REF_FRAMES) {
809       gm_mv[0] = gm_get_motion_vector(&cm->global_motion[ref_frame],
810                                       allow_high_precision_mv, bsize, mi_col,
811                                       mi_row, force_integer_mv);
812       gm_mv[1].as_int = 0;
813       if (global_mvs != NULL) global_mvs[ref_frame] = gm_mv[0];
814     } else {
815       MV_REFERENCE_FRAME rf[2];
816       av1_set_ref_frame(rf, ref_frame);
817       gm_mv[0] = gm_get_motion_vector(&cm->global_motion[rf[0]],
818                                       allow_high_precision_mv, bsize, mi_col,
819                                       mi_row, force_integer_mv);
820       gm_mv[1] = gm_get_motion_vector(&cm->global_motion[rf[1]],
821                                       allow_high_precision_mv, bsize, mi_col,
822                                       mi_row, force_integer_mv);
823     }
824   }
825 
826   setup_ref_mv_list(cm, xd, ref_frame, &ref_mv_count[ref_frame],
827                     ref_mv_stack[ref_frame], ref_mv_weight[ref_frame],
828                     mv_ref_list ? mv_ref_list[ref_frame] : NULL, gm_mv, mi_row,
829                     mi_col, mode_context);
830 }
831 
av1_find_best_ref_mvs(int allow_hp,int_mv * mvlist,int_mv * nearest_mv,int_mv * near_mv,int is_integer)832 void av1_find_best_ref_mvs(int allow_hp, int_mv *mvlist, int_mv *nearest_mv,
833                            int_mv *near_mv, int is_integer) {
834   int i;
835   // Make sure all the candidates are properly clamped etc
836   for (i = 0; i < MAX_MV_REF_CANDIDATES; ++i) {
837     lower_mv_precision(&mvlist[i].as_mv, allow_hp, is_integer);
838   }
839   *nearest_mv = mvlist[0];
840   *near_mv = mvlist[1];
841 }
842 
av1_setup_frame_buf_refs(AV1_COMMON * cm)843 void av1_setup_frame_buf_refs(AV1_COMMON *cm) {
844   cm->cur_frame->order_hint = cm->current_frame.order_hint;
845   cm->cur_frame->display_order_hint = cm->current_frame.display_order_hint;
846   cm->cur_frame->pyramid_level = cm->current_frame.pyramid_level;
847   MV_REFERENCE_FRAME ref_frame;
848   for (ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ++ref_frame) {
849     const RefCntBuffer *const buf = get_ref_frame_buf(cm, ref_frame);
850     if (buf != NULL) {
851       cm->cur_frame->ref_order_hints[ref_frame - LAST_FRAME] = buf->order_hint;
852       cm->cur_frame->ref_display_order_hint[ref_frame - LAST_FRAME] =
853           buf->display_order_hint;
854     }
855   }
856 }
857 
av1_setup_frame_sign_bias(AV1_COMMON * cm)858 void av1_setup_frame_sign_bias(AV1_COMMON *cm) {
859   MV_REFERENCE_FRAME ref_frame;
860   for (ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ++ref_frame) {
861     const RefCntBuffer *const buf = get_ref_frame_buf(cm, ref_frame);
862     if (cm->seq_params->order_hint_info.enable_order_hint && buf != NULL) {
863       const int ref_order_hint = buf->order_hint;
864       cm->ref_frame_sign_bias[ref_frame] =
865           (get_relative_dist(&cm->seq_params->order_hint_info, ref_order_hint,
866                              (int)cm->current_frame.order_hint) <= 0)
867               ? 0
868               : 1;
869     } else {
870       cm->ref_frame_sign_bias[ref_frame] = 0;
871     }
872   }
873 }
874 
875 #define MAX_OFFSET_WIDTH 64
876 #define MAX_OFFSET_HEIGHT 0
877 
get_block_position(AV1_COMMON * cm,int * mi_r,int * mi_c,int blk_row,int blk_col,MV mv,int sign_bias)878 static int get_block_position(AV1_COMMON *cm, int *mi_r, int *mi_c, int blk_row,
879                               int blk_col, MV mv, int sign_bias) {
880   const int base_blk_row = (blk_row >> 3) << 3;
881   const int base_blk_col = (blk_col >> 3) << 3;
882 
883   const int row_offset = (mv.row >= 0) ? (mv.row >> (4 + MI_SIZE_LOG2))
884                                        : -((-mv.row) >> (4 + MI_SIZE_LOG2));
885 
886   const int col_offset = (mv.col >= 0) ? (mv.col >> (4 + MI_SIZE_LOG2))
887                                        : -((-mv.col) >> (4 + MI_SIZE_LOG2));
888 
889   const int row =
890       (sign_bias == 1) ? blk_row - row_offset : blk_row + row_offset;
891   const int col =
892       (sign_bias == 1) ? blk_col - col_offset : blk_col + col_offset;
893 
894   if (row < 0 || row >= (cm->mi_params.mi_rows >> 1) || col < 0 ||
895       col >= (cm->mi_params.mi_cols >> 1))
896     return 0;
897 
898   if (row < base_blk_row - (MAX_OFFSET_HEIGHT >> 3) ||
899       row >= base_blk_row + 8 + (MAX_OFFSET_HEIGHT >> 3) ||
900       col < base_blk_col - (MAX_OFFSET_WIDTH >> 3) ||
901       col >= base_blk_col + 8 + (MAX_OFFSET_WIDTH >> 3))
902     return 0;
903 
904   *mi_r = row;
905   *mi_c = col;
906 
907   return 1;
908 }
909 
910 // Note: motion_filed_projection finds motion vectors of current frame's
911 // reference frame, and projects them to current frame. To make it clear,
912 // let's call current frame's reference frame as start frame.
913 // Call Start frame's reference frames as reference frames.
914 // Call ref_offset as frame distances between start frame and its reference
915 // frames.
motion_field_projection(AV1_COMMON * cm,MV_REFERENCE_FRAME start_frame,int dir)916 static int motion_field_projection(AV1_COMMON *cm,
917                                    MV_REFERENCE_FRAME start_frame, int dir) {
918   TPL_MV_REF *tpl_mvs_base = cm->tpl_mvs;
919   int ref_offset[REF_FRAMES] = { 0 };
920 
921   const RefCntBuffer *const start_frame_buf =
922       get_ref_frame_buf(cm, start_frame);
923   if (start_frame_buf == NULL) return 0;
924 
925   if (start_frame_buf->frame_type == KEY_FRAME ||
926       start_frame_buf->frame_type == INTRA_ONLY_FRAME)
927     return 0;
928 
929   if (start_frame_buf->mi_rows != cm->mi_params.mi_rows ||
930       start_frame_buf->mi_cols != cm->mi_params.mi_cols)
931     return 0;
932 
933   const int start_frame_order_hint = start_frame_buf->order_hint;
934   const unsigned int *const ref_order_hints =
935       &start_frame_buf->ref_order_hints[0];
936   const int cur_order_hint = cm->cur_frame->order_hint;
937   int start_to_current_frame_offset = get_relative_dist(
938       &cm->seq_params->order_hint_info, start_frame_order_hint, cur_order_hint);
939 
940   for (MV_REFERENCE_FRAME rf = LAST_FRAME; rf <= INTER_REFS_PER_FRAME; ++rf) {
941     ref_offset[rf] = get_relative_dist(&cm->seq_params->order_hint_info,
942                                        start_frame_order_hint,
943                                        ref_order_hints[rf - LAST_FRAME]);
944   }
945 
946   if (dir == 2) start_to_current_frame_offset = -start_to_current_frame_offset;
947 
948   MV_REF *mv_ref_base = start_frame_buf->mvs;
949   const int mvs_rows = (cm->mi_params.mi_rows + 1) >> 1;
950   const int mvs_cols = (cm->mi_params.mi_cols + 1) >> 1;
951 
952   for (int blk_row = 0; blk_row < mvs_rows; ++blk_row) {
953     for (int blk_col = 0; blk_col < mvs_cols; ++blk_col) {
954       MV_REF *mv_ref = &mv_ref_base[blk_row * mvs_cols + blk_col];
955       MV fwd_mv = mv_ref->mv.as_mv;
956 
957       if (mv_ref->ref_frame > INTRA_FRAME) {
958         int_mv this_mv;
959         int mi_r, mi_c;
960         const int ref_frame_offset = ref_offset[mv_ref->ref_frame];
961 
962         int pos_valid =
963             abs(ref_frame_offset) <= MAX_FRAME_DISTANCE &&
964             ref_frame_offset > 0 &&
965             abs(start_to_current_frame_offset) <= MAX_FRAME_DISTANCE;
966 
967         if (pos_valid) {
968           get_mv_projection(&this_mv.as_mv, fwd_mv,
969                             start_to_current_frame_offset, ref_frame_offset);
970           pos_valid = get_block_position(cm, &mi_r, &mi_c, blk_row, blk_col,
971                                          this_mv.as_mv, dir >> 1);
972         }
973 
974         if (pos_valid) {
975           const int mi_offset = mi_r * (cm->mi_params.mi_stride >> 1) + mi_c;
976 
977           tpl_mvs_base[mi_offset].mfmv0.as_mv.row = fwd_mv.row;
978           tpl_mvs_base[mi_offset].mfmv0.as_mv.col = fwd_mv.col;
979           tpl_mvs_base[mi_offset].ref_frame_offset = ref_frame_offset;
980         }
981       }
982     }
983   }
984 
985   return 1;
986 }
987 
988 // cm->ref_frame_side is calculated here, and will be used in
989 // av1_copy_frame_mvs() to affect how mvs are copied.
av1_calculate_ref_frame_side(AV1_COMMON * cm)990 void av1_calculate_ref_frame_side(AV1_COMMON *cm) {
991   const OrderHintInfo *const order_hint_info = &cm->seq_params->order_hint_info;
992 
993   memset(cm->ref_frame_side, 0, sizeof(cm->ref_frame_side));
994   if (!order_hint_info->enable_order_hint) return;
995 
996   const int cur_order_hint = cm->cur_frame->order_hint;
997 
998   for (int ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ref_frame++) {
999     const RefCntBuffer *const buf = get_ref_frame_buf(cm, ref_frame);
1000     int order_hint = 0;
1001 
1002     if (buf != NULL) order_hint = buf->order_hint;
1003 
1004     if (get_relative_dist(order_hint_info, order_hint, cur_order_hint) > 0)
1005       cm->ref_frame_side[ref_frame] = 1;
1006     else if (order_hint == cur_order_hint)
1007       cm->ref_frame_side[ref_frame] = -1;
1008   }
1009 }
1010 
av1_setup_motion_field(AV1_COMMON * cm)1011 void av1_setup_motion_field(AV1_COMMON *cm) {
1012   const OrderHintInfo *const order_hint_info = &cm->seq_params->order_hint_info;
1013 
1014   if (!order_hint_info->enable_order_hint) return;
1015 
1016   TPL_MV_REF *tpl_mvs_base = cm->tpl_mvs;
1017   int size = ((cm->mi_params.mi_rows + MAX_MIB_SIZE) >> 1) *
1018              (cm->mi_params.mi_stride >> 1);
1019   for (int idx = 0; idx < size; ++idx) {
1020     tpl_mvs_base[idx].mfmv0.as_int = INVALID_MV;
1021     tpl_mvs_base[idx].ref_frame_offset = 0;
1022   }
1023 
1024   const int cur_order_hint = cm->cur_frame->order_hint;
1025   const RefCntBuffer *ref_buf[INTER_REFS_PER_FRAME];
1026   int ref_order_hint[INTER_REFS_PER_FRAME];
1027 
1028   for (int ref_frame = LAST_FRAME; ref_frame <= ALTREF_FRAME; ref_frame++) {
1029     const int ref_idx = ref_frame - LAST_FRAME;
1030     const RefCntBuffer *const buf = get_ref_frame_buf(cm, ref_frame);
1031     int order_hint = 0;
1032 
1033     if (buf != NULL) order_hint = buf->order_hint;
1034 
1035     ref_buf[ref_idx] = buf;
1036     ref_order_hint[ref_idx] = order_hint;
1037   }
1038 
1039   int ref_stamp = MFMV_STACK_SIZE - 1;
1040 
1041   if (ref_buf[LAST_FRAME - LAST_FRAME] != NULL) {
1042     const int alt_of_lst_order_hint =
1043         ref_buf[LAST_FRAME - LAST_FRAME]
1044             ->ref_order_hints[ALTREF_FRAME - LAST_FRAME];
1045 
1046     const int is_lst_overlay =
1047         (alt_of_lst_order_hint == ref_order_hint[GOLDEN_FRAME - LAST_FRAME]);
1048     if (!is_lst_overlay) motion_field_projection(cm, LAST_FRAME, 2);
1049     --ref_stamp;
1050   }
1051 
1052   if (get_relative_dist(order_hint_info,
1053                         ref_order_hint[BWDREF_FRAME - LAST_FRAME],
1054                         cur_order_hint) > 0) {
1055     if (motion_field_projection(cm, BWDREF_FRAME, 0)) --ref_stamp;
1056   }
1057 
1058   if (get_relative_dist(order_hint_info,
1059                         ref_order_hint[ALTREF2_FRAME - LAST_FRAME],
1060                         cur_order_hint) > 0) {
1061     if (motion_field_projection(cm, ALTREF2_FRAME, 0)) --ref_stamp;
1062   }
1063 
1064   if (get_relative_dist(order_hint_info,
1065                         ref_order_hint[ALTREF_FRAME - LAST_FRAME],
1066                         cur_order_hint) > 0 &&
1067       ref_stamp >= 0)
1068     if (motion_field_projection(cm, ALTREF_FRAME, 0)) --ref_stamp;
1069 
1070   if (ref_stamp >= 0) motion_field_projection(cm, LAST2_FRAME, 2);
1071 }
1072 
record_samples(const MB_MODE_INFO * mbmi,int * pts,int * pts_inref,int row_offset,int sign_r,int col_offset,int sign_c)1073 static inline void record_samples(const MB_MODE_INFO *mbmi, int *pts,
1074                                   int *pts_inref, int row_offset, int sign_r,
1075                                   int col_offset, int sign_c) {
1076   const int bw = block_size_wide[mbmi->bsize];
1077   const int bh = block_size_high[mbmi->bsize];
1078   const int x = col_offset * MI_SIZE + sign_c * bw / 2 - 1;
1079   const int y = row_offset * MI_SIZE + sign_r * bh / 2 - 1;
1080 
1081   pts[0] = GET_MV_SUBPEL(x);
1082   pts[1] = GET_MV_SUBPEL(y);
1083   pts_inref[0] = pts[0] + mbmi->mv[0].as_mv.col;
1084   pts_inref[1] = pts[1] + mbmi->mv[0].as_mv.row;
1085 }
1086 
1087 // Select samples according to the motion vector difference.
av1_selectSamples(MV * mv,int * pts,int * pts_inref,int len,BLOCK_SIZE bsize)1088 uint8_t av1_selectSamples(MV *mv, int *pts, int *pts_inref, int len,
1089                           BLOCK_SIZE bsize) {
1090   const int bw = block_size_wide[bsize];
1091   const int bh = block_size_high[bsize];
1092   const int thresh = clamp(AOMMAX(bw, bh), 16, 112);
1093   uint8_t ret = 0;
1094   assert(len <= LEAST_SQUARES_SAMPLES_MAX);
1095 
1096   // Only keep the samples with MV differences within threshold.
1097   for (int i = 0; i < len; ++i) {
1098     const int diff = abs(pts_inref[2 * i] - pts[2 * i] - mv->col) +
1099                      abs(pts_inref[2 * i + 1] - pts[2 * i + 1] - mv->row);
1100     if (diff > thresh) continue;
1101     if (ret != i) {
1102       memcpy(pts + 2 * ret, pts + 2 * i, 2 * sizeof(pts[0]));
1103       memcpy(pts_inref + 2 * ret, pts_inref + 2 * i, 2 * sizeof(pts_inref[0]));
1104     }
1105     ++ret;
1106   }
1107   // Keep at least 1 sample.
1108   return AOMMAX(ret, 1);
1109 }
1110 
1111 // Note: Samples returned are at 1/8-pel precision
1112 // Sample are the neighbor block center point's coordinates relative to the
1113 // left-top pixel of current block.
av1_findSamples(const AV1_COMMON * cm,MACROBLOCKD * xd,int * pts,int * pts_inref)1114 uint8_t av1_findSamples(const AV1_COMMON *cm, MACROBLOCKD *xd, int *pts,
1115                         int *pts_inref) {
1116   const MB_MODE_INFO *const mbmi0 = xd->mi[0];
1117   const int ref_frame = mbmi0->ref_frame[0];
1118   const int up_available = xd->up_available;
1119   const int left_available = xd->left_available;
1120   uint8_t np = 0;
1121   int do_tl = 1;
1122   int do_tr = 1;
1123   const int mi_stride = xd->mi_stride;
1124   const int mi_row = xd->mi_row;
1125   const int mi_col = xd->mi_col;
1126 
1127   // scan the nearest above rows
1128   if (up_available) {
1129     const int mi_row_offset = -1;
1130     const MB_MODE_INFO *mbmi = xd->mi[mi_row_offset * mi_stride];
1131     uint8_t superblock_width = mi_size_wide[mbmi->bsize];
1132 
1133     if (xd->width <= superblock_width) {
1134       // Handle "current block width <= above block width" case.
1135       const int col_offset = -mi_col % superblock_width;
1136 
1137       if (col_offset < 0) do_tl = 0;
1138       if (col_offset + superblock_width > xd->width) do_tr = 0;
1139 
1140       if (mbmi->ref_frame[0] == ref_frame && mbmi->ref_frame[1] == NONE_FRAME) {
1141         record_samples(mbmi, pts, pts_inref, 0, -1, col_offset, 1);
1142         pts += 2;
1143         pts_inref += 2;
1144         if (++np >= LEAST_SQUARES_SAMPLES_MAX) return LEAST_SQUARES_SAMPLES_MAX;
1145       }
1146     } else {
1147       // Handle "current block width > above block width" case.
1148       for (int i = 0; i < AOMMIN(xd->width, cm->mi_params.mi_cols - mi_col);
1149            i += superblock_width) {
1150         mbmi = xd->mi[i + mi_row_offset * mi_stride];
1151         superblock_width = mi_size_wide[mbmi->bsize];
1152 
1153         if (mbmi->ref_frame[0] == ref_frame &&
1154             mbmi->ref_frame[1] == NONE_FRAME) {
1155           record_samples(mbmi, pts, pts_inref, 0, -1, i, 1);
1156           pts += 2;
1157           pts_inref += 2;
1158           if (++np >= LEAST_SQUARES_SAMPLES_MAX)
1159             return LEAST_SQUARES_SAMPLES_MAX;
1160         }
1161       }
1162     }
1163   }
1164   assert(np <= LEAST_SQUARES_SAMPLES_MAX);
1165 
1166   // scan the nearest left columns
1167   if (left_available) {
1168     const int mi_col_offset = -1;
1169     const MB_MODE_INFO *mbmi = xd->mi[mi_col_offset];
1170     uint8_t superblock_height = mi_size_high[mbmi->bsize];
1171 
1172     if (xd->height <= superblock_height) {
1173       // Handle "current block height <= above block height" case.
1174       const int row_offset = -mi_row % superblock_height;
1175 
1176       if (row_offset < 0) do_tl = 0;
1177 
1178       if (mbmi->ref_frame[0] == ref_frame && mbmi->ref_frame[1] == NONE_FRAME) {
1179         record_samples(mbmi, pts, pts_inref, row_offset, 1, 0, -1);
1180         pts += 2;
1181         pts_inref += 2;
1182         np++;
1183         if (np >= LEAST_SQUARES_SAMPLES_MAX) return LEAST_SQUARES_SAMPLES_MAX;
1184       }
1185     } else {
1186       // Handle "current block height > above block height" case.
1187       for (int i = 0; i < AOMMIN(xd->height, cm->mi_params.mi_rows - mi_row);
1188            i += superblock_height) {
1189         mbmi = xd->mi[mi_col_offset + i * mi_stride];
1190         superblock_height = mi_size_high[mbmi->bsize];
1191 
1192         if (mbmi->ref_frame[0] == ref_frame &&
1193             mbmi->ref_frame[1] == NONE_FRAME) {
1194           record_samples(mbmi, pts, pts_inref, i, 1, 0, -1);
1195           pts += 2;
1196           pts_inref += 2;
1197           if (++np >= LEAST_SQUARES_SAMPLES_MAX)
1198             return LEAST_SQUARES_SAMPLES_MAX;
1199         }
1200       }
1201     }
1202   }
1203   assert(np <= LEAST_SQUARES_SAMPLES_MAX);
1204 
1205   // Top-left block
1206   if (do_tl && left_available && up_available) {
1207     const int mi_row_offset = -1;
1208     const int mi_col_offset = -1;
1209     MB_MODE_INFO *mbmi = xd->mi[mi_col_offset + mi_row_offset * mi_stride];
1210 
1211     if (mbmi->ref_frame[0] == ref_frame && mbmi->ref_frame[1] == NONE_FRAME) {
1212       record_samples(mbmi, pts, pts_inref, 0, -1, 0, -1);
1213       pts += 2;
1214       pts_inref += 2;
1215       if (++np >= LEAST_SQUARES_SAMPLES_MAX) return LEAST_SQUARES_SAMPLES_MAX;
1216     }
1217   }
1218   assert(np <= LEAST_SQUARES_SAMPLES_MAX);
1219 
1220   // Top-right block
1221   if (do_tr &&
1222       has_top_right(cm, xd, mi_row, mi_col, AOMMAX(xd->width, xd->height))) {
1223     const POSITION trb_pos = { -1, xd->width };
1224     const TileInfo *const tile = &xd->tile;
1225     if (is_inside(tile, mi_col, mi_row, &trb_pos)) {
1226       const int mi_row_offset = -1;
1227       const int mi_col_offset = xd->width;
1228       const MB_MODE_INFO *mbmi =
1229           xd->mi[mi_col_offset + mi_row_offset * mi_stride];
1230 
1231       if (mbmi->ref_frame[0] == ref_frame && mbmi->ref_frame[1] == NONE_FRAME) {
1232         record_samples(mbmi, pts, pts_inref, 0, -1, xd->width, 1);
1233         if (++np >= LEAST_SQUARES_SAMPLES_MAX) return LEAST_SQUARES_SAMPLES_MAX;
1234       }
1235     }
1236   }
1237   assert(np <= LEAST_SQUARES_SAMPLES_MAX);
1238 
1239   return np;
1240 }
1241 
av1_setup_skip_mode_allowed(AV1_COMMON * cm)1242 void av1_setup_skip_mode_allowed(AV1_COMMON *cm) {
1243   const OrderHintInfo *const order_hint_info = &cm->seq_params->order_hint_info;
1244   SkipModeInfo *const skip_mode_info = &cm->current_frame.skip_mode_info;
1245 
1246   skip_mode_info->skip_mode_allowed = 0;
1247   skip_mode_info->ref_frame_idx_0 = INVALID_IDX;
1248   skip_mode_info->ref_frame_idx_1 = INVALID_IDX;
1249 
1250   if (!order_hint_info->enable_order_hint || frame_is_intra_only(cm) ||
1251       cm->current_frame.reference_mode == SINGLE_REFERENCE)
1252     return;
1253 
1254   const int cur_order_hint = cm->current_frame.order_hint;
1255   int ref_order_hints[2] = { -1, INT_MAX };
1256   int ref_idx[2] = { INVALID_IDX, INVALID_IDX };
1257 
1258   // Identify the nearest forward and backward references.
1259   for (int i = 0; i < INTER_REFS_PER_FRAME; ++i) {
1260     const RefCntBuffer *const buf = get_ref_frame_buf(cm, LAST_FRAME + i);
1261     if (buf == NULL) continue;
1262 
1263     const int ref_order_hint = buf->order_hint;
1264     if (get_relative_dist(order_hint_info, ref_order_hint, cur_order_hint) <
1265         0) {
1266       // Forward reference
1267       if (ref_order_hints[0] == -1 ||
1268           get_relative_dist(order_hint_info, ref_order_hint,
1269                             ref_order_hints[0]) > 0) {
1270         ref_order_hints[0] = ref_order_hint;
1271         ref_idx[0] = i;
1272       }
1273     } else if (get_relative_dist(order_hint_info, ref_order_hint,
1274                                  cur_order_hint) > 0) {
1275       // Backward reference
1276       if (ref_order_hints[1] == INT_MAX ||
1277           get_relative_dist(order_hint_info, ref_order_hint,
1278                             ref_order_hints[1]) < 0) {
1279         ref_order_hints[1] = ref_order_hint;
1280         ref_idx[1] = i;
1281       }
1282     }
1283   }
1284 
1285   if (ref_idx[0] != INVALID_IDX && ref_idx[1] != INVALID_IDX) {
1286     // == Bi-directional prediction ==
1287     skip_mode_info->skip_mode_allowed = 1;
1288     skip_mode_info->ref_frame_idx_0 = AOMMIN(ref_idx[0], ref_idx[1]);
1289     skip_mode_info->ref_frame_idx_1 = AOMMAX(ref_idx[0], ref_idx[1]);
1290   } else if (ref_idx[0] != INVALID_IDX && ref_idx[1] == INVALID_IDX) {
1291     // == Forward prediction only ==
1292     // Identify the second nearest forward reference.
1293     ref_order_hints[1] = -1;
1294     for (int i = 0; i < INTER_REFS_PER_FRAME; ++i) {
1295       const RefCntBuffer *const buf = get_ref_frame_buf(cm, LAST_FRAME + i);
1296       if (buf == NULL) continue;
1297 
1298       const int ref_order_hint = buf->order_hint;
1299       if ((ref_order_hints[0] != -1 &&
1300            get_relative_dist(order_hint_info, ref_order_hint,
1301                              ref_order_hints[0]) < 0) &&
1302           (ref_order_hints[1] == -1 ||
1303            get_relative_dist(order_hint_info, ref_order_hint,
1304                              ref_order_hints[1]) > 0)) {
1305         // Second closest forward reference
1306         ref_order_hints[1] = ref_order_hint;
1307         ref_idx[1] = i;
1308       }
1309     }
1310     if (ref_order_hints[1] != -1) {
1311       skip_mode_info->skip_mode_allowed = 1;
1312       skip_mode_info->ref_frame_idx_0 = AOMMIN(ref_idx[0], ref_idx[1]);
1313       skip_mode_info->ref_frame_idx_1 = AOMMAX(ref_idx[0], ref_idx[1]);
1314     }
1315   }
1316 }
1317 
1318 typedef struct {
1319   int map_idx;        // frame map index
1320   RefCntBuffer *buf;  // frame buffer
1321   int sort_idx;       // index based on the offset to be used for sorting
1322 } REF_FRAME_INFO;
1323 
1324 // Compares the sort_idx fields. If they are equal, then compares the map_idx
1325 // fields to break the tie. This ensures a stable sort.
compare_ref_frame_info(const void * arg_a,const void * arg_b)1326 static int compare_ref_frame_info(const void *arg_a, const void *arg_b) {
1327   const REF_FRAME_INFO *info_a = (REF_FRAME_INFO *)arg_a;
1328   const REF_FRAME_INFO *info_b = (REF_FRAME_INFO *)arg_b;
1329 
1330   const int sort_idx_diff = info_a->sort_idx - info_b->sort_idx;
1331   if (sort_idx_diff != 0) return sort_idx_diff;
1332   return info_a->map_idx - info_b->map_idx;
1333 }
1334 
set_ref_frame_info(int * remapped_ref_idx,int frame_idx,REF_FRAME_INFO * ref_info)1335 static inline void set_ref_frame_info(int *remapped_ref_idx, int frame_idx,
1336                                       REF_FRAME_INFO *ref_info) {
1337   assert(frame_idx >= 0 && frame_idx < INTER_REFS_PER_FRAME);
1338 
1339   remapped_ref_idx[frame_idx] = ref_info->map_idx;
1340 }
1341 
av1_set_frame_refs(AV1_COMMON * const cm,int * remapped_ref_idx,int lst_map_idx,int gld_map_idx)1342 void av1_set_frame_refs(AV1_COMMON *const cm, int *remapped_ref_idx,
1343                         int lst_map_idx, int gld_map_idx) {
1344   int lst_frame_sort_idx = -1;
1345   int gld_frame_sort_idx = -1;
1346 
1347   assert(cm->seq_params->order_hint_info.enable_order_hint);
1348   assert(cm->seq_params->order_hint_info.order_hint_bits_minus_1 >= 0);
1349   const int cur_order_hint = (int)cm->current_frame.order_hint;
1350   const int cur_frame_sort_idx =
1351       1 << cm->seq_params->order_hint_info.order_hint_bits_minus_1;
1352 
1353   REF_FRAME_INFO ref_frame_info[REF_FRAMES];
1354   int ref_flag_list[INTER_REFS_PER_FRAME] = { 0, 0, 0, 0, 0, 0, 0 };
1355 
1356   for (int i = 0; i < REF_FRAMES; ++i) {
1357     const int map_idx = i;
1358 
1359     ref_frame_info[i].map_idx = map_idx;
1360     ref_frame_info[i].sort_idx = -1;
1361 
1362     RefCntBuffer *const buf = cm->ref_frame_map[map_idx];
1363     ref_frame_info[i].buf = buf;
1364 
1365     if (buf == NULL) continue;
1366     // If this assertion fails, there is a reference leak.
1367     assert(buf->ref_count > 0);
1368 
1369     const int offset = (int)buf->order_hint;
1370     ref_frame_info[i].sort_idx =
1371         (offset == -1) ? -1
1372                        : cur_frame_sort_idx +
1373                              get_relative_dist(&cm->seq_params->order_hint_info,
1374                                                offset, cur_order_hint);
1375     assert(ref_frame_info[i].sort_idx >= -1);
1376 
1377     if (map_idx == lst_map_idx) lst_frame_sort_idx = ref_frame_info[i].sort_idx;
1378     if (map_idx == gld_map_idx) gld_frame_sort_idx = ref_frame_info[i].sort_idx;
1379   }
1380 
1381   // Confirm both LAST_FRAME and GOLDEN_FRAME are valid forward reference
1382   // frames.
1383   if (lst_frame_sort_idx == -1 || lst_frame_sort_idx >= cur_frame_sort_idx) {
1384     aom_internal_error(cm->error, AOM_CODEC_CORRUPT_FRAME,
1385                        "Inter frame requests a look-ahead frame as LAST");
1386   }
1387   if (gld_frame_sort_idx == -1 || gld_frame_sort_idx >= cur_frame_sort_idx) {
1388     aom_internal_error(cm->error, AOM_CODEC_CORRUPT_FRAME,
1389                        "Inter frame requests a look-ahead frame as GOLDEN");
1390   }
1391 
1392   // Sort ref frames based on their frame_offset values.
1393   qsort(ref_frame_info, REF_FRAMES, sizeof(REF_FRAME_INFO),
1394         compare_ref_frame_info);
1395 
1396   // Identify forward and backward reference frames.
1397   // Forward  reference: offset < order_hint
1398   // Backward reference: offset >= order_hint
1399   int fwd_start_idx = 0, fwd_end_idx = REF_FRAMES - 1;
1400 
1401   for (int i = 0; i < REF_FRAMES; i++) {
1402     if (ref_frame_info[i].sort_idx == -1) {
1403       fwd_start_idx++;
1404       continue;
1405     }
1406 
1407     if (ref_frame_info[i].sort_idx >= cur_frame_sort_idx) {
1408       fwd_end_idx = i - 1;
1409       break;
1410     }
1411   }
1412 
1413   int bwd_start_idx = fwd_end_idx + 1;
1414   int bwd_end_idx = REF_FRAMES - 1;
1415 
1416   // === Backward Reference Frames ===
1417 
1418   // == ALTREF_FRAME ==
1419   if (bwd_start_idx <= bwd_end_idx) {
1420     set_ref_frame_info(remapped_ref_idx, ALTREF_FRAME - LAST_FRAME,
1421                        &ref_frame_info[bwd_end_idx]);
1422     ref_flag_list[ALTREF_FRAME - LAST_FRAME] = 1;
1423     bwd_end_idx--;
1424   }
1425 
1426   // == BWDREF_FRAME ==
1427   if (bwd_start_idx <= bwd_end_idx) {
1428     set_ref_frame_info(remapped_ref_idx, BWDREF_FRAME - LAST_FRAME,
1429                        &ref_frame_info[bwd_start_idx]);
1430     ref_flag_list[BWDREF_FRAME - LAST_FRAME] = 1;
1431     bwd_start_idx++;
1432   }
1433 
1434   // == ALTREF2_FRAME ==
1435   if (bwd_start_idx <= bwd_end_idx) {
1436     set_ref_frame_info(remapped_ref_idx, ALTREF2_FRAME - LAST_FRAME,
1437                        &ref_frame_info[bwd_start_idx]);
1438     ref_flag_list[ALTREF2_FRAME - LAST_FRAME] = 1;
1439   }
1440 
1441   // === Forward Reference Frames ===
1442 
1443   for (int i = fwd_start_idx; i <= fwd_end_idx; ++i) {
1444     // == LAST_FRAME ==
1445     if (ref_frame_info[i].map_idx == lst_map_idx) {
1446       set_ref_frame_info(remapped_ref_idx, LAST_FRAME - LAST_FRAME,
1447                          &ref_frame_info[i]);
1448       ref_flag_list[LAST_FRAME - LAST_FRAME] = 1;
1449     }
1450 
1451     // == GOLDEN_FRAME ==
1452     if (ref_frame_info[i].map_idx == gld_map_idx) {
1453       set_ref_frame_info(remapped_ref_idx, GOLDEN_FRAME - LAST_FRAME,
1454                          &ref_frame_info[i]);
1455       ref_flag_list[GOLDEN_FRAME - LAST_FRAME] = 1;
1456     }
1457   }
1458 
1459   assert(ref_flag_list[LAST_FRAME - LAST_FRAME] == 1 &&
1460          ref_flag_list[GOLDEN_FRAME - LAST_FRAME] == 1);
1461 
1462   // == LAST2_FRAME ==
1463   // == LAST3_FRAME ==
1464   // == BWDREF_FRAME ==
1465   // == ALTREF2_FRAME ==
1466   // == ALTREF_FRAME ==
1467 
1468   // Set up the reference frames in the anti-chronological order.
1469   static const MV_REFERENCE_FRAME ref_frame_list[INTER_REFS_PER_FRAME - 2] = {
1470     LAST2_FRAME, LAST3_FRAME, BWDREF_FRAME, ALTREF2_FRAME, ALTREF_FRAME
1471   };
1472 
1473   int ref_idx;
1474   for (ref_idx = 0; ref_idx < (INTER_REFS_PER_FRAME - 2); ref_idx++) {
1475     const MV_REFERENCE_FRAME ref_frame = ref_frame_list[ref_idx];
1476 
1477     if (ref_flag_list[ref_frame - LAST_FRAME] == 1) continue;
1478 
1479     while (fwd_start_idx <= fwd_end_idx &&
1480            (ref_frame_info[fwd_end_idx].map_idx == lst_map_idx ||
1481             ref_frame_info[fwd_end_idx].map_idx == gld_map_idx)) {
1482       fwd_end_idx--;
1483     }
1484     if (fwd_start_idx > fwd_end_idx) break;
1485 
1486     set_ref_frame_info(remapped_ref_idx, ref_frame - LAST_FRAME,
1487                        &ref_frame_info[fwd_end_idx]);
1488     ref_flag_list[ref_frame - LAST_FRAME] = 1;
1489 
1490     fwd_end_idx--;
1491   }
1492 
1493   // Assign all the remaining frame(s), if any, to the earliest reference
1494   // frame.
1495   for (; ref_idx < (INTER_REFS_PER_FRAME - 2); ref_idx++) {
1496     const MV_REFERENCE_FRAME ref_frame = ref_frame_list[ref_idx];
1497     if (ref_flag_list[ref_frame - LAST_FRAME] == 1) continue;
1498     set_ref_frame_info(remapped_ref_idx, ref_frame - LAST_FRAME,
1499                        &ref_frame_info[fwd_start_idx]);
1500     ref_flag_list[ref_frame - LAST_FRAME] = 1;
1501   }
1502 
1503   for (int i = 0; i < INTER_REFS_PER_FRAME; i++) {
1504     assert(ref_flag_list[i] == 1);
1505   }
1506 }
1507