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FFmpeg/libavcodec/hevc_mvs.c

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  1. /*

  2.  * HEVC video decoder

  3.  *

  4.  * Copyright (C) 2012 - 2013 Guillaume Martres

  5.  * Copyright (C) 2013 Anand Meher Kotra

  6.  *

  7.  * This file is part of Libav.

  8.  *

  9.  * Libav is free software; you can redistribute it and/or

  10.  * modify it under the terms of the GNU Lesser General Public

  11.  * License as published by the Free Software Foundation; either

  12.  * version 2.1 of the License, or (at your option) any later version.

  13.  *

  14.  * Libav is distributed in the hope that it will be useful,

  15.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  16.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

  17.  * Lesser General Public License for more details.

  18.  *

  19.  * You should have received a copy of the GNU Lesser General Public

  20.  * License along with Libav; if not, write to the Free Software

  21.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  22.  */

  23. 

  24. #include "hevc.h"

  25. 

  26. static const uint8_t l0_l1_cand_idx[12][2] = {

  27.     { 0, 1, },

  28.     { 1, 0, },

  29.     { 0, 2, },

  30.     { 2, 0, },

  31.     { 1, 2, },

  32.     { 2, 1, },

  33.     { 0, 3, },

  34.     { 3, 0, },

  35.     { 1, 3, },

  36.     { 3, 1, },

  37.     { 2, 3, },

  38.     { 3, 2, },

  39. };

  40. 

  41. void ff_hevc_set_neighbour_available(HEVCContext *s, int x0, int y0,

  42.                                      int nPbW, int nPbH)

  43. {

  44.     HEVCLocalContext *lc = &s->HEVClc;

  45.     int x0b = x0 & ((1 << s->sps->log2_ctb_size) - 1);

  46.     int y0b = y0 & ((1 << s->sps->log2_ctb_size) - 1);

  47. 

  48.     lc->na.cand_up       = (lc->ctb_up_flag   || y0b);

  49.     lc->na.cand_left     = (lc->ctb_left_flag || x0b);

  50.     lc->na.cand_up_left  = (!x0b && !y0b) ? lc->ctb_up_left_flag : lc->na.cand_left && lc->na.cand_up;

  51.     lc->na.cand_up_right_sap =

  52.             ((x0b + nPbW) == (1 << s->sps->log2_ctb_size)) ?

  53.                     lc->ctb_up_right_flag && !y0b : lc->na.cand_up;

  54.     lc->na.cand_up_right =

  55.             ((x0b + nPbW) == (1 << s->sps->log2_ctb_size) ?

  56.                     lc->ctb_up_right_flag && !y0b : lc->na.cand_up )

  57.                      && (x0 + nPbW) < lc->end_of_tiles_x;

  58.     lc->na.cand_bottom_left = ((y0 + nPbH) >= lc->end_of_tiles_y) ? 0 : lc->na.cand_left;

  59. }

  60. 

  61. /*

  62.  * 6.4.1 Derivation process for z-scan order block availability

  63.  */

  64. static int z_scan_block_avail(HEVCContext *s, int xCurr, int yCurr,

  65.                               int xN, int yN)

  66. {

  67. #define MIN_TB_ADDR_ZS(x, y)                                            \

  68.     s->pps->min_tb_addr_zs[(y) * s->sps->min_tb_width + (x)]

  69.     int Curr = MIN_TB_ADDR_ZS(xCurr >> s->sps->log2_min_tb_size,

  70.                               yCurr >> s->sps->log2_min_tb_size);

  71.     int N;

  72. 

  73.     if (xN < 0 || yN < 0 ||

  74.         xN >= s->sps->width ||

  75.         yN >= s->sps->height)

  76.         return 0;

  77. 

  78.     N = MIN_TB_ADDR_ZS(xN >> s->sps->log2_min_tb_size,

  79.                        yN >> s->sps->log2_min_tb_size);

  80. 

  81.     return N <= Curr;

  82. }

  83. 

  84. static int same_prediction_block(HEVCLocalContext *lc, int log2_cb_size,

  85.                                  int x0, int y0, int nPbW, int nPbH,

  86.                                  int xA1, int yA1, int partIdx)

  87. {

  88.     return !(nPbW << 1 == 1 << log2_cb_size &&

  89.              nPbH << 1 == 1 << log2_cb_size && partIdx == 1 &&

  90.              lc->cu.x + nPbW > xA1 &&

  91.              lc->cu.y + nPbH <= yA1);

  92. }

  93. 

  94. /*

  95.  * 6.4.2 Derivation process for prediction block availability

  96.  */

  97. static int check_prediction_block_available(HEVCContext *s, int log2_cb_size,

  98.                                             int x0, int y0, int nPbW, int nPbH,

  99.                                             int xA1, int yA1, int partIdx)

  100. {

  101.     HEVCLocalContext *lc = &s->HEVClc;

  102. 

  103.     if (lc->cu.x < xA1 && lc->cu.y < yA1 &&

  104.         (lc->cu.x + (1 << log2_cb_size)) > xA1 &&

  105.         (lc->cu.y + (1 << log2_cb_size)) > yA1)

  106.         return same_prediction_block(lc, log2_cb_size, x0, y0,

  107.                                      nPbW, nPbH, xA1, yA1, partIdx);

  108.     else

  109.         return z_scan_block_avail(s, x0, y0, xA1, yA1);

  110. }

  111. 

  112. //check if the two luma locations belong to the same mostion estimation region

  113. static int isDiffMER(HEVCContext *s, int xN, int yN, int xP, int yP)

  114. {

  115.     uint8_t plevel = s->pps->log2_parallel_merge_level;

  116. 

  117.     return xN >> plevel == xP >> plevel &&

  118.            yN >> plevel == yP >> plevel;

  119. }

  120. 

  121. #define MATCH(x) (A.x == B.x)

  122. 

  123. // check if the mv's and refidx are the same between A and B

  124. static int compareMVrefidx(struct MvField A, struct MvField B)

  125. {

  126.     if (A.pred_flag[0] && A.pred_flag[1] && B.pred_flag[0] && B.pred_flag[1])

  127.         return MATCH(ref_idx[0]) && MATCH(mv[0].x) && MATCH(mv[0].y) &&

  128.                MATCH(ref_idx[1]) && MATCH(mv[1].x) && MATCH(mv[1].y);

  129. 

  130.     if (A.pred_flag[0] && !A.pred_flag[1] && B.pred_flag[0] && !B.pred_flag[1])

  131.         return MATCH(ref_idx[0]) && MATCH(mv[0].x) && MATCH(mv[0].y);

  132. 

  133.     if (!A.pred_flag[0] && A.pred_flag[1] && !B.pred_flag[0] && B.pred_flag[1])

  134.         return MATCH(ref_idx[1]) && MATCH(mv[1].x) && MATCH(mv[1].y);

  135. 

  136.     return 0;

  137. }

  138. 

  139. static av_always_inline void mv_scale(Mv *dst, Mv *src, int td, int tb)

  140. {

  141.     int tx, scale_factor;

  142. 

  143.     td = av_clip_int8_c(td);

  144.     tb = av_clip_int8_c(tb);

  145.     tx = (0x4000 + abs(td / 2)) / td;

  146.     scale_factor = av_clip_c((tb * tx + 32) >> 6, -4096, 4095);

  147.     dst->x = av_clip_int16_c((scale_factor * src->x + 127 +

  148.                              (scale_factor * src->x < 0)) >> 8);

  149.     dst->y = av_clip_int16_c((scale_factor * src->y + 127 +

  150.                              (scale_factor * src->y < 0)) >> 8);

  151. }

  152. 

  153. static int check_mvset(Mv *mvLXCol, Mv *mvCol,

  154.                        int colPic, int poc,

  155.                        RefPicList *refPicList, int X, int refIdxLx,

  156.                        RefPicList *refPicList_col, int listCol, int refidxCol)

  157. {

  158.     int cur_lt = refPicList[X].isLongTerm[refIdxLx];

  159.     int col_lt = refPicList_col[listCol].isLongTerm[refidxCol];

  160.     int col_poc_diff, cur_poc_diff;

  161. 

  162.     if (cur_lt != col_lt) {

  163.         mvLXCol->x = 0;

  164.         mvLXCol->y = 0;

  165.         return 0;

  166.     }

  167. 

  168.     col_poc_diff = colPic - refPicList_col[listCol].list[refidxCol];

  169.     cur_poc_diff = poc    - refPicList[X].list[refIdxLx];

  170. 

  171.     if (!col_poc_diff)

  172.         col_poc_diff = 1;  // error resilience

  173. 

  174.     if (cur_lt || col_poc_diff == cur_poc_diff) {

  175.         mvLXCol->x = mvCol->x;

  176.         mvLXCol->y = mvCol->y;

  177.     } else {

  178.         mv_scale(mvLXCol, mvCol, col_poc_diff, cur_poc_diff);

  179.     }

  180.     return 1;

  181. }

  182. 

  183. #define CHECK_MVSET(l)                                          \

  184.     check_mvset(mvLXCol, temp_col.mv + l,                       \

  185.                 colPic, s->poc,                                 \

  186.                 refPicList, X, refIdxLx,                        \

  187.                 refPicList_col, L ## l, temp_col.ref_idx[l])

  188. 

  189. // derive the motion vectors section 8.5.3.1.8

  190. static int derive_temporal_colocated_mvs(HEVCContext *s, MvField temp_col,

  191.                                          int refIdxLx, Mv *mvLXCol, int X,

  192.                                          int colPic, RefPicList *refPicList_col)

  193. {

  194.     RefPicList *refPicList = s->ref->refPicList;

  195. 

  196.     if (temp_col.is_intra) {

  197.         mvLXCol->x = 0;

  198.         mvLXCol->y = 0;

  199.         return 0;

  200.     }

  201. 

  202.     if (temp_col.pred_flag[0] == 0)

  203.         return CHECK_MVSET(1);

  204.     else if (temp_col.pred_flag[0] == 1 && temp_col.pred_flag[1] == 0)

  205.         return CHECK_MVSET(0);

  206.     else if (temp_col.pred_flag[0] == 1 && temp_col.pred_flag[1] == 1) {

  207.         int check_diffpicount = 0;

  208.         int i = 0;

  209.         for (i = 0; i < refPicList[0].nb_refs; i++) {

  210.             if (refPicList[0].list[i] > s->poc)

  211.                 check_diffpicount++;

  212.         }

  213.         for (i = 0; i < refPicList[1].nb_refs; i++) {

  214.             if (refPicList[1].list[i] > s->poc)

  215.                 check_diffpicount++;

  216.         }

  217.         if (check_diffpicount == 0 && X == 0)

  218.             return CHECK_MVSET(0);

  219.         else if (check_diffpicount == 0 && X == 1)

  220.             return CHECK_MVSET(1);

  221.         else {

  222.             if (s->sh.collocated_list == L1)

  223.                 return CHECK_MVSET(0);

  224.             else

  225.                 return CHECK_MVSET(1);

  226.         }

  227.     }

  228. 

  229.     return 0;

  230. }

  231. 

  232. #define TAB_MVF(x, y)                                                   \

  233.     tab_mvf[(y) * min_pu_width + x]

  234. 

  235. #define TAB_MVF_PU(v)                                                   \

  236.     TAB_MVF(x ## v ## _pu, y ## v ## _pu)

  237. 

  238. #define DERIVE_TEMPORAL_COLOCATED_MVS                                   \

  239.     derive_temporal_colocated_mvs(s, temp_col,                          \

  240.                                   refIdxLx, mvLXCol, X, colPic,         \

  241.                                   ff_hevc_get_ref_list(s, ref, x, y))

  242. 

  243. /*

  244.  * 8.5.3.1.7  temporal luma motion vector prediction

  245.  */

  246. static int temporal_luma_motion_vector(HEVCContext *s, int x0, int y0,

  247.                                        int nPbW, int nPbH, int refIdxLx,

  248.                                        Mv *mvLXCol, int X)

  249. {

  250.     MvField *tab_mvf;

  251.     MvField temp_col;

  252.     int x, y, x_pu, y_pu;

  253.     int min_pu_width = s->sps->min_pu_width;

  254.     int availableFlagLXCol = 0;

  255.     int colPic;

  256. 

  257.     HEVCFrame *ref = s->ref->collocated_ref;

  258. 

  259.     if (!ref)

  260.         return 0;

  261. 

  262.     tab_mvf = ref->tab_mvf;

  263.     colPic  = ref->poc;

  264. 

  265.     //bottom right collocated motion vector

  266.     x = x0 + nPbW;

  267.     y = y0 + nPbH;

  268. 

  269.     ff_thread_await_progress(&ref->tf, y, 0);

  270.     if (tab_mvf &&

  271.         (y0 >> s->sps->log2_ctb_size) == (y >> s->sps->log2_ctb_size) &&

  272.         y < s->sps->height &&

  273.         x < s->sps->width) {

  274.         x                  = ((x >> 4) << 4);

  275.         y                  = ((y >> 4) << 4);

  276.         x_pu               = x >> s->sps->log2_min_pu_size;

  277.         y_pu               = y >> s->sps->log2_min_pu_size;

  278.         temp_col           = TAB_MVF(x_pu, y_pu);

  279.         availableFlagLXCol = DERIVE_TEMPORAL_COLOCATED_MVS;

  280.     }

  281. 

  282.     // derive center collocated motion vector

  283.     if (tab_mvf && !availableFlagLXCol) {

  284.         x                  = x0 + (nPbW >> 1);

  285.         y                  = y0 + (nPbH >> 1);

  286.         x                  = ((x >> 4) << 4);

  287.         y                  = ((y >> 4) << 4);

  288.         x_pu               = x >> s->sps->log2_min_pu_size;

  289.         y_pu               = y >> s->sps->log2_min_pu_size;

  290.         temp_col           = TAB_MVF(x_pu, y_pu);

  291.         availableFlagLXCol = DERIVE_TEMPORAL_COLOCATED_MVS;

  292.     }

  293.     return availableFlagLXCol;

  294. }

  295. 

  296. #define AVAILABLE(cand, v)                                      \

  297.     (cand && !TAB_MVF_PU(v).is_intra)

  298. 

  299. #define PRED_BLOCK_AVAILABLE(v)                                 \

  300.     check_prediction_block_available(s, log2_cb_size,           \

  301.                                      x0, y0, nPbW, nPbH,        \

  302.                                      x ## v, y ## v, part_idx)

  303. 

  304. #define COMPARE_MV_REFIDX(a, b)                                 \

  305.     compareMVrefidx(TAB_MVF_PU(a), TAB_MVF_PU(b))

  306. 

  307. /*

  308.  * 8.5.3.1.2  Derivation process for spatial merging candidates

  309.  */

  310. static void derive_spatial_merge_candidates(HEVCContext *s, int x0, int y0,

  311.                                             int nPbW, int nPbH,

  312.                                             int log2_cb_size,

  313.                                             int singleMCLFlag, int part_idx,

  314.                                             struct MvField mergecandlist[])

  315. {

  316.     HEVCLocalContext *lc   = &s->HEVClc;

  317.     RefPicList *refPicList = s->ref->refPicList;

  318.     MvField *tab_mvf       = s->ref->tab_mvf;

  319. 

  320.     const int min_pu_width = s->sps->min_pu_width;

  321. 

  322.     const int cand_bottom_left = lc->na.cand_bottom_left;

  323.     const int cand_left        = lc->na.cand_left;

  324.     const int cand_up_left     = lc->na.cand_up_left;

  325.     const int cand_up          = lc->na.cand_up;

  326.     const int cand_up_right    = lc->na.cand_up_right_sap;

  327. 

  328.     const int xA1    = x0 - 1;

  329.     const int yA1    = y0 + nPbH - 1;

  330.     const int xA1_pu = xA1 >> s->sps->log2_min_pu_size;

  331.     const int yA1_pu = yA1 >> s->sps->log2_min_pu_size;

  332. 

  333.     const int xB1    = x0 + nPbW - 1;

  334.     const int yB1    = y0 - 1;

  335.     const int xB1_pu = xB1 >> s->sps->log2_min_pu_size;

  336.     const int yB1_pu = yB1 >> s->sps->log2_min_pu_size;

  337. 

  338.     const int xB0    = x0 + nPbW;

  339.     const int yB0    = y0 - 1;

  340.     const int xB0_pu = xB0 >> s->sps->log2_min_pu_size;

  341.     const int yB0_pu = yB0 >> s->sps->log2_min_pu_size;

  342. 

  343.     const int xA0    = x0 - 1;

  344.     const int yA0    = y0 + nPbH;

  345.     const int xA0_pu = xA0 >> s->sps->log2_min_pu_size;

  346.     const int yA0_pu = yA0 >> s->sps->log2_min_pu_size;

  347. 

  348.     const int xB2    = x0 - 1;

  349.     const int yB2    = y0 - 1;

  350.     const int xB2_pu = xB2 >> s->sps->log2_min_pu_size;

  351.     const int yB2_pu = yB2 >> s->sps->log2_min_pu_size;

  352. 

  353.     const int nb_refs = (s->sh.slice_type == P_SLICE) ?

  354.                         s->sh.nb_refs[0] : FFMIN(s->sh.nb_refs[0], s->sh.nb_refs[1]);

  355.     int check_MER   = 1;

  356.     int check_MER_1 = 1;

  357. 

  358.     int zero_idx = 0;

  359. 

  360.     int nb_merge_cand = 0;

  361.     int nb_orig_merge_cand = 0;

  362. 

  363.     int is_available_a0;

  364.     int is_available_a1;

  365.     int is_available_b0;

  366.     int is_available_b1;

  367.     int is_available_b2;

  368.     int check_B0;

  369.     int check_A0;

  370. 

  371.     //first left spatial merge candidate

  372.     is_available_a1 = AVAILABLE(cand_left, A1);

  373. 

  374.     if (!singleMCLFlag && part_idx == 1 &&

  375.         (lc->cu.part_mode == PART_Nx2N ||

  376.          lc->cu.part_mode == PART_nLx2N ||

  377.          lc->cu.part_mode == PART_nRx2N) ||

  378.         isDiffMER(s, xA1, yA1, x0, y0)) {

  379.         is_available_a1 = 0;

  380.     }

  381. 

  382.     if (is_available_a1)

  383.         mergecandlist[nb_merge_cand++] = TAB_MVF_PU(A1);

  384. 

  385.     // above spatial merge candidate

  386.     is_available_b1 = AVAILABLE(cand_up, B1);

  387. 

  388.     if (!singleMCLFlag && part_idx == 1 &&

  389.         (lc->cu.part_mode == PART_2NxN ||

  390.          lc->cu.part_mode == PART_2NxnU ||

  391.          lc->cu.part_mode == PART_2NxnD) ||

  392.         isDiffMER(s, xB1, yB1, x0, y0)) {

  393.         is_available_b1 = 0;

  394.     }

  395. 

  396.     if (is_available_a1 && is_available_b1)

  397.         check_MER = !COMPARE_MV_REFIDX(B1, A1);

  398. 

  399.     if (is_available_b1 && check_MER)

  400.         mergecandlist[nb_merge_cand++] = TAB_MVF_PU(B1);

  401. 

  402.     // above right spatial merge candidate

  403.     check_MER = 1;

  404.     check_B0  = PRED_BLOCK_AVAILABLE(B0);

  405. 

  406.     is_available_b0 = check_B0 && AVAILABLE(cand_up_right, B0);

  407. 

  408.     if (isDiffMER(s, xB0, yB0, x0, y0))

  409.         is_available_b0 = 0;

  410. 

  411.     if (is_available_b1 && is_available_b0)

  412.         check_MER = !COMPARE_MV_REFIDX(B0, B1);

  413. 

  414.     if (is_available_b0 && check_MER)

  415.         mergecandlist[nb_merge_cand++] = TAB_MVF_PU(B0);

  416. 

  417.     // left bottom spatial merge candidate

  418.     check_MER = 1;

  419.     check_A0  = PRED_BLOCK_AVAILABLE(A0);

  420. 

  421.     is_available_a0 = check_A0 && AVAILABLE(cand_bottom_left, A0);

  422. 

  423.     if (isDiffMER(s, xA0, yA0, x0, y0))

  424.         is_available_a0 = 0;

  425. 

  426.     if (is_available_a1 && is_available_a0)

  427.         check_MER = !COMPARE_MV_REFIDX(A0, A1);

  428. 

  429.     if (is_available_a0 && check_MER)

  430.         mergecandlist[nb_merge_cand++] = TAB_MVF_PU(A0);

  431. 

  432.     // above left spatial merge candidate

  433.     check_MER = 1;

  434. 

  435.     is_available_b2 = AVAILABLE(cand_up_left, B2);

  436. 

  437.     if (isDiffMER(s, xB2, yB2, x0, y0))

  438.         is_available_b2 = 0;

  439. 

  440.     if (is_available_a1 && is_available_b2)

  441.         check_MER = !COMPARE_MV_REFIDX(B2, A1);

  442. 

  443.     if (is_available_b1 && is_available_b2)

  444.         check_MER_1 = !COMPARE_MV_REFIDX(B2, B1);

  445. 

  446.     if (is_available_b2 && check_MER && check_MER_1 && nb_merge_cand != 4)

  447.         mergecandlist[nb_merge_cand++] = TAB_MVF_PU(B2);

  448. 

  449.     // temporal motion vector candidate

  450.     if (s->sh.slice_temporal_mvp_enabled_flag &&

  451.         nb_merge_cand < s->sh.max_num_merge_cand) {

  452.         Mv mv_l0_col, mv_l1_col;

  453.         int available_l0 = temporal_luma_motion_vector(s, x0, y0, nPbW, nPbH,

  454.                                                        0, &mv_l0_col, 0);

  455.         int available_l1 = (s->sh.slice_type == B_SLICE) ?

  456.                            temporal_luma_motion_vector(s, x0, y0, nPbW, nPbH,

  457.                                                        0, &mv_l1_col, 1) : 0;

  458. 

  459.         if (available_l0 || available_l1) {

  460.             mergecandlist[nb_merge_cand].is_intra     = 0;

  461.             mergecandlist[nb_merge_cand].pred_flag[0] = available_l0;

  462.             mergecandlist[nb_merge_cand].pred_flag[1] = available_l1;

  463.             if (available_l0) {

  464.                 mergecandlist[nb_merge_cand].mv[0]      = mv_l0_col;

  465.                 mergecandlist[nb_merge_cand].ref_idx[0] = 0;

  466.             }

  467.             if (available_l1) {

  468.                 mergecandlist[nb_merge_cand].mv[1]      = mv_l1_col;

  469.                 mergecandlist[nb_merge_cand].ref_idx[1] = 0;

  470.             }

  471.             nb_merge_cand++;

  472.         }

  473.     }

  474. 

  475.     nb_orig_merge_cand = nb_merge_cand;

  476. 

  477.     // combined bi-predictive merge candidates  (applies for B slices)

  478.     if (s->sh.slice_type == B_SLICE && nb_orig_merge_cand > 1 &&

  479.         nb_orig_merge_cand < s->sh.max_num_merge_cand) {

  480.         int comb_idx;

  481. 

  482.         for (comb_idx = 0; nb_merge_cand < s->sh.max_num_merge_cand &&

  483.                            comb_idx < nb_orig_merge_cand * (nb_orig_merge_cand - 1); comb_idx++) {

  484.             int l0_cand_idx = l0_l1_cand_idx[comb_idx][0];

  485.             int l1_cand_idx = l0_l1_cand_idx[comb_idx][1];

  486.             MvField l0_cand = mergecandlist[l0_cand_idx];

  487.             MvField l1_cand = mergecandlist[l1_cand_idx];

  488. 

  489.             if (l0_cand.pred_flag[0] && l1_cand.pred_flag[1] &&

  490.                 (refPicList[0].list[l0_cand.ref_idx[0]] !=

  491.                  refPicList[1].list[l1_cand.ref_idx[1]] ||

  492.                  l0_cand.mv[0].x != l1_cand.mv[1].x ||

  493.                  l0_cand.mv[0].y != l1_cand.mv[1].y)) {

  494.                 mergecandlist[nb_merge_cand].ref_idx[0]   = l0_cand.ref_idx[0];

  495.                 mergecandlist[nb_merge_cand].ref_idx[1]   = l1_cand.ref_idx[1];

  496.                 mergecandlist[nb_merge_cand].pred_flag[0] = 1;

  497.                 mergecandlist[nb_merge_cand].pred_flag[1] = 1;

  498.                 mergecandlist[nb_merge_cand].mv[0].x      = l0_cand.mv[0].x;

  499.                 mergecandlist[nb_merge_cand].mv[0].y      = l0_cand.mv[0].y;

  500.                 mergecandlist[nb_merge_cand].mv[1].x      = l1_cand.mv[1].x;

  501.                 mergecandlist[nb_merge_cand].mv[1].y      = l1_cand.mv[1].y;

  502.                 mergecandlist[nb_merge_cand].is_intra     = 0;

  503.                 nb_merge_cand++;

  504.             }

  505.         }

  506.     }

  507. 

  508.     // append Zero motion vector candidates

  509.     while (nb_merge_cand < s->sh.max_num_merge_cand) {

  510.         mergecandlist[nb_merge_cand].pred_flag[0] = 1;

  511.         mergecandlist[nb_merge_cand].pred_flag[1] = s->sh.slice_type == B_SLICE;

  512.         mergecandlist[nb_merge_cand].mv[0].x      = 0;

  513.         mergecandlist[nb_merge_cand].mv[0].y      = 0;

  514.         mergecandlist[nb_merge_cand].mv[1].x      = 0;

  515.         mergecandlist[nb_merge_cand].mv[1].y      = 0;

  516.         mergecandlist[nb_merge_cand].is_intra     = 0;

  517.         mergecandlist[nb_merge_cand].ref_idx[0]   = zero_idx < nb_refs ? zero_idx : 0;

  518.         mergecandlist[nb_merge_cand].ref_idx[1]   = zero_idx < nb_refs ? zero_idx : 0;

  519. 

  520.         nb_merge_cand++;

  521.         zero_idx++;

  522.     }

  523. }

  524. 

  525. /*

  526.  * 8.5.3.1.1 Derivation process of luma Mvs for merge mode

  527.  */

  528. void ff_hevc_luma_mv_merge_mode(HEVCContext *s, int x0, int y0, int nPbW,

  529.                                 int nPbH, int log2_cb_size, int part_idx,

  530.                                 int merge_idx, MvField *mv)

  531. {

  532.     int singleMCLFlag = 0;

  533.     int nCS = 1 << log2_cb_size;

  534.     struct MvField mergecand_list[MRG_MAX_NUM_CANDS] = { { { { 0 } } } };

  535.     int nPbW2 = nPbW;

  536.     int nPbH2 = nPbH;

  537.     HEVCLocalContext *lc = &s->HEVClc;

  538. 

  539.     if (s->pps->log2_parallel_merge_level > 2 && nCS == 8) {

  540.         singleMCLFlag = 1;

  541.         x0            = lc->cu.x;

  542.         y0            = lc->cu.y;

  543.         nPbW          = nCS;

  544.         nPbH          = nCS;

  545.         part_idx      = 0;

  546.     }

  547. 

  548.     ff_hevc_set_neighbour_available(s, x0, y0, nPbW, nPbH);

  549.     derive_spatial_merge_candidates(s, x0, y0, nPbW, nPbH, log2_cb_size,

  550.                                     singleMCLFlag, part_idx, mergecand_list);

  551. 

  552.     if (mergecand_list[merge_idx].pred_flag[0] == 1 &&

  553.         mergecand_list[merge_idx].pred_flag[1] == 1 &&

  554.         (nPbW2 + nPbH2) == 12) {

  555.         mergecand_list[merge_idx].ref_idx[1]   = -1;

  556.         mergecand_list[merge_idx].pred_flag[1] = 0;

  557.     }

  558. 

  559.     *mv = mergecand_list[merge_idx];

  560. }

  561. 

  562. static av_always_inline void dist_scale(HEVCContext *s, Mv *mv,

  563.                                         int min_pu_width, int x, int y,

  564.                                         int elist, int ref_idx_curr, int ref_idx)

  565. {

  566.     RefPicList *refPicList = s->ref->refPicList;

  567.     MvField *tab_mvf       = s->ref->tab_mvf;

  568.     int ref_pic_elist      = refPicList[elist].list[TAB_MVF(x, y).ref_idx[elist]];

  569.     int ref_pic_curr       = refPicList[ref_idx_curr].list[ref_idx];

  570. 

  571.     if (ref_pic_elist != ref_pic_curr) {

  572.         int poc_diff = s->poc - ref_pic_elist;

  573.         if (!poc_diff)

  574.             poc_diff = 1;

  575.         mv_scale(mv, mv, poc_diff, s->poc - ref_pic_curr);

  576.     }

  577. }

  578. 

  579. static int mv_mp_mode_mx(HEVCContext *s, int x, int y, int pred_flag_index,

  580.                          Mv *mv, int ref_idx_curr, int ref_idx)

  581. {

  582.     MvField *tab_mvf = s->ref->tab_mvf;

  583.     int min_pu_width = s->sps->min_pu_width;

  584. 

  585.     RefPicList *refPicList = s->ref->refPicList;

  586. 

  587.     if (TAB_MVF(x, y).pred_flag[pred_flag_index] == 1 &&

  588.         refPicList[pred_flag_index].list[TAB_MVF(x, y).ref_idx[pred_flag_index]] == refPicList[ref_idx_curr].list[ref_idx]) {

  589.         *mv = TAB_MVF(x, y).mv[pred_flag_index];

  590.         return 1;

  591.     }

  592.     return 0;

  593. }

  594. 

  595. static int mv_mp_mode_mx_lt(HEVCContext *s, int x, int y, int pred_flag_index,

  596.                             Mv *mv, int ref_idx_curr, int ref_idx)

  597. {

  598.     MvField *tab_mvf = s->ref->tab_mvf;

  599.     int min_pu_width = s->sps->min_pu_width;

  600. 

  601.     RefPicList *refPicList = s->ref->refPicList;

  602.     int currIsLongTerm     = refPicList[ref_idx_curr].isLongTerm[ref_idx];

  603. 

  604.     int colIsLongTerm =

  605.         refPicList[pred_flag_index].isLongTerm[(TAB_MVF(x, y).ref_idx[pred_flag_index])];

  606. 

  607.     if (TAB_MVF(x, y).pred_flag[pred_flag_index] &&

  608.         colIsLongTerm == currIsLongTerm) {

  609.         *mv = TAB_MVF(x, y).mv[pred_flag_index];

  610.         if (!currIsLongTerm)

  611.             dist_scale(s, mv, min_pu_width, x, y,

  612.                        pred_flag_index, ref_idx_curr, ref_idx);

  613.         return 1;

  614.     }

  615.     return 0;

  616. }

  617. 

  618. #define MP_MX(v, pred, mx)                                      \

  619.     mv_mp_mode_mx(s, x ## v ## _pu, y ## v ## _pu, pred,        \

  620.                   &mx, ref_idx_curr, ref_idx)

  621. 

  622. #define MP_MX_LT(v, pred, mx)                                   \

  623.     mv_mp_mode_mx_lt(s, x ## v ## _pu, y ## v ## _pu, pred,     \

  624.                      &mx, ref_idx_curr, ref_idx)

  625. 

  626. void ff_hevc_luma_mv_mvp_mode(HEVCContext *s, int x0, int y0, int nPbW,

  627.                               int nPbH, int log2_cb_size, int part_idx,

  628.                               int merge_idx, MvField *mv,

  629.                               int mvp_lx_flag, int LX)

  630. {

  631.     HEVCLocalContext *lc = &s->HEVClc;

  632.     MvField *tab_mvf = s->ref->tab_mvf;

  633.     int isScaledFlag_L0 = 0;

  634.     int availableFlagLXA0 = 0;

  635.     int availableFlagLXB0 = 0;

  636.     int numMVPCandLX = 0;

  637.     int min_pu_width = s->sps->min_pu_width;

  638. 

  639.     int xA0, yA0;

  640.     int xA0_pu, yA0_pu;

  641.     int is_available_a0;

  642. 

  643.     int xA1, yA1;

  644.     int xA1_pu, yA1_pu;

  645.     int is_available_a1;

  646. 

  647.     int xB0, yB0;

  648.     int xB0_pu, yB0_pu;

  649.     int is_available_b0;

  650. 

  651.     int xB1, yB1;

  652.     int xB1_pu = 0, yB1_pu = 0;

  653.     int is_available_b1 = 0;

  654. 

  655.     int xB2, yB2;

  656.     int xB2_pu = 0, yB2_pu = 0;

  657.     int is_available_b2 = 0;

  658.     Mv mvpcand_list[2] = { { 0 } };

  659.     Mv mxA = { 0 };

  660.     Mv mxB = { 0 };

  661.     int ref_idx_curr = 0;

  662.     int ref_idx = 0;

  663.     int pred_flag_index_l0;

  664.     int pred_flag_index_l1;

  665.     int x0b = x0 & ((1 << s->sps->log2_ctb_size) - 1);

  666.     int y0b = y0 & ((1 << s->sps->log2_ctb_size) - 1);

  667. 

  668.     int cand_up = (lc->ctb_up_flag || y0b);

  669.     int cand_left = (lc->ctb_left_flag || x0b);

  670.     int cand_up_left =

  671.             (!x0b && !y0b) ? lc->ctb_up_left_flag : cand_left && cand_up;

  672.     int cand_up_right =

  673.             (x0b + nPbW == (1 << s->sps->log2_ctb_size) ||

  674.              x0  + nPbW >= lc->end_of_tiles_x) ? lc->ctb_up_right_flag && !y0b

  675.                                                : cand_up;

  676.     int cand_bottom_left = (y0 + nPbH >= lc->end_of_tiles_y) ? 0 : cand_left;

  677. 

  678.     ref_idx_curr       = LX;

  679.     ref_idx            = mv->ref_idx[LX];

  680.     pred_flag_index_l0 = LX;

  681.     pred_flag_index_l1 = !LX;

  682. 

  683.     // left bottom spatial candidate

  684.     xA0 = x0 - 1;

  685.     yA0 = y0 + nPbH;

  686.     xA0_pu = xA0 >> s->sps->log2_min_pu_size;

  687.     yA0_pu = yA0 >> s->sps->log2_min_pu_size;

  688. 

  689.     is_available_a0 = PRED_BLOCK_AVAILABLE(A0) && AVAILABLE(cand_bottom_left, A0);

  690. 

  691.     //left spatial merge candidate

  692.     xA1    = x0 - 1;

  693.     yA1    = y0 + nPbH - 1;

  694.     xA1_pu = xA1 >> s->sps->log2_min_pu_size;

  695.     yA1_pu = yA1 >> s->sps->log2_min_pu_size;

  696. 

  697.     is_available_a1 = AVAILABLE(cand_left, A1);

  698.     if (is_available_a0 || is_available_a1)

  699.         isScaledFlag_L0 = 1;

  700. 

  701.     if (is_available_a0) {

  702.         availableFlagLXA0 = MP_MX(A0, pred_flag_index_l0, mxA);

  703.         if (!availableFlagLXA0)

  704.             availableFlagLXA0 = MP_MX(A0, pred_flag_index_l1, mxA);

  705.     }

  706. 

  707.     if (is_available_a1 && !availableFlagLXA0) {

  708.         availableFlagLXA0 = MP_MX(A1, pred_flag_index_l0, mxA);

  709.         if (!availableFlagLXA0)

  710.             availableFlagLXA0 = MP_MX(A1, pred_flag_index_l1, mxA);

  711.     }

  712. 

  713.     if (is_available_a0 && !availableFlagLXA0) {

  714.         availableFlagLXA0 = MP_MX_LT(A0, pred_flag_index_l0, mxA);

  715.         if (!availableFlagLXA0)

  716.             availableFlagLXA0 = MP_MX_LT(A0, pred_flag_index_l1, mxA);

  717.     }

  718. 

  719.     if (is_available_a1 && !availableFlagLXA0) {

  720.         availableFlagLXA0 = MP_MX_LT(A1, pred_flag_index_l0, mxA);

  721.         if (!availableFlagLXA0)

  722.             availableFlagLXA0 = MP_MX_LT(A1, pred_flag_index_l1, mxA);

  723.     }

  724. 

  725.     // B candidates

  726.     // above right spatial merge candidate

  727.     xB0    = x0 + nPbW;

  728.     yB0    = y0 - 1;

  729.     xB0_pu = xB0 >> s->sps->log2_min_pu_size;

  730.     yB0_pu = yB0 >> s->sps->log2_min_pu_size;

  731. 

  732.     is_available_b0 = PRED_BLOCK_AVAILABLE(B0) && AVAILABLE(cand_up_right, B0);

  733. 

  734.     if (is_available_b0) {

  735.         availableFlagLXB0 = MP_MX(B0, pred_flag_index_l0, mxB);

  736.         if (!availableFlagLXB0)

  737.             availableFlagLXB0 = MP_MX(B0, pred_flag_index_l1, mxB);

  738.     }

  739. 

  740.     if (!availableFlagLXB0) {

  741.         // above spatial merge candidate

  742.         xB1    = x0 + nPbW - 1;

  743.         yB1    = y0 - 1;

  744.         xB1_pu = xB1 >> s->sps->log2_min_pu_size;

  745.         yB1_pu = yB1 >> s->sps->log2_min_pu_size;

  746. 

  747.         is_available_b1 = AVAILABLE(cand_up, B1);

  748. 

  749.         if (is_available_b1) {

  750.             availableFlagLXB0 = MP_MX(B1, pred_flag_index_l0, mxB);

  751.             if (!availableFlagLXB0)

  752.                 availableFlagLXB0 = MP_MX(B1, pred_flag_index_l1, mxB);

  753.         }

  754.     }

  755. 

  756.     if (!availableFlagLXB0) {

  757.         // above left spatial merge candidate

  758.         xB2 = x0 - 1;

  759.         yB2 = y0 - 1;

  760.         xB2_pu = xB2 >> s->sps->log2_min_pu_size;

  761.         yB2_pu = yB2 >> s->sps->log2_min_pu_size;

  762.         is_available_b2 = AVAILABLE(cand_up_left, B2);

  763. 

  764.         if (is_available_b2) {

  765.             availableFlagLXB0 = MP_MX(B2, pred_flag_index_l0, mxB);

  766.             if (!availableFlagLXB0)

  767.                 availableFlagLXB0 = MP_MX(B2, pred_flag_index_l1, mxB);

  768.         }

  769.     }

  770. 

  771.     if (isScaledFlag_L0 == 0) {

  772.         if (availableFlagLXB0) {

  773.             availableFlagLXA0 = 1;

  774.             mxA = mxB;

  775.         }

  776.         availableFlagLXB0 = 0;

  777. 

  778.         // XB0 and L1

  779.         if (is_available_b0) {

  780.             availableFlagLXB0 = MP_MX_LT(B0, pred_flag_index_l0, mxB);

  781.             if (!availableFlagLXB0)

  782.                 availableFlagLXB0 = MP_MX_LT(B0, pred_flag_index_l1, mxB);

  783.         }

  784. 

  785.         if (is_available_b1 && !availableFlagLXB0) {

  786.             availableFlagLXB0 = MP_MX_LT(B1, pred_flag_index_l0, mxB);

  787.             if (!availableFlagLXB0)

  788.                 availableFlagLXB0 = MP_MX_LT(B1, pred_flag_index_l1, mxB);

  789.         }

  790. 

  791.         if (is_available_b2 && !availableFlagLXB0) {

  792.             availableFlagLXB0 = MP_MX_LT(B2, pred_flag_index_l0, mxB);

  793.             if (!availableFlagLXB0)

  794.                 availableFlagLXB0 = MP_MX_LT(B2, pred_flag_index_l1, mxB);

  795.         }

  796.     }

  797. 

  798.     if (availableFlagLXA0)

  799.         mvpcand_list[numMVPCandLX++] = mxA;

  800. 

  801.     if (availableFlagLXB0 && (!availableFlagLXA0 || mxA.x != mxB.x || mxA.y != mxB.y))

  802.         mvpcand_list[numMVPCandLX++] = mxB;

  803. 

  804.     //temporal motion vector prediction candidate

  805.     if (numMVPCandLX < 2 && s->sh.slice_temporal_mvp_enabled_flag) {

  806.         Mv mv_col;

  807.         int available_col = temporal_luma_motion_vector(s, x0, y0, nPbW,

  808.                                                         nPbH, ref_idx,

  809.                                                         &mv_col, LX);

  810.         if (available_col)

  811.             mvpcand_list[numMVPCandLX++] = mv_col;

  812.     }

  813. 

  814.     // insert zero motion vectors when the number of available candidates are less than 2

  815.     while (numMVPCandLX < 2)

  816.         mvpcand_list[numMVPCandLX++] = (Mv){ 0, 0 };

  817. 

  818.     mv->mv[LX].x = mvpcand_list[mvp_lx_flag].x;

  819.     mv->mv[LX].y = mvpcand_list[mvp_lx_flag].y;

  820. }