vp8/common/entropymv.h

   1 /*
   2  *  Copyright (c) 2010 The VP8 project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license and patent
   5  *  grant that can be found in the LICENSE file in the root of the source
   6  *  tree. All contributing project authors may be found in the AUTHORS
   7  *  file in the root of the source tree.
   8  */
   9
  10
  11 #ifndef __INC_ENTROPYMV_H
  12 #define __INC_ENTROPYMV_H
  13
  14 #include "treecoder.h"
  15
  16 enum
  17 {
  18     mv_max  = 1023,              /* max absolute value of a MV component */
  19     MVvals = (2 * mv_max) + 1,   /* # possible values "" */
  20
  21     mvlong_width = 10,       /* Large MVs have 9 bit magnitudes */
  22     mvnum_short = 8,         /* magnitudes 0 through 7 */
  23
  24     /* probability offsets for coding each MV component */
  25
  26     mvpis_short = 0,         /* short (<= 7) vs long (>= 8) */
  27     MVPsign,                /* sign for non-zero */
  28     MVPshort,               /* 8 short values = 7-position tree */
  29
  30     MVPbits = MVPshort + mvnum_short - 1, /* mvlong_width long value bits */
  31     MVPcount = MVPbits + mvlong_width    /* (with independent probabilities) */
  32 };
  33
  34 typedef struct mv_context
  35 {
  36     vp8_prob prob[MVPcount];  /* often come in row, col pairs */
  37 } MV_CONTEXT;
  38
  39 extern const MV_CONTEXT vp8_mv_update_probs[2], vp8_default_mv_context[2];
  40
  41 #endif