ref: cd95543ee4a0d86a72dc1c7b9cbc280c5a60d0b0
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"
// 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->error_resilient_mode && 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.");
}
}