vp9_mvref_common.c 10.28 KiB
/*
 *  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
typedef enum {
  BOTH_ZERO = 0,
  ZERO_PLUS_PREDICTED = 1,
  BOTH_PREDICTED = 2,
  NEW_PLUS_NON_INTRA = 3,
  BOTH_NEW = 4,
  INTRA_PLUS_NON_INTRA = 5,
  BOTH_INTRA = 6,
  INVALID_CASE = 9
} motion_vector_context;
// This is used to figure out a context for the ref blocks. The code flattens
// an array that would have 3 possible counts (0, 1 & 2) for 3 choices by
// adding 9 for each intra block, 3 for each zero mv and 1 for each new
// motion vector. This single number is then converted into a context
// with a single lookup ( counter_to_context ).
static const int mode_2_counter[MB_MODE_COUNT] = {
  9,  // DC_PRED
  9,  // V_PRED
  9,  // H_PRED
  9,  // D45_PRED
  9,  // D135_PRED
  9,  // D117_PRED
  9,  // D153_PRED
  9,  // D27_PRED
  9,  // D63_PRED
  9,  // TM_PRED
  0,  // NEARESTMV
  0,  // NEARMV
  3,  // ZEROMV
  1,  // NEWMV
// There are 3^3 different combinations of 3 counts that can be either 0,1 or
// 2. However the actual count can never be greater than 2 so the highest
// counter we need is 18. 9 is an invalid counter that's never used.
static const int counter_to_context[19] = {
  BOTH_PREDICTED,  // 0
  NEW_PLUS_NON_INTRA,  // 1
  BOTH_NEW,  // 2
  ZERO_PLUS_PREDICTED,  // 3
  NEW_PLUS_NON_INTRA,  // 4
  INVALID_CASE,  // 5
  BOTH_ZERO,  // 6
  INVALID_CASE,  // 7
  INVALID_CASE,  // 8
  INTRA_PLUS_NON_INTRA,  // 9
  INTRA_PLUS_NON_INTRA,  // 10
  INVALID_CASE,  // 11
  INTRA_PLUS_NON_INTRA,  // 12
  INVALID_CASE,  // 13
  INVALID_CASE,  // 14
  INVALID_CASE,  // 15
  INVALID_CASE,  // 16
  INVALID_CASE,  // 17
  BOTH_INTRA  // 18
7172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140
}; static const MV mv_ref_blocks[BLOCK_SIZES][MVREF_NEIGHBOURS] = { // 4X4 {{-1, 0}, {0, -1}, {-1, -1}, {-2, 0}, {0, -2}, {-2, -1}, {-1, -2}, {-2, -2}}, // 4X8 {{-1, 0}, {0, -1}, {-1, -1}, {-2, 0}, {0, -2}, {-2, -1}, {-1, -2}, {-2, -2}}, // 8X4 {{-1, 0}, {0, -1}, {-1, -1}, {-2, 0}, {0, -2}, {-2, -1}, {-1, -2}, {-2, -2}}, // 8X8 {{-1, 0}, {0, -1}, {-1, -1}, {-2, 0}, {0, -2}, {-2, -1}, {-1, -2}, {-2, -2}}, // 8X16 {{0, -1}, {-1, 0}, {1, -1}, {-1, -1}, {0, -2}, {-2, 0}, {-2, -1}, {-1, -2}}, // 16X8 {{-1, 0}, {0, -1}, {-1, 1}, {-1, -1}, {-2, 0}, {0, -2}, {-1, -2}, {-2, -1}}, // 16X16 {{-1, 0}, {0, -1}, {-1, 1}, {1, -1}, {-1, -1}, {-3, 0}, {0, -3}, {-3, -3}}, // 16X32 {{0, -1}, {-1, 0}, {2, -1}, {-1, -1}, {-1, 1}, {0, -3}, {-3, 0}, {-3, -3}}, // 32X16 {{-1, 0}, {0, -1}, {-1, 2}, {-1, -1}, {1, -1}, {-3, 0}, {0, -3}, {-3, -3}}, // 32X32 {{-1, 1}, {1, -1}, {-1, 2}, {2, -1}, {-1, -1}, {-3, 0}, {0, -3}, {-3, -3}}, // 32X64 {{0, -1}, {-1, 0}, {4, -1}, {-1, 2}, {-1, -1}, {0, -3}, {-3, 0}, {2, -1}}, // 64X32 {{-1, 0}, {0, -1}, {-1, 4}, {2, -1}, {-1, -1}, {-3, 0}, {0, -3}, {-1, 2}}, // 64X64 {{-1, 3}, {3, -1}, {-1, 4}, {4, -1}, {-1, -1}, {-1, 0}, {0, -1}, {-1, 6}} }; static const int idx_n_column_to_subblock[4][2] = { {1, 2}, {1, 3}, {3, 2}, {3, 3} }; // clamp_mv_ref #define MV_BORDER (16 << 3) // Allow 16 pels in 1/8th pel units 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 returns either the appropriate sub block or block's mv // on whether the block_size < 8x8 and we have check_sub_blocks set. static INLINE int_mv get_sub_block_mv(const MODE_INFO *candidate, int check_sub_blocks, int which_mv, int search_col, int block_idx) { return (check_sub_blocks && candidate->mbmi.sb_type < BLOCK_8X8 ? candidate->bmi[idx_n_column_to_subblock[block_idx][search_col == 0]] .as_mv[which_mv] : candidate->mbmi.mv[which_mv]); } // Performs mv sign inversion if indicated by the reference frame combination. static INLINE int_mv scale_mv(const MODE_INFO *candidate, const int which_mv, const MV_REFERENCE_FRAME this_ref_frame, const int *ref_sign_bias) { int_mv return_mv = candidate->mbmi.mv[which_mv]; // Sign inversion where appropriate. if (ref_sign_bias[candidate->mbmi.ref_frame[which_mv]] != ref_sign_bias[this_ref_frame]) { return_mv.as_mv.row *= -1;
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return_mv.as_mv.col *= -1; } return return_mv; } // This macro is used to add a motion vector mv_ref list if it isn't // already in the list. If it's the second motion vector it will also // skip all additional processing and jump to done! #define ADD_MV_REF_LIST(MV) \ if (refmv_count) { \ if ((MV).as_int != mv_ref_list[0].as_int) { \ mv_ref_list[refmv_count] = (MV); \ goto Done; \ } \ } else { \ mv_ref_list[refmv_count++] = (MV); \ } // If either reference frame is different, not INTRA, and they // are different from each other scale and add the mv to our list. #define IF_DIFF_REF_FRAME_ADD_MV(CANDIDATE) \ if ((CANDIDATE)->mbmi.ref_frame[0] != ref_frame) { \ ADD_MV_REF_LIST(scale_mv((CANDIDATE), 0, ref_frame, ref_sign_bias)); \ } \ if ((CANDIDATE)->mbmi.ref_frame[1] != ref_frame && \ (CANDIDATE)->mbmi.ref_frame[1] > INTRA_FRAME && \ (CANDIDATE)->mbmi.mv[1].as_int != (CANDIDATE)->mbmi.mv[0].as_int) { \ ADD_MV_REF_LIST(scale_mv((CANDIDATE), 1, ref_frame, ref_sign_bias)); \ } // Checks that the given mi_row, mi_col and search point // are inside the borders of the tile. static INLINE int is_inside(int mi_col, int mi_row, int cur_tile_mi_col_start, const MV *mv_ref) { // Check that the candidate is within the border. We only need to check // the left side because all the positive right side ones are for blocks that // are large enough to support the + value they have within their border. return !(mi_row + mv_ref->row < 0 || mi_col + mv_ref->col < cur_tile_mi_col_start); } // 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, const MODE_INFO *lf_here, const MV_REFERENCE_FRAME ref_frame, int_mv *mv_ref_list, const int *ref_sign_bias, const int block_idx, const int mi_row, const int mi_col) { int idx; MB_MODE_INFO *mbmi = &xd->mode_info_context->mbmi; int refmv_count = 0; const MV *mv_ref_search = mv_ref_blocks[mbmi->sb_type]; const MODE_INFO *candidate; const int check_sub_blocks = block_idx >= 0; 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 (idx = 0; idx < 2; ++idx) { const MV *mv_ref = &mv_ref_search[idx]; if (!is_inside(mi_col, mi_row, cm->cur_tile_mi_col_start, mv_ref)) continue;
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candidate = here + mv_ref->col + mv_ref->row * xd->mode_info_stride; // Keep counts for entropy encoding. context_counter += mode_2_counter[candidate->mbmi.mode]; // Check if the candidate comes from the same reference frame. if (candidate->mbmi.ref_frame[0] == ref_frame) { ADD_MV_REF_LIST(get_sub_block_mv(candidate, check_sub_blocks, 0, mv_ref->col, block_idx)); different_ref_found = candidate->mbmi.ref_frame[1] != ref_frame; } else { different_ref_found = 1; if (candidate->mbmi.ref_frame[1] == ref_frame) { // Add second motion vector if it has the same ref_frame. ADD_MV_REF_LIST(get_sub_block_mv(candidate, check_sub_blocks, 1, mv_ref->col, block_idx)); } } } // 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 (; idx < MVREF_NEIGHBOURS; ++idx) { const MV *mv_ref = &mv_ref_search[idx]; if (!is_inside(mi_col, mi_row, cm->cur_tile_mi_col_start, mv_ref)) continue; candidate = here + mv_ref->col + mv_ref->row * xd->mode_info_stride; if (candidate->mbmi.ref_frame[0] == ref_frame) { ADD_MV_REF_LIST(candidate->mbmi.mv[0]); different_ref_found = candidate->mbmi.ref_frame[1] != ref_frame; } else { different_ref_found = 1; if (candidate->mbmi.ref_frame[1] == ref_frame) { ADD_MV_REF_LIST(candidate->mbmi.mv[1]); } } } // Check the last frame's mode and mv info. if (lf_here != NULL) { if (lf_here->mbmi.ref_frame[0] == ref_frame) { ADD_MV_REF_LIST(lf_here->mbmi.mv[0]); } else if (lf_here->mbmi.ref_frame[1] == ref_frame) { ADD_MV_REF_LIST(lf_here->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 (idx = 0; idx < MVREF_NEIGHBOURS; ++idx) { const MV *mv_ref = &mv_ref_search[idx]; if (!is_inside(mi_col, mi_row, cm->cur_tile_mi_col_start, mv_ref)) continue; candidate = here + mv_ref->col + mv_ref->row * xd->mode_info_stride; // If the candidate is INTRA we don't want to consider its mv. if (!is_inter_block(&candidate->mbmi)) continue; IF_DIFF_REF_FRAME_ADD_MV(candidate); } } // Since we still don't have a candidate we'll try the last frame.
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if (lf_here != NULL && is_inter_block(&lf_here->mbmi)) { IF_DIFF_REF_FRAME_ADD_MV(lf_here); } Done: mbmi->mb_mode_context[ref_frame] = counter_to_context[context_counter]; // Clamp vectors for (idx = 0; idx < MAX_MV_REF_CANDIDATES; ++idx) clamp_mv_ref(&mv_ref_list[idx].as_mv, xd); } #undef ADD_MV_REF_LIST #undef IF_DIFF_REF_FRAME_ADD_MV