1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libvpx/vp8/common/treecoder.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,90 @@
1.4 +/*
1.5 + * Copyright (c) 2010 The WebM project authors. All Rights Reserved.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license
1.8 + * that can be found in the LICENSE file in the root of the source
1.9 + * tree. An additional intellectual property rights grant can be found
1.10 + * in the file PATENTS. All contributing project authors may
1.11 + * be found in the AUTHORS file in the root of the source tree.
1.12 + */
1.13 +
1.14 +
1.15 +#ifndef __INC_TREECODER_H
1.16 +#define __INC_TREECODER_H
1.17 +
1.18 +typedef unsigned char vp8bc_index_t; /* probability index */
1.19 +
1.20 +
1.21 +typedef unsigned char vp8_prob;
1.22 +
1.23 +#define vp8_prob_half ( (vp8_prob) 128)
1.24 +
1.25 +typedef signed char vp8_tree_index;
1.26 +struct bool_coder_spec;
1.27 +
1.28 +typedef struct bool_coder_spec bool_coder_spec;
1.29 +typedef struct bool_writer bool_writer;
1.30 +typedef struct bool_reader bool_reader;
1.31 +
1.32 +typedef const bool_coder_spec c_bool_coder_spec;
1.33 +typedef const bool_writer c_bool_writer;
1.34 +typedef const bool_reader c_bool_reader;
1.35 +
1.36 +
1.37 +
1.38 +# define vp8_complement( x) (255 - x)
1.39 +
1.40 +
1.41 +/* We build coding trees compactly in arrays.
1.42 + Each node of the tree is a pair of vp8_tree_indices.
1.43 + Array index often references a corresponding probability table.
1.44 + Index <= 0 means done encoding/decoding and value = -Index,
1.45 + Index > 0 means need another bit, specification at index.
1.46 + Nonnegative indices are always even; processing begins at node 0. */
1.47 +
1.48 +typedef const vp8_tree_index vp8_tree[], *vp8_tree_p;
1.49 +
1.50 +
1.51 +typedef const struct vp8_token_struct
1.52 +{
1.53 + int value;
1.54 + int Len;
1.55 +} vp8_token;
1.56 +
1.57 +/* Construct encoding array from tree. */
1.58 +
1.59 +void vp8_tokens_from_tree(struct vp8_token_struct *, vp8_tree);
1.60 +void vp8_tokens_from_tree_offset(struct vp8_token_struct *, vp8_tree,
1.61 + int offset);
1.62 +
1.63 +
1.64 +/* Convert array of token occurrence counts into a table of probabilities
1.65 + for the associated binary encoding tree. Also writes count of branches
1.66 + taken for each node on the tree; this facilitiates decisions as to
1.67 + probability updates. */
1.68 +
1.69 +void vp8_tree_probs_from_distribution(
1.70 + int n, /* n = size of alphabet */
1.71 + vp8_token tok [ /* n */ ],
1.72 + vp8_tree tree,
1.73 + vp8_prob probs [ /* n-1 */ ],
1.74 + unsigned int branch_ct [ /* n-1 */ ] [2],
1.75 + const unsigned int num_events[ /* n */ ],
1.76 + unsigned int Pfactor,
1.77 + int Round
1.78 +);
1.79 +
1.80 +/* Variant of above using coder spec rather than hardwired 8-bit probs. */
1.81 +
1.82 +void vp8bc_tree_probs_from_distribution(
1.83 + int n, /* n = size of alphabet */
1.84 + vp8_token tok [ /* n */ ],
1.85 + vp8_tree tree,
1.86 + vp8_prob probs [ /* n-1 */ ],
1.87 + unsigned int branch_ct [ /* n-1 */ ] [2],
1.88 + const unsigned int num_events[ /* n */ ],
1.89 + c_bool_coder_spec *s
1.90 +);
1.91 +
1.92 +
1.93 +#endif
