vlc.c File Reference

VLC support functions. More...

#include "contributors.h"
#include "global.h"
#include "vlc.h"
#include "elements.h"

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Defines

#define SYMTRACESTRING(s)

Functions

int ue_v (char *tracestring, Bitstream *bitstream)
int se_v (char *tracestring, Bitstream *bitstream)
int u_v (int LenInBits, char *tracestring, Bitstream *bitstream)
int i_v (int LenInBits, char *tracestring, Bitstream *bitstream)
Boolean u_1 (char *tracestring, Bitstream *bitstream)
void linfo_ue (int len, int info, int *value1, int *dummy)
void linfo_se (int len, int info, int *value1, int *dummy)
void linfo_cbp_intra_normal (int len, int info, int *cbp, int *dummy)
void linfo_cbp_intra_other (int len, int info, int *cbp, int *dummy)
void linfo_cbp_inter_normal (int len, int info, int *cbp, int *dummy)
void linfo_cbp_inter_other (int len, int info, int *cbp, int *dummy)
void linfo_levrun_inter (int len, int info, int *level, int *irun)
void linfo_levrun_c2x2 (int len, int info, int *level, int *irun)
int readSyntaxElement_VLC (SyntaxElement *sym, Bitstream *currStream)
int readSyntaxElement_UVLC (SyntaxElement *sym, ImageParameters *p_Img, struct datapartition *dP)
int readSyntaxElement_Intra4x4PredictionMode (SyntaxElement *sym, ImageParameters *p_Img, Bitstream *currStream)
int GetVLCSymbol_IntraMode (byte buffer[], int totbitoffset, int *info, int bytecount)
int more_rbsp_data (byte buffer[], int totbitoffset, int bytecount)
int uvlc_startcode_follows (Slice *currSlice, int dummy)
int GetVLCSymbol (byte buffer[], int totbitoffset, int *info, int bytecount)
static int ShowBitsThres (int inf, int numbits)
int code_from_bitstream_2d (SyntaxElement *sym, Bitstream *currStream, const byte *lentab, const byte *codtab, int tabwidth, int tabheight, int *code)
int readSyntaxElement_FLC (SyntaxElement *sym, Bitstream *currStream)
int readSyntaxElement_NumCoeffTrailingOnes (SyntaxElement *sym, Bitstream *currStream, char *type)
int readSyntaxElement_NumCoeffTrailingOnesChromaDC (ImageParameters *p_Img, SyntaxElement *sym, Bitstream *currStream)
int readSyntaxElement_Level_VLC0 (SyntaxElement *sym, Bitstream *currStream)
int readSyntaxElement_Level_VLCN (SyntaxElement *sym, int vlc, Bitstream *currStream)
int readSyntaxElement_TotalZeros (SyntaxElement *sym, Bitstream *currStream)
int readSyntaxElement_TotalZerosChromaDC (ImageParameters *p_Img, SyntaxElement *sym, Bitstream *currStream)
int readSyntaxElement_Run (SyntaxElement *sym, Bitstream *currStream)
int GetBits (byte buffer[], int totbitoffset, int *info, int bitcount, int numbits)
int ShowBits (byte buffer[], int totbitoffset, int bitcount, int numbits)


Detailed Description

VLC support functions.

Author:
Main contributors (see contributors.h for copyright, address and affiliation details)

Definition in file vlc.c.


Function Documentation

int code_from_bitstream_2d ( SyntaxElement sym,
Bitstream currStream,
const byte lentab,
const byte codtab,
int  tabwidth,
int  tabheight,
int *  code 
)

int GetBits ( byte  buffer[],
int  totbitoffset,
int *  info,
int  bitcount,
int  numbits 
)

Reads bits from the bitstream buffer.

Parameters:
buffer containing VLC-coded data bits
totbitoffset bit offset from start of partition
info returns value of the read bits
bitcount total bytes in bitstream
numbits number of bits to read

Definition at line 1211 of file vlc.c.

Referenced by readIPCM_CABAC(), and readSyntaxElement_FLC().

int GetVLCSymbol ( byte  buffer[],
int  totbitoffset,
int *  info,
int  bytecount 
)

read one exp-golomb VLC symbol

Parameters:
buffer containing VLC-coded data bits
totbitoffset bit offset from start of partition
info returns the value of the symbol
bytecount buffer length
Returns:
bits read

Definition at line 535 of file vlc.c.

Referenced by readSyntaxElement_VLC().

int i_v ( int  LenInBits,
char *  tracestring,
Bitstream bitstream 
)

i_v, reads an i(v) syntax element, the length in bits is stored in the global p_Dec->UsedBits variable

Parameters:
LenInBits length of the syntax element
tracestring the string for the trace file
bitstream the stream to be read from
Returns:
the value of the coded syntax element

Definition at line 148 of file vlc.c.

References syntaxelement::inf, syntaxelement::len, linfo_ue(), syntaxelement::mapping, readSyntaxElement_FLC(), SE_HEADER, and syntaxelement::type.

Referenced by interpret_picture_timing_info().

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void linfo_cbp_inter_normal ( int  len,
int  info,
int *  cbp,
int *  dummy 
)

Input:
length and info
Output:
cbp (inter)

Definition at line 270 of file vlc.c.

References linfo_ue(), and NCBP.

Referenced by decode_one_frame().

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void linfo_cbp_inter_other ( int  len,
int  info,
int *  cbp,
int *  dummy 
)

Input:
length and info
Output:
cbp (inter)

Definition at line 286 of file vlc.c.

References linfo_ue(), and NCBP.

Referenced by decode_one_frame().

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void linfo_cbp_intra_normal ( int  len,
int  info,
int *  cbp,
int *  dummy 
)

Input:
length and info
Output:
cbp (intra)

Definition at line 237 of file vlc.c.

References linfo_ue(), and NCBP.

Referenced by decode_one_frame().

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void linfo_cbp_intra_other ( int  len,
int  info,
int *  cbp,
int *  dummy 
)

Input:
length and info
Output:
cbp (intra)

Definition at line 254 of file vlc.c.

References linfo_ue(), and NCBP.

Referenced by decode_one_frame().

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void linfo_levrun_c2x2 ( int  len,
int  info,
int *  level,
int *  irun 
)

Input:
length and info
Output:
level, run

Definition at line 337 of file vlc.c.

References LEVRUN3.

Referenced by read_CBP_and_coeffs_from_NAL_CABAC().

void linfo_levrun_inter ( int  len,
int  info,
int *  level,
int *  irun 
)

Input:
length and info
Output:
level, run

Definition at line 302 of file vlc.c.

References NTAB1.

Referenced by read_CBP_and_coeffs_from_NAL_CABAC(), read_CBP_and_coeffs_from_NAL_CAVLC(), and readCompCoeff4x4SMB_CABAC().

void linfo_se ( int  len,
int  info,
int *  value1,
int *  dummy 
)

mapping rule for se(v) syntax elements

Input:
lenght and info
Output:
signed mvd

Definition at line 219 of file vlc.c.

Referenced by read_motion_info_from_NAL_b_slice(), read_motion_info_from_NAL_p_slice(), and se_v().

void linfo_ue ( int  len,
int  info,
int *  value1,
int *  dummy 
)

mapping rule for ue(v) syntax elements

Input:
lenght and info
Output:
number in the code table

Definition at line 203 of file vlc.c.

Referenced by i_v(), linfo_cbp_inter_normal(), linfo_cbp_inter_other(), linfo_cbp_intra_normal(), linfo_cbp_intra_other(), prepareListforRefIdx(), read_ipred_modes(), read_one_macroblock_b_slice(), read_one_macroblock_i_slice(), read_one_macroblock_p_slice(), u_v(), and ue_v().

int more_rbsp_data ( byte  buffer[],
int  totbitoffset,
int  bytecount 
)

test if bit buffer contains only stop bit

Parameters:
buffer buffer containing VLC-coded data bits
totbitoffset bit offset from start of partition
bytecount buffer length
Returns:
true if more bits available

Definition at line 467 of file vlc.c.

Referenced by InterpretPPS(), and uvlc_startcode_follows().

int readSyntaxElement_FLC ( SyntaxElement sym,
Bitstream currStream 
)

int readSyntaxElement_Intra4x4PredictionMode ( SyntaxElement sym,
ImageParameters *  p_Img,
Bitstream currStream 
)

read next VLC codeword for 4x4 Intra Prediction Mode and map it to the corresponding Intra Prediction Direction

Definition at line 404 of file vlc.c.

References Bitstream::bitstream_length, Bitstream::frame_bitoffset, syntaxelement::inf, syntaxelement::len, Bitstream::streamBuffer, TRACE, and syntaxelement::value1.

Referenced by read_ipred_modes().

int readSyntaxElement_Level_VLC0 ( SyntaxElement sym,
Bitstream currStream 
)

read Level VLC0 codeword from UVLC-partition

Definition at line 865 of file vlc.c.

References Bitstream::bitstream_length, Bitstream::frame_bitoffset, syntaxelement::inf, syntaxelement::len, ShowBits(), and Bitstream::streamBuffer.

Referenced by readCoeff4x4_CAVLC().

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int readSyntaxElement_Level_VLCN ( SyntaxElement sym,
int  vlc,
Bitstream currStream 
)

read Level VLC codeword from UVLC-partition

Definition at line 923 of file vlc.c.

References Bitstream::bitstream_length, Bitstream::frame_bitoffset, syntaxelement::inf, syntaxelement::len, ShowBits(), and Bitstream::streamBuffer.

Referenced by readCoeff4x4_CAVLC().

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int readSyntaxElement_NumCoeffTrailingOnes ( SyntaxElement sym,
Bitstream currStream,
char *  type 
)

read NumCoeff/TrailingOnes codeword from UVLC-partition

Definition at line 694 of file vlc.c.

References Bitstream::bitstream_length, code_from_bitstream_2d(), Bitstream::frame_bitoffset, syntaxelement::len, ShowBits(), Bitstream::streamBuffer, syntaxelement::value1, and syntaxelement::value2.

Referenced by readCoeff4x4_CAVLC().

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int readSyntaxElement_NumCoeffTrailingOnesChromaDC ( ImageParameters *  p_Img,
SyntaxElement sym,
Bitstream currStream 
)

read NumCoeff/TrailingOnes codeword from UVLC-partition ChromaDC

Definition at line 798 of file vlc.c.

References code_from_bitstream_2d(), syntaxelement::len, syntaxelement::value1, and syntaxelement::value2.

Referenced by readCoeff4x4_CAVLC().

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int readSyntaxElement_Run ( SyntaxElement sym,
Bitstream currStream 
)

read Run codeword from UVLC-partition

Definition at line 1152 of file vlc.c.

References code_from_bitstream_2d(), syntaxelement::len, and syntaxelement::value1.

Referenced by readCoeff4x4_CAVLC().

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int readSyntaxElement_TotalZeros ( SyntaxElement sym,
Bitstream currStream 
)

read Total Zeros codeword from UVLC-partition

Definition at line 997 of file vlc.c.

References code_from_bitstream_2d(), syntaxelement::len, and syntaxelement::value1.

Referenced by readCoeff4x4_CAVLC().

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int readSyntaxElement_TotalZerosChromaDC ( ImageParameters *  p_Img,
SyntaxElement sym,
Bitstream currStream 
)

read Total Zeros Chroma DC codeword from UVLC-partition

Definition at line 1061 of file vlc.c.

References code_from_bitstream_2d(), syntaxelement::len, and syntaxelement::value1.

Referenced by readCoeff4x4_CAVLC().

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int readSyntaxElement_UVLC ( SyntaxElement sym,
ImageParameters *  p_Img,
struct datapartition dP 
)

read next UVLC codeword from UVLC-partition and map it to the corresponding syntax element

Definition at line 392 of file vlc.c.

References readSyntaxElement_VLC().

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int readSyntaxElement_VLC ( SyntaxElement sym,
Bitstream currStream 
)

read next UVLC codeword from UVLC-partition and map it to the corresponding syntax element

Definition at line 367 of file vlc.c.

References Bitstream::bitstream_length, Bitstream::frame_bitoffset, GetVLCSymbol(), syntaxelement::inf, syntaxelement::len, syntaxelement::mapping, Bitstream::streamBuffer, syntaxelement::value1, and syntaxelement::value2.

Referenced by readSyntaxElement_UVLC(), se_v(), and ue_v().

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int se_v ( char *  tracestring,
Bitstream bitstream 
)

ue_v, reads an se(v) syntax element, the length in bits is stored in the global p_Dec->UsedBits variable

Parameters:
tracestring the string for the trace file
bitstream the stream to be read from
Returns:
the value of the coded syntax element

Definition at line 79 of file vlc.c.

References syntaxelement::len, linfo_se(), syntaxelement::mapping, readSyntaxElement_VLC(), SE_HEADER, syntaxelement::type, and syntaxelement::value1.

Referenced by interpret_film_grain_characteristics_info(), interpret_pan_scan_rect_info(), interpret_post_filter_hints_info(), InterpretPPS(), pred_weight_table(), and RestOfSliceHeader().

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int ShowBits ( byte  buffer[],
int  totbitoffset,
int  bitcount,
int  numbits 
)

Reads bits from the bitstream buffer.

Parameters:
buffer buffer containing VLC-coded data bits
totbitoffset bit offset from start of partition
bitcount total bytes in bitstream
numbits number of bits to read

Definition at line 1262 of file vlc.c.

Referenced by readSyntaxElement_Level_VLC0(), readSyntaxElement_Level_VLCN(), and readSyntaxElement_NumCoeffTrailingOnes().

static int ShowBitsThres ( int  inf,
int  numbits 
) [inline, static]

Reads bits from the bitstream buffer (Threshold based).

Parameters:
inf bytes to extract numbits from with bitoffset already applied
numbits number of bits to read

Definition at line 592 of file vlc.c.

Referenced by code_from_bitstream_2d().

Boolean u_1 ( char *  tracestring,
Bitstream bitstream 
)

int u_v ( int  LenInBits,
char *  tracestring,
Bitstream bitstream 
)

ue_v, reads an u(v) syntax element, the length in bits is stored in the global p_Dec->UsedBits variable

Parameters:
LenInBits length of the syntax element
tracestring the string for the trace file
bitstream the stream to be read from
Returns:
the value of the coded syntax element

Definition at line 113 of file vlc.c.

References syntaxelement::inf, syntaxelement::len, linfo_ue(), syntaxelement::mapping, readSyntaxElement_FLC(), SE_HEADER, and syntaxelement::type.

Referenced by FirstPartOfSliceHeader(), interpret_buffering_period_info(), interpret_film_grain_characteristics_info(), interpret_motion_constrained_slice_group_set_info(), interpret_picture_timing_info(), interpret_post_filter_hints_info(), interpret_recovery_point_info(), interpret_subsequence_characteristics_info(), interpret_subsequence_layer_characteristics_info(), InterpretPPS(), RestOfSliceHeader(), and u_1().

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int ue_v ( char *  tracestring,
Bitstream bitstream 
)

int uvlc_startcode_follows ( Slice currSlice,
int  dummy 
)

Check if there are symbols for the next MB.

Definition at line 506 of file vlc.c.

References assignSE2partition, Bitstream::bitstream_length, slice::dp_mode, Bitstream::frame_bitoffset, more_rbsp_data(), slice::partArr, and Bitstream::streamBuffer.

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