vp9_encodemv.c

/*
 *  Copyright (c) 2010 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_common.h"
#include "vp9/encoder/vp9_encodemv.h"
#include "vp9/common/vp9_entropymode.h"
#include "vp9/common/vp9_systemdependent.h"

#include <math.h>

#ifdef ENTROPY_STATS
extern unsigned int active_section;
#endif

static void encode_mv_component(vp9_writer* w, int comp,
                                const nmv_component* mvcomp, int usehp) {
  int offset;
  const int sign = comp < 0;
  const int mag = sign ? -comp : comp;
  const int mv_class = vp9_get_mv_class(mag - 1, &offset);
  const int d = offset >> 3;                // int mv data
  const int fr = (offset >> 1) & 3;         // fractional mv data
  const int hp = offset & 1;                // high precision mv data

  assert(comp != 0);

  // Sign
  vp9_write(w, sign, mvcomp->sign);

  // Class
  write_token(w, vp9_mv_class_tree, mvcomp->classes,
              &vp9_mv_class_encodings[mv_class]);

  // Integer bits
  if (mv_class == MV_CLASS_0) {
    write_token(w, vp9_mv_class0_tree, mvcomp->class0,
                &vp9_mv_class0_encodings[d]);
  } else {
    int i;
    const int n = mv_class + CLASS0_BITS - 1;  // number of bits
    for (i = 0; i < n; ++i)
      vp9_write(w, (d >> i) & 1, mvcomp->bits[i]);
  }

  // Fractional bits
  write_token(w, vp9_mv_fp_tree,
              mv_class == MV_CLASS_0 ?  mvcomp->class0_fp[d] : mvcomp->fp,
              &vp9_mv_fp_encodings[fr]);

  // High precision bit
  if (usehp)
    vp9_write(w, hp,
              mv_class == MV_CLASS_0 ? mvcomp->class0_hp : mvcomp->hp);
}


static void build_nmv_component_cost_table(int *mvcost,
                                           const nmv_component* const mvcomp,
                                           int usehp) {
  int i, v;
  int sign_cost[2], class_cost[MV_CLASSES], class0_cost[CLASS0_SIZE];
  int bits_cost[MV_OFFSET_BITS][2];