bitstream.c File Reference

bitstream api. More...

#include "libavutil/avassert.h"
#include "libavutil/qsort.h"
#include "avcodec.h"
#include "internal.h"
#include "mathops.h"
#include "put_bits.h"
#include "vlc.h"

Classes
struct	VLCcode

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

Typedefs
typedef struct VLCcode	VLCcode

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. More...
void	avpriv_copy_bits (PutBitContext *pb, const uint8_t *src, int length)
	Copy the content of src to the bitstream. More...
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.

Macro Definition Documentation

COPY

#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 %"PRIx32" for %d in "  \
                   "init_vlc\n", buf[j].code, i);                           \
            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++;                                                                \
    }

GET_DATA

#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;                                              \
    case 4:                                                 \
        v = *(const uint32_t *)ptr;                         \
        break;                                              \
    default:                                                \
        av_assert1(0);                                      \
    }                                                       \
}

Function Documentation

avpriv_copy_bits()

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

avpriv_put_string()

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

Variable Documentation

ff_log2_run

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,
}