ref: c58f01724cd5f0887e9d0c23396f9f03f78e18d3
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 neighborhood 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,
MODE_INFO *mi, MV_REFERENCE_FRAME ref_frame,
int_mv *mv_ref_list, int block, int mi_row,
int mi_col, uint8_t *mode_context) {
const int *ref_sign_bias = cm->ref_frame_sign_bias;
int i, refmv_count = 0;
const POSITION *const mv_ref_search = mv_ref_blocks[mi->sb_type];
int different_ref_found = 0;
int context_counter = 0;
const MV_REF *const prev_frame_mvs =
cm->use_prev_frame_mvs
? cm->prev_frame->mvs + mi_row * cm->mi_cols + mi_col
: NULL;
const TileInfo *const tile = &xd->tile;
// Blank the reference vector list
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];
// Keep counts for entropy encoding.
context_counter += mode_2_counter[candidate_mi->mode];
different_ref_found = 1;
if (candidate_mi->ref_frame[0] == ref_frame)
ADD_MV_REF_LIST(get_sub_block_mv(candidate_mi, 0, mv_ref->col, block),
refmv_count, mv_ref_list, Done);
else if (candidate_mi->ref_frame[1] == ref_frame)
ADD_MV_REF_LIST(get_sub_block_mv(candidate_mi, 1, mv_ref->col, block),
refmv_count, mv_ref_list, Done);
}
}
// 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 MODE_INFO *const candidate_mi =
xd->mi[mv_ref->col + mv_ref->row * xd->mi_stride];
different_ref_found = 1;
if (candidate_mi->ref_frame[0] == ref_frame)
ADD_MV_REF_LIST(candidate_mi->mv[0], refmv_count, mv_ref_list, Done);
else if (candidate_mi->ref_frame[1] == ref_frame)
ADD_MV_REF_LIST(candidate_mi->mv[1], refmv_count, mv_ref_list, Done);
}
}
// Check the last frame's mode and mv info.
if (cm->use_prev_frame_mvs) {
if (prev_frame_mvs->ref_frame[0] == ref_frame) {
ADD_MV_REF_LIST(prev_frame_mvs->mv[0], refmv_count, mv_ref_list, Done);
} else if (prev_frame_mvs->ref_frame[1] == ref_frame) {
ADD_MV_REF_LIST(prev_frame_mvs->mv[1], refmv_count, mv_ref_list, Done);
}
}
// 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 MODE_INFO *const candidate_mi =
xd->mi[mv_ref->col + mv_ref->row * xd->mi_stride];
// If the candidate is INTRA we don't want to consider its mv.
IF_DIFF_REF_FRAME_ADD_MV(candidate_mi, ref_frame, ref_sign_bias,
refmv_count, mv_ref_list, Done);
}
}
}
// Since we still don't have a candidate we'll try the last frame.
if (cm->use_prev_frame_mvs) {
if (prev_frame_mvs->ref_frame[0] != ref_frame &&
prev_frame_mvs->ref_frame[0] > INTRA_FRAME) {
int_mv mv = prev_frame_mvs->mv[0];
if (ref_sign_bias[prev_frame_mvs->ref_frame[0]] !=
ref_sign_bias[ref_frame]) {
mv.as_mv.row *= -1;
mv.as_mv.col *= -1;
}
ADD_MV_REF_LIST(mv, refmv_count, mv_ref_list, Done);
}
if (prev_frame_mvs->ref_frame[1] > INTRA_FRAME &&
prev_frame_mvs->ref_frame[1] != ref_frame &&
prev_frame_mvs->mv[1].as_int != prev_frame_mvs->mv[0].as_int) {
int_mv mv = prev_frame_mvs->mv[1];
if (ref_sign_bias[prev_frame_mvs->ref_frame[1]] !=
ref_sign_bias[ref_frame]) {
mv.as_mv.row *= -1;
mv.as_mv.col *= -1;
}
ADD_MV_REF_LIST(mv, refmv_count, mv_ref_list, Done);
}
}
Done:
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,
MODE_INFO *mi, MV_REFERENCE_FRAME ref_frame,
int_mv *mv_ref_list, int mi_row, int mi_col,
uint8_t *mode_context) {
find_mv_refs_idx(cm, xd, mi, ref_frame, mv_ref_list, -1, mi_row, mi_col,
mode_context);
}
void vp9_find_best_ref_mvs(MACROBLOCKD *xd, int allow_hp, int_mv *mvlist,
int_mv *nearest_mv, int_mv *near_mv) {
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_mv = mvlist[0];
*near_mv = mvlist[1];
}
void vp9_append_sub8x8_mvs_for_idx(VP9_COMMON *cm, MACROBLOCKD *xd, int block,
int ref, int mi_row, int mi_col,
int_mv *nearest_mv, int_mv *near_mv,
uint8_t *mode_context) {
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, mi, mi->ref_frame[ref], mv_list, block, mi_row,
mi_col, mode_context);
near_mv->as_int = 0;
switch (block) {
case 0:
nearest_mv->as_int = mv_list[0].as_int;
near_mv->as_int = mv_list[1].as_int;
break;
case 1:
case 2:
nearest_mv->as_int = bmi[0].as_mv[ref].as_int;
for (n = 0; n < MAX_MV_REF_CANDIDATES; ++n)
if (nearest_mv->as_int != mv_list[n].as_int) {
near_mv->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_mv->as_int = bmi[2].as_mv[ref].as_int;
for (n = 0; n < 2 + MAX_MV_REF_CANDIDATES; ++n)
if (nearest_mv->as_int != candidates[n].as_int) {
near_mv->as_int = candidates[n].as_int;
break;
}
break;
}
default: assert(0 && "Invalid block index.");
}
}