bitstream.c File Reference

bitstream api. More...

#include "libavutil/atomic.h"
#include "libavutil/avassert.h"
#include "avcodec.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, 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 88 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);\
            if (!(flags & INIT_VLC_USE_NEW_STATIC))                         \
                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");       \
            if (!(flags & INIT_VLC_USE_NEW_STATIC))                         \
                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++;                                                                \
    }

Referenced by avfilter_register_all(), backup_duplicate_context(), ff_idct_put_altivec(), ff_init_vlc_sparse(), and update_duplicate_context_after_me().

Function Documentation

void avpriv_align_put_bits

(

PutBitContext *

s

)

Pad the bitstream with zeros up to the next byte boundary.

Definition at line 47 of file bitstream.c.

Referenced by avpriv_copy_pce_data(), encode_block(), encode_frame(), encode_picture_ls(), ff_flv_encode_picture_header(), ff_h261_encode_picture_header(), ff_h263_encode_picture_header(), ff_msmpeg4_encode_picture_header(), ff_rv10_encode_picture_header(), latm_write_packet(), put_bitstream_info(), put_header(), write_slice_end(), xsub_encode(), and xsub_encode_rle().

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

Put the string string in the bitstream.

Parameters

terminate_string

0-terminates the written string if value is 1

Definition at line 52 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

length

the number of bits of src to copy

Definition at line 63 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 105 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 121 of file bitstream.c.

Referenced by build_table().

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

static

Definition at line 137 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

vlc	the context to be initted
table_nb_bits	max length of vlc codes to store directly in this table (Longer codes are delegated to subtables.)
nb_codes	number of elements in codes[]
codes	descriptions 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 156 of file bitstream.c.

Referenced by 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 at line 265 of file bitstream.c.

Referenced by build_huff(), build_huff_tree(), build_vlc(), ff_ccitt_unpack_init(), generate_joint_tables(), init_ralf_vlc(), init_vlcs(), mpc8_decode_init(), mss4_init_vlc(), read_code_table(), rv34_gen_vlc(), and rv40_init_tables().

void ff_free_vlc

(

VLC *

vlc

)

Definition at line 353 of file bitstream.c.

Referenced by cook_decode_close(), decode_argb_frame(), decode_close(), decode_end(), decode_plane(), decode_rgb24_frame(), decode_rle(), decode_yuv_frame(), dnxhd_decode_close(), dnxhd_init_vlc(), ff_dvvideo_init(), ff_ivi_dec_huff_desc(), ff_ivi_decode_close(), ff_mjpeg_decode_dht(), ff_mjpeg_decode_end(), ff_wma_end(), fraps2_decode_plane(), free_vlcs(), generate_joint_tables(), image_ctx_free(), ivi_free_buffers(), jpg_free_context(), mimic_decode_end(), mp_decode_frame(), mss4_free_vlcs(), read_huffman_code_normal(), read_huffman_tables(), read_old_huffman_tables(), smacker_decode_header_tree(), smka_decode_frame(), tm2_free_codes(), vorbis_free(), vp3_decode_end(), vp6_build_huff_tree(), and vp6_decode_free_context().

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 38 of file bitstream.c.

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