shithub: libvpx

ref: 7ec916e8183332df6f1bd94b58f344f9923833b7
dir: /vp8/common/entropymv.h/

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/*
 *  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.
 */

#ifndef VPX_VP8_COMMON_ENTROPYMV_H_
#define VPX_VP8_COMMON_ENTROPYMV_H_

#include "treecoder.h"

#ifdef __cplusplus
extern "C" {
#endif

enum {
  mv_max = 1023,             /* max absolute value of a MV component */
  MVvals = (2 * mv_max) + 1, /* # possible values "" */
  mvfp_max = 255, /* max absolute value of a full pixel MV component */
  MVfpvals = (2 * mvfp_max) + 1, /* # possible full pixel MV values */

  mvlong_width = 10, /* Large MVs have 9 bit magnitudes */
  mvnum_short = 8,   /* magnitudes 0 through 7 */

  /* probability offsets for coding each MV component */

  mvpis_short = 0, /* short (<= 7) vs long (>= 8) */
  MVPsign,         /* sign for non-zero */
  MVPshort,        /* 8 short values = 7-position tree */

  MVPbits = MVPshort + mvnum_short - 1, /* mvlong_width long value bits */
  MVPcount = MVPbits + mvlong_width     /* (with independent probabilities) */
};

typedef struct mv_context {
  vp8_prob prob[MVPcount]; /* often come in row, col pairs */
} MV_CONTEXT;

extern const MV_CONTEXT vp8_mv_update_probs[2], vp8_default_mv_context[2];

#ifdef __cplusplus
}  // extern "C"
#endif

#endif  // VPX_VP8_COMMON_ENTROPYMV_H_