ref: b91b146d1df46a3f3bbd544548839643cae662c1
dir: /vp9/common/vp9_mvref_common.c/
/*
* Copyright (c) 2012 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "vp9/common/vp9_mvref_common.h"
#define MVREF_NEIGHBOURS 8
typedef struct position {
int row;
int col;
} POSITION;
typedef enum {
BOTH_ZERO = 0,
ZERO_PLUS_PREDICTED = 1,
BOTH_PREDICTED = 2,
NEW_PLUS_NON_INTRA = 3,
BOTH_NEW = 4,
INTRA_PLUS_NON_INTRA = 5,
BOTH_INTRA = 6,
INVALID_CASE = 9
} motion_vector_context;
// This is used to figure out a context for the ref blocks. The code flattens
// an array that would have 3 possible counts (0, 1 & 2) for 3 choices by
// adding 9 for each intra block, 3 for each zero mv and 1 for each new
// motion vector. This single number is then converted into a context
// with a single lookup ( counter_to_context ).
static const int mode_2_counter[MB_MODE_COUNT] = {
9, // DC_PRED
9, // V_PRED
9, // H_PRED
9, // D45_PRED
9, // D135_PRED
9, // D117_PRED
9, // D153_PRED
9, // D207_PRED
9, // D63_PRED
9, // TM_PRED
0, // NEARESTMV
0, // NEARMV
3, // ZEROMV
1, // NEWMV
};
// There are 3^3 different combinations of 3 counts that can be either 0,1 or
// 2. However the actual count can never be greater than 2 so the highest
// counter we need is 18. 9 is an invalid counter that's never used.
static const int counter_to_context[19] = {
BOTH_PREDICTED, // 0
NEW_PLUS_NON_INTRA, // 1
BOTH_NEW, // 2
ZERO_PLUS_PREDICTED, // 3
NEW_PLUS_NON_INTRA, // 4
INVALID_CASE, // 5
BOTH_ZERO, // 6
INVALID_CASE, // 7
INVALID_CASE, // 8
INTRA_PLUS_NON_INTRA, // 9
INTRA_PLUS_NON_INTRA, // 10
INVALID_CASE, // 11
INTRA_PLUS_NON_INTRA, // 12
INVALID_CASE, // 13
INVALID_CASE, // 14
INVALID_CASE, // 15
INVALID_CASE, // 16
INVALID_CASE, // 17
BOTH_INTRA // 18
};
static const POSITION mv_ref_blocks[BLOCK_SIZES][MVREF_NEIGHBOURS] = {
// 4X4
{{-1, 0}, {0, -1}, {-1, -1}, {-2, 0}, {0, -2}, {-2, -1}, {-1, -2}, {-2, -2}},
// 4X8
{{-1, 0}, {0, -1}, {-1, -1}, {-2, 0}, {0, -2}, {-2, -1}, {-1, -2}, {-2, -2}},
// 8X4
{{-1, 0}, {0, -1}, {-1, -1}, {-2, 0}, {0, -2}, {-2, -1}, {-1, -2}, {-2, -2}},
// 8X8
{{-1, 0}, {0, -1}, {-1, -1}, {-2, 0}, {0, -2}, {-2, -1}, {-1, -2}, {-2, -2}},
// 8X16
{{0, -1}, {-1, 0}, {1, -1}, {-1, -1}, {0, -2}, {-2, 0}, {-2, -1}, {-1, -2}},
// 16X8
{{-1, 0}, {0, -1}, {-1, 1}, {-1, -1}, {-2, 0}, {0, -2}, {-1, -2}, {-2, -1}},
// 16X16
{{-1, 0}, {0, -1}, {-1, 1}, {1, -1}, {-1, -1}, {-3, 0}, {0, -3}, {-3, -3}},
// 16X32
{{0, -1}, {-1, 0}, {2, -1}, {-1, -1}, {-1, 1}, {0, -3}, {-3, 0}, {-3, -3}},
// 32X16
{{-1, 0}, {0, -1}, {-1, 2}, {-1, -1}, {1, -1}, {-3, 0}, {0, -3}, {-3, -3}},
// 32X32
{{-1, 1}, {1, -1}, {-1, 2}, {2, -1}, {-1, -1}, {-3, 0}, {0, -3}, {-3, -3}},
// 32X64
{{0, -1}, {-1, 0}, {4, -1}, {-1, 2}, {-1, -1}, {0, -3}, {-3, 0}, {2, -1}},
// 64X32
{{-1, 0}, {0, -1}, {-1, 4}, {2, -1}, {-1, -1}, {-3, 0}, {0, -3}, {-1, 2}},
// 64X64
{{-1, 3}, {3, -1}, {-1, 4}, {4, -1}, {-1, -1}, {-1, 0}, {0, -1}, {-1, 6}}
};
static const int idx_n_column_to_subblock[4][2] = {
{1, 2},
{1, 3},
{3, 2},
{3, 3}
};
// clamp_mv_ref
#define MV_BORDER (16 << 3) // Allow 16 pels in 1/8th pel units
static void clamp_mv_ref(MV *mv, const MACROBLOCKD *xd) {
clamp_mv(mv, xd->mb_to_left_edge - MV_BORDER,
xd->mb_to_right_edge + MV_BORDER,
xd->mb_to_top_edge - MV_BORDER,
xd->mb_to_bottom_edge + MV_BORDER);
}
// This function returns either the appropriate sub block or block's mv
// on whether the block_size < 8x8 and we have check_sub_blocks set.
static INLINE int_mv get_sub_block_mv(const MODE_INFO *candidate, int which_mv,
int search_col, int block_idx) {
return block_idx >= 0 && candidate->mbmi.sb_type < BLOCK_8X8
? candidate->bmi[idx_n_column_to_subblock[block_idx][search_col == 0]]
.as_mv[which_mv]
: candidate->mbmi.mv[which_mv];
}
// Performs mv sign inversion if indicated by the reference frame combination.
static INLINE int_mv scale_mv(const MB_MODE_INFO *mbmi, int ref,
const MV_REFERENCE_FRAME this_ref_frame,
const int *ref_sign_bias) {
int_mv mv = mbmi->mv[ref];
if (ref_sign_bias[mbmi->ref_frame[ref]] != ref_sign_bias[this_ref_frame]) {
mv.as_mv.row *= -1;
mv.as_mv.col *= -1;
}
return mv;
}
// This macro is used to add a motion vector mv_ref list if it isn't
// already in the list. If it's the second motion vector it will also
// skip all additional processing and jump to done!
#define ADD_MV_REF_LIST(mv) \
do { \
if (refmv_count) { \
if ((mv).as_int != mv_ref_list[0].as_int) { \
mv_ref_list[refmv_count] = (mv); \
goto Done; \
} \
} else { \
mv_ref_list[refmv_count++] = (mv); \
} \
} while (0)
// If either reference frame is different, not INTRA, and they
// are different from each other scale and add the mv to our list.
#define IF_DIFF_REF_FRAME_ADD_MV(mbmi) \
do { \
if (is_inter_block(mbmi)) { \
if ((mbmi)->ref_frame[0] != ref_frame) \
ADD_MV_REF_LIST(scale_mv((mbmi), 0, ref_frame, ref_sign_bias)); \
if (has_second_ref(mbmi) && \
(mbmi)->ref_frame[1] != ref_frame && \
(mbmi)->mv[1].as_int != (mbmi)->mv[0].as_int) \
ADD_MV_REF_LIST(scale_mv((mbmi), 1, ref_frame, ref_sign_bias)); \
} \
} while (0)
// Checks that the given mi_row, mi_col and search point
// are inside the borders of the tile.
static INLINE int is_inside(const TileInfo *const tile,
int mi_col, int mi_row, int mi_rows,
const POSITION *mi_pos) {
return !(mi_row + mi_pos->row < 0 ||
mi_col + mi_pos->col < tile->mi_col_start ||
mi_row + mi_pos->row >= mi_rows ||
mi_col + mi_pos->col >= tile->mi_col_end);
}
// This function searches the neighbourhood of a given MB/SB
// to try and find candidate reference vectors.
static void find_mv_refs_idx(const VP9_COMMON *cm, const MACROBLOCKD *xd,
const TileInfo *const tile,
MODE_INFO *mi, MV_REFERENCE_FRAME ref_frame,
int_mv *mv_ref_list,
int block, int mi_row, int mi_col) {
const int *ref_sign_bias = cm->ref_frame_sign_bias;
int i, refmv_count = 0;
const MODE_INFO *prev_mi = cm->coding_use_prev_mi && cm->prev_mi
? cm->prev_mi_grid_visible[mi_row * xd->mi_stride + mi_col]
: NULL;
const MB_MODE_INFO *const prev_mbmi = prev_mi ? &prev_mi->mbmi : NULL;
const POSITION *const mv_ref_search = mv_ref_blocks[mi->mbmi.sb_type];
int different_ref_found = 0;
int context_counter = 0;
// Blank the reference vector list
vpx_memset(mv_ref_list, 0, sizeof(*mv_ref_list) * MAX_MV_REF_CANDIDATES);
// The nearest 2 blocks are treated differently
// if the size < 8x8 we get the mv from the bmi substructure,
// and we also need to keep a mode count.
for (i = 0; i < 2; ++i) {
const POSITION *const mv_ref = &mv_ref_search[i];
if (is_inside(tile, mi_col, mi_row, cm->mi_rows, mv_ref)) {
const MODE_INFO *const candidate_mi = xd->mi[mv_ref->col + mv_ref->row *
xd->mi_stride];
const MB_MODE_INFO *const candidate = &candidate_mi->mbmi;
// Keep counts for entropy encoding.
context_counter += mode_2_counter[candidate->mode];
different_ref_found = 1;
if (candidate->ref_frame[0] == ref_frame)
ADD_MV_REF_LIST(get_sub_block_mv(candidate_mi, 0, mv_ref->col, block));
else if (candidate->ref_frame[1] == ref_frame)
ADD_MV_REF_LIST(get_sub_block_mv(candidate_mi, 1, mv_ref->col, block));
}
}
// Check the rest of the neighbors in much the same way
// as before except we don't need to keep track of sub blocks or
// mode counts.
for (; i < MVREF_NEIGHBOURS; ++i) {
const POSITION *const mv_ref = &mv_ref_search[i];
if (is_inside(tile, mi_col, mi_row, cm->mi_rows, mv_ref)) {
const MB_MODE_INFO *const candidate = &xd->mi[mv_ref->col + mv_ref->row *
xd->mi_stride]->mbmi;
different_ref_found = 1;
if (candidate->ref_frame[0] == ref_frame)
ADD_MV_REF_LIST(candidate->mv[0]);
else if (candidate->ref_frame[1] == ref_frame)
ADD_MV_REF_LIST(candidate->mv[1]);
}
}
// Check the last frame's mode and mv info.
if (prev_mbmi) {
if (prev_mbmi->ref_frame[0] == ref_frame)
ADD_MV_REF_LIST(prev_mbmi->mv[0]);
else if (prev_mbmi->ref_frame[1] == ref_frame)
ADD_MV_REF_LIST(prev_mbmi->mv[1]);
}
// Since we couldn't find 2 mvs from the same reference frame
// go back through the neighbors and find motion vectors from
// different reference frames.
if (different_ref_found) {
for (i = 0; i < MVREF_NEIGHBOURS; ++i) {
const POSITION *mv_ref = &mv_ref_search[i];
if (is_inside(tile, mi_col, mi_row, cm->mi_rows, mv_ref)) {
const MB_MODE_INFO *const candidate = &xd->mi[mv_ref->col + mv_ref->row
* xd->mi_stride]->mbmi;
// If the candidate is INTRA we don't want to consider its mv.
IF_DIFF_REF_FRAME_ADD_MV(candidate);
}
}
}
// Since we still don't have a candidate we'll try the last frame.
if (prev_mbmi)
IF_DIFF_REF_FRAME_ADD_MV(prev_mbmi);
Done:
mi->mbmi.mode_context[ref_frame] = counter_to_context[context_counter];
// Clamp vectors
for (i = 0; i < MAX_MV_REF_CANDIDATES; ++i)
clamp_mv_ref(&mv_ref_list[i].as_mv, xd);
}
void vp9_find_mv_refs(const VP9_COMMON *cm, const MACROBLOCKD *xd,
const TileInfo *const tile,
MODE_INFO *mi, MV_REFERENCE_FRAME ref_frame,
int_mv *mv_ref_list,
int mi_row, int mi_col) {
find_mv_refs_idx(cm, xd, tile, mi, ref_frame, mv_ref_list, -1,
mi_row, mi_col);
}
static void lower_mv_precision(MV *mv, int allow_hp) {
const int use_hp = allow_hp && vp9_use_mv_hp(mv);
if (!use_hp) {
if (mv->row & 1)
mv->row += (mv->row > 0 ? -1 : 1);
if (mv->col & 1)
mv->col += (mv->col > 0 ? -1 : 1);
}
}
void vp9_find_best_ref_mvs(MACROBLOCKD *xd, int allow_hp,
int_mv *mvlist, int_mv *nearest, int_mv *near) {
int i;
// Make sure all the candidates are properly clamped etc
for (i = 0; i < MAX_MV_REF_CANDIDATES; ++i) {
lower_mv_precision(&mvlist[i].as_mv, allow_hp);
clamp_mv2(&mvlist[i].as_mv, xd);
}
*nearest = mvlist[0];
*near = mvlist[1];
}
void vp9_append_sub8x8_mvs_for_idx(VP9_COMMON *cm, MACROBLOCKD *xd,
const TileInfo *const tile,
int block, int ref, int mi_row, int mi_col,
int_mv *nearest, int_mv *near) {
int_mv mv_list[MAX_MV_REF_CANDIDATES];
MODE_INFO *const mi = xd->mi[0];
b_mode_info *bmi = mi->bmi;
int n;
assert(MAX_MV_REF_CANDIDATES == 2);
find_mv_refs_idx(cm, xd, tile, mi, mi->mbmi.ref_frame[ref], mv_list, block,
mi_row, mi_col);
near->as_int = 0;
switch (block) {
case 0:
nearest->as_int = mv_list[0].as_int;
near->as_int = mv_list[1].as_int;
break;
case 1:
case 2:
nearest->as_int = bmi[0].as_mv[ref].as_int;
for (n = 0; n < MAX_MV_REF_CANDIDATES; ++n)
if (nearest->as_int != mv_list[n].as_int) {
near->as_int = mv_list[n].as_int;
break;
}
break;
case 3: {
int_mv candidates[2 + MAX_MV_REF_CANDIDATES];
candidates[0] = bmi[1].as_mv[ref];
candidates[1] = bmi[0].as_mv[ref];
candidates[2] = mv_list[0];
candidates[3] = mv_list[1];
nearest->as_int = bmi[2].as_mv[ref].as_int;
for (n = 0; n < 2 + MAX_MV_REF_CANDIDATES; ++n)
if (nearest->as_int != candidates[n].as_int) {
near->as_int = candidates[n].as_int;
break;
}
break;
}
default:
assert("Invalid block index.");
}
}