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| 1 : | edgomez | 972 | /***************************************************************************** |
| 2 : | * | ||
| 3 : | * XVID MPEG-4 VIDEO CODEC | ||
| 4 : | * - Bitstream reader/writer inlined functions and constants- | ||
| 5 : | * | ||
| 6 : | edgomez | 1382 | * Copyright (C) 2001-2003 Peter Ross <pross@xvid.org> |
| 7 : | edgomez | 972 | * |
| 8 : | edgomez | 1382 | * This program is free software ; you can redistribute it and/or modify |
| 9 : | * it under the terms of the GNU General Public License as published by | ||
| 10 : | * the Free Software Foundation ; either version 2 of the License, or | ||
| 11 : | edgomez | 972 | * (at your option) any later version. |
| 12 : | * | ||
| 13 : | * This program is distributed in the hope that it will be useful, | ||
| 14 : | edgomez | 1382 | * but WITHOUT ANY WARRANTY ; without even the implied warranty of |
| 15 : | edgomez | 972 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 : | * GNU General Public License for more details. | ||
| 17 : | * | ||
| 18 : | * You should have received a copy of the GNU General Public License | ||
| 19 : | edgomez | 1382 | * along with this program ; if not, write to the Free Software |
| 20 : | edgomez | 972 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 21 : | * | ||
| 22 : | Isibaar | 1913 | * $Id: bitstream.h,v 1.25 2010-12-18 16:02:00 Isibaar Exp $ |
| 23 : | edgomez | 972 | * |
| 24 : | ****************************************************************************/ | ||
| 25 : | Isibaar | 3 | |
| 26 : | #ifndef _BITSTREAM_H_ | ||
| 27 : | #define _BITSTREAM_H_ | ||
| 28 : | |||
| 29 : | #include "../portab.h" | ||
| 30 : | #include "../decoder.h" | ||
| 31 : | #include "../encoder.h" | ||
| 32 : | |||
| 33 : | edgomez | 466 | |
| 34 : | edgomez | 972 | /***************************************************************************** |
| 35 : | * Constants | ||
| 36 : | ****************************************************************************/ | ||
| 37 : | edgomez | 466 | |
| 38 : | edgomez | 972 | /* comment any #defs we dont use */ |
| 39 : | |||
| 40 : | Isibaar | 3 | #define VIDOBJ_START_CODE 0x00000100 /* ..0x0000011f */ |
| 41 : | #define VIDOBJLAY_START_CODE 0x00000120 /* ..0x0000012f */ | ||
| 42 : | #define VISOBJSEQ_START_CODE 0x000001b0 | ||
| 43 : | #define VISOBJSEQ_STOP_CODE 0x000001b1 /* ??? */ | ||
| 44 : | #define USERDATA_START_CODE 0x000001b2 | ||
| 45 : | #define GRPOFVOP_START_CODE 0x000001b3 | ||
| 46 : | edgomez | 972 | /*#define VIDSESERR_ERROR_CODE 0x000001b4 */ |
| 47 : | Isibaar | 3 | #define VISOBJ_START_CODE 0x000001b5 |
| 48 : | edgomez | 851 | #define VOP_START_CODE 0x000001b6 |
| 49 : | edgomez | 972 | /*#define STUFFING_START_CODE 0x000001c3 */ |
| 50 : | Isibaar | 3 | |
| 51 : | |||
| 52 : | #define VISOBJ_TYPE_VIDEO 1 | ||
| 53 : | edgomez | 972 | /*#define VISOBJ_TYPE_STILLTEXTURE 2 */ |
| 54 : | /*#define VISOBJ_TYPE_MESH 3 */ | ||
| 55 : | /*#define VISOBJ_TYPE_FBA 4 */ | ||
| 56 : | /*#define VISOBJ_TYPE_3DMESH 5 */ | ||
| 57 : | Isibaar | 3 | |
| 58 : | |||
| 59 : | #define VIDOBJLAY_TYPE_SIMPLE 1 | ||
| 60 : | edgomez | 972 | /*#define VIDOBJLAY_TYPE_SIMPLE_SCALABLE 2 */ |
| 61 : | edgomez | 1382 | /*#define VIDOBJLAY_TYPE_CORE 3 */ |
| 62 : | /*#define VIDOBJLAY_TYPE_MAIN 4 */ | ||
| 63 : | edgomez | 972 | /*#define VIDOBJLAY_TYPE_NBIT 5 */ |
| 64 : | /*#define VIDOBJLAY_TYPE_ANIM_TEXT 6 */ | ||
| 65 : | /*#define VIDOBJLAY_TYPE_ANIM_MESH 7 */ | ||
| 66 : | /*#define VIDOBJLAY_TYPE_SIMPLE_FACE 8 */ | ||
| 67 : | /*#define VIDOBJLAY_TYPE_STILL_SCALABLE 9 */ | ||
| 68 : | edgomez | 851 | #define VIDOBJLAY_TYPE_ART_SIMPLE 10 |
| 69 : | edgomez | 972 | /*#define VIDOBJLAY_TYPE_CORE_SCALABLE 11 */ |
| 70 : | edgomez | 1382 | /*#define VIDOBJLAY_TYPE_ACE 12 */ |
| 71 : | /*#define VIDOBJLAY_TYPE_ADVANCED_SCALABLE_TEXTURE 13 */ | ||
| 72 : | /*#define VIDOBJLAY_TYPE_SIMPLE_FBA 14 */ | ||
| 73 : | /*#define VIDEOJLAY_TYPE_SIMPLE_STUDIO 15*/ | ||
| 74 : | /*#define VIDEOJLAY_TYPE_CORE_STUDIO 16*/ | ||
| 75 : | #define VIDOBJLAY_TYPE_ASP 17 | ||
| 76 : | /*#define VIDOBJLAY_TYPE_FGS 18*/ | ||
| 77 : | Isibaar | 3 | |
| 78 : | |||
| 79 : | edgomez | 972 | /*#define VIDOBJLAY_AR_SQUARE 1 */ |
| 80 : | /*#define VIDOBJLAY_AR_625TYPE_43 2 */ | ||
| 81 : | /*#define VIDOBJLAY_AR_525TYPE_43 3 */ | ||
| 82 : | /*#define VIDOBJLAY_AR_625TYPE_169 8 */ | ||
| 83 : | /*#define VIDOBJLAY_AR_525TYPE_169 9 */ | ||
| 84 : | Isibaar | 3 | #define VIDOBJLAY_AR_EXTPAR 15 |
| 85 : | |||
| 86 : | |||
| 87 : | #define VIDOBJLAY_SHAPE_RECTANGULAR 0 | ||
| 88 : | #define VIDOBJLAY_SHAPE_BINARY 1 | ||
| 89 : | #define VIDOBJLAY_SHAPE_BINARY_ONLY 2 | ||
| 90 : | #define VIDOBJLAY_SHAPE_GRAYSCALE 3 | ||
| 91 : | |||
| 92 : | |||
| 93 : | edgomez | 851 | #define SPRITE_NONE 0 |
| 94 : | #define SPRITE_STATIC 1 | ||
| 95 : | #define SPRITE_GMC 2 | ||
| 96 : | |||
| 97 : | |||
| 98 : | |||
| 99 : | Isibaar | 3 | #define READ_MARKER() BitstreamSkip(bs, 1) |
| 100 : | #define WRITE_MARKER() BitstreamPutBit(bs, 1) | ||
| 101 : | |||
| 102 : | edgomez | 972 | /* vop coding types */ |
| 103 : | /* intra, prediction, backward, sprite, not_coded */ | ||
| 104 : | Isibaar | 3 | #define I_VOP 0 |
| 105 : | #define P_VOP 1 | ||
| 106 : | #define B_VOP 2 | ||
| 107 : | #define S_VOP 3 | ||
| 108 : | #define N_VOP 4 | ||
| 109 : | |||
| 110 : | edgomez | 972 | /* resync-specific */ |
| 111 : | suxen_drol | 248 | #define NUMBITS_VP_RESYNC_MARKER 17 |
| 112 : | #define RESYNC_MARKER 1 | ||
| 113 : | Isibaar | 3 | |
| 114 : | suxen_drol | 248 | |
| 115 : | edgomez | 972 | /***************************************************************************** |
| 116 : | * Prototypes | ||
| 117 : | ****************************************************************************/ | ||
| 118 : | |||
| 119 : | edgomez | 1382 | int read_video_packet_header(Bitstream *bs, |
| 120 : | DECODER * dec, | ||
| 121 : | const int addbits, | ||
| 122 : | int *quant, | ||
| 123 : | edgomez | 972 | int *fcode_forward, |
| 124 : | int *fcode_backward, | ||
| 125 : | int *intra_dc_threshold); | ||
| 126 : | edgomez | 466 | |
| 127 : | edgomez | 972 | /* header stuff */ |
| 128 : | edgomez | 195 | int BitstreamReadHeaders(Bitstream * bs, |
| 129 : | DECODER * dec, | ||
| 130 : | uint32_t * rounding, | ||
| 131 : | uint32_t * quant, | ||
| 132 : | uint32_t * fcode_forward, | ||
| 133 : | uint32_t * fcode_backward, | ||
| 134 : | edgomez | 851 | uint32_t * intra_dc_threshold, |
| 135 : | WARPPOINTS * gmc_warp); | ||
| 136 : | Isibaar | 3 | |
| 137 : | |||
| 138 : | void BitstreamWriteVolHeader(Bitstream * const bs, | ||
| 139 : | edgomez | 195 | const MBParam * pParam, |
| 140 : | Isibaar | 1913 | const FRAMEINFO * const frame, |
| 141 : | const int num_slices); | ||
| 142 : | Isibaar | 3 | |
| 143 : | void BitstreamWriteVopHeader(Bitstream * const bs, | ||
| 144 : | edgomez | 195 | const MBParam * pParam, |
| 145 : | edgomez | 851 | const FRAMEINFO * const frame, |
| 146 : | edgomez | 1382 | int vop_coded, |
| 147 : | unsigned int quant); | ||
| 148 : | Isibaar | 3 | |
| 149 : | edgomez | 1382 | void BitstreamWriteUserData(Bitstream * const bs, |
| 150 : | Skal | 1617 | const char *data, |
| 151 : | const unsigned int length); | ||
| 152 : | |||
| 153 : | Skal | 1616 | void |
| 154 : | BitstreamWriteEndOfSequence(Bitstream * const bs); | ||
| 155 : | edgomez | 466 | |
| 156 : | Skal | 1616 | void |
| 157 : | BitstreamWriteGroupOfVopHeader(Bitstream * const bs, | ||
| 158 : | const MBParam * pParam, | ||
| 159 : | uint32_t is_closed_gov); | ||
| 160 : | |||
| 161 : | void write_video_packet_header(Bitstream * const bs, | ||
| 162 : | const MBParam * pParam, | ||
| 163 : | const FRAMEINFO * const frame, | ||
| 164 : | int mbnum); | ||
| 165 : | |||
| 166 : | Skal | 1726 | /***************************************************************************** |
| 167 : | * Bitstream | ||
| 168 : | ****************************************************************************/ | ||
| 169 : | |||
| 170 : | /* Input buffer should be readable as full chunks of 8bytes, including | ||
| 171 : | the end of the buffer. Padding might be appropriate. If only chunks | ||
| 172 : | of 4bytes are applicable, define XVID_SAFE_BS_TAIL. Note that this will | ||
| 173 : | slow decoding, so consider this as a last-resort solution */ | ||
| 174 : | /* #define XVID_SAFE_BS_TAIL */ | ||
| 175 : | |||
| 176 : | Isibaar | 3 | /* initialise bitstream structure */ |
| 177 : | |||
| 178 : | edgomez | 195 | static void __inline |
| 179 : | BitstreamInit(Bitstream * const bs, | ||
| 180 : | void *const bitstream, | ||
| 181 : | uint32_t length) | ||
| 182 : | Isibaar | 3 | { |
| 183 : | uint32_t tmp; | ||
| 184 : | edgomez | 972 | size_t bitpos; |
| 185 : | ptr_t adjbitstream = (ptr_t)bitstream; | ||
| 186 : | Isibaar | 3 | |
| 187 : | edgomez | 972 | /* |
| 188 : | * Start the stream on a uint32_t boundary, by rounding down to the | ||
| 189 : | * previous uint32_t and skipping the intervening bytes. | ||
| 190 : | */ | ||
| 191 : | bitpos = ((sizeof(uint32_t)-1) & (size_t)bitstream); | ||
| 192 : | adjbitstream = adjbitstream - bitpos; | ||
| 193 : | bs->start = bs->tail = (uint32_t *) adjbitstream; | ||
| 194 : | Isibaar | 3 | |
| 195 : | edgomez | 972 | tmp = *bs->start; |
| 196 : | Isibaar | 3 | #ifndef ARCH_IS_BIG_ENDIAN |
| 197 : | BSWAP(tmp); | ||
| 198 : | #endif | ||
| 199 : | bs->bufa = tmp; | ||
| 200 : | |||
| 201 : | edgomez | 972 | tmp = *(bs->start + 1); |
| 202 : | Isibaar | 3 | #ifndef ARCH_IS_BIG_ENDIAN |
| 203 : | BSWAP(tmp); | ||
| 204 : | #endif | ||
| 205 : | bs->bufb = tmp; | ||
| 206 : | |||
| 207 : | edgomez | 972 | bs->pos = bs->initpos = bitpos*8; |
| 208 : | Skal | 1699 | /* preserve the intervening bytes */ |
| 209 : | if (bs->initpos > 0) | ||
| 210 : | bs->buf = bs->bufa & (0xffffffff << (32 - bs->initpos)); | ||
| 211 : | else | ||
| 212 : | bs->buf = 0; | ||
| 213 : | Isibaar | 3 | bs->length = length; |
| 214 : | } | ||
| 215 : | |||
| 216 : | |||
| 217 : | /* reset bitstream state */ | ||
| 218 : | |||
| 219 : | edgomez | 195 | static void __inline |
| 220 : | BitstreamReset(Bitstream * const bs) | ||
| 221 : | Isibaar | 3 | { |
| 222 : | uint32_t tmp; | ||
| 223 : | |||
| 224 : | bs->tail = bs->start; | ||
| 225 : | |||
| 226 : | tmp = *bs->start; | ||
| 227 : | #ifndef ARCH_IS_BIG_ENDIAN | ||
| 228 : | BSWAP(tmp); | ||
| 229 : | #endif | ||
| 230 : | bs->bufa = tmp; | ||
| 231 : | |||
| 232 : | tmp = *(bs->start + 1); | ||
| 233 : | #ifndef ARCH_IS_BIG_ENDIAN | ||
| 234 : | BSWAP(tmp); | ||
| 235 : | #endif | ||
| 236 : | bs->bufb = tmp; | ||
| 237 : | |||
| 238 : | Skal | 1699 | /* preserve the intervening bytes */ |
| 239 : | if (bs->initpos > 0) | ||
| 240 : | bs->buf = bs->bufa & (0xffffffff << (32 - bs->initpos)); | ||
| 241 : | else | ||
| 242 : | bs->buf = 0; | ||
| 243 : | edgomez | 972 | bs->pos = bs->initpos; |
| 244 : | Isibaar | 3 | } |
| 245 : | |||
| 246 : | |||
| 247 : | /* reads n bits from bitstream without changing the stream pos */ | ||
| 248 : | |||
| 249 : | edgomez | 195 | static uint32_t __inline |
| 250 : | BitstreamShowBits(Bitstream * const bs, | ||
| 251 : | const uint32_t bits) | ||
| 252 : | Isibaar | 3 | { |
| 253 : | int nbit = (bits + bs->pos) - 32; | ||
| 254 : | edgomez | 195 | |
| 255 : | if (nbit > 0) { | ||
| 256 : | return ((bs->bufa & (0xffffffff >> bs->pos)) << nbit) | (bs-> | ||
| 257 : | bufb >> (32 - | ||
| 258 : | nbit)); | ||
| 259 : | } else { | ||
| 260 : | Isibaar | 3 | return (bs->bufa & (0xffffffff >> bs->pos)) >> (32 - bs->pos - bits); |
| 261 : | } | ||
| 262 : | } | ||
| 263 : | |||
| 264 : | |||
| 265 : | /* skip n bits forward in bitstream */ | ||
| 266 : | |||
| 267 : | edgomez | 851 | static __inline void |
| 268 : | edgomez | 195 | BitstreamSkip(Bitstream * const bs, |
| 269 : | const uint32_t bits) | ||
| 270 : | Isibaar | 3 | { |
| 271 : | bs->pos += bits; | ||
| 272 : | |||
| 273 : | edgomez | 195 | if (bs->pos >= 32) { |
| 274 : | Isibaar | 3 | uint32_t tmp; |
| 275 : | |||
| 276 : | bs->bufa = bs->bufb; | ||
| 277 : | Skal | 1726 | #if defined(XVID_SAFE_BS_TAIL) |
| 278 : | if (bs->tail<(bs->start+((bs->length+3)>>2))) | ||
| 279 : | #endif | ||
| 280 : | { | ||
| 281 : | tmp = *((uint32_t *) bs->tail + 2); | ||
| 282 : | Isibaar | 3 | #ifndef ARCH_IS_BIG_ENDIAN |
| 283 : | Skal | 1726 | BSWAP(tmp); |
| 284 : | Isibaar | 3 | #endif |
| 285 : | Skal | 1726 | bs->bufb = tmp; |
| 286 : | bs->tail++; | ||
| 287 : | } | ||
| 288 : | #if defined(XVID_SAFE_BS_TAIL) | ||
| 289 : | else { | ||
| 290 : | bs->bufb = 0; | ||
| 291 : | } | ||
| 292 : | #endif | ||
| 293 : | Isibaar | 3 | bs->pos -= 32; |
| 294 : | } | ||
| 295 : | } | ||
| 296 : | |||
| 297 : | |||
| 298 : | edgomez | 972 | /* number of bits to next byte alignment */ |
| 299 : | edgomez | 1382 | static __inline uint32_t |
| 300 : | suxen_drol | 248 | BitstreamNumBitsToByteAlign(Bitstream *bs) |
| 301 : | { | ||
| 302 : | uint32_t n = (32 - bs->pos) % 8; | ||
| 303 : | return n == 0 ? 8 : n; | ||
| 304 : | } | ||
| 305 : | |||
| 306 : | |||
| 307 : | edgomez | 972 | /* show nbits from next byte alignment */ |
| 308 : | edgomez | 851 | static __inline uint32_t |
| 309 : | suxen_drol | 248 | BitstreamShowBitsFromByteAlign(Bitstream *bs, int bits) |
| 310 : | { | ||
| 311 : | int bspos = bs->pos + BitstreamNumBitsToByteAlign(bs); | ||
| 312 : | int nbit = (bits + bspos) - 32; | ||
| 313 : | |||
| 314 : | if (bspos >= 32) { | ||
| 315 : | return bs->bufb >> (32 - nbit); | ||
| 316 : | } else if (nbit > 0) { | ||
| 317 : | return ((bs->bufa & (0xffffffff >> bspos)) << nbit) | (bs-> | ||
| 318 : | bufb >> (32 - | ||
| 319 : | nbit)); | ||
| 320 : | } else { | ||
| 321 : | return (bs->bufa & (0xffffffff >> bspos)) >> (32 - bspos - bits); | ||
| 322 : | } | ||
| 323 : | |||
| 324 : | } | ||
| 325 : | |||
| 326 : | |||
| 327 : | |||
| 328 : | Isibaar | 3 | /* move forward to the next byte boundary */ |
| 329 : | |||
| 330 : | edgomez | 851 | static __inline void |
| 331 : | edgomez | 195 | BitstreamByteAlign(Bitstream * const bs) |
| 332 : | Isibaar | 3 | { |
| 333 : | uint32_t remainder = bs->pos % 8; | ||
| 334 : | edgomez | 195 | |
| 335 : | if (remainder) { | ||
| 336 : | Isibaar | 3 | BitstreamSkip(bs, 8 - remainder); |
| 337 : | } | ||
| 338 : | } | ||
| 339 : | |||
| 340 : | |||
| 341 : | /* bitstream length (unit bits) */ | ||
| 342 : | |||
| 343 : | edgomez | 195 | static uint32_t __inline |
| 344 : | BitstreamPos(const Bitstream * const bs) | ||
| 345 : | Isibaar | 3 | { |
| 346 : | edgomez | 972 | return((uint32_t)(8*((ptr_t)bs->tail - (ptr_t)bs->start) + bs->pos - bs->initpos)); |
| 347 : | Isibaar | 3 | } |
| 348 : | |||
| 349 : | |||
| 350 : | edgomez | 972 | /* |
| 351 : | * flush the bitstream & return length (unit bytes) | ||
| 352 : | * NOTE: assumes no futher bitstream functions will be called. | ||
| 353 : | Isibaar | 3 | */ |
| 354 : | |||
| 355 : | edgomez | 195 | static uint32_t __inline |
| 356 : | BitstreamLength(Bitstream * const bs) | ||
| 357 : | Isibaar | 3 | { |
| 358 : | edgomez | 972 | uint32_t len = (uint32_t)((ptr_t)bs->tail - (ptr_t)bs->start); |
| 359 : | Isibaar | 3 | |
| 360 : | edgomez | 195 | if (bs->pos) { |
| 361 : | Isibaar | 3 | uint32_t b = bs->buf; |
| 362 : | edgomez | 195 | |
| 363 : | Isibaar | 3 | #ifndef ARCH_IS_BIG_ENDIAN |
| 364 : | BSWAP(b); | ||
| 365 : | #endif | ||
| 366 : | *bs->tail = b; | ||
| 367 : | |||
| 368 : | len += (bs->pos + 7) / 8; | ||
| 369 : | edgomez | 195 | } |
| 370 : | Isibaar | 3 | |
| 371 : | edgomez | 972 | /* initpos is always on a byte boundary */ |
| 372 : | if (bs->initpos) | ||
| 373 : | len -= bs->initpos/8; | ||
| 374 : | |||
| 375 : | Isibaar | 3 | return len; |
| 376 : | } | ||
| 377 : | |||
| 378 : | |||
| 379 : | /* move bitstream position forward by n bits and write out buffer if needed */ | ||
| 380 : | |||
| 381 : | edgomez | 195 | static void __inline |
| 382 : | BitstreamForward(Bitstream * const bs, | ||
| 383 : | const uint32_t bits) | ||
| 384 : | Isibaar | 3 | { |
| 385 : | edgomez | 195 | bs->pos += bits; |
| 386 : | Isibaar | 3 | |
| 387 : | edgomez | 195 | if (bs->pos >= 32) { |
| 388 : | Isibaar | 3 | uint32_t b = bs->buf; |
| 389 : | edgomez | 195 | |
| 390 : | Isibaar | 3 | #ifndef ARCH_IS_BIG_ENDIAN |
| 391 : | BSWAP(b); | ||
| 392 : | #endif | ||
| 393 : | *bs->tail++ = b; | ||
| 394 : | bs->buf = 0; | ||
| 395 : | bs->pos -= 32; | ||
| 396 : | edgomez | 195 | } |
| 397 : | Isibaar | 3 | } |
| 398 : | |||
| 399 : | /* read n bits from bitstream */ | ||
| 400 : | |||
| 401 : | edgomez | 195 | static uint32_t __inline |
| 402 : | BitstreamGetBits(Bitstream * const bs, | ||
| 403 : | const uint32_t n) | ||
| 404 : | Isibaar | 3 | { |
| 405 : | uint32_t ret = BitstreamShowBits(bs, n); | ||
| 406 : | edgomez | 195 | |
| 407 : | Isibaar | 3 | BitstreamSkip(bs, n); |
| 408 : | return ret; | ||
| 409 : | } | ||
| 410 : | |||
| 411 : | |||
| 412 : | /* read single bit from bitstream */ | ||
| 413 : | |||
| 414 : | edgomez | 195 | static uint32_t __inline |
| 415 : | BitstreamGetBit(Bitstream * const bs) | ||
| 416 : | Isibaar | 3 | { |
| 417 : | return BitstreamGetBits(bs, 1); | ||
| 418 : | } | ||
| 419 : | |||
| 420 : | |||
| 421 : | /* write single bit to bitstream */ | ||
| 422 : | |||
| 423 : | edgomez | 195 | static void __inline |
| 424 : | BitstreamPutBit(Bitstream * const bs, | ||
| 425 : | const uint32_t bit) | ||
| 426 : | Isibaar | 3 | { |
| 427 : | edgomez | 195 | if (bit) |
| 428 : | Isibaar | 3 | bs->buf |= (0x80000000 >> bs->pos); |
| 429 : | |||
| 430 : | edgomez | 195 | BitstreamForward(bs, 1); |
| 431 : | Isibaar | 3 | } |
| 432 : | |||
| 433 : | |||
| 434 : | /* write n bits to bitstream */ | ||
| 435 : | |||
| 436 : | edgomez | 195 | static void __inline |
| 437 : | BitstreamPutBits(Bitstream * const bs, | ||
| 438 : | const uint32_t value, | ||
| 439 : | const uint32_t size) | ||
| 440 : | Isibaar | 3 | { |
| 441 : | uint32_t shift = 32 - bs->pos - size; | ||
| 442 : | |||
| 443 : | if (shift <= 32) { | ||
| 444 : | bs->buf |= value << shift; | ||
| 445 : | BitstreamForward(bs, size); | ||
| 446 : | } else { | ||
| 447 : | uint32_t remainder; | ||
| 448 : | |||
| 449 : | shift = size - (32 - bs->pos); | ||
| 450 : | bs->buf |= value >> shift; | ||
| 451 : | BitstreamForward(bs, size - shift); | ||
| 452 : | remainder = shift; | ||
| 453 : | |||
| 454 : | shift = 32 - shift; | ||
| 455 : | edgomez | 195 | |
| 456 : | Isibaar | 3 | bs->buf |= value << shift; |
| 457 : | BitstreamForward(bs, remainder); | ||
| 458 : | } | ||
| 459 : | } | ||
| 460 : | |||
| 461 : | edgomez | 851 | static const int stuffing_codes[8] = |
| 462 : | { | ||
| 463 : | /* nbits stuffing code */ | ||
| 464 : | 0, /* 1 0 */ | ||
| 465 : | 1, /* 2 01 */ | ||
| 466 : | 3, /* 3 011 */ | ||
| 467 : | 7, /* 4 0111 */ | ||
| 468 : | 0xf, /* 5 01111 */ | ||
| 469 : | 0x1f, /* 6 011111 */ | ||
| 470 : | 0x3f, /* 7 0111111 */ | ||
| 471 : | 0x7f, /* 8 01111111 */ | ||
| 472 : | }; | ||
| 473 : | |||
| 474 : | /* pad bitstream to the next byte boundary */ | ||
| 475 : | |||
| 476 : | static void __inline | ||
| 477 : | BitstreamPad(Bitstream * const bs) | ||
| 478 : | { | ||
| 479 : | int bits = 8 - (bs->pos % 8); | ||
| 480 : | if (bits < 8) | ||
| 481 : | BitstreamPutBits(bs, stuffing_codes[bits - 1], bits); | ||
| 482 : | } | ||
| 483 : | |||
| 484 : | |||
| 485 : | edgomez | 972 | /* |
| 486 : | edgomez | 1382 | * pad bitstream to the next byte boundary |
| 487 : | edgomez | 972 | * alway pad: even if currently at the byte boundary |
| 488 : | */ | ||
| 489 : | edgomez | 851 | |
| 490 : | static void __inline | ||
| 491 : | BitstreamPadAlways(Bitstream * const bs) | ||
| 492 : | { | ||
| 493 : | int bits = 8 - (bs->pos % 8); | ||
| 494 : | BitstreamPutBits(bs, stuffing_codes[bits - 1], bits); | ||
| 495 : | } | ||
| 496 : | |||
| 497 : | edgomez | 972 | #endif /* _BITSTREAM_H_ */ |
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