110 строки
4.0 KiB
C
110 строки
4.0 KiB
C
/*
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* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef VP8_COMMON_ENTROPY_H_
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#define VP8_COMMON_ENTROPY_H_
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#include "treecoder.h"
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#include "blockd.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Coefficient token alphabet */
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#define ZERO_TOKEN 0 /* 0 Extra Bits 0+0 */
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#define ONE_TOKEN 1 /* 1 Extra Bits 0+1 */
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#define TWO_TOKEN 2 /* 2 Extra Bits 0+1 */
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#define THREE_TOKEN 3 /* 3 Extra Bits 0+1 */
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#define FOUR_TOKEN 4 /* 4 Extra Bits 0+1 */
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#define DCT_VAL_CATEGORY1 5 /* 5-6 Extra Bits 1+1 */
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#define DCT_VAL_CATEGORY2 6 /* 7-10 Extra Bits 2+1 */
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#define DCT_VAL_CATEGORY3 7 /* 11-18 Extra Bits 3+1 */
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#define DCT_VAL_CATEGORY4 8 /* 19-34 Extra Bits 4+1 */
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#define DCT_VAL_CATEGORY5 9 /* 35-66 Extra Bits 5+1 */
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#define DCT_VAL_CATEGORY6 10 /* 67+ Extra Bits 11+1 */
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#define DCT_EOB_TOKEN 11 /* EOB Extra Bits 0+0 */
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#define MAX_ENTROPY_TOKENS 12
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#define ENTROPY_NODES 11
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extern const vp8_tree_index vp8_coef_tree[];
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extern const struct vp8_token_struct vp8_coef_encodings[MAX_ENTROPY_TOKENS];
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typedef struct
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{
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vp8_tree_p tree;
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const vp8_prob *prob;
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int Len;
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int base_val;
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} vp8_extra_bit_struct;
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extern const vp8_extra_bit_struct vp8_extra_bits[12]; /* indexed by token value */
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#define PROB_UPDATE_BASELINE_COST 7
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#define MAX_PROB 255
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#define DCT_MAX_VALUE 2048
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/* Coefficients are predicted via a 3-dimensional probability table. */
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/* Outside dimension. 0 = Y no DC, 1 = Y2, 2 = UV, 3 = Y with DC */
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#define BLOCK_TYPES 4
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/* Middle dimension is a coarsening of the coefficient's
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position within the 4x4 DCT. */
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#define COEF_BANDS 8
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extern DECLARE_ALIGNED(16, const unsigned char, vp8_coef_bands[16]);
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/* Inside dimension is 3-valued measure of nearby complexity, that is,
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the extent to which nearby coefficients are nonzero. For the first
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coefficient (DC, unless block type is 0), we look at the (already encoded)
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blocks above and to the left of the current block. The context index is
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then the number (0,1,or 2) of these blocks having nonzero coefficients.
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After decoding a coefficient, the measure is roughly the size of the
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most recently decoded coefficient (0 for 0, 1 for 1, 2 for >1).
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Note that the intuitive meaning of this measure changes as coefficients
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are decoded, e.g., prior to the first token, a zero means that my neighbors
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are empty while, after the first token, because of the use of end-of-block,
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a zero means we just decoded a zero and hence guarantees that a non-zero
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coefficient will appear later in this block. However, this shift
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in meaning is perfectly OK because our context depends also on the
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coefficient band (and since zigzag positions 0, 1, and 2 are in
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distinct bands). */
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/*# define DC_TOKEN_CONTEXTS 3*/ /* 00, 0!0, !0!0 */
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# define PREV_COEF_CONTEXTS 3
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extern DECLARE_ALIGNED(16, const unsigned char, vp8_prev_token_class[MAX_ENTROPY_TOKENS]);
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extern const vp8_prob vp8_coef_update_probs [BLOCK_TYPES] [COEF_BANDS] [PREV_COEF_CONTEXTS] [ENTROPY_NODES];
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struct VP8Common;
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void vp8_default_coef_probs(struct VP8Common *);
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extern DECLARE_ALIGNED(16, const int, vp8_default_zig_zag1d[16]);
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extern DECLARE_ALIGNED(16, const short, vp8_default_inv_zig_zag[16]);
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extern DECLARE_ALIGNED(16, const short, vp8_default_zig_zag_mask[16]);
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extern const int vp8_mb_feature_data_bits[MB_LVL_MAX];
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void vp8_coef_tree_initialize(void);
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#ifdef __cplusplus
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} // extern "C"
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#endif
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#endif // VP8_COMMON_ENTROPY_H_
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