1 /*
2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 
12 #ifndef VP8_COMMON_ENTROPYMV_H_
13 #define VP8_COMMON_ENTROPYMV_H_
14 
15 #include "treecoder.h"
16 
17 #ifdef __cplusplus
18 extern "C" {
19 #endif
20 
21 enum
22 {
23     mv_max  = 1023,              /* max absolute value of a MV component */
24     MVvals = (2 * mv_max) + 1,   /* # possible values "" */
25     mvfp_max  = 255,              /* max absolute value of a full pixel MV component */
26     MVfpvals = (2 * mvfp_max) +1, /* # possible full pixel MV values */
27 
28     mvlong_width = 10,       /* Large MVs have 9 bit magnitudes */
29     mvnum_short = 8,         /* magnitudes 0 through 7 */
30 
31     /* probability offsets for coding each MV component */
32 
33     mvpis_short = 0,         /* short (<= 7) vs long (>= 8) */
34     MVPsign,                /* sign for non-zero */
35     MVPshort,               /* 8 short values = 7-position tree */
36 
37     MVPbits = MVPshort + mvnum_short - 1, /* mvlong_width long value bits */
38     MVPcount = MVPbits + mvlong_width    /* (with independent probabilities) */
39 };
40 
41 typedef struct mv_context
42 {
43     vp8_prob prob[MVPcount];  /* often come in row, col pairs */
44 } MV_CONTEXT;
45 
46 extern const MV_CONTEXT vp8_mv_update_probs[2], vp8_default_mv_context[2];
47 
48 #ifdef __cplusplus
49 }  // extern "C"
50 #endif
51 
52 #endif  // VP8_COMMON_ENTROPYMV_H_
53