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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 #ifndef VP8_COMMON_ENTROPYMV_H_
12 #define VP8_COMMON_ENTROPYMV_H_
13 
14 #include "treecoder.h"
15 
16 #ifdef __cplusplus
17 extern "C" {
18 #endif
19 
20 enum {
21   mv_max = 1023,             /* max absolute value of a MV component */
22   MVvals = (2 * mv_max) + 1, /* # possible values "" */
23   mvfp_max = 255, /* max absolute value of a full pixel MV component */
24   MVfpvals = (2 * mvfp_max) + 1, /* # possible full pixel MV values */
25 
26   mvlong_width = 10, /* Large MVs have 9 bit magnitudes */
27   mvnum_short = 8,   /* magnitudes 0 through 7 */
28 
29   /* probability offsets for coding each MV component */
30 
31   mvpis_short = 0, /* short (<= 7) vs long (>= 8) */
32   MVPsign,         /* sign for non-zero */
33   MVPshort,        /* 8 short values = 7-position tree */
34 
35   MVPbits = MVPshort + mvnum_short - 1, /* mvlong_width long value bits */
36   MVPcount = MVPbits + mvlong_width     /* (with independent probabilities) */
37 };
38 
39 typedef struct mv_context {
40   vp8_prob prob[MVPcount]; /* often come in row, col pairs */
41 } MV_CONTEXT;
42 
43 extern const MV_CONTEXT vp8_mv_update_probs[2], vp8_default_mv_context[2];
44 
45 #ifdef __cplusplus
46 }  // extern "C"
47 #endif
48 
49 #endif  // VP8_COMMON_ENTROPYMV_H_
50