vpx/vp8/common/treecoder.h
Deb Mukherjee 00f9eb6590 New motion vector entropy coding
Adds a new experiment with redesigned/refactored motion vector entropy
coding. The patch also takes a first step towards separating the
integer and fractional pel components of a MV. However the fractional
pel encoding still depends on the integer pel part and so they are
not fully independent. Further experiments are in progress to see
how much they can be decoupled without affecting performance.
All components including entropy coding/decoding, costing for MV
search, forward updates and backward updates to probability tables,
have been implemented.

Results so far:
derf: +0.19%
std-hd: +0.28%
yt: +0.80%
hd: +1.15%

Patch: Simplifies the fractional pel models:
derf: +0.284%
std-hd: +0.289%
yt: +0.849%
hd: +1.254%

Patch: Some changes in the models, rebased.
derf: +0.330%
std-hd: +0.306%
yt: +0.816%
hd: +1.225%

Change-Id: I646b3c48f3587f4cc909639b78c3798da6402678
2012-09-06 08:28:21 -07:00

91 lines
2.7 KiB
C

/*
* 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 __INC_TREECODER_H
#define __INC_TREECODER_H
typedef unsigned char vp8bc_index_t; /* probability index */
typedef unsigned char vp8_prob;
#define vp8_prob_half ( (vp8_prob) 128)
typedef signed char vp8_tree_index;
struct bool_coder_spec;
typedef struct bool_coder_spec bool_coder_spec;
typedef struct bool_writer bool_writer;
typedef struct bool_reader bool_reader;
typedef const bool_coder_spec c_bool_coder_spec;
typedef const bool_writer c_bool_writer;
typedef const bool_reader c_bool_reader;
# define vp8_complement( x) (255 - x)
/* We build coding trees compactly in arrays.
Each node of the tree is a pair of vp8_tree_indices.
Array index often references a corresponding probability table.
Index <= 0 means done encoding/decoding and value = -Index,
Index > 0 means need another bit, specification at index.
Nonnegative indices are always even; processing begins at node 0. */
typedef const vp8_tree_index vp8_tree[], *vp8_tree_p;
typedef const struct vp8_token_struct {
int value;
int Len;
} vp8_token;
/* Construct encoding array from tree. */
void vp8_tokens_from_tree(struct vp8_token_struct *, vp8_tree);
void vp8_tokens_from_tree_offset(struct vp8_token_struct *, vp8_tree,
int offset);
/* Convert array of token occurrence counts into a table of probabilities
for the associated binary encoding tree. Also writes count of branches
taken for each node on the tree; this facilitiates decisions as to
probability updates. */
void vp8_tree_probs_from_distribution(
int n, /* n = size of alphabet */
vp8_token tok [ /* n */ ],
vp8_tree tree,
vp8_prob probs [ /* n-1 */ ],
unsigned int branch_ct [ /* n-1 */ ] [2],
const unsigned int num_events[ /* n */ ],
unsigned int Pfactor,
int Round
);
/* Variant of above using coder spec rather than hardwired 8-bit probs. */
void vp8bc_tree_probs_from_distribution(
int n, /* n = size of alphabet */
vp8_token tok [ /* n */ ],
vp8_tree tree,
vp8_prob probs [ /* n-1 */ ],
unsigned int branch_ct [ /* n-1 */ ] [2],
const unsigned int num_events[ /* n */ ],
c_bool_coder_spec *s
);
vp8_prob vp8_bin_prob_from_distribution(const unsigned int counts[2]);
#endif