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      1 /*
      2  * Copyright (c) 2016, Alliance for Open Media. All rights reserved
      3  *
      4  * This source code is subject to the terms of the BSD 2 Clause License and
      5  * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
      6  * was not distributed with this source code in the LICENSE file, you can
      7  * obtain it at www.aomedia.org/license/software. If the Alliance for Open
      8  * Media Patent License 1.0 was not distributed with this source code in the
      9  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
     10  */
     11 
     12 #include <math.h>
     13 
     14 #include "av1/common/common.h"
     15 #include "av1/common/entropymode.h"
     16 
     17 #include "av1/encoder/cost.h"
     18 #include "av1/encoder/encodemv.h"
     19 
     20 #include "aom_dsp/aom_dsp_common.h"
     21 #include "aom_ports/bitops.h"
     22 
     23 static INLINE int mv_class_base(MV_CLASS_TYPE c) {
     24   return c ? CLASS0_SIZE << (c + 2) : 0;
     25 }
     26 
     27 // If n != 0, returns the floor of log base 2 of n. If n == 0, returns 0.
     28 static INLINE uint8_t log_in_base_2(unsigned int n) {
     29   // get_msb() is only valid when n != 0.
     30   return n == 0 ? 0 : get_msb(n);
     31 }
     32 
     33 static INLINE MV_CLASS_TYPE get_mv_class(int z, int *offset) {
     34   const MV_CLASS_TYPE c = (z >= CLASS0_SIZE * 4096)
     35                               ? MV_CLASS_10
     36                               : (MV_CLASS_TYPE)log_in_base_2(z >> 3);
     37   if (offset) *offset = z - mv_class_base(c);
     38   return c;
     39 }
     40 
     41 static void encode_mv_component(aom_writer *w, int comp, nmv_component *mvcomp,
     42                                 MvSubpelPrecision precision) {
     43   assert(comp != 0);
     44   int offset;
     45   const int sign = comp < 0;
     46   const int mag = sign ? -comp : comp;
     47   const int mv_class = get_mv_class(mag - 1, &offset);
     48   const int d = offset >> 3;         // int mv data
     49   const int fr = (offset >> 1) & 3;  // fractional mv data
     50   const int hp = offset & 1;         // high precision mv data
     51 
     52   // Sign
     53   aom_write_symbol(w, sign, mvcomp->sign_cdf, 2);
     54 
     55   // Class
     56   aom_write_symbol(w, mv_class, mvcomp->classes_cdf, MV_CLASSES);
     57 
     58   // Integer bits
     59   if (mv_class == MV_CLASS_0) {
     60     aom_write_symbol(w, d, mvcomp->class0_cdf, CLASS0_SIZE);
     61   } else {
     62     int i;
     63     const int n = mv_class + CLASS0_BITS - 1;  // number of bits
     64     for (i = 0; i < n; ++i)
     65       aom_write_symbol(w, (d >> i) & 1, mvcomp->bits_cdf[i], 2);
     66   }
     67   // Fractional bits
     68   if (precision > MV_SUBPEL_NONE) {
     69     aom_write_symbol(
     70         w, fr,
     71         mv_class == MV_CLASS_0 ? mvcomp->class0_fp_cdf[d] : mvcomp->fp_cdf,
     72         MV_FP_SIZE);
     73   }
     74 
     75   // High precision bit
     76   if (precision > MV_SUBPEL_LOW_PRECISION)
     77     aom_write_symbol(
     78         w, hp, mv_class == MV_CLASS_0 ? mvcomp->class0_hp_cdf : mvcomp->hp_cdf,
     79         2);
     80 }
     81 
     82 static void build_nmv_component_cost_table(int *mvcost,
     83                                            const nmv_component *const mvcomp,
     84                                            MvSubpelPrecision precision) {
     85   int i, v;
     86   int sign_cost[2], class_cost[MV_CLASSES], class0_cost[CLASS0_SIZE];
     87   int bits_cost[MV_OFFSET_BITS][2];
     88   int class0_fp_cost[CLASS0_SIZE][MV_FP_SIZE], fp_cost[MV_FP_SIZE];
     89   int class0_hp_cost[2], hp_cost[2];
     90 
     91   av1_cost_tokens_from_cdf(sign_cost, mvcomp->sign_cdf, NULL);
     92   av1_cost_tokens_from_cdf(class_cost, mvcomp->classes_cdf, NULL);
     93   av1_cost_tokens_from_cdf(class0_cost, mvcomp->class0_cdf, NULL);
     94   for (i = 0; i < MV_OFFSET_BITS; ++i) {
     95     av1_cost_tokens_from_cdf(bits_cost[i], mvcomp->bits_cdf[i], NULL);
     96   }
     97 
     98   for (i = 0; i < CLASS0_SIZE; ++i)
     99     av1_cost_tokens_from_cdf(class0_fp_cost[i], mvcomp->class0_fp_cdf[i], NULL);
    100   av1_cost_tokens_from_cdf(fp_cost, mvcomp->fp_cdf, NULL);
    101 
    102   if (precision > MV_SUBPEL_LOW_PRECISION) {
    103     av1_cost_tokens_from_cdf(class0_hp_cost, mvcomp->class0_hp_cdf, NULL);
    104     av1_cost_tokens_from_cdf(hp_cost, mvcomp->hp_cdf, NULL);
    105   }
    106   mvcost[0] = 0;
    107   for (v = 1; v <= MV_MAX; ++v) {
    108     int z, c, o, d, e, f, cost = 0;
    109     z = v - 1;
    110     c = get_mv_class(z, &o);
    111     cost += class_cost[c];
    112     d = (o >> 3);     /* int mv data */
    113     f = (o >> 1) & 3; /* fractional pel mv data */
    114     e = (o & 1);      /* high precision mv data */
    115     if (c == MV_CLASS_0) {
    116       cost += class0_cost[d];
    117     } else {
    118       const int b = c + CLASS0_BITS - 1; /* number of bits */
    119       for (i = 0; i < b; ++i) cost += bits_cost[i][((d >> i) & 1)];
    120     }
    121     if (precision > MV_SUBPEL_NONE) {
    122       if (c == MV_CLASS_0) {
    123         cost += class0_fp_cost[d][f];
    124       } else {
    125         cost += fp_cost[f];
    126       }
    127       if (precision > MV_SUBPEL_LOW_PRECISION) {
    128         if (c == MV_CLASS_0) {
    129           cost += class0_hp_cost[e];
    130         } else {
    131           cost += hp_cost[e];
    132         }
    133       }
    134     }
    135     mvcost[v] = cost + sign_cost[0];
    136     mvcost[-v] = cost + sign_cost[1];
    137   }
    138 }
    139 
    140 void av1_encode_mv(AV1_COMP *cpi, aom_writer *w, const MV *mv, const MV *ref,
    141                    nmv_context *mvctx, int usehp) {
    142   const MV diff = { mv->row - ref->row, mv->col - ref->col };
    143   const MV_JOINT_TYPE j = av1_get_mv_joint(&diff);
    144   if (cpi->common.cur_frame_force_integer_mv) {
    145     usehp = MV_SUBPEL_NONE;
    146   }
    147   aom_write_symbol(w, j, mvctx->joints_cdf, MV_JOINTS);
    148   if (mv_joint_vertical(j))
    149     encode_mv_component(w, diff.row, &mvctx->comps[0], usehp);
    150 
    151   if (mv_joint_horizontal(j))
    152     encode_mv_component(w, diff.col, &mvctx->comps[1], usehp);
    153 
    154   // If auto_mv_step_size is enabled then keep track of the largest
    155   // motion vector component used.
    156   if (cpi->sf.mv.auto_mv_step_size) {
    157     unsigned int maxv = AOMMAX(abs(mv->row), abs(mv->col)) >> 3;
    158     cpi->max_mv_magnitude = AOMMAX(maxv, cpi->max_mv_magnitude);
    159   }
    160 }
    161 
    162 void av1_encode_dv(aom_writer *w, const MV *mv, const MV *ref,
    163                    nmv_context *mvctx) {
    164   // DV and ref DV should not have sub-pel.
    165   assert((mv->col & 7) == 0);
    166   assert((mv->row & 7) == 0);
    167   assert((ref->col & 7) == 0);
    168   assert((ref->row & 7) == 0);
    169   const MV diff = { mv->row - ref->row, mv->col - ref->col };
    170   const MV_JOINT_TYPE j = av1_get_mv_joint(&diff);
    171 
    172   aom_write_symbol(w, j, mvctx->joints_cdf, MV_JOINTS);
    173   if (mv_joint_vertical(j))
    174     encode_mv_component(w, diff.row, &mvctx->comps[0], MV_SUBPEL_NONE);
    175 
    176   if (mv_joint_horizontal(j))
    177     encode_mv_component(w, diff.col, &mvctx->comps[1], MV_SUBPEL_NONE);
    178 }
    179 
    180 void av1_build_nmv_cost_table(int *mvjoint, int *mvcost[2],
    181                               const nmv_context *ctx,
    182                               MvSubpelPrecision precision) {
    183   av1_cost_tokens_from_cdf(mvjoint, ctx->joints_cdf, NULL);
    184   build_nmv_component_cost_table(mvcost[0], &ctx->comps[0], precision);
    185   build_nmv_component_cost_table(mvcost[1], &ctx->comps[1], precision);
    186 }
    187 
    188 int_mv av1_get_ref_mv_from_stack(int ref_idx,
    189                                  const MV_REFERENCE_FRAME *ref_frame,
    190                                  int ref_mv_idx,
    191                                  const MB_MODE_INFO_EXT *mbmi_ext) {
    192   const int8_t ref_frame_type = av1_ref_frame_type(ref_frame);
    193   const CANDIDATE_MV *curr_ref_mv_stack =
    194       mbmi_ext->ref_mv_stack[ref_frame_type];
    195   int_mv ref_mv;
    196   ref_mv.as_int = INVALID_MV;
    197 
    198   if (ref_frame[1] > INTRA_FRAME) {
    199     if (ref_idx == 0) {
    200       ref_mv = curr_ref_mv_stack[ref_mv_idx].this_mv;
    201     } else {
    202       assert(ref_idx == 1);
    203       ref_mv = curr_ref_mv_stack[ref_mv_idx].comp_mv;
    204     }
    205   } else {
    206     assert(ref_idx == 0);
    207     if (ref_mv_idx < mbmi_ext->ref_mv_count[ref_frame_type]) {
    208       ref_mv = curr_ref_mv_stack[ref_mv_idx].this_mv;
    209     } else {
    210       ref_mv = mbmi_ext->global_mvs[ref_frame_type];
    211     }
    212   }
    213   return ref_mv;
    214 }
    215 
    216 int_mv av1_get_ref_mv(const MACROBLOCK *x, int ref_idx) {
    217   const MACROBLOCKD *xd = &x->e_mbd;
    218   const MB_MODE_INFO *mbmi = xd->mi[0];
    219   int ref_mv_idx = mbmi->ref_mv_idx;
    220   if (mbmi->mode == NEAR_NEWMV || mbmi->mode == NEW_NEARMV) {
    221     assert(has_second_ref(mbmi));
    222     ref_mv_idx += 1;
    223   }
    224   return av1_get_ref_mv_from_stack(ref_idx, mbmi->ref_frame, ref_mv_idx,
    225                                    x->mbmi_ext);
    226 }
    227 
    228 void av1_find_best_ref_mvs_from_stack(int allow_hp,
    229                                       const MB_MODE_INFO_EXT *mbmi_ext,
    230                                       MV_REFERENCE_FRAME ref_frame,
    231                                       int_mv *nearest_mv, int_mv *near_mv,
    232                                       int is_integer) {
    233   const int ref_idx = 0;
    234   MV_REFERENCE_FRAME ref_frames[2] = { ref_frame, NONE_FRAME };
    235   *nearest_mv = av1_get_ref_mv_from_stack(ref_idx, ref_frames, 0, mbmi_ext);
    236   lower_mv_precision(&nearest_mv->as_mv, allow_hp, is_integer);
    237   *near_mv = av1_get_ref_mv_from_stack(ref_idx, ref_frames, 1, mbmi_ext);
    238   lower_mv_precision(&near_mv->as_mv, allow_hp, is_integer);
    239 }
    240