FFmpeg
Data Structures | Macros | Functions
vlc.h File Reference
#include <stdint.h>

Go to the source code of this file.

Data Structures

struct  VLC
 
struct  RL_VLC_ELEM
 

Macros

#define VLC_TYPE   int16_t
 
#define init_vlc(vlc, nb_bits, nb_codes, bits, bits_wrap, bits_size, codes, codes_wrap, codes_size, flags)
 
#define INIT_VLC_INPUT_LE   2
 
#define INIT_VLC_OUTPUT_LE   8
 
#define INIT_VLC_LE   (INIT_VLC_INPUT_LE | INIT_VLC_OUTPUT_LE)
 
#define INIT_VLC_USE_NEW_STATIC   4
 
#define INIT_VLC_STATIC_OVERLONG   (1 | INIT_VLC_USE_NEW_STATIC)
 
#define INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, h, i, j, flags, static_size)
 
#define INIT_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, h, i, j, static_size)
 
#define INIT_LE_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, h, i, j, static_size)
 
#define INIT_CUSTOM_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, flags, static_size)
 
#define INIT_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, static_size)   INIT_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, NULL, 0, 0, static_size)
 
#define INIT_LE_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, static_size)   INIT_LE_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, NULL, 0, 0, static_size)
 
#define INIT_VLC_STATIC_FROM_LENGTHS(vlc, bits, nb_codes, lens, len_wrap, symbols, symbols_wrap, symbols_size, offset, flags, static_size)
 

Functions

int ff_init_vlc_sparse (VLC *vlc, 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)
 
int ff_init_vlc_from_lengths (VLC *vlc, int nb_bits, int nb_codes, const int8_t *lens, int lens_wrap, const void *symbols, int symbols_wrap, int symbols_size, int offset, int flags, void *logctx)
 Build VLC decoding tables suitable for use with get_vlc2() More...
 
void ff_free_vlc (VLC *vlc)
 

Macro Definition Documentation

◆ VLC_TYPE

#define VLC_TYPE   int16_t

Definition at line 24 of file vlc.h.

◆ init_vlc

#define init_vlc (   vlc,
  nb_bits,
  nb_codes,
  bits,
  bits_wrap,
  bits_size,
  codes,
  codes_wrap,
  codes_size,
  flags 
)
Value:
ff_init_vlc_sparse(vlc, nb_bits, nb_codes, \
bits, bits_wrap, bits_size, \
codes, codes_wrap, codes_size, \
NULL, 0, 0, flags)

Definition at line 38 of file vlc.h.

◆ INIT_VLC_INPUT_LE

#define INIT_VLC_INPUT_LE   2

Definition at line 91 of file vlc.h.

◆ INIT_VLC_OUTPUT_LE

#define INIT_VLC_OUTPUT_LE   8

Definition at line 93 of file vlc.h.

◆ INIT_VLC_LE

#define INIT_VLC_LE   (INIT_VLC_INPUT_LE | INIT_VLC_OUTPUT_LE)

Definition at line 94 of file vlc.h.

◆ INIT_VLC_USE_NEW_STATIC

#define INIT_VLC_USE_NEW_STATIC   4

Definition at line 95 of file vlc.h.

◆ INIT_VLC_STATIC_OVERLONG

#define INIT_VLC_STATIC_OVERLONG   (1 | INIT_VLC_USE_NEW_STATIC)

Definition at line 96 of file vlc.h.

◆ INIT_CUSTOM_VLC_SPARSE_STATIC

#define INIT_CUSTOM_VLC_SPARSE_STATIC (   vlc,
  bits,
  a,
  b,
  c,
  d,
  e,
  f,
  g,
  h,
  i,
  j,
  flags,
  static_size 
)
Value:
do { \
static VLC_TYPE table[static_size][2]; \
(vlc)->table = table; \
(vlc)->table_allocated = static_size; \
ff_init_vlc_sparse(vlc, bits, a, b, c, d, e, f, g, h, i, j, \
} while (0)

Definition at line 98 of file vlc.h.

◆ INIT_VLC_SPARSE_STATIC

#define INIT_VLC_SPARSE_STATIC (   vlc,
  bits,
  a,
  b,
  c,
  d,
  e,
  f,
  g,
  h,
  i,
  j,
  static_size 
)
Value:
h, i, j, 0, static_size)

Definition at line 108 of file vlc.h.

◆ INIT_LE_VLC_SPARSE_STATIC

#define INIT_LE_VLC_SPARSE_STATIC (   vlc,
  bits,
  a,
  b,
  c,
  d,
  e,
  f,
  g,
  h,
  i,
  j,
  static_size 
)
Value:
h, i, j, INIT_VLC_LE, static_size)

Definition at line 112 of file vlc.h.

◆ INIT_CUSTOM_VLC_STATIC

#define INIT_CUSTOM_VLC_STATIC (   vlc,
  bits,
  a,
  b,
  c,
  d,
  e,
  f,
  g,
  flags,
  static_size 
)
Value:
NULL, 0, 0, flags, static_size)

Definition at line 116 of file vlc.h.

◆ INIT_VLC_STATIC

#define INIT_VLC_STATIC (   vlc,
  bits,
  a,
  b,
  c,
  d,
  e,
  f,
  g,
  static_size 
)    INIT_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, NULL, 0, 0, static_size)

Definition at line 120 of file vlc.h.

◆ INIT_LE_VLC_STATIC

#define INIT_LE_VLC_STATIC (   vlc,
  bits,
  a,
  b,
  c,
  d,
  e,
  f,
  g,
  static_size 
)    INIT_LE_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, NULL, 0, 0, static_size)

Definition at line 123 of file vlc.h.

◆ INIT_VLC_STATIC_FROM_LENGTHS

#define INIT_VLC_STATIC_FROM_LENGTHS (   vlc,
  bits,
  nb_codes,
  lens,
  len_wrap,
  symbols,
  symbols_wrap,
  symbols_size,
  offset,
  flags,
  static_size 
)
Value:
do { \
static VLC_TYPE table[static_size][2]; \
(vlc)->table = table; \
(vlc)->table_allocated = static_size; \
ff_init_vlc_from_lengths(vlc, bits, nb_codes, lens, len_wrap, \
symbols, symbols_wrap, symbols_size, \
NULL); \
} while (0)

Definition at line 126 of file vlc.h.

Function Documentation

◆ ff_init_vlc_sparse()

int ff_init_vlc_sparse ( VLC vlc,
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 
)

◆ ff_init_vlc_from_lengths()

int ff_init_vlc_from_lengths ( VLC vlc,
int  nb_bits,
int  nb_codes,
const int8_t *  lens,
int  lens_wrap,
const void *  symbols,
int  symbols_wrap,
int  symbols_size,
int  offset,
int  flags,
void *  logctx 
)

Build VLC decoding tables suitable for use with get_vlc2()

This function takes lengths and symbols and calculates the codes from them. For this the input lengths and symbols have to be sorted according to "left nodes in the corresponding tree first".

Parameters
[in,out]vlcThe VLC to be initialized; table and table_allocated must have been set when initializing a static VLC, otherwise this will be treated as uninitialized.
[in]nb_bitsThe number of bits to use for the VLC table; higher values take up more memory and cache, but allow to read codes with fewer reads.
[in]nb_codesThe number of provided length and (if supplied) symbol entries.
[in]lensThe lengths of the codes. Entries > 0 correspond to valid codes; entries == 0 will be skipped and entries with len < 0 indicate that the tree is incomplete and has an open end of length -len at this position.
[in]lens_wrapStride (in bytes) of the lengths.
[in]symbolsThe symbols, i.e. what is returned from get_vlc2() when the corresponding code is encountered. May be NULL, then 0, 1, 2, 3, 4,... will be used.
[in]symbols_wrapStride (in bytes) of the symbols.
[in]symbols_sizeSize of the symbols. 1 and 2 are supported.
[in]offsetAn offset to apply to all the valid symbols.
[in]flagsA combination of the INIT_VLC_* flags; notice that INIT_VLC_INPUT_LE is pointless and ignored.

Definition at line 381 of file bitstream.c.

Referenced by atrac3_init_static_data(), atrac9_init_vlc(), build_canonical_huff(), build_huff(), build_vlc(), clv_init_static(), ff_mjpeg_build_vlc(), huff_build(), imc_init_static(), mobiclip_init_static(), mp_decode_frame(), mpc7_init_static(), mpeg4_init_static(), mpegaudiodec_common_init_static(), mss4_init_vlc(), on2avc_decode_init(), qdmc_init_static_data(), read_code_table(), rv10_build_vlc(), rv40_init_table(), rv40_init_tables(), smacker_decode_header_tree(), smka_decode_frame(), tm2_build_huff_table(), tscc2_init_vlc(), vp3_decode_init(), wma_decode_init(), and x8_init_vlc().

◆ ff_free_vlc()

void ff_free_vlc ( VLC vlc)
b
#define b
Definition: input.c:40
table
static const uint16_t table[]
Definition: prosumer.c:206
INIT_VLC_LE
#define INIT_VLC_LE
Definition: vlc.h:94
VLC_TYPE
#define VLC_TYPE
Definition: vlc.h:24
g
const char * g
Definition: vf_curves.c:117
bits
uint8_t bits
Definition: vp3data.h:141
f
#define f(width, name)
Definition: cbs_vp9.c:255
NULL
#define NULL
Definition: coverity.c:32
INIT_VLC_USE_NEW_STATIC
#define INIT_VLC_USE_NEW_STATIC
Definition: vlc.h:95
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
INIT_CUSTOM_VLC_SPARSE_STATIC
#define INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, h, i, j, flags, static_size)
Definition: vlc.h:98
a
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:41
offset
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Definition: writing_filters.txt:86
ff_init_vlc_sparse
int ff_init_vlc_sparse(VLC *vlc, 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)
Definition: bitstream.c:323
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
d
d
Definition: ffmpeg_filter.c:156
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
h
h
Definition: vp9dsp_template.c:2038