// Performs mv adjustment based on reference frame and clamps the MV
// if it goes off the edge of the buffer.
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
) {
if (candidate_ref_frame != this_ref_frame) {
//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_since_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]);
}
*/
}
// Clamp the MV so it does not point out of the frame buffer
clamp_mv(xd, candidate_mv);
}
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 searches the neighbourhood of a given MB/SB and populates a
// list of candidate reference vectors.
//
void vp9_find_mv_refs(
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 candidate_mvs[MAX_MV_REF_CANDIDATES];
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 index = 0;
int split_count = 0;
int (*mv_ref_search)[2];
int *ref_distance_weight;
// 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_mvs, 0, sizeof(int_mv) * MAX_MV_REF_CANDIDATES);
vpx_memset(candidate_scores, 0, sizeof(candidate_scores));
if (mbmi->sb_type) {
mv_ref_search = sb_mv_ref_search;
ref_distance_weight = sb_ref_distance_weight;
} else {
mv_ref_search = mb_mv_ref_search;
ref_distance_weight = mb_ref_distance_weight;
}
// We first scan for candidate vectors that match the current reference frame
// Look at nearest neigbours
for (i = 0; i < 2; ++i) {
if (((mv_ref_search[i][0] << 7) >= xd->mb_to_left_edge) &&
((mv_ref_search[i][1] << 7) >= 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)) {
clamp_mv(xd, &c_refmv);
addmv_and_shuffle(candidate_mvs, candidate_scores,
&index, c_refmv, ref_distance_weight[i] + 16);
}
split_count += (candidate_mi->mbmi.mode == SPLITMV);
}
}
// Look in the last frame
candidate_mi = lf_here;
if (get_matching_candidate(candidate_mi, ref_frame, &c_refmv)) {
clamp_mv(xd, &c_refmv);
addmv_and_shuffle(candidate_mvs, candidate_scores,
&index, c_refmv, 18);
}
// More distant neigbours
for (i = 2; (i < MVREF_NEIGHBOURS) &&
(index < (MAX_MV_REF_CANDIDATES - 1)); ++i) {
if (((mv_ref_search[i][0] << 7) >= xd->mb_to_left_edge) &&
((mv_ref_search[i][1] << 7) >= 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)) {
clamp_mv(xd, &c_refmv);
addmv_and_shuffle(candidate_mvs, candidate_scores,
&index, c_refmv, ref_distance_weight[i] + 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
if (index < (MAX_MV_REF_CANDIDATES - 1)) {
for (i = 0; i < MVREF_NEIGHBOURS; ++i) {
if (((mv_ref_search[i][0] << 7) >= xd->mb_to_left_edge) &&
((mv_ref_search[i][1] << 7) >= 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);
addmv_and_shuffle(candidate_mvs, candidate_scores,
&index, c_refmv, ref_distance_weight[i]);
}
if (c2_ref_frame != INTRA_FRAME) {
scale_mv(xd, ref_frame, c2_ref_frame, &c2_refmv, ref_sign_bias);
addmv_and_shuffle(candidate_mvs, candidate_scores,
&index, c2_refmv, ref_distance_weight[i]);
}
}
if (index >= (MAX_MV_REF_CANDIDATES - 1)) {
break;
}
}
}
// Look at the last frame
if (index < (MAX_MV_REF_CANDIDATES - 1)) {
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);
addmv_and_shuffle(candidate_mvs, candidate_scores,
&index, c_refmv, 2);
}
if (c2_ref_frame != INTRA_FRAME) {
scale_mv(xd, ref_frame, c2_ref_frame, &c2_refmv, ref_sign_bias);
addmv_and_shuffle(candidate_mvs, candidate_scores,
&index, c2_refmv, 2);
}
}
// Define inter mode coding context.
// 0,0 was best
if (candidate_mvs[0].as_int == 0) {
// 0,0 is only candidate
if (index <= 1) {
mbmi->mb_mode_context[ref_frame] = 0;
// non zero candidates candidates available
} else if (split_count == 0) {
mbmi->mb_mode_context[ref_frame] = 1;
} else {
mbmi->mb_mode_context[ref_frame] = 2;
}
// Non zero best, No Split MV cases
} else if (split_count == 0) {
if (candidate_scores[0] >= 32) {
mbmi->mb_mode_context[ref_frame] = 3;
} else {
mbmi->mb_mode_context[ref_frame] = 4;
}
// Non zero best, some split mv
} else {
if (candidate_scores[0] >= 32) {
mbmi->mb_mode_context[ref_frame] = 5;
} else {
mbmi->mb_mode_context[ref_frame] = 6;
}
}
// 0,0 is always a valid reference.
for (i = 0; i < MAX_MV_REF_CANDIDATES; ++i) {
if (candidate_mvs[i].as_int == 0)
break;
}
if (i == MAX_MV_REF_CANDIDATES) {
candidate_mvs[MAX_MV_REF_CANDIDATES-1].as_int = 0;
}
// Copy over the candidate list.
vpx_memcpy(mv_ref_list, candidate_mvs, sizeof(candidate_mvs));
}