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)

• Inge Lille-Langøy <inge.lille-langoy@telenor.com>
• Detlev Marpe <marpe@hhi.de>
• Gabi Blaettermann

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
	)

code from bitstream (2d tables)

Definition at line 618 of file vlc.c.

References Bitstream::frame_bitoffset, syntaxelement::len, ShowBitsThres(), Bitstream::streamBuffer, syntaxelement::value1, and syntaxelement::value2.

Referenced by readSyntaxElement_NumCoeffTrailingOnes(), readSyntaxElement_NumCoeffTrailingOnesChromaDC(), readSyntaxElement_Run(), readSyntaxElement_TotalZeros(), and readSyntaxElement_TotalZerosChromaDC().

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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
	)

read FLC codeword from UVLC-partition

Definition at line 668 of file vlc.c.

References Bitstream::bitstream_length, Bitstream::frame_bitoffset, GetBits(), syntaxelement::inf, syntaxelement::len, Bitstream::streamBuffer, and syntaxelement::value1.

Referenced by i_v(), read_CBP_and_coeffs_from_NAL_CABAC(), read_CBP_and_coeffs_from_NAL_CAVLC(), read_IPCM_coeffs_from_NAL(), read_one_macroblock_b_slice(), read_one_macroblock_i_slice(), read_one_macroblock_p_slice(), readCoeff4x4_CAVLC(), readRefPictureIdx_FLC(), and u_v().

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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
	)

ue_v, reads an u(1) 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 186 of file vlc.c.

References u_v().

Referenced by dec_ref_pic_marking(), interpret_deblocking_filter_display_preference_info(), interpret_dec_ref_pic_marking_repetition_info(), interpret_film_grain_characteristics_info(), interpret_motion_constrained_slice_group_set_info(), interpret_pan_scan_rect_info(), interpret_picture_timing_info(), interpret_post_filter_hints_info(), interpret_recovery_point_info(), interpret_spare_pic(), interpret_stereo_video_info_info(), interpret_subsequence_characteristics_info(), interpret_subsequence_info(), interpret_subsequence_layer_characteristics_info(), InterpretPPS(), pred_weight_table(), ref_pic_list_reordering(), and RestOfSliceHeader().

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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
	)

ue_v, reads an ue(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 48 of file vlc.c.

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

Referenced by dec_ref_pic_marking(), FirstPartOfSliceHeader(), interpret_buffering_period_info(), interpret_deblocking_filter_display_preference_info(), interpret_dec_ref_pic_marking_repetition_info(), interpret_film_grain_characteristics_info(), interpret_full_frame_freeze_info(), interpret_full_frame_snapshot_info(), interpret_motion_constrained_slice_group_set_info(), interpret_pan_scan_rect_info(), interpret_post_filter_hints_info(), interpret_progressive_refinement_end_info(), interpret_progressive_refinement_start_info(), interpret_recovery_point_info(), interpret_scene_information(), interpret_spare_pic(), interpret_subsequence_characteristics_info(), interpret_subsequence_info(), interpret_subsequence_layer_characteristics_info(), InterpretPPS(), pred_weight_table(), read_new_slice(), ref_pic_list_reordering(), and RestOfSliceHeader().

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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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