ref: b7750812838eb84b55b8bcf25b9398cc41cdc0eb
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
static int mv_ref_blocks[BLOCK_SIZE_TYPES][MVREF_NEIGHBOURS][2] = {
// SB4X4
{{0, -1}, {-1, 0}, {-1, -1}, {0, -2}, {-2, 0}, {-1, -2}, {-2, -1}, {-2, -2}},
// SB4X8
{{0, -1}, {-1, 0}, {-1, -1}, {0, -2}, {-2, 0}, {-1, -2}, {-2, -1}, {-2, -2}},
// SB8X4
{{0, -1}, {-1, 0}, {-1, -1}, {0, -2}, {-2, 0}, {-1, -2}, {-2, -1}, {-2, -2}},
// SB8X8
{{0, -1}, {-1, 0}, {-1, -1}, {0, -2}, {-2, 0}, {-1, -2}, {-2, -1}, {-2, -2}},
// SB8X16
{{-1, 0}, {0, -1}, {-1, 1}, {-1, -1}, {-2, 0}, {0, -2}, {-1, -2}, {-2, -1}},
// SB16X8
{{0, -1}, {-1, 0}, {1, -1}, {-1, -1}, {0, -2}, {-2, 0}, {-2, -1}, {-1, -2}},
// SB16X16
{{0, -1}, {-1, 0}, {1, -1}, {-1, 1}, {-1, -1}, {0, -3}, {-3, 0}, {-3, -3}},
// SB16X32
{{-1, 0}, {0, -1}, {-1, 2}, {-1, -1}, {1, -1}, {-3, 0}, {0, -3}, {-3, -3}},
// SB32X16
{{0, -1}, {-1, 0}, {2, -1}, {-1, -1}, {-1, 1}, {0, -3}, {-3, 0}, {-3, -3}},
// SB32X32
{{1, -1}, {-1, 1}, {2, -1}, {-1, 2}, {-1, -1}, {0, -3}, {-3, 0}, {-3, -3}},
// SB32X64
{{-1, 0}, {0, -1}, {-1, 4}, {2, -1}, {-1, -1}, {-3, 0}, {0, -3}, {-1, 2}},
// SB64X32
{{0, -1}, {-1, 0}, {4, -1}, {-1, 2}, {-1, -1}, {0, -3}, {-3, 0}, {2, -1}},
// SB64X64
{{3, -1}, {-1, 3}, {4, -1}, {-1, 4}, {-1, -1}, {0, -1}, {-1, 0}, {6, -1}}
};
// clamp_mv_ref
#define MV_BORDER (16 << 3) // Allow 16 pels in 1/8th pel units
static void clamp_mv_ref(const MACROBLOCKD *xd, int_mv *mv) {
mv->as_mv.col = clamp(mv->as_mv.col, xd->mb_to_left_edge - MV_BORDER,
xd->mb_to_right_edge + MV_BORDER);
mv->as_mv.row = clamp(mv->as_mv.row, xd->mb_to_top_edge - MV_BORDER,
xd->mb_to_bottom_edge + MV_BORDER);
}
// Gets a candidate reference motion vector from the given mode info
// structure if one exists that matches the given reference frame.
static int get_matching_candidate(const MODE_INFO *candidate_mi,
MV_REFERENCE_FRAME ref_frame,
int_mv *c_mv, int block_idx) {
if (ref_frame == candidate_mi->mbmi.ref_frame[0]) {
if (block_idx >= 0 && candidate_mi->mbmi.sb_type < BLOCK_SIZE_SB8X8)
c_mv->as_int = candidate_mi->bmi[block_idx].as_mv[0].as_int;
else
c_mv->as_int = candidate_mi->mbmi.mv[0].as_int;
} else if (ref_frame == candidate_mi->mbmi.ref_frame[1]) {
if (block_idx >= 0 && candidate_mi->mbmi.sb_type < BLOCK_SIZE_SB8X8)
c_mv->as_int = candidate_mi->bmi[block_idx].as_mv[1].as_int;
else
c_mv->as_int = candidate_mi->mbmi.mv[1].as_int;
} else {
return 0;
}
return 1;
}
// Gets candidate reference motion vector(s) from the given mode info
// structure if they exists and do NOT match the given reference frame.
static void get_non_matching_candidates(const MODE_INFO *candidate_mi,
MV_REFERENCE_FRAME ref_frame,
MV_REFERENCE_FRAME *c_ref_frame,
int_mv *c_mv,
MV_REFERENCE_FRAME *c2_ref_frame,
int_mv *c2_mv) {
c_mv->as_int = 0;
c2_mv->as_int = 0;
*c_ref_frame = INTRA_FRAME;
*c2_ref_frame = INTRA_FRAME;
// If first candidate not valid neither will be.
if (candidate_mi->mbmi.ref_frame[0] > INTRA_FRAME) {
// First candidate
if (candidate_mi->mbmi.ref_frame[0] != ref_frame) {
*c_ref_frame = candidate_mi->mbmi.ref_frame[0];
c_mv->as_int = candidate_mi->mbmi.mv[0].as_int;
}
// Second candidate
if ((candidate_mi->mbmi.ref_frame[1] > INTRA_FRAME) &&
(candidate_mi->mbmi.ref_frame[1] != ref_frame) &&
(candidate_mi->mbmi.mv[1].as_int != candidate_mi->mbmi.mv[0].as_int)) {
*c2_ref_frame = candidate_mi->mbmi.ref_frame[1];
c2_mv->as_int = candidate_mi->mbmi.mv[1].as_int;
}
}
}
// Performs mv sign inversion if indicated by the reference frame combination.
static void scale_mv(MACROBLOCKD *xd, MV_REFERENCE_FRAME this_ref_frame,
MV_REFERENCE_FRAME candidate_ref_frame,
int_mv *candidate_mv, int *ref_sign_bias) {
// Sign inversion where appropriate.
if (ref_sign_bias[candidate_ref_frame] != ref_sign_bias[this_ref_frame]) {
candidate_mv->as_mv.row = -candidate_mv->as_mv.row;
candidate_mv->as_mv.col = -candidate_mv->as_mv.col;
}
}
// Add a candidate mv.
// Discard if it has already been seen.
static void add_candidate_mv(int_mv *mv_list, int *mv_scores,
int *candidate_count, int_mv candidate_mv,
int weight) {
if (*candidate_count == 0) {
mv_list[0].as_int = candidate_mv.as_int;
mv_scores[0] = weight;
*candidate_count += 1;
} else if ((*candidate_count == 1) &&
(candidate_mv.as_int != mv_list[0].as_int)) {
mv_list[1].as_int = candidate_mv.as_int;
mv_scores[1] = weight;
*candidate_count += 1;
}
}
// This function searches the neighbourhood of a given MB/SB
// to try and find candidate reference vectors.
//
void vp9_find_mv_refs_idx(VP9_COMMON *cm, MACROBLOCKD *xd, MODE_INFO *here,
MODE_INFO *lf_here, MV_REFERENCE_FRAME ref_frame,
int_mv *mv_ref_list, int *ref_sign_bias,
int block_idx) {
int i;
MODE_INFO *candidate_mi;
MB_MODE_INFO * mbmi = &xd->mode_info_context->mbmi;
int_mv c_refmv;
int_mv c2_refmv;
MV_REFERENCE_FRAME c_ref_frame;
MV_REFERENCE_FRAME c2_ref_frame;
int candidate_scores[MAX_MV_REF_CANDIDATES] = { 0 };
int refmv_count = 0;
int split_count = 0;
int (*mv_ref_search)[2];
const int mi_col = get_mi_col(xd);
const int mi_row = get_mi_row(xd);
int intra_count = 0;
int zero_count = 0;
int newmv_count = 0;
int x_idx = 0, y_idx = 0;
// Blank the reference vector lists and other local structures.
vpx_memset(mv_ref_list, 0, sizeof(int_mv) * MAX_MV_REF_CANDIDATES);
mv_ref_search = mv_ref_blocks[mbmi->sb_type];
if (mbmi->sb_type < BLOCK_SIZE_SB8X8) {
x_idx = block_idx & 1;
y_idx = block_idx >> 1;
}
// We first scan for candidate vectors that match the current reference frame
// Look at nearest neigbours
for (i = 0; i < 2; ++i) {
const int mi_search_col = mi_col + mv_ref_search[i][0];
const int mi_search_row = mi_row + mv_ref_search[i][1];
if ((mi_search_col >= cm->cur_tile_mi_col_start) &&
(mi_search_col < cm->cur_tile_mi_col_end) &&
(mi_search_row >= 0) && (mi_search_row < cm->mi_rows)) {
int b;
candidate_mi = here + mv_ref_search[i][0] +
(mv_ref_search[i][1] * xd->mode_info_stride);
if (block_idx >= 0) {
if (mv_ref_search[i][0])
b = 1 + y_idx * 2;
else
b = 2 + x_idx;
} else {
b = -1;
}
if (get_matching_candidate(candidate_mi, ref_frame, &c_refmv, b)) {
add_candidate_mv(mv_ref_list, candidate_scores,
&refmv_count, c_refmv, 16);
}
split_count += (candidate_mi->mbmi.sb_type < BLOCK_SIZE_SB8X8 &&
candidate_mi->mbmi.ref_frame[0] != INTRA_FRAME);
// Count number of neihgbours coded intra and zeromv
intra_count += (candidate_mi->mbmi.mode < NEARESTMV);
zero_count += (candidate_mi->mbmi.mode == ZEROMV);
newmv_count += (candidate_mi->mbmi.mode >= NEWMV);
}
}
// More distant neigbours
for (i = 2; (i < MVREF_NEIGHBOURS) &&
(refmv_count < MAX_MV_REF_CANDIDATES); ++i) {
const int mi_search_col = mi_col + mv_ref_search[i][0];
const int mi_search_row = mi_row + mv_ref_search[i][1];
if ((mi_search_col >= cm->cur_tile_mi_col_start) &&
(mi_search_col < cm->cur_tile_mi_col_end) &&
(mi_search_row >= 0) && (mi_search_row < cm->mi_rows)) {
candidate_mi = here + mv_ref_search[i][0] +
(mv_ref_search[i][1] * xd->mode_info_stride);
if (get_matching_candidate(candidate_mi, ref_frame, &c_refmv, -1)) {
add_candidate_mv(mv_ref_list, candidate_scores,
&refmv_count, c_refmv, 16);
}
}
}
// Look in the last frame if it exists
if (lf_here && (refmv_count < MAX_MV_REF_CANDIDATES)) {
candidate_mi = lf_here;
if (get_matching_candidate(candidate_mi, ref_frame, &c_refmv, -1)) {
add_candidate_mv(mv_ref_list, candidate_scores,
&refmv_count, c_refmv, 16);
}
}
// If we have not found enough candidates consider ones where the
// reference frame does not match. Break out when we have
// MAX_MV_REF_CANDIDATES candidates.
// Look first at spatial neighbours
for (i = 0; (i < MVREF_NEIGHBOURS) &&
(refmv_count < MAX_MV_REF_CANDIDATES); ++i) {
const int mi_search_col = mi_col + mv_ref_search[i][0];
const int mi_search_row = mi_row + mv_ref_search[i][1];
if ((mi_search_col >= cm->cur_tile_mi_col_start) &&
(mi_search_col < cm->cur_tile_mi_col_end) &&
(mi_search_row >= 0) && (mi_search_row < cm->mi_rows)) {
candidate_mi = here + mv_ref_search[i][0] +
(mv_ref_search[i][1] * xd->mode_info_stride);
get_non_matching_candidates(candidate_mi, ref_frame,
&c_ref_frame, &c_refmv,
&c2_ref_frame, &c2_refmv);
if (c_ref_frame != INTRA_FRAME) {
scale_mv(xd, ref_frame, c_ref_frame, &c_refmv, ref_sign_bias);
add_candidate_mv(mv_ref_list, candidate_scores,
&refmv_count, c_refmv, 1);
}
if (c2_ref_frame != INTRA_FRAME) {
scale_mv(xd, ref_frame, c2_ref_frame, &c2_refmv, ref_sign_bias);
add_candidate_mv(mv_ref_list, candidate_scores,
&refmv_count, c2_refmv, 1);
}
}
}
// Look at the last frame if it exists
if (lf_here && (refmv_count < MAX_MV_REF_CANDIDATES)) {
candidate_mi = lf_here;
get_non_matching_candidates(candidate_mi, ref_frame,
&c_ref_frame, &c_refmv,
&c2_ref_frame, &c2_refmv);
if (c_ref_frame != INTRA_FRAME) {
scale_mv(xd, ref_frame, c_ref_frame, &c_refmv, ref_sign_bias);
add_candidate_mv(mv_ref_list, candidate_scores,
&refmv_count, c_refmv, 1);
}
if (c2_ref_frame != INTRA_FRAME) {
scale_mv(xd, ref_frame, c2_ref_frame, &c2_refmv, ref_sign_bias);
add_candidate_mv(mv_ref_list, candidate_scores,
&refmv_count, c2_refmv, 1);
}
}
if (!intra_count) {
if (!newmv_count) {
// 0 = both zero mv
// 1 = one zero mv + one a predicted mv
// 2 = two predicted mvs
mbmi->mb_mode_context[ref_frame] = 2 - zero_count;
} else {
// 3 = one predicted/zero and one new mv
// 4 = two new mvs
mbmi->mb_mode_context[ref_frame] = 2 + newmv_count;
}
} else {
// 5 = one intra neighbour + x
// 6 = two intra neighbours
mbmi->mb_mode_context[ref_frame] = 4 + intra_count;
}
// Clamp vectors
for (i = 0; i < MAX_MV_REF_CANDIDATES; ++i) {
clamp_mv_ref(xd, &mv_ref_list[i]);
}
}