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Data Structures | Macros | Functions | Variables
bitstream.c File Reference

bitstream api. More...

#include "libavutil/atomic.h"
#include "libavutil/avassert.h"
#include "avcodec.h"
#include "internal.h"
#include "mathops.h"
#include "get_bits.h"
#include "put_bits.h"

Go to the source code of this file.

Data Structures

struct  VLCcode
 

Macros

#define GET_DATA(v, table, i, wrap, size)
 
#define COPY(condition)
 

Functions

void avpriv_align_put_bits (PutBitContext *s)
 Pad the bitstream with zeros up to the next byte boundary.
 
void avpriv_put_string (PutBitContext *pb, const char *string, int terminate_string)
 Put the string string in the bitstream.
 
void avpriv_copy_bits (PutBitContext *pb, const uint8_t *src, int length)
 Copy the content of src to the bitstream.
 
static int alloc_table (VLC *vlc, int size, int use_static)
 
static av_always_inline uint32_t bitswap_32 (uint32_t x)
 
static int compare_vlcspec (const void *a, const void *b)
 
static int build_table (VLC *vlc, int table_nb_bits, int nb_codes, VLCcode *codes, int flags)
 Build VLC decoding tables suitable for use with get_vlc().
 
int ff_init_vlc_sparse (VLC *vlc_arg, int nb_bits, int nb_codes, const void *bits, int bits_wrap, int bits_size, const void *codes, int codes_wrap, int codes_size, const void *symbols, int symbols_wrap, int symbols_size, int flags)
 
void ff_free_vlc (VLC *vlc)
 

Variables

const uint8_t ff_log2_run [41]
 

Detailed Description

bitstream api.

Definition in file bitstream.c.

Macro Definition Documentation

#define GET_DATA (   v,
  table,
  i,
  wrap,
  size 
)
Value:
{ \
const uint8_t *ptr = (const uint8_t *)table + i * wrap; \
switch(size) { \
case 1: \
v = *(const uint8_t *)ptr; \
break; \
case 2: \
v = *(const uint16_t *)ptr; \
break; \
default: \
v = *(const uint32_t *)ptr; \
break; \
} \
}

Definition at line 89 of file bitstream.c.

#define COPY (   condition)
Value:
for (i = 0; i < nb_codes; i++) { \
GET_DATA(buf[j].bits, bits, i, bits_wrap, bits_size); \
if (!(condition)) \
continue; \
if (buf[j].bits > 3*nb_bits || buf[j].bits>32) { \
av_log(NULL, AV_LOG_ERROR, "Too long VLC (%d) in init_vlc\n", buf[j].bits);\
av_free(buf); \
return -1; \
} \
GET_DATA(buf[j].code, codes, i, codes_wrap, codes_size); \
if (buf[j].code >= (1LL<<buf[j].bits)) { \
av_log(NULL, AV_LOG_ERROR, "Invalid code in init_vlc\n"); \
av_free(buf); \
return -1; \
} \
if (flags & INIT_VLC_LE) \
buf[j].code = bitswap_32(buf[j].code); \
else \
buf[j].code <<= 32 - buf[j].bits; \
if (symbols) \
GET_DATA(buf[j].symbol, symbols, i, symbols_wrap, symbols_size) \
else \
buf[j].symbol = i; \
j++; \
}

Function Documentation

void avpriv_align_put_bits ( PutBitContext s)
void avpriv_put_string ( PutBitContext pb,
const char *  string,
int  terminate_string 
)

Put the string string in the bitstream.

Parameters
terminate_string0-terminates the written string if value is 1

Definition at line 53 of file bitstream.c.

Referenced by jpeg_put_comments(), and mpeg4_encode_vol_header().

void avpriv_copy_bits ( PutBitContext pb,
const uint8_t src,
int  length 
)

Copy the content of src to the bitstream.

Parameters
lengththe number of bits of src to copy

Definition at line 64 of file bitstream.c.

Referenced by copy_bits(), encode_thread(), ff_mpeg4_merge_partitions(), latm_write_frame_header(), latm_write_packet(), merge_context_after_encode(), save_bits(), and svq1_encode_plane().

static int alloc_table ( VLC vlc,
int  size,
int  use_static 
)
static

Definition at line 106 of file bitstream.c.

Referenced by build_table(), and mp_decode_layer2().

static av_always_inline uint32_t bitswap_32 ( uint32_t  x)
static

Definition at line 126 of file bitstream.c.

Referenced by build_table().

static int compare_vlcspec ( const void a,
const void b 
)
static

Definition at line 142 of file bitstream.c.

Referenced by ff_init_vlc_sparse().

static int build_table ( VLC vlc,
int  table_nb_bits,
int  nb_codes,
VLCcode codes,
int  flags 
)
static

Build VLC decoding tables suitable for use with get_vlc().

Parameters
vlcthe context to be initted
table_nb_bitsmax length of vlc codes to store directly in this table (Longer codes are delegated to subtables.)
nb_codesnumber of elements in codes[]
codesdescriptions of the vlc codes These must be ordered such that codes going into the same subtable are contiguous. Sorting by VLCcode.code is sufficient, though not necessary.

Definition at line 161 of file bitstream.c.

Referenced by ff_init_vlc_sparse().

int ff_init_vlc_sparse ( VLC vlc_arg,
int  nb_bits,
int  nb_codes,
const void bits,
int  bits_wrap,
int  bits_size,
const void codes,
int  codes_wrap,
int  codes_size,
const void symbols,
int  symbols_wrap,
int  symbols_size,
int  flags 
)
void ff_free_vlc ( VLC vlc)

Variable Documentation

const uint8_t ff_log2_run[41]
Initial value:
={
0, 0, 0, 0, 1, 1, 1, 1,
2, 2, 2, 2, 3, 3, 3, 3,
4, 4, 5, 5, 6, 6, 7, 7,
8, 9,10,11,12,13,14,15,
16,17,18,19,20,21,22,23,
24,
}

Definition at line 39 of file bitstream.c.

Referenced by decode_line(), encode_line(), ls_decode_line(), ls_encode_line(), and ls_encode_run().