Go to the documentation of this file.
26 #ifndef AVCODEC_GET_BITS_H
27 #define AVCODEC_GET_BITS_H
52 #ifndef UNCHECKED_BITSTREAM_READER
53 #define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
56 #ifndef CACHED_BITSTREAM_READER
57 #define CACHED_BITSTREAM_READER 0
60 #if CACHED_BITSTREAM_READER
65 #ifndef BITSTREAM_READER_LE
67 # define BITSTREAM_DEFAULT_BE
74 #undef BITSTREAM_DEFAULT_BE
78 #define get_bits_count bits_tell
79 #define get_bits_left bits_left
80 #define skip_bits_long bits_skip
81 #define skip_bits bits_skip
82 #define get_bits bits_read_nz
83 #define get_bitsz bits_read
84 #define get_bits_long bits_read
85 #define get_bits1 bits_read_bit
86 #define get_bits64 bits_read_64
87 #define get_xbits bits_read_xbits
88 #define get_sbits bits_read_signed_nz
89 #define get_sbits_long bits_read_signed
90 #define show_bits bits_peek
91 #define show_bits_long bits_peek
92 #define init_get_bits bits_init
93 #define init_get_bits8 bits_init8
94 #define align_get_bits bits_align
95 #define get_vlc2 bits_read_vlc
96 #define get_vlc_multi bits_read_vlc_multi
98 #define init_get_bits8_le(s, buffer, byte_size) bits_init8_le((BitstreamContextLE*)s, buffer, byte_size)
99 #define get_bits_le(s, n) bits_read_le((BitstreamContextLE*)s, n)
101 #define show_bits1(s) bits_peek(s, 1)
102 #define skip_bits1(s) bits_skip(s, 1)
104 #define skip_1stop_8data_bits bits_skip_1stop_8data
106 #else // CACHED_BITSTREAM_READER
166 #if defined LONG_BITSTREAM_READER
167 # define MIN_CACHE_BITS 32
169 # define MIN_CACHE_BITS 25
172 #define OPEN_READER_NOSIZE(name, gb) \
173 unsigned int name ## _index = (gb)->index; \
174 unsigned int av_unused name ## _cache
176 #if UNCHECKED_BITSTREAM_READER
177 #define OPEN_READER(name, gb) OPEN_READER_NOSIZE(name, gb)
179 #define BITS_AVAILABLE(name, gb) 1
181 #define OPEN_READER(name, gb) \
182 OPEN_READER_NOSIZE(name, gb); \
183 unsigned int name ## _size_plus8 = (gb)->size_in_bits_plus8
185 #define BITS_AVAILABLE(name, gb) name ## _index < name ## _size_plus8
188 #define CLOSE_READER(name, gb) (gb)->index = name ## _index
190 #define UPDATE_CACHE_BE_EXT(name, gb, bits, dst_bits) name ## _cache = \
191 AV_RB ## bits((gb)->buffer + (name ## _index >> 3)) << (name ## _index & 7) >> (bits - dst_bits)
193 #define UPDATE_CACHE_LE_EXT(name, gb, bits, dst_bits) name ## _cache = \
194 (uint ## dst_bits ## _t)(AV_RL ## bits((gb)->buffer + (name ## _index >> 3)) >> (name ## _index & 7))
197 # define UPDATE_CACHE_LE_32(name, gb) UPDATE_CACHE_LE_EXT(name, (gb), 64, 32)
199 # define UPDATE_CACHE_BE_32(name, gb) UPDATE_CACHE_BE_EXT(name, (gb), 64, 32)
201 # ifdef LONG_BITSTREAM_READER
203 # define UPDATE_CACHE_LE(name, gb) UPDATE_CACHE_LE_32(name, (gb))
205 # define UPDATE_CACHE_BE(name, gb) UPDATE_CACHE_BE_32(name, (gb))
209 # define UPDATE_CACHE_LE(name, gb) UPDATE_CACHE_LE_EXT(name, (gb), 32, 32)
211 # define UPDATE_CACHE_BE(name, gb) UPDATE_CACHE_BE_EXT(name, (gb), 32, 32)
216 #ifdef BITSTREAM_READER_LE
218 # define UPDATE_CACHE(name, gb) UPDATE_CACHE_LE(name, gb)
219 # define UPDATE_CACHE_32(name, gb) UPDATE_CACHE_LE_32(name, (gb))
221 # define SKIP_CACHE(name, gb, num) name ## _cache >>= (num)
225 # define UPDATE_CACHE(name, gb) UPDATE_CACHE_BE(name, gb)
226 # define UPDATE_CACHE_32(name, gb) UPDATE_CACHE_BE_32(name, (gb))
228 # define SKIP_CACHE(name, gb, num) name ## _cache <<= (num)
232 #if UNCHECKED_BITSTREAM_READER
233 # define SKIP_COUNTER(name, gb, num) name ## _index += (num)
235 # define SKIP_COUNTER(name, gb, num) \
236 name ## _index = FFMIN(name ## _size_plus8, name ## _index + (num))
239 #define BITS_LEFT(name, gb) ((int)((gb)->size_in_bits - name ## _index))
241 #define SKIP_BITS(name, gb, num) \
243 SKIP_CACHE(name, gb, num); \
244 SKIP_COUNTER(name, gb, num); \
247 #define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
249 #define SHOW_UBITS_LE(name, gb, num) zero_extend(name ## _cache, num)
250 #define SHOW_SBITS_LE(name, gb, num) sign_extend(name ## _cache, num)
252 #define SHOW_UBITS_BE(name, gb, num) NEG_USR32(name ## _cache, num)
253 #define SHOW_SBITS_BE(name, gb, num) NEG_SSR32(name ## _cache, num)
255 #ifdef BITSTREAM_READER_LE
256 # define SHOW_UBITS(name, gb, num) SHOW_UBITS_LE(name, gb, num)
257 # define SHOW_SBITS(name, gb, num) SHOW_SBITS_LE(name, gb, num)
259 # define SHOW_UBITS(name, gb, num) SHOW_UBITS_BE(name, gb, num)
260 # define SHOW_SBITS(name, gb, num) SHOW_SBITS_BE(name, gb, num)
263 #define GET_CACHE(name, gb) ((uint32_t) name ## _cache)
280 #if UNCHECKED_BITSTREAM_READER
283 s->index +=
av_clip(n, -
s->index,
s->size_in_bits_plus8 -
s->index);
303 return (
NEG_USR32(sign ^ cache, n) ^ sign) - sign;
317 return (
zero_extend(sign ^ cache, n) ^ sign) - sign;
337 register unsigned int tmp;
373 register unsigned int tmp;
390 unsigned int index =
s->index;
392 #ifdef BITSTREAM_READER_LE
399 #if !UNCHECKED_BITSTREAM_READER
400 if (
s->index <
s->size_in_bits_plus8)
439 #ifdef BITSTREAM_READER_LE
458 #ifdef BITSTREAM_READER_LE
526 buffer_size = (bit_size + 7) >> 3;
529 s->size_in_bits = bit_size;
530 s->size_in_bits_plus8 = bit_size + 8;
531 s->buffer_end =
buffer + buffer_size;
548 if (byte_size > INT_MAX / 8 || byte_size < 0)
556 if (byte_size > INT_MAX / 8 || byte_size < 0)
566 return s->buffer + (
s->index >> 3);
574 #define GET_VLC(code, name, gb, table, bits, max_depth) \
577 unsigned int index; \
579 index = SHOW_UBITS(name, gb, bits); \
580 code = table[index].sym; \
581 n = table[index].len; \
583 if (max_depth > 1 && n < 0) { \
584 LAST_SKIP_BITS(name, gb, bits); \
585 UPDATE_CACHE(name, gb); \
589 index = SHOW_UBITS(name, gb, nb_bits) + code; \
590 code = table[index].sym; \
591 n = table[index].len; \
592 if (max_depth > 2 && n < 0) { \
593 LAST_SKIP_BITS(name, gb, nb_bits); \
594 UPDATE_CACHE(name, gb); \
598 index = SHOW_UBITS(name, gb, nb_bits) + code; \
599 code = table[index].sym; \
600 n = table[index].len; \
603 SKIP_BITS(name, gb, n); \
606 #define GET_RL_VLC(level, run, name, gb, table, bits, \
607 max_depth, need_update) \
610 unsigned int index; \
612 index = SHOW_UBITS(name, gb, bits); \
613 level = table[index].level; \
614 n = table[index].len; \
616 if (max_depth > 1 && n < 0) { \
617 SKIP_BITS(name, gb, bits); \
619 UPDATE_CACHE(name, gb); \
624 index = SHOW_UBITS(name, gb, nb_bits) + level; \
625 level = table[index].level; \
626 n = table[index].len; \
627 if (max_depth > 2 && n < 0) { \
628 LAST_SKIP_BITS(name, gb, nb_bits); \
630 UPDATE_CACHE(name, gb); \
634 index = SHOW_UBITS(name, gb, nb_bits) + level; \
635 level = table[index].level; \
636 n = table[index].len; \
639 run = table[index].run; \
640 SKIP_BITS(name, gb, n); \
653 int bits,
int max_depth)
670 const int bits,
const int max_depth)
713 #endif // CACHED_BITSTREAM_READER
static void skip_bits_long(GetBitContext *s, int n)
Skips the specified number of bits.
static unsigned int show_bits_long(GetBitContext *s, int n)
Show 0-32 bits.
static unsigned int show_bits1(GetBitContext *s)
static int get_bits_left(GetBitContext *gb)
#define GET_VLC(code, name, gb, table, bits, max_depth)
If the vlc code is invalid and max_depth=1, then no bits will be removed.
static unsigned int get_bits_long(GetBitContext *s, int n)
Read 0-32 bits.
static int get_bits_count(const GetBitContext *s)
static const uint16_t table[]
static av_const unsigned zero_extend(unsigned val, unsigned bits)
#define UPDATE_CACHE(name, gb)
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
#define OPEN_READER_NOSIZE(name, gb)
#define GET_CACHE(name, gb)
static void skip_bits(GetBitContext *s, int n)
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
static int64_t get_sbits64(GetBitContext *s, int n)
Read 0-64 bits as a signed integer.
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
#define CLOSE_READER(name, gb)
#define SHOW_SBITS(name, gb, num)
static av_const int64_t sign_extend64(int64_t val, unsigned bits)
static unsigned int get_bits_le(GetBitContext *s, int n)
static int get_sbits(GetBitContext *s, int n)
static int decode012(GetBitContext *gb)
#define SHOW_UBITS_LE(name, gb, num)
and forward the result(frame or status change) to the corresponding input. If nothing is possible
static unsigned int get_bits1(GetBitContext *s)
#define LAST_SKIP_BITS(name, gb, num)
static av_always_inline int get_vlc2(GetBitContext *s, const VLCElem *table, int bits, int max_depth)
Parse a vlc code.
static int get_vlc_multi(GetBitContext *s, uint8_t *dst, const VLC_MULTI_ELEM *const Jtable, const VLCElem *const table, const int bits, const int max_depth)
#define OPEN_READER(name, gb)
static int get_xbits(GetBitContext *s, int n)
Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB).
static void skip_bits1(GetBitContext *s)
static uint64_t get_bits64(GetBitContext *s, int n)
Read 0-64 bits.
#define av_assert2(cond)
assert() equivalent, that does lie in speed critical code.
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some it can consider them to be part of the FIFO and delay acknowledging a status change accordingly Example code
static unsigned int show_bits(GetBitContext *s, int n)
Show 1-25 bits.
#define av_builtin_constant_p
const uint8_t * buffer_end
static int get_xbits_le(GetBitContext *s, int n)
static const uint8_t * align_get_bits(GetBitContext *s)
#define AV_INPUT_BUFFER_PADDING_SIZE
static int skip_1stop_8data_bits(GetBitContext *gb)
#define SHOW_UBITS(name, gb, num)
#define UPDATE_CACHE_LE(name, gb)
the frame and frame reference mechanism is intended to as much as expensive copies of that data while still allowing the filters to produce correct results The data is stored in buffers represented by AVFrame structures Several references can point to the same frame buffer
static av_const int sign_extend(int val, unsigned bits)
static int decode210(GetBitContext *gb)
#define UPDATE_CACHE_32(name, gb)
static av_always_inline int get_bitsz(GetBitContext *s, int n)
Read 0-25 bits.
static int init_get_bits8_le(GetBitContext *s, const uint8_t *buffer, int byte_size)
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
static int get_sbits_long(GetBitContext *s, int n)
Read 0-32 bits as a signed integer.