vpx/vp9/common/vp9_mvref_common.c
Paul Wilkins 6ff3eb1647 New inter mode context.
This patch creates a new inter mode contest that avoids
a dependence on the reconstructed motion vectors from
neighboring blocks. This was a change requested by
a hardware vendor to improve decode performance.

As part of this change I have also made some modifications
to stats output code (under a flag) to allow accumulation of
inter mode context flags over multiple clips

Some further changes will be required to accommodate the
deprecation of the split mv mode over the next few days.

Performance as stands is around -0.25% on derf and
std-hd but up on the YT and YT-HD sets. With further tuning
or some adjustment to the context criteria it should be
possible to make this change broadly neutral.

Change-Id: Ia15cb4470969b9e87332a59c546ae0bd40676f6c
2013-05-16 12:09:19 +01:00

322 lines
12 KiB
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 b_mv_ref_search[MVREF_NEIGHBOURS][2] = {
{0, -1}, {-1, 0}, {-1, -1}, {0, -2},
{-2, 0}, {-1, -2}, {-2, -1}, {-2, -2}
};
static int mb_mv_ref_search[MVREF_NEIGHBOURS][2] = {
{0, -1}, {-1, 0}, {-1, -1}, {0, -3},
{-3, 0}, {-1, -3}, {-3, -1}, {-3, -3}
};
static int sb_mv_ref_search[MVREF_NEIGHBOURS][2] = {
{0, -1}, {-1, 0}, {2, -1}, {-1, 2},
{-1, -1}, {0, -3}, {-3, 0}, {-1, -3}
};
static int sb64_mv_ref_search[MVREF_NEIGHBOURS][2] = {
{0, -1}, {-1, 0}, {2, -1}, {-1, 2},
{4, -1}, {-1, 4}, {6, -1}, {-1, -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 refenence 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) {
if (ref_frame == candidate_mi->mbmi.ref_frame) {
c_mv->as_int = candidate_mi->mbmi.mv[0].as_int;
} else if (ref_frame == candidate_mi->mbmi.second_ref_frame) {
c_mv->as_int = candidate_mi->mbmi.mv[1].as_int;
} else {
return 0;
}
return 1;
}
// Gets candidate refenence 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 > INTRA_FRAME) {
// First candidate
if (candidate_mi->mbmi.ref_frame != ref_frame) {
*c_ref_frame = candidate_mi->mbmi.ref_frame;
c_mv->as_int = candidate_mi->mbmi.mv[0].as_int;
}
// Second candidate
if ((candidate_mi->mbmi.second_ref_frame > INTRA_FRAME) &&
(candidate_mi->mbmi.second_ref_frame != ref_frame) &&
(candidate_mi->mbmi.mv[1].as_int != candidate_mi->mbmi.mv[0].as_int)) {
*c2_ref_frame = candidate_mi->mbmi.second_ref_frame;
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) {
// int frame_distances[MAX_REF_FRAMES];
// int last_distance = 1;
// int gf_distance = xd->frames_since_golden;
// int arf_distance = xd->frames_till_alt_ref_frame;
// 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;
}
/*
// Scale based on frame distance if the reference frames not the same.
frame_distances[INTRA_FRAME] = 1; // should never be used
frame_distances[LAST_FRAME] = 1;
frame_distances[GOLDEN_FRAME] =
(xd->frames_since_golden) ? xd->frames_si nce_golden : 1;
frame_distances[ALTREF_FRAME] =
(xd->frames_till_alt_ref_frame) ? xd->frames_till_alt_ref_frame : 1;
if (frame_distances[this_ref_frame] &&
frame_distances[candidate_ref_frame]) {
candidate_mv->as_mv.row =
(short)(((int)(candidate_mv->as_mv.row) *
frame_distances[this_ref_frame]) /
frame_distances[candidate_ref_frame]);
candidate_mv->as_mv.col =
(short)(((int)(candidate_mv->as_mv.col) *
frame_distances[this_ref_frame]) /
frame_distances[candidate_ref_frame]);
}
*/
}
// 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(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 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];
int refmv_count = 0;
int split_count = 0;
int (*mv_ref_search)[2];
const int mi_col = get_mi_col(xd);
int intra_count = 0;
int zero_count = 0;
int newmv_count = 0;
// Blank the reference vector lists and other local structures.
vpx_memset(mv_ref_list, 0, sizeof(int_mv) * MAX_MV_REF_CANDIDATES);
vpx_memset(candidate_scores, 0, sizeof(candidate_scores));
if (mbmi->sb_type == BLOCK_SIZE_SB64X64) {
mv_ref_search = sb64_mv_ref_search;
} else if (mbmi->sb_type >= BLOCK_SIZE_SB32X32) {
mv_ref_search = sb_mv_ref_search;
} else if (mbmi->sb_type >= BLOCK_SIZE_MB16X16) {
mv_ref_search = mb_mv_ref_search;
} else {
mv_ref_search = b_mv_ref_search;
}
// 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];
if ((mi_search_col >= cm->cur_tile_mi_col_start) &&
(mi_search_col < cm->cur_tile_mi_col_end) &&
((mv_ref_search[i][1] << 6) >= xd->mb_to_top_edge)) {
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)) {
add_candidate_mv(mv_ref_list, candidate_scores,
&refmv_count, c_refmv, 16);
}
split_count += (candidate_mi->mbmi.mode == SPLITMV);
// 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);
}
}
// If at this stage wwe have a 0 vector and a non zero vector from the
// correct reference frame then make sure that the non zero one is given
// precedence as we have other options for coding 0,0
/* if (refmv_count == MAX_MV_REF_CANDIDATES) {
if (mv_ref_list[1].as_int && !mv_ref_list[0].as_int) {
mv_ref_list[0].as_int = mv_ref_list[1].as_int;
mv_ref_list[1].as_int = 0;
}
} */
// 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];
if ((mi_search_col >= cm->cur_tile_mi_col_start) &&
(mi_search_col < cm->cur_tile_mi_col_end) &&
((mv_ref_search[i][1] << 6) >= xd->mb_to_top_edge)) {
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)) {
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)) {
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];
if ((mi_search_col >= cm->cur_tile_mi_col_start) &&
(mi_search_col < cm->cur_tile_mi_col_end) &&
((mv_ref_search[i][1] << 6) >= xd->mb_to_top_edge)) {
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]);
}
}