lavc: add a HEVC decoder.

Initially written by Guillaume Martres <smarter@ubuntu.com> as a GSoC
project. Further contributions by the OpenHEVC project and other
developers, namely:

Mickaël Raulet <mraulet@insa-rennes.fr>
Seppo Tomperi <seppo.tomperi@vtt.fi>
Gildas Cocherel <gildas.cocherel@laposte.net>
Khaled Jerbi <khaled_jerbi@yahoo.fr>
Wassim Hamidouche <wassim.hamidouche@insa-rennes.fr>
Vittorio Giovara <vittorio.giovara@gmail.com>
Jan Ekström <jeebjp@gmail.com>
Anton Khirnov <anton@khirnov.net>
Martin Storsjö <martin@martin.st>
Luca Barbato <lu_zero@gentoo.org>
Yusuke Nakamura <muken.the.vfrmaniac@gmail.com>

Signed-off-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 1011 insertions, 0 deletions

diff --git a/libavcodec/hevc_mvs.c b/libavcodec/hevc_mvs.c
new file mode 100644
index 0000000000..f23a0d9e12
--- /dev/null
+++ b/libavcodec/hevc_mvs.c
@@ -0,0 +1,1011 @@
+/*
+ * HEVC video Decoder
+ *
+ * Copyright (C) 2012 - 2013 Guillaume Martres
+ * Copyright (C) 2013 Anand Meher Kotra
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "hevc.h"
+
+static const uint8_t l0_l1_cand_idx[12][2] = {
+    { 0, 1, },
+    { 1, 0, },
+    { 0, 2, },
+    { 2, 0, },
+    { 1, 2, },
+    { 2, 1, },
+    { 0, 3, },
+    { 3, 0, },
+    { 1, 3, },
+    { 3, 1, },
+    { 2, 3, },
+    { 3, 2, },
+};
+
+void ff_hevc_set_neighbour_available(HEVCContext *s, int x0, int y0, int nPbW, int nPbH)
+{
+    HEVCLocalContext *lc = &s->HEVClc;
+    int x0b = x0 & ((1 << s->sps->log2_ctb_size) - 1);
+    int y0b = y0 & ((1 << s->sps->log2_ctb_size) - 1);
+
+    lc->na.cand_up       = (lc->ctb_up_flag   || y0b);
+    lc->na.cand_left     = (lc->ctb_left_flag || x0b);
+    lc->na.cand_up_left  = (!x0b && !y0b) ? lc->ctb_up_left_flag : lc->na.cand_left && lc->na.cand_up;
+    lc->na.cand_up_right_sap =
+            ((x0b + nPbW) == (1 << s->sps->log2_ctb_size)) ?
+                    lc->ctb_up_right_flag && !y0b : lc->na.cand_up;
+    lc->na.cand_up_right =
+            ((x0b + nPbW) == (1 << s->sps->log2_ctb_size) ?
+                    lc->ctb_up_right_flag && !y0b : lc->na.cand_up )
+                     && (x0 + nPbW) < lc->end_of_tiles_x;
+    lc->na.cand_bottom_left = ((y0 + nPbH) >= lc->end_of_tiles_y) ? 0 : lc->na.cand_left;
+}
+
+/*
+ * 6.4.1 Derivation process for z-scan order block availability
+ */
+static int z_scan_block_avail(HEVCContext *s, int xCurr, int yCurr,
+                              int xN, int yN)
+{
+#define MIN_TB_ADDR_ZS(x, y)                                            \
+    s->pps->min_tb_addr_zs[(y) * s->sps->min_tb_width + (x)]
+    int Curr =  MIN_TB_ADDR_ZS(xCurr >> s->sps->log2_min_transform_block_size,
+                               yCurr >> s->sps->log2_min_transform_block_size);
+    int N;
+
+    if ((xN < 0) || (yN < 0) ||
+        (xN >= s->sps->width) ||
+        (yN >= s->sps->height))
+        return 0;
+
+    N = MIN_TB_ADDR_ZS(xN >> s->sps->log2_min_transform_block_size,
+                       yN >> s->sps->log2_min_transform_block_size);
+
+    return N <= Curr;
+}
+
+
+static int same_prediction_block(HEVCLocalContext *lc, int log2_cb_size,
+                                 int x0, int y0, int nPbW, int nPbH,
+                                 int xA1, int yA1, int partIdx)
+{
+    return !(nPbW << 1 == 1 << log2_cb_size &&
+             nPbH << 1 == 1 << log2_cb_size && partIdx == 1 &&
+             lc->cu.x + nPbW > xA1 &&
+             lc->cu.y + nPbH <= yA1);
+}
+
+/*
+ * 6.4.2 Derivation process for prediction block availability
+ */
+static int check_prediction_block_available(HEVCContext *s, int log2_cb_size,
+                                            int x0, int y0, int nPbW, int nPbH,
+                                            int xA1, int yA1, int partIdx)
+{
+    HEVCLocalContext *lc = &s->HEVClc;
+
+    if (lc->cu.x < xA1 && lc->cu.y < yA1 &&
+        (lc->cu.x + (1 << log2_cb_size)) > xA1 &&
+        (lc->cu.y + (1 << log2_cb_size)) > yA1)
+        return same_prediction_block(lc, log2_cb_size, x0, y0,
+                                     nPbW, nPbH, xA1, yA1, partIdx);
+    else
+        return z_scan_block_avail(s, x0, y0, xA1, yA1);
+}
+
+//check if the two luma locations belong to the same mostion estimation region
+static int isDiffMER(HEVCContext *s, int xN, int yN, int xP, int yP)
+{
+    uint8_t plevel = s->pps->log2_parallel_merge_level;
+
+    return xN >> plevel == xP >> plevel &&
+           yN >> plevel == yP >> plevel;
+}
+
+#define MATCH(x) (A.x == B.x)
+
+// check if the mv's and refidx are the same between A and B
+static int compareMVrefidx(struct MvField A, struct MvField B)
+{
+    if (A.pred_flag[0] && A.pred_flag[1] && B.pred_flag[0] && B.pred_flag[1])
+        return MATCH(ref_idx[0]) && MATCH(mv[0].x) && MATCH(mv[0].y) &&
+               MATCH(ref_idx[1]) && MATCH(mv[1].x) && MATCH(mv[1].y);
+
+    if (A.pred_flag[0] && !A.pred_flag[1] && B.pred_flag[0] && !B.pred_flag[1])
+        return MATCH(ref_idx[0]) && MATCH(mv[0].x) && MATCH(mv[0].y);
+
+    if (!A.pred_flag[0] && A.pred_flag[1] && !B.pred_flag[0] && B.pred_flag[1])
+        return MATCH(ref_idx[1]) && MATCH(mv[1].x) && MATCH(mv[1].y);
+
+    return 0;
+}
+
+static av_always_inline void mv_scale(Mv *dst, Mv *src, int td, int tb)
+{
+    int tx, scale_factor;
+
+    td = av_clip_int8_c(td);
+    tb = av_clip_int8_c(tb);
+    tx = (0x4000 + abs(td / 2)) / td;
+    scale_factor = av_clip_c((tb * tx + 32) >> 6, -4096, 4095);
+    dst->x = av_clip_int16_c((scale_factor * src->x + 127 +
+                             (scale_factor * src->x < 0)) >> 8);
+    dst->y = av_clip_int16_c((scale_factor * src->y + 127 +
+                             (scale_factor * src->y < 0)) >> 8);
+}
+
+static int check_mvset(Mv *mvLXCol, Mv *mvCol,
+                       int colPic, int poc,
+                       RefPicList *refPicList, int X, int refIdxLx,
+                       RefPicList *refPicList_col, int listCol, int refidxCol)
+{
+    int cur_lt = refPicList[X].isLongTerm[refIdxLx];
+    int col_lt = refPicList_col[listCol].isLongTerm[refidxCol];
+    int col_poc_diff, cur_poc_diff;
+
+    if (cur_lt != col_lt) {
+        mvLXCol->x = 0;
+        mvLXCol->y = 0;
+        return 0;
+    }
+
+    col_poc_diff = colPic - refPicList_col[listCol].list[refidxCol];
+    cur_poc_diff = poc    - refPicList[X].list[refIdxLx];
+
+    if (!col_poc_diff)
+        col_poc_diff = 1; // error resilience
+
+    if (cur_lt || col_poc_diff == cur_poc_diff) {
+        mvLXCol->x = mvCol->x;
+        mvLXCol->y = mvCol->y;
+    } else {
+        mv_scale(mvLXCol, mvCol, col_poc_diff, cur_poc_diff);
+    }
+    return 1;
+}
+
+#define CHECK_MVSET(l) \
+    check_mvset(mvLXCol, temp_col.mv + l, \
+                colPic, s->poc, \
+                refPicList, X, refIdxLx, \
+                refPicList_col, L##l, temp_col.ref_idx[l])
+
+// derive the motion vectors section 8.5.3.1.8
+static int derive_temporal_colocated_mvs(HEVCContext *s, MvField temp_col,
+                                         int refIdxLx, Mv* mvLXCol, int X,
+                                         int colPic, RefPicList* refPicList_col)
+{
+    RefPicList *refPicList = s->ref->refPicList;
+
+    if (temp_col.is_intra) {
+        mvLXCol->x = 0;
+        mvLXCol->y = 0;
+        return 0;
+    }
+
+    if (temp_col.pred_flag[0] == 0)
+        return CHECK_MVSET(1);
+    else if (temp_col.pred_flag[0] == 1 && temp_col.pred_flag[1] == 0)
+        return CHECK_MVSET(0);
+    else if (temp_col.pred_flag[0] == 1 && temp_col.pred_flag[1] == 1) {
+        int check_diffpicount = 0;
+        int i = 0;
+        for (i = 0; i < refPicList[0].nb_refs; i++) {
+            if (refPicList[0].list[i] > s->poc)
+                check_diffpicount++;
+        }
+        for (i = 0; i < refPicList[1].nb_refs; i++) {
+            if (refPicList[1].list[i] > s->poc)
+                check_diffpicount++;
+        }
+        if (check_diffpicount == 0 && X == 0)
+            return CHECK_MVSET(0);
+        else if (check_diffpicount == 0 && X == 1)
+            return CHECK_MVSET(1);
+        else {
+            if (s->sh.collocated_list == L1)
+                return CHECK_MVSET(0);
+            else
+                return CHECK_MVSET(1);
+        }
+    }
+
+    return 0;
+}
+
+#define TAB_MVF(x, y) \
+    tab_mvf[(y) * pic_width_in_min_pu + x]
+
+#define TAB_MVF_PU(v) \
+    TAB_MVF(x##v##_pu, y##v##_pu)
+
+#define DERIVE_TEMPORAL_COLOCATED_MVS(v) \
+    derive_temporal_colocated_mvs(s, temp_col, \
+                                  refIdxLx, mvLXCol, X, colPic, \
+                                  ff_hevc_get_ref_list(s, ref, \
+                                                       x##v, y##v))
+
+/*
+ * 8.5.3.1.7  temporal luma motion vector prediction
+ */
+static int temporal_luma_motion_vector(HEVCContext *s, int x0, int y0,
+                                       int nPbW, int nPbH, int refIdxLx,
+                                       Mv* mvLXCol, int X)
+{
+    MvField *tab_mvf;
+    MvField temp_col;
+    int xPRb, yPRb;
+    int xPRb_pu;
+    int yPRb_pu;
+    int xPCtr, yPCtr;
+    int xPCtr_pu;
+    int yPCtr_pu;
+    int pic_width_in_min_pu = s->sps->width >> s->sps->log2_min_pu_size;
+    int availableFlagLXCol = 0;
+    int colPic;
+
+    HEVCFrame *ref = s->ref->collocated_ref;
+
+    if (!ref)
+        return 0;
+
+    tab_mvf = ref->tab_mvf;
+    colPic  = ref->poc;
+
+    //bottom right collocated motion vector
+    xPRb = x0 + nPbW;
+    yPRb = y0 + nPbH;
+
+    ff_thread_await_progress(&ref->tf, INT_MAX, 0);
+    if (tab_mvf &&
+        y0 >> s->sps->log2_ctb_size == yPRb >> s->sps->log2_ctb_size &&
+        yPRb < s->sps->height &&
+        xPRb < s->sps->width) {
+        xPRb = ((xPRb >> 4) << 4);
+        yPRb = ((yPRb >> 4) << 4);
+        xPRb_pu = xPRb >> s->sps->log2_min_pu_size;
+        yPRb_pu = yPRb >> s->sps->log2_min_pu_size;
+        temp_col = TAB_MVF_PU(PRb);
+        availableFlagLXCol = DERIVE_TEMPORAL_COLOCATED_MVS(PRb);
+    } else {
+        mvLXCol->x = 0;
+        mvLXCol->y = 0;
+        availableFlagLXCol = 0;
+    }
+
+    // derive center collocated motion vector
+    if (tab_mvf && availableFlagLXCol == 0) {
+        xPCtr = x0 + (nPbW >> 1);
+        yPCtr = y0 + (nPbH >> 1);
+        xPCtr = ((xPCtr >> 4) << 4);
+        yPCtr = ((yPCtr >> 4) << 4);
+        xPCtr_pu = xPCtr >> s->sps->log2_min_pu_size;
+        yPCtr_pu = yPCtr >> s->sps->log2_min_pu_size;
+        temp_col = TAB_MVF_PU(PCtr);
+        availableFlagLXCol = DERIVE_TEMPORAL_COLOCATED_MVS(PCtr);
+    }
+    return availableFlagLXCol;
+}
+
+#define AVAILABLE(cand, v) \
+    (cand && !TAB_MVF_PU(v).is_intra)
+
+#define PRED_BLOCK_AVAILABLE(v) \
+    check_prediction_block_available(s, log2_cb_size, \
+                                     x0, y0, nPbW, nPbH, \
+                                     x##v, y##v, part_idx)
+
+#define COMPARE_MV_REFIDX(a, b) \
+    compareMVrefidx(TAB_MVF_PU(a), TAB_MVF_PU(b))
+
+/*
+ * 8.5.3.1.2  Derivation process for spatial merging candidates
+ */
+static void derive_spatial_merge_candidates(HEVCContext *s, int x0, int y0,
+                                            int nPbW, int nPbH, int log2_cb_size,
+                                            int singleMCLFlag, int part_idx,
+                                            struct MvField mergecandlist[])
+{
+    HEVCLocalContext *lc = &s->HEVClc;
+    RefPicList *refPicList = s->ref->refPicList;
+    MvField *tab_mvf = s->ref->tab_mvf;
+
+    int available_a1_flag = 0;
+    int available_b1_flag = 0;
+    int available_b0_flag = 0;
+    int available_a0_flag = 0;
+    int available_b2_flag = 0;
+    struct MvField spatialCMVS[MRG_MAX_NUM_CANDS];
+    struct MvField combCand = { { { 0 } } };
+    struct MvField TMVPCand = { { { 0 } } };
+    struct Mv mvL0Col = { 0 };
+    struct Mv mvL1Col = { 0 };
+
+    //first left spatial merge candidate
+    int xA1 = x0 - 1;
+    int yA1 = y0 + nPbH - 1;
+    int is_available_a1;
+    int pic_width_in_min_pu = s->sps->width >> s->sps->log2_min_pu_size;
+
+    int check_MER = 1;
+    int check_MER_1 = 1;
+
+    int xB1, yB1;
+    int is_available_b1;
+    int xB1_pu;
+    int yB1_pu;
+
+    int check_B0;
+    int xB0, yB0;
+    int isAvailableB0;
+    int xB0_pu;
+    int yB0_pu;
+
+    int check_A0;
+    int xA0, yA0;
+    int is_available_a0;
+    int xA0_pu;
+    int yA0_pu;
+
+    int xB2, yB2;
+    int isAvailableB2;
+    int xB2_pu;
+    int yB2_pu;
+    int mergearray_index = 0;
+
+    struct MvField zerovector;
+    int numRefIdx = 0;
+    int zeroIdx = 0;
+
+    int numMergeCand = 0;
+    int numOrigMergeCand = 0;
+    int sumcandidates = 0;
+    int combIdx = 0;
+    int combStop = 0;
+    int l0CandIdx = 0;
+    int l1CandIdx = 0;
+
+    int refIdxL0Col = 0;
+    int refIdxL1Col = 0;
+    int availableFlagLXCol = 0;
+
+    int cand_bottom_left = lc->na.cand_bottom_left;
+    int cand_left        = lc->na.cand_left;
+    int cand_up_left     = lc->na.cand_up_left;
+    int cand_up          = lc->na.cand_up;
+    int cand_up_right    = lc->na.cand_up_right_sap;
+
+
+    int xA1_pu = xA1 >> s->sps->log2_min_pu_size;
+    int yA1_pu = yA1 >> s->sps->log2_min_pu_size;
+
+    int availableFlagL0Col = 0;
+    int availableFlagL1Col = 0;
+
+    is_available_a1 = AVAILABLE(cand_left, A1);
+
+    if (!singleMCLFlag && part_idx == 1 &&
+        (lc->cu.part_mode == PART_Nx2N ||
+         lc->cu.part_mode == PART_nLx2N ||
+         lc->cu.part_mode == PART_nRx2N) ||
+        isDiffMER(s, xA1, yA1, x0, y0)) {
+        is_available_a1 = 0;
+    }
+
+    if (is_available_a1) {
+        available_a1_flag = 1;
+        spatialCMVS[0] = TAB_MVF_PU(A1);
+    } else {
+        available_a1_flag = 0;
+        spatialCMVS[0].ref_idx[0] = -1;
+        spatialCMVS[0].ref_idx[1] = -1;
+        spatialCMVS[0].mv[0].x = 0;
+        spatialCMVS[0].mv[0].y = 0;
+        spatialCMVS[0].mv[1].x = 0;
+        spatialCMVS[0].mv[1].y = 0;
+        spatialCMVS[0].pred_flag[0] = 0;
+        spatialCMVS[0].pred_flag[1] = 0;
+        spatialCMVS[0].is_intra = 0;
+    }
+
+    // above spatial merge candidate
+
+    xB1 = x0 + nPbW - 1;
+    yB1 = y0 - 1;
+    xB1_pu = xB1 >> s->sps->log2_min_pu_size;
+    yB1_pu = yB1 >> s->sps->log2_min_pu_size;
+
+    is_available_b1 = AVAILABLE(cand_up, B1);
+
+    if (!singleMCLFlag && part_idx == 1 &&
+        (lc->cu.part_mode == PART_2NxN ||
+         lc->cu.part_mode == PART_2NxnU ||
+         lc->cu.part_mode == PART_2NxnD) ||
+        isDiffMER(s, xB1, yB1, x0, y0)) {
+        is_available_b1 = 0;
+    }
+
+    if (is_available_a1 && is_available_b1)
+        check_MER = !COMPARE_MV_REFIDX(B1, A1);
+
+    if (is_available_b1 && check_MER) {
+        available_b1_flag = 1;
+        spatialCMVS[1] = TAB_MVF_PU(B1);
+    } else {
+        available_b1_flag = 0;
+        spatialCMVS[1].ref_idx[0] = -1;
+        spatialCMVS[1].ref_idx[1] = -1;
+        spatialCMVS[1].mv[0].x = 0;
+        spatialCMVS[1].mv[0].y = 0;
+        spatialCMVS[1].mv[1].x = 0;
+        spatialCMVS[1].mv[1].y = 0;
+        spatialCMVS[1].pred_flag[0] = 0;
+        spatialCMVS[1].pred_flag[1] = 0;
+        spatialCMVS[1].is_intra = 0;
+    }
+
+    // above right spatial merge candidate
+    xB0 = x0 + nPbW;
+    yB0 = y0 - 1;
+    check_MER = 1;
+    xB0_pu = xB0 >> s->sps->log2_min_pu_size;
+    yB0_pu = yB0 >> s->sps->log2_min_pu_size;
+    check_B0 = PRED_BLOCK_AVAILABLE(B0);
+
+    isAvailableB0 = check_B0 && AVAILABLE(cand_up_right, B0);
+
+    if (isDiffMER(s, xB0, yB0, x0, y0))
+        isAvailableB0 = 0;
+
+    if (is_available_b1 && isAvailableB0)
+        check_MER = !COMPARE_MV_REFIDX(B0, B1);
+
+    if (isAvailableB0 && check_MER) {
+        available_b0_flag = 1;
+        spatialCMVS[2] = TAB_MVF_PU(B0);
+    } else {
+        available_b0_flag = 0;
+        spatialCMVS[2].ref_idx[0] = -1;
+        spatialCMVS[2].ref_idx[1] = -1;
+        spatialCMVS[2].mv[0].x = 0;
+        spatialCMVS[2].mv[0].y = 0;
+        spatialCMVS[2].mv[1].x = 0;
+        spatialCMVS[2].mv[1].y = 0;
+        spatialCMVS[2].pred_flag[0] = 0;
+        spatialCMVS[2].pred_flag[1] = 0;
+        spatialCMVS[2].is_intra = 0;
+    }
+
+    // left bottom spatial merge candidate
+    xA0 = x0 - 1;
+    yA0 = y0 + nPbH;
+    check_MER = 1;
+    xA0_pu = xA0 >> s->sps->log2_min_pu_size;
+    yA0_pu = yA0 >> s->sps->log2_min_pu_size;
+    check_A0 = PRED_BLOCK_AVAILABLE(A0);
+
+    is_available_a0 = check_A0 && AVAILABLE(cand_bottom_left, A0);
+
+    if (isDiffMER(s, xA0, yA0, x0, y0))
+        is_available_a0 = 0;
+
+    if (is_available_a1 && is_available_a0)
+        check_MER = !COMPARE_MV_REFIDX(A0, A1);
+
+    if (is_available_a0 && check_MER) {
+        available_a0_flag = 1;
+        spatialCMVS[3] = TAB_MVF_PU(A0);
+    } else {
+        available_a0_flag = 0;
+        spatialCMVS[3].ref_idx[0] = -1;
+        spatialCMVS[3].ref_idx[1] = -1;
+        spatialCMVS[3].mv[0].x = 0;
+        spatialCMVS[3].mv[0].y = 0;
+        spatialCMVS[3].mv[1].x = 0;
+        spatialCMVS[3].mv[1].y = 0;
+        spatialCMVS[3].pred_flag[0] = 0;
+        spatialCMVS[3].pred_flag[1] = 0;
+        spatialCMVS[3].is_intra = 0;
+    }
+
+    // above left spatial merge candidate
+    xB2 = x0 - 1;
+    yB2 = y0 - 1;
+    check_MER = 1;
+    xB2_pu = xB2 >> s->sps->log2_min_pu_size;
+    yB2_pu = yB2 >> s->sps->log2_min_pu_size;
+
+    isAvailableB2 = AVAILABLE(cand_up_left, B2);
+
+    if (isDiffMER(s, xB2, yB2, x0, y0))
+        isAvailableB2 = 0;
+
+    if (is_available_a1 && isAvailableB2)
+        check_MER = !COMPARE_MV_REFIDX(B2, A1);
+
+    if (is_available_b1 && isAvailableB2)
+        check_MER_1 = !COMPARE_MV_REFIDX(B2, B1);
+
+    sumcandidates = available_a1_flag + available_b1_flag + available_b0_flag
+            + available_a0_flag;
+
+    if (isAvailableB2 && check_MER && check_MER_1 && sumcandidates != 4) {
+        available_b2_flag = 1;
+        spatialCMVS[4] = TAB_MVF_PU(B2);
+    } else {
+        available_b2_flag = 0;
+        spatialCMVS[4].ref_idx[0] = -1;
+        spatialCMVS[4].ref_idx[1] = -1;
+        spatialCMVS[4].mv[0].x = 0;
+        spatialCMVS[4].mv[0].y = 0;
+        spatialCMVS[4].mv[1].x = 0;
+        spatialCMVS[4].mv[1].y = 0;
+        spatialCMVS[4].pred_flag[0] = 0;
+        spatialCMVS[4].pred_flag[1] = 0;
+        spatialCMVS[4].is_intra = 0;
+    }
+
+    // temporal motion vector candidate
+    // one optimization is that do temporal checking only if the number of
+    // available candidates < MRG_MAX_NUM_CANDS
+    if (s->sh.slice_temporal_mvp_enabled_flag == 0) {
+        availableFlagLXCol = 0;
+    } else {
+        availableFlagL0Col = temporal_luma_motion_vector(s, x0, y0, nPbW, nPbH,
+                                                         refIdxL0Col, &mvL0Col, 0);
+        // one optimization is that l1 check can be done only when the current slice type is B_SLICE
+        if (s->sh.slice_type == B_SLICE) {
+            availableFlagL1Col = temporal_luma_motion_vector(s, x0, y0, nPbW,
+                                                             nPbH, refIdxL1Col, &mvL1Col, 1);
+        }
+        availableFlagLXCol = availableFlagL0Col || availableFlagL1Col;
+        if (availableFlagLXCol) {
+            TMVPCand.is_intra = 0;
+            TMVPCand.pred_flag[0] = availableFlagL0Col;
+            TMVPCand.pred_flag[1] = availableFlagL1Col;
+            if (TMVPCand.pred_flag[0]) {
+                TMVPCand.mv[0] = mvL0Col;
+                TMVPCand.ref_idx[0] = refIdxL0Col;
+            }
+            if (TMVPCand.pred_flag[1]) {
+                TMVPCand.mv[1] = mvL1Col;
+                TMVPCand.ref_idx[1] = refIdxL1Col;
+            }
+        }
+    }
+
+    if (available_a1_flag) {
+        mergecandlist[mergearray_index] = spatialCMVS[0];
+        mergearray_index++;
+    }
+    if (available_b1_flag) {
+        mergecandlist[mergearray_index] = spatialCMVS[1];
+        mergearray_index++;
+    }
+    if (available_b0_flag) {
+        mergecandlist[mergearray_index] = spatialCMVS[2];
+        mergearray_index++;
+    }
+    if (available_a0_flag) {
+        mergecandlist[mergearray_index] = spatialCMVS[3];
+        mergearray_index++;
+    }
+    if (available_b2_flag) {
+        mergecandlist[mergearray_index] = spatialCMVS[4];
+        mergearray_index++;
+    }
+    if (availableFlagLXCol && mergearray_index < s->sh.max_num_merge_cand) {
+        mergecandlist[mergearray_index] = TMVPCand;
+        mergearray_index++;
+    }
+    numMergeCand = mergearray_index;
+    numOrigMergeCand = mergearray_index;
+
+    // combined bi-predictive merge candidates  (applies for B slices)
+    if (s->sh.slice_type == B_SLICE) {
+        if (numOrigMergeCand > 1 &&
+            numOrigMergeCand < s->sh.max_num_merge_cand) {
+
+            combIdx = 0;
+            combStop = 0;
+            while (combStop != 1) {
+                MvField l0Cand;
+                MvField l1Cand;
+                l0CandIdx = l0_l1_cand_idx[combIdx][0];
+                l1CandIdx = l0_l1_cand_idx[combIdx][1];
+                l0Cand = mergecandlist[l0CandIdx];
+                l1Cand = mergecandlist[l1CandIdx];
+                if (l0Cand.pred_flag[0] == 1 &&
+                    l1Cand.pred_flag[1] == 1 &&
+                    (refPicList[0].list[l0Cand.ref_idx[0]] !=
+                     refPicList[1].list[l1Cand.ref_idx[1]] ||
+                     l0Cand.mv[0].x != l1Cand.mv[1].x ||
+                     l0Cand.mv[0].y != l1Cand.mv[1].y)) {
+                    combCand.ref_idx[0] = l0Cand.ref_idx[0];
+                    combCand.ref_idx[1] = l1Cand.ref_idx[1];
+                    combCand.pred_flag[0] = 1;
+                    combCand.pred_flag[1] = 1;
+                    combCand.mv[0].x = l0Cand.mv[0].x;
+                    combCand.mv[0].y = l0Cand.mv[0].y;
+                    combCand.mv[1].x = l1Cand.mv[1].x;
+                    combCand.mv[1].y = l1Cand.mv[1].y;
+                    combCand.is_intra = 0;
+                    mergecandlist[numMergeCand] = combCand;
+                    numMergeCand++;
+                }
+                combIdx++;
+                if (combIdx == numOrigMergeCand * (numOrigMergeCand - 1) ||
+                    numMergeCand == s->sh.max_num_merge_cand)
+                    combStop = 1;
+            }
+        }
+    }
+
+    /*
+     * append Zero motion vector candidates
+     */
+    if (s->sh.slice_type == P_SLICE) {
+        numRefIdx = s->sh.nb_refs[0];
+    } else if (s->sh.slice_type == B_SLICE) {
+        numRefIdx = FFMIN(s->sh.nb_refs[0],
+                          s->sh.nb_refs[1]);
+    }
+    while (numMergeCand < s->sh.max_num_merge_cand) {
+        if (s->sh.slice_type == P_SLICE) {
+            zerovector.ref_idx[0] = (zeroIdx < numRefIdx) ? zeroIdx : 0;
+            zerovector.ref_idx[1] = -1;
+            zerovector.pred_flag[0] = 1;
+            zerovector.pred_flag[1] = 0;
+            zerovector.mv[0].x = 0;
+            zerovector.mv[0].y = 0;
+            zerovector.mv[1].x = 0;
+            zerovector.mv[1].y = 0;
+            zerovector.is_intra = 0;
+        } else {
+            zerovector.ref_idx[0] = (zeroIdx < numRefIdx) ? zeroIdx : 0;
+            zerovector.ref_idx[1] = (zeroIdx < numRefIdx) ? zeroIdx : 0;
+            zerovector.pred_flag[0] = 1;
+            zerovector.pred_flag[1] = 1;
+            zerovector.mv[0].x = 0;
+            zerovector.mv[0].y = 0;
+            zerovector.mv[1].x = 0;
+            zerovector.mv[1].y = 0;
+            zerovector.is_intra = 0;
+        }
+
+        mergecandlist[numMergeCand] = zerovector;
+        numMergeCand++;
+        zeroIdx++;
+    }
+}
+
+/*
+ * 8.5.3.1.1 Derivation process of luma Mvs for merge mode
+ */
+void ff_hevc_luma_mv_merge_mode(HEVCContext *s, int x0, int y0, int nPbW,
+                                int nPbH, int log2_cb_size, int part_idx,
+                                int merge_idx, MvField *mv)
+{
+    int singleMCLFlag = 0;
+    int nCS = 1 << log2_cb_size;
+    struct MvField mergecand_list[MRG_MAX_NUM_CANDS] = { { { { 0 } } } };
+    int nPbW2 = nPbW;
+    int nPbH2 = nPbH;
+    HEVCLocalContext *lc = &s->HEVClc;
+
+    if (s->pps->log2_parallel_merge_level > 2 && nCS == 8) {
+        singleMCLFlag = 1;
+        x0 = lc->cu.x;
+        y0 = lc->cu.y;
+        nPbW = nCS;
+        nPbH = nCS;
+        part_idx = 0;
+    }
+
+    ff_hevc_set_neighbour_available(s, x0, y0, nPbW, nPbH);
+    derive_spatial_merge_candidates(s, x0, y0, nPbW, nPbH, log2_cb_size,
+                                    singleMCLFlag, part_idx, mergecand_list);
+
+    if (mergecand_list[merge_idx].pred_flag[0] == 1 &&
+        mergecand_list[merge_idx].pred_flag[1] == 1 &&
+        (nPbW2 + nPbH2) == 12) {
+        mergecand_list[merge_idx].ref_idx[1] = -1;
+        mergecand_list[merge_idx].pred_flag[1] = 0;
+    }
+
+    *mv = mergecand_list[merge_idx];
+}
+
+static av_always_inline void dist_scale(HEVCContext *s, Mv * mv,
+                                        int pic_width_in_min_pu, int x, int y,
+                                        int elist, int ref_idx_curr, int ref_idx)
+{
+    RefPicList *refPicList = s->ref->refPicList;
+    MvField *tab_mvf = s->ref->tab_mvf;
+    int ref_pic_elist = refPicList[elist].list[TAB_MVF(x, y).ref_idx[elist]];
+    int ref_pic_curr  = refPicList[ref_idx_curr].list[ref_idx];
+
+    if (ref_pic_elist != ref_pic_curr)
+        mv_scale(mv, mv, s->poc - ref_pic_elist, s->poc - ref_pic_curr);
+}
+
+static int mv_mp_mode_mx(HEVCContext *s, int x, int y, int pred_flag_index,
+                         Mv *mv, int ref_idx_curr, int ref_idx)
+{
+    MvField *tab_mvf = s->ref->tab_mvf;
+    int pic_width_in_min_pu = s->sps->width >> s->sps->log2_min_pu_size;
+
+    RefPicList *refPicList = s->ref->refPicList;
+
+    if (TAB_MVF(x, y).pred_flag[pred_flag_index] == 1 &&
+        refPicList[pred_flag_index].list[TAB_MVF(x, y).ref_idx[pred_flag_index]] == refPicList[ref_idx_curr].list[ref_idx]) {
+        *mv = TAB_MVF(x, y).mv[pred_flag_index];
+        return 1;
+    }
+    return 0;
+}
+
+
+static int mv_mp_mode_mx_lt(HEVCContext *s, int x, int y, int pred_flag_index,
+                            Mv *mv, int ref_idx_curr, int ref_idx)
+{
+    MvField *tab_mvf = s->ref->tab_mvf;
+    int pic_width_in_min_pu = s->sps->width >> s->sps->log2_min_pu_size;
+
+    RefPicList *refPicList = s->ref->refPicList;
+    int currIsLongTerm = refPicList[ref_idx_curr].isLongTerm[ref_idx];
+
+    int colIsLongTerm =
+        refPicList[pred_flag_index].isLongTerm[(TAB_MVF(x, y).ref_idx[pred_flag_index])];
+
+    if (TAB_MVF(x, y).pred_flag[pred_flag_index] && colIsLongTerm == currIsLongTerm) {
+        *mv = TAB_MVF(x, y).mv[pred_flag_index];
+        if (!currIsLongTerm)
+            dist_scale(s, mv, pic_width_in_min_pu, x, y, pred_flag_index, ref_idx_curr, ref_idx);
+        return 1;
+    }
+    return 0;
+}
+
+#define MP_MX(v, pred, mx) \
+    mv_mp_mode_mx(s, x##v##_pu, y##v##_pu, pred, &mx, ref_idx_curr, ref_idx)
+
+#define MP_MX_LT(v, pred, mx) \
+    mv_mp_mode_mx_lt(s, x##v##_pu, y##v##_pu, pred, &mx, ref_idx_curr, ref_idx)
+
+void ff_hevc_luma_mv_mvp_mode(HEVCContext *s, int x0, int y0, int nPbW,
+                              int nPbH, int log2_cb_size, int part_idx,
+                              int merge_idx, MvField *mv,
+                              int mvp_lx_flag, int LX)
+{
+    HEVCLocalContext *lc = &s->HEVClc;
+    MvField *tab_mvf = s->ref->tab_mvf;
+    int isScaledFlag_L0 = 0;
+    int availableFlagLXA0 = 0;
+    int availableFlagLXB0 = 0;
+    int availableFlagLXCol = 0;
+    int numMVPCandLX = 0;
+    int pic_width_in_min_pu = s->sps->width >> s->sps->log2_min_pu_size;
+
+    int xA0, yA0;
+    int xA0_pu, yA0_pu;
+    int is_available_a0;
+
+    int xA1, yA1;
+    int xA1_pu, yA1_pu;
+    int is_available_a1;
+
+    int xB0, yB0;
+    int xB0_pu, yB0_pu;
+    int is_available_b0;
+
+    int xB1, yB1;
+    int xB1_pu = 0, yB1_pu = 0;
+    int is_available_b1 = 0;
+
+    int xB2, yB2;
+    int xB2_pu = 0, yB2_pu = 0;
+    int is_available_b2 = 0;
+    Mv mvpcand_list[2] = { { 0 } };
+    Mv mxA = { 0 };
+    Mv mxB = { 0 };
+    Mv mvLXCol = { 0 };
+    int ref_idx_curr = 0;
+    int ref_idx = 0;
+    int pred_flag_index_l0;
+    int pred_flag_index_l1;
+    int x0b = x0 & ((1 << s->sps->log2_ctb_size) - 1);
+    int y0b = y0 & ((1 << s->sps->log2_ctb_size) - 1);
+
+    int cand_up = (lc->ctb_up_flag || y0b);
+    int cand_left = (lc->ctb_left_flag || x0b);
+    int cand_up_left =
+            (!x0b && !y0b) ? lc->ctb_up_left_flag : cand_left && cand_up;
+    int cand_up_right =
+            (x0b + nPbW == (1 << s->sps->log2_ctb_size) ||
+             x0  + nPbW >= lc->end_of_tiles_x) ? lc->ctb_up_right_flag && !y0b
+                                               : cand_up;
+    int cand_bottom_left = (y0 + nPbH >= lc->end_of_tiles_y) ? 0 : cand_left;
+
+    ref_idx_curr       = LX;
+    ref_idx            = mv->ref_idx[LX];
+    pred_flag_index_l0 = LX;
+    pred_flag_index_l1 = !LX;
+
+    // left bottom spatial candidate
+    xA0 = x0 - 1;
+    yA0 = y0 + nPbH;
+    xA0_pu = xA0 >> s->sps->log2_min_pu_size;
+    yA0_pu = yA0 >> s->sps->log2_min_pu_size;
+
+    is_available_a0 = AVAILABLE(cand_bottom_left, A0);
+    if (is_available_a0)
+        is_available_a0 = PRED_BLOCK_AVAILABLE(A0);
+
+    //left spatial merge candidate
+    xA1 = x0 - 1;
+    yA1 = y0 + nPbH - 1;
+    xA1_pu = xA1 >> s->sps->log2_min_pu_size;
+    yA1_pu = yA1 >> s->sps->log2_min_pu_size;
+
+    is_available_a1 = AVAILABLE(cand_left, A1);
+    if (is_available_a0 || is_available_a1) {
+        isScaledFlag_L0 = 1;
+    }
+
+    if (is_available_a0) {
+        availableFlagLXA0 = MP_MX(A0, pred_flag_index_l0, mxA);
+        if (!availableFlagLXA0)
+            availableFlagLXA0 = MP_MX(A0, pred_flag_index_l1, mxA);
+    }
+
+    if (is_available_a1 && !availableFlagLXA0) {
+        availableFlagLXA0 = MP_MX(A1, pred_flag_index_l0, mxA);
+        if (!availableFlagLXA0)
+            availableFlagLXA0 = MP_MX(A1, pred_flag_index_l1, mxA);
+    }
+
+    if (is_available_a0 && !availableFlagLXA0) {
+        availableFlagLXA0 = MP_MX_LT(A0, pred_flag_index_l0, mxA);
+        if (!availableFlagLXA0)
+            availableFlagLXA0 = MP_MX_LT(A0, pred_flag_index_l1, mxA);
+    }
+
+    if (is_available_a1 && !availableFlagLXA0) {
+        availableFlagLXA0 = MP_MX_LT(A1, pred_flag_index_l0, mxA);
+        if (!availableFlagLXA0)
+            availableFlagLXA0 = MP_MX_LT(A1, pred_flag_index_l1, mxA);
+    }
+
+    // B candidates
+    // above right spatial merge candidate
+    xB0 = x0 + nPbW;
+    yB0 = y0 - 1;
+    xB0_pu = xB0 >> s->sps->log2_min_pu_size;
+    yB0_pu = yB0 >> s->sps->log2_min_pu_size;
+
+    is_available_b0 = AVAILABLE(cand_up_right, B0);
+    if (is_available_b0)
+        is_available_b0 = PRED_BLOCK_AVAILABLE(B0);
+
+    if (is_available_b0) {
+        availableFlagLXB0 = MP_MX(B0, pred_flag_index_l0, mxB);
+        if (!availableFlagLXB0)
+            availableFlagLXB0 = MP_MX(B0, pred_flag_index_l1, mxB);
+    }
+
+    if (!availableFlagLXB0) {
+        // above spatial merge candidate
+        xB1 = x0 + nPbW - 1;
+        yB1 = y0 - 1;
+        xB1_pu = xB1 >> s->sps->log2_min_pu_size;
+        yB1_pu = yB1 >> s->sps->log2_min_pu_size;
+
+        is_available_b1 = AVAILABLE(cand_up, B1);
+
+        if (is_available_b1) {
+            availableFlagLXB0 = MP_MX(B1, pred_flag_index_l0, mxB);
+            if (!availableFlagLXB0)
+                availableFlagLXB0 = MP_MX(B1, pred_flag_index_l1, mxB);
+        }
+    }
+
+    if (!availableFlagLXB0) {
+        // above left spatial merge candidate
+        xB2 = x0 - 1;
+        yB2 = y0 - 1;
+        xB2_pu = xB2 >> s->sps->log2_min_pu_size;
+        yB2_pu = yB2 >> s->sps->log2_min_pu_size;
+        is_available_b2 = AVAILABLE(cand_up_left, B2);
+
+        if (is_available_b2) {
+            availableFlagLXB0 = MP_MX(B2, pred_flag_index_l0, mxB);
+            if (!availableFlagLXB0)
+                availableFlagLXB0 = MP_MX(B2, pred_flag_index_l1, mxB);
+        }
+    }
+
+    if (isScaledFlag_L0 == 0) {
+        if (availableFlagLXB0) {
+            availableFlagLXA0 = 1;
+            mxA = mxB;
+        }
+        availableFlagLXB0 = 0;
+
+        // XB0 and L1
+        if (is_available_b0) {
+            availableFlagLXB0 = MP_MX_LT(B0, pred_flag_index_l0, mxB);
+            if (!availableFlagLXB0)
+                availableFlagLXB0 = MP_MX_LT(B0, pred_flag_index_l1, mxB);
+        }
+
+        if (is_available_b1 && !availableFlagLXB0) {
+            availableFlagLXB0 = MP_MX_LT(B1, pred_flag_index_l0, mxB);
+            if (!availableFlagLXB0)
+                availableFlagLXB0 = MP_MX_LT(B1, pred_flag_index_l1, mxB);
+        }
+
+        if (is_available_b2 && !availableFlagLXB0) {
+            availableFlagLXB0 = MP_MX_LT(B2, pred_flag_index_l0, mxB);
+            if (!availableFlagLXB0)
+                availableFlagLXB0 = MP_MX_LT(B2, pred_flag_index_l1, mxB);
+        }
+    }
+
+    if (availableFlagLXA0 && availableFlagLXB0 &&
+        (mxA.x != mxB.x || mxA.y != mxB.y)) {
+        availableFlagLXCol = 0;
+    } else {
+        //temporal motion vector prediction candidate
+        if (s->sh.slice_temporal_mvp_enabled_flag == 0) {
+            availableFlagLXCol = 0;
+        } else {
+            availableFlagLXCol = temporal_luma_motion_vector(s, x0, y0, nPbW,
+                    nPbH, ref_idx, &mvLXCol, LX);
+        }
+    }
+
+    if (availableFlagLXA0) {
+        mvpcand_list[numMVPCandLX] = mxA;
+        numMVPCandLX++;
+    }
+    if (availableFlagLXB0) {
+        mvpcand_list[numMVPCandLX] = mxB;
+        numMVPCandLX++;
+    }
+
+    if (availableFlagLXA0 && availableFlagLXB0 &&
+        mxA.x == mxB.x && mxA.y == mxB.y) {
+        numMVPCandLX--;
+    }
+
+    if (availableFlagLXCol && numMVPCandLX < 2) {
+        mvpcand_list[numMVPCandLX] = mvLXCol;
+        numMVPCandLX++;
+    }
+
+    while (numMVPCandLX < 2) { // insert zero motion vectors when the number of available candidates are less than 2
+        mvpcand_list[numMVPCandLX].x = 0;
+        mvpcand_list[numMVPCandLX].y = 0;
+        numMVPCandLX++;
+    }
+
+    mv->mv[LX].x = mvpcand_list[mvp_lx_flag].x;
+    mv->mv[LX].y = mvpcand_list[mvp_lx_flag].y;
+}