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/*
* Copyright (c) 1992 The Regents of the University of California.
* All rights reserved.
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without written agreement is
* hereby granted, provided that the above copyright notice and the following
* two paragraphs appear in all copies of this software.
*
* IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
* OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
* CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/
/*
* decoders.h
*
* This file contains the declarations of structures required for Huffman
* decoding
*
*/
/* Include util.h for bit i/o parsing macros. */
#include "util.h"
/* Code for unbound values in decoding tables */
#define ERROR -1
#define DCT_ERROR 63
#define MACRO_BLOCK_STUFFING 34
#define MACRO_BLOCK_ESCAPE 35
/* Two types of DCT Coefficients */
#define DCT_COEFF_FIRST 0
#define DCT_COEFF_NEXT 1
/* Special values for DCT Coefficients */
#define END_OF_BLOCK 62
#define ESCAPE 61
/* Structure for an entry in the decoding table of
* macroblock_address_increment */
typedef struct {
unsigned int value; /* value for macroblock_address_increment */
int num_bits; /* length of the Huffman code */
} mb_addr_inc_entry;
/* Decoding table for macroblock_address_increment */
extern mb_addr_inc_entry mb_addr_inc[2048];
/* Structure for an entry in the decoding table of macroblock_type */
typedef struct {
unsigned int mb_quant; /* macroblock_quant */
unsigned int mb_motion_forward; /* macroblock_motion_forward */
unsigned int mb_motion_backward; /* macroblock_motion_backward */
unsigned int mb_pattern; /* macroblock_pattern */
unsigned int mb_intra; /* macroblock_intra */
int num_bits; /* length of the Huffman code */
} mb_type_entry;
/* Decoding table for macroblock_type in predictive-coded pictures */
extern mb_type_entry mb_type_P[64];
/* Decoding table for macroblock_type in bidirectionally-coded pictures */
extern mb_type_entry mb_type_B[64];
/* Structures for an entry in the decoding table of coded_block_pattern */
typedef struct {
unsigned int cbp; /* coded_block_pattern */
int num_bits; /* length of the Huffman code */
} coded_block_pattern_entry;
/* External declaration of coded block pattern table. */
extern coded_block_pattern_entry coded_block_pattern[512];
/* Structure for an entry in the decoding table of motion vectors */
typedef struct {
int code; /* value for motion_horizontal_forward_code,
* motion_vertical_forward_code,
* motion_horizontal_backward_code, or
* motion_vertical_backward_code.
*/
int num_bits; /* length of the Huffman code */
} motion_vectors_entry;
/* Decoding table for motion vectors */
extern motion_vectors_entry motion_vectors[2048];
/* Structure for an entry in the decoding table of dct_dc_size */
typedef struct {
unsigned int value; /* value of dct_dc_size (luminance or chrominance) */
int num_bits; /* length of the Huffman code */
} dct_dc_size_entry;
/* External declaration of dct dc size lumiance table. */
extern dct_dc_size_entry dct_dc_size_luminance[128];
/* External declaration of dct dc size chrom table. */
extern dct_dc_size_entry dct_dc_size_chrominance[256];
/* DCT coeff tables. */
#define RUN_MASK 0xfc00
#define LEVEL_MASK 0x03f0
#define NUM_MASK 0x000f
#define RUN_SHIFT 10
#define LEVEL_SHIFT 4
/* External declaration of dct coeff tables. */
extern unsigned short int dct_coeff_tbl_0[256];
extern unsigned short int dct_coeff_tbl_1[16];
extern unsigned short int dct_coeff_tbl_2[4];
extern unsigned short int dct_coeff_tbl_3[4];
extern unsigned short int dct_coeff_next[256];
extern unsigned short int dct_coeff_first[256];
#define DecodeDCTDCSizeLum(macro_val) \
{ \
unsigned int index; \
\
show_bits7(index); \
\
macro_val = dct_dc_size_luminance[index].value; \
\
flush_bits(dct_dc_size_luminance[index].num_bits); \
}
#define DecodeDCTDCSizeChrom(macro_val) \
{ \
unsigned int index; \
\
show_bits8(index); \
\
macro_val = dct_dc_size_chrominance[index].value; \
\
flush_bits(dct_dc_size_chrominance[index].num_bits); \
}
#define DecodeDCTCoeff(dct_coeff_tbl, run, level) \
{ \
unsigned int temp, index; \
unsigned int value, next32bits, flushed; \
\
/* \
* Grab the next 32 bits and use it to improve performance of \
* getting the bits to parse. Thus, calls are translated as: \
* \
* show_bitsX <--> next32bits >> (32-X) \
* get_bitsX <--> val = next32bits >> (32-flushed-X); \
* flushed += X; \
* next32bits &= bitMask[flushed]; \
* flush_bitsX <--> flushed += X; \
* next32bits &= bitMask[flushed]; \
* \
* I've streamlined the code a lot, so that we don't have to mask \
* out the low order bits and a few of the extra adds are removed. \
*/ \
show_bits32(next32bits); \
\
/* show_bits8(index); */ \
index = next32bits >> 24; \
\
if (index > 3) { \
value = dct_coeff_tbl[index]; \
run = value >> RUN_SHIFT; \
if (run != END_OF_BLOCK) { \
/* num_bits = (value & NUM_MASK) + 1; */ \
/* flush_bits(num_bits); */ \
if (run != ESCAPE) { \
/* get_bits1(value); */ \
/* if (value) level = -level; */ \
flushed = (value & NUM_MASK) + 2; \
level = (value & LEVEL_MASK) >> LEVEL_SHIFT; \
value = next32bits >> (32-flushed); \
value &= 0x1; \
if (value) level = -level; \
/* next32bits &= ((~0) >> flushed); last op before update */ \
} \
else { /* run == ESCAPE */ \
/* Get the next six into run, and next 8 into temp */ \
/* get_bits14(temp); */ \
flushed = (value & NUM_MASK) + 1; \
temp = next32bits >> (18-flushed); \
/* Normally, we'd ad 14 to flushed, but I've saved a few \
* instr by moving the add below */ \
temp &= 0x3fff; \
run = temp >> 8; \
temp &= 0xff; \
if (temp == 0) { \
/* get_bits8(level); */ \
level = next32bits >> (10-flushed); \
level &= 0xff; \
flushed += 22; \
assert(level >= 128); \
} else if (temp != 128) { \
/* Grab sign bit */ \
flushed += 14; \
level = ((int) (temp << 24)) >> 24; \
} else { \
/* get_bits8(level); */ \
level = next32bits >> (10-flushed); \
level &= 0xff; \
flushed += 22; \
level = level - 256; \
assert(level <= -128 && level >= -255); \
} \
} \
/* Update bitstream... */ \
flush_bits(flushed); \
assert (flushed <= 32); \
} \
} \
else { \
if (index == 2) { \
/* show_bits10(index); */ \
index = next32bits >> 22; \
value = dct_coeff_tbl_2[index & 3]; \
} \
else if (index == 3) { \
/* show_bits10(index); */ \
index = next32bits >> 22; \
value = dct_coeff_tbl_3[index & 3]; \
} \
else if (index) { /* index == 1 */ \
/* show_bits12(index); */ \
index = next32bits >> 20; \
value = dct_coeff_tbl_1[index & 15]; \
} \
else { /* index == 0 */ \
/* show_bits16(index); */ \
index = next32bits >> 16; \
value = dct_coeff_tbl_0[index & 255]; \
} \
run = value >> RUN_SHIFT; \
level = (value & LEVEL_MASK) >> LEVEL_SHIFT; \
\
/* \
* Fold these operations together to make it fast... \
*/ \
/* num_bits = (value & NUM_MASK) + 1; */ \
/* flush_bits(num_bits); */ \
/* get_bits1(value); */ \
/* if (value) level = -level; */ \
\
flushed = (value & NUM_MASK) + 2; \
value = next32bits >> (32-flushed); \
value &= 0x1; \
if (value) level = -level; \
\
/* Update bitstream ... */ \
flush_bits(flushed); \
assert (flushed <= 32); \
} \
}
#define DecodeDCTCoeffFirst(runval, levelval) \
{ \
DecodeDCTCoeff(dct_coeff_first, runval, levelval); \
}
#define DecodeDCTCoeffNext(runval, levelval) \
{ \
DecodeDCTCoeff(dct_coeff_next, runval, levelval); \
}
/*
*--------------------------------------------------------------
*
* DecodeMBAddrInc --
*
* Huffman Decoder for macro_block_address_increment; the location
* in which the result will be placed is being passed as argument.
* The decoded value is obtained by doing a table lookup on
* mb_addr_inc.
*
* Results:
* The decoded value for macro_block_address_increment or ERROR
* for unbound values will be placed in the location specified.
*
* Side effects:
* Bit stream is irreversibly parsed.
*
*--------------------------------------------------------------
*/
#define DecodeMBAddrInc(val) \
{ \
unsigned int index; \
show_bits11(index); \
val = mb_addr_inc[index].value; \
flush_bits(mb_addr_inc[index].num_bits); \
}
/*
*--------------------------------------------------------------
*
* DecodeMotionVectors --
*
* Huffman Decoder for the various motion vectors, including
* motion_horizontal_forward_code, motion_vertical_forward_code,
* motion_horizontal_backward_code, motion_vertical_backward_code.
* Location where the decoded result will be placed is being passed
* as argument. The decoded values are obtained by doing a table
* lookup on motion_vectors.
*
* Results:
* The decoded value for the motion vector or ERROR for unbound
* values will be placed in the location specified.
*
* Side effects:
* Bit stream is irreversibly parsed.
*
*--------------------------------------------------------------
*/
#define DecodeMotionVectors(value) \
{ \
unsigned int index; \
show_bits11(index); \
value = motion_vectors[index].code; \
flush_bits(motion_vectors[index].num_bits); \
}
/*
*--------------------------------------------------------------
*
* DecodeMBTypeB --
*
* Huffman Decoder for macro_block_type in bidirectionally-coded
* pictures;locations in which the decoded results: macroblock_quant,
* macroblock_motion_forward, macro_block_motion_backward,
* macroblock_pattern, macro_block_intra, will be placed are
* being passed as argument. The decoded values are obtained by
* doing a table lookup on mb_type_B.
*
* Results:
* The various decoded values for macro_block_type in
* bidirectionally-coded pictures or ERROR for unbound values will
* be placed in the locations specified.
*
* Side effects:
* Bit stream is irreversibly parsed.
*
*--------------------------------------------------------------
*/
#define DecodeMBTypeB(quant, motion_fwd, motion_bwd, pat, intra) \
{ \
unsigned int index; \
\
show_bits6(index); \
\
quant = mb_type_B[index].mb_quant; \
motion_fwd = mb_type_B[index].mb_motion_forward; \
motion_bwd = mb_type_B[index].mb_motion_backward; \
pat = mb_type_B[index].mb_pattern; \
intra = mb_type_B[index].mb_intra; \
flush_bits(mb_type_B[index].num_bits); \
}
/*
*--------------------------------------------------------------
*
* DecodeMBTypeI --
*
* Huffman Decoder for macro_block_type in intra-coded pictures;
* locations in which the decoded results: macroblock_quant,
* macroblock_motion_forward, macro_block_motion_backward,
* macroblock_pattern, macro_block_intra, will be placed are
* being passed as argument.
*
* Results:
* The various decoded values for macro_block_type in intra-coded
* pictures or ERROR for unbound values will be placed in the
* locations specified.
*
* Side effects:
* Bit stream is irreversibly parsed.
*
*--------------------------------------------------------------
*/
#define DecodeMBTypeI(quant, motion_fwd, motion_bwd, pat, intra) \
{ \
unsigned int index; \
static int quantTbl[4] = {ERROR, 1, 0, 0}; \
\
show_bits2(index); \
\
motion_fwd = 0; \
motion_bwd = 0; \
pat = 0; \
intra = 1; \
quant = quantTbl[index]; \
if (index) { \
flush_bits (1 + quant); \
} \
}
/*
*--------------------------------------------------------------
*
* DecodeMBTypeP --
*
* Huffman Decoder for macro_block_type in predictive-coded pictures;
* locations in which the decoded results: macroblock_quant,
* macroblock_motion_forward, macro_block_motion_backward,
* macroblock_pattern, macro_block_intra, will be placed are
* being passed as argument. The decoded values are obtained by
* doing a table lookup on mb_type_P.
*
* Results:
* The various decoded values for macro_block_type in
* predictive-coded pictures or ERROR for unbound values will be
* placed in the locations specified.
*
* Side effects:
* Bit stream is irreversibly parsed.
*
*--------------------------------------------------------------
*/
#define DecodeMBTypeP(quant, motion_fwd, motion_bwd, pat, intra) \
{ \
unsigned int index; \
\
show_bits6(index); \
\
quant = mb_type_P[index].mb_quant; \
motion_fwd = mb_type_P[index].mb_motion_forward; \
motion_bwd = mb_type_P[index].mb_motion_backward; \
pat = mb_type_P[index].mb_pattern; \
intra = mb_type_P[index].mb_intra; \
\
flush_bits(mb_type_P[index].num_bits); \
}
/*
*--------------------------------------------------------------
*
* DecodeCBP --
*
* Huffman Decoder for coded_block_pattern; location in which the
* decoded result will be placed is being passed as argument. The
* decoded values are obtained by doing a table lookup on
* coded_block_pattern.
*
* Results:
* The decoded value for coded_block_pattern or ERROR for unbound
* values will be placed in the location specified.
*
* Side effects:
* Bit stream is irreversibly parsed.
*
*--------------------------------------------------------------
*/
#define DecodeCBP(coded_bp) \
{ \
unsigned int index; \
\
show_bits9(index); \
coded_bp = coded_block_pattern[index].cbp; \
flush_bits(coded_block_pattern[index].num_bits); \
}
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