1/* 2 * Monkey's Audio lossless audio decoder 3 * Copyright (c) 2007 Benjamin Zores <ben@geexbox.org> 4 * based upon libdemac from Dave Chapman. 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#define ALT_BITSTREAM_READER_LE 24#include "avcodec.h" 25#include "dsputil.h" 26#include "bitstream.h" 27#include "bytestream.h" 28 29/** 30 * @file libavcodec/apedec.c 31 * Monkey's Audio lossless audio decoder 32 */ 33 34#define BLOCKS_PER_LOOP 4608 35#define MAX_CHANNELS 2 36#define MAX_BYTESPERSAMPLE 3 37 38#define APE_FRAMECODE_MONO_SILENCE 1 39#define APE_FRAMECODE_STEREO_SILENCE 3 40#define APE_FRAMECODE_PSEUDO_STEREO 4 41 42#define HISTORY_SIZE 512 43#define PREDICTOR_ORDER 8 44/** Total size of all predictor histories */ 45#define PREDICTOR_SIZE 50 46 47#define YDELAYA (18 + PREDICTOR_ORDER*4) 48#define YDELAYB (18 + PREDICTOR_ORDER*3) 49#define XDELAYA (18 + PREDICTOR_ORDER*2) 50#define XDELAYB (18 + PREDICTOR_ORDER) 51 52#define YADAPTCOEFFSA 18 53#define XADAPTCOEFFSA 14 54#define YADAPTCOEFFSB 10 55#define XADAPTCOEFFSB 5 56 57/** 58 * Possible compression levels 59 * @{ 60 */ 61enum APECompressionLevel { 62 COMPRESSION_LEVEL_FAST = 1000, 63 COMPRESSION_LEVEL_NORMAL = 2000, 64 COMPRESSION_LEVEL_HIGH = 3000, 65 COMPRESSION_LEVEL_EXTRA_HIGH = 4000, 66 COMPRESSION_LEVEL_INSANE = 5000 67}; 68/** @} */ 69 70#define APE_FILTER_LEVELS 3 71 72/** Filter orders depending on compression level */ 73static const uint16_t ape_filter_orders[5][APE_FILTER_LEVELS] = { 74 { 0, 0, 0 }, 75 { 16, 0, 0 }, 76 { 64, 0, 0 }, 77 { 32, 256, 0 }, 78 { 16, 256, 1280 } 79}; 80 81/** Filter fraction bits depending on compression level */ 82static const uint8_t ape_filter_fracbits[5][APE_FILTER_LEVELS] = { 83 { 0, 0, 0 }, 84 { 11, 0, 0 }, 85 { 11, 0, 0 }, 86 { 10, 13, 0 }, 87 { 11, 13, 15 } 88}; 89 90 91/** Filters applied to the decoded data */ 92typedef struct APEFilter { 93 int16_t *coeffs; ///< actual coefficients used in filtering 94 int16_t *adaptcoeffs; ///< adaptive filter coefficients used for correcting of actual filter coefficients 95 int16_t *historybuffer; ///< filter memory 96 int16_t *delay; ///< filtered values 97 98 int avg; 99} APEFilter; 100 101typedef struct APERice { 102 uint32_t k; 103 uint32_t ksum; 104} APERice; 105 106typedef struct APERangecoder { 107 uint32_t low; ///< low end of interval 108 uint32_t range; ///< length of interval 109 uint32_t help; ///< bytes_to_follow resp. intermediate value 110 unsigned int buffer; ///< buffer for input/output 111} APERangecoder; 112 113/** Filter histories */ 114typedef struct APEPredictor { 115 int32_t *buf; 116 117 int32_t lastA[2]; 118 119 int32_t filterA[2]; 120 int32_t filterB[2]; 121 122 int32_t coeffsA[2][4]; ///< adaption coefficients 123 int32_t coeffsB[2][5]; ///< adaption coefficients 124 int32_t historybuffer[HISTORY_SIZE + PREDICTOR_SIZE]; 125} APEPredictor; 126 127/** Decoder context */ 128typedef struct APEContext { 129 AVCodecContext *avctx; 130 DSPContext dsp; 131 int channels; 132 int samples; ///< samples left to decode in current frame 133 134 int fileversion; ///< codec version, very important in decoding process 135 int compression_level; ///< compression levels 136 int fset; ///< which filter set to use (calculated from compression level) 137 int flags; ///< global decoder flags 138 139 uint32_t CRC; ///< frame CRC 140 int frameflags; ///< frame flags 141 int currentframeblocks; ///< samples (per channel) in current frame 142 int blocksdecoded; ///< count of decoded samples in current frame 143 APEPredictor predictor; ///< predictor used for final reconstruction 144 145 int32_t decoded0[BLOCKS_PER_LOOP]; ///< decoded data for the first channel 146 int32_t decoded1[BLOCKS_PER_LOOP]; ///< decoded data for the second channel 147 148 int16_t* filterbuf[APE_FILTER_LEVELS]; ///< filter memory 149 150 APERangecoder rc; ///< rangecoder used to decode actual values 151 APERice riceX; ///< rice code parameters for the second channel 152 APERice riceY; ///< rice code parameters for the first channel 153 APEFilter filters[APE_FILTER_LEVELS][2]; ///< filters used for reconstruction 154 155 uint8_t *data; ///< current frame data 156 uint8_t *data_end; ///< frame data end 157 const uint8_t *ptr; ///< current position in frame data 158 const uint8_t *last_ptr; ///< position where last 4608-sample block ended 159 160 int error; 161} APEContext; 162 163// TODO: dsputilize 164 165static av_cold int ape_decode_init(AVCodecContext * avctx) 166{ 167 APEContext *s = avctx->priv_data; 168 int i; 169 170 if (avctx->extradata_size != 6) { 171 av_log(avctx, AV_LOG_ERROR, "Incorrect extradata\n"); 172 return -1; 173 } 174 if (avctx->bits_per_coded_sample != 16) { 175 av_log(avctx, AV_LOG_ERROR, "Only 16-bit samples are supported\n"); 176 return -1; 177 } 178 if (avctx->channels > 2) { 179 av_log(avctx, AV_LOG_ERROR, "Only mono and stereo is supported\n"); 180 return -1; 181 } 182 s->avctx = avctx; 183 s->channels = avctx->channels; 184 s->fileversion = AV_RL16(avctx->extradata); 185 s->compression_level = AV_RL16(avctx->extradata + 2); 186 s->flags = AV_RL16(avctx->extradata + 4); 187 188 av_log(avctx, AV_LOG_DEBUG, "Compression Level: %d - Flags: %d\n", s->compression_level, s->flags); 189 if (s->compression_level % 1000 || s->compression_level > COMPRESSION_LEVEL_INSANE) { 190 av_log(avctx, AV_LOG_ERROR, "Incorrect compression level %d\n", s->compression_level); 191 return -1; 192 } 193 s->fset = s->compression_level / 1000 - 1; 194 for (i = 0; i < APE_FILTER_LEVELS; i++) { 195 if (!ape_filter_orders[s->fset][i]) 196 break; 197 s->filterbuf[i] = av_malloc((ape_filter_orders[s->fset][i] * 3 + HISTORY_SIZE) * 4); 198 } 199 200 dsputil_init(&s->dsp, avctx); 201 avctx->sample_fmt = SAMPLE_FMT_S16; 202 avctx->channel_layout = (avctx->channels==2) ? CH_LAYOUT_STEREO : CH_LAYOUT_MONO; 203 return 0; 204} 205 206static av_cold int ape_decode_close(AVCodecContext * avctx) 207{ 208 APEContext *s = avctx->priv_data; 209 int i; 210 211 for (i = 0; i < APE_FILTER_LEVELS; i++) 212 av_freep(&s->filterbuf[i]); 213 214 return 0; 215} 216 217/** 218 * @defgroup rangecoder APE range decoder 219 * @{ 220 */ 221 222#define CODE_BITS 32 223#define TOP_VALUE ((unsigned int)1 << (CODE_BITS-1)) 224#define SHIFT_BITS (CODE_BITS - 9) 225#define EXTRA_BITS ((CODE_BITS-2) % 8 + 1) 226#define BOTTOM_VALUE (TOP_VALUE >> 8) 227 228/** Start the decoder */ 229static inline void range_start_decoding(APEContext * ctx) 230{ 231 ctx->rc.buffer = bytestream_get_byte(&ctx->ptr); 232 ctx->rc.low = ctx->rc.buffer >> (8 - EXTRA_BITS); 233 ctx->rc.range = (uint32_t) 1 << EXTRA_BITS; 234} 235 236/** Perform normalization */ 237static inline void range_dec_normalize(APEContext * ctx) 238{ 239 while (ctx->rc.range <= BOTTOM_VALUE) { 240 ctx->rc.buffer <<= 8; 241 if(ctx->ptr < ctx->data_end) 242 ctx->rc.buffer += *ctx->ptr; 243 ctx->ptr++; 244 ctx->rc.low = (ctx->rc.low << 8) | ((ctx->rc.buffer >> 1) & 0xFF); 245 ctx->rc.range <<= 8; 246 } 247} 248 249/** 250 * Calculate culmulative frequency for next symbol. Does NO update! 251 * @param ctx decoder context 252 * @param tot_f is the total frequency or (code_value)1<<shift 253 * @return the culmulative frequency 254 */ 255static inline int range_decode_culfreq(APEContext * ctx, int tot_f) 256{ 257 range_dec_normalize(ctx); 258 ctx->rc.help = ctx->rc.range / tot_f; 259 return ctx->rc.low / ctx->rc.help; 260} 261 262/** 263 * Decode value with given size in bits 264 * @param ctx decoder context 265 * @param shift number of bits to decode 266 */ 267static inline int range_decode_culshift(APEContext * ctx, int shift) 268{ 269 range_dec_normalize(ctx); 270 ctx->rc.help = ctx->rc.range >> shift; 271 return ctx->rc.low / ctx->rc.help; 272} 273 274 275/** 276 * Update decoding state 277 * @param ctx decoder context 278 * @param sy_f the interval length (frequency of the symbol) 279 * @param lt_f the lower end (frequency sum of < symbols) 280 */ 281static inline void range_decode_update(APEContext * ctx, int sy_f, int lt_f) 282{ 283 ctx->rc.low -= ctx->rc.help * lt_f; 284 ctx->rc.range = ctx->rc.help * sy_f; 285} 286 287/** Decode n bits (n <= 16) without modelling */ 288static inline int range_decode_bits(APEContext * ctx, int n) 289{ 290 int sym = range_decode_culshift(ctx, n); 291 range_decode_update(ctx, 1, sym); 292 return sym; 293} 294 295 296#define MODEL_ELEMENTS 64 297 298/** 299 * Fixed probabilities for symbols in Monkey Audio version 3.97 300 */ 301static const uint16_t counts_3970[22] = { 302 0, 14824, 28224, 39348, 47855, 53994, 58171, 60926, 303 62682, 63786, 64463, 64878, 65126, 65276, 65365, 65419, 304 65450, 65469, 65480, 65487, 65491, 65493, 305}; 306 307/** 308 * Probability ranges for symbols in Monkey Audio version 3.97 309 */ 310static const uint16_t counts_diff_3970[21] = { 311 14824, 13400, 11124, 8507, 6139, 4177, 2755, 1756, 312 1104, 677, 415, 248, 150, 89, 54, 31, 313 19, 11, 7, 4, 2, 314}; 315 316/** 317 * Fixed probabilities for symbols in Monkey Audio version 3.98 318 */ 319static const uint16_t counts_3980[22] = { 320 0, 19578, 36160, 48417, 56323, 60899, 63265, 64435, 321 64971, 65232, 65351, 65416, 65447, 65466, 65476, 65482, 322 65485, 65488, 65490, 65491, 65492, 65493, 323}; 324 325/** 326 * Probability ranges for symbols in Monkey Audio version 3.98 327 */ 328static const uint16_t counts_diff_3980[21] = { 329 19578, 16582, 12257, 7906, 4576, 2366, 1170, 536, 330 261, 119, 65, 31, 19, 10, 6, 3, 331 3, 2, 1, 1, 1, 332}; 333 334/** 335 * Decode symbol 336 * @param ctx decoder context 337 * @param counts probability range start position 338 * @param counts_diff probability range widths 339 */ 340static inline int range_get_symbol(APEContext * ctx, 341 const uint16_t counts[], 342 const uint16_t counts_diff[]) 343{ 344 int symbol, cf; 345 346 cf = range_decode_culshift(ctx, 16); 347 348 if(cf > 65492){ 349 symbol= cf - 65535 + 63; 350 range_decode_update(ctx, 1, cf); 351 if(cf > 65535) 352 ctx->error=1; 353 return symbol; 354 } 355 /* figure out the symbol inefficiently; a binary search would be much better */ 356 for (symbol = 0; counts[symbol + 1] <= cf; symbol++); 357 358 range_decode_update(ctx, counts_diff[symbol], counts[symbol]); 359 360 return symbol; 361} 362/** @} */ // group rangecoder 363 364static inline void update_rice(APERice *rice, int x) 365{ 366 int lim = rice->k ? (1 << (rice->k + 4)) : 0; 367 rice->ksum += ((x + 1) / 2) - ((rice->ksum + 16) >> 5); 368 369 if (rice->ksum < lim) 370 rice->k--; 371 else if (rice->ksum >= (1 << (rice->k + 5))) 372 rice->k++; 373} 374 375static inline int ape_decode_value(APEContext * ctx, APERice *rice) 376{ 377 int x, overflow; 378 379 if (ctx->fileversion < 3990) { 380 int tmpk; 381 382 overflow = range_get_symbol(ctx, counts_3970, counts_diff_3970); 383 384 if (overflow == (MODEL_ELEMENTS - 1)) { 385 tmpk = range_decode_bits(ctx, 5); 386 overflow = 0; 387 } else 388 tmpk = (rice->k < 1) ? 0 : rice->k - 1; 389 390 if (tmpk <= 16) 391 x = range_decode_bits(ctx, tmpk); 392 else { 393 x = range_decode_bits(ctx, 16); 394 x |= (range_decode_bits(ctx, tmpk - 16) << 16); 395 } 396 x += overflow << tmpk; 397 } else { 398 int base, pivot; 399 400 pivot = rice->ksum >> 5; 401 if (pivot == 0) 402 pivot = 1; 403 404 overflow = range_get_symbol(ctx, counts_3980, counts_diff_3980); 405 406 if (overflow == (MODEL_ELEMENTS - 1)) { 407 overflow = range_decode_bits(ctx, 16) << 16; 408 overflow |= range_decode_bits(ctx, 16); 409 } 410 411 base = range_decode_culfreq(ctx, pivot); 412 range_decode_update(ctx, 1, base); 413 414 x = base + overflow * pivot; 415 } 416 417 update_rice(rice, x); 418 419 /* Convert to signed */ 420 if (x & 1) 421 return (x >> 1) + 1; 422 else 423 return -(x >> 1); 424} 425 426static void entropy_decode(APEContext * ctx, int blockstodecode, int stereo) 427{ 428 int32_t *decoded0 = ctx->decoded0; 429 int32_t *decoded1 = ctx->decoded1; 430 431 ctx->blocksdecoded = blockstodecode; 432 433 if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) { 434 /* We are pure silence, just memset the output buffer. */ 435 memset(decoded0, 0, blockstodecode * sizeof(int32_t)); 436 memset(decoded1, 0, blockstodecode * sizeof(int32_t)); 437 } else { 438 while (blockstodecode--) { 439 *decoded0++ = ape_decode_value(ctx, &ctx->riceY); 440 if (stereo) 441 *decoded1++ = ape_decode_value(ctx, &ctx->riceX); 442 } 443 } 444 445 if (ctx->blocksdecoded == ctx->currentframeblocks) 446 range_dec_normalize(ctx); /* normalize to use up all bytes */ 447} 448 449static void init_entropy_decoder(APEContext * ctx) 450{ 451 /* Read the CRC */ 452 ctx->CRC = bytestream_get_be32(&ctx->ptr); 453 454 /* Read the frame flags if they exist */ 455 ctx->frameflags = 0; 456 if ((ctx->fileversion > 3820) && (ctx->CRC & 0x80000000)) { 457 ctx->CRC &= ~0x80000000; 458 459 ctx->frameflags = bytestream_get_be32(&ctx->ptr); 460 } 461 462 /* Keep a count of the blocks decoded in this frame */ 463 ctx->blocksdecoded = 0; 464 465 /* Initialize the rice structs */ 466 ctx->riceX.k = 10; 467 ctx->riceX.ksum = (1 << ctx->riceX.k) * 16; 468 ctx->riceY.k = 10; 469 ctx->riceY.ksum = (1 << ctx->riceY.k) * 16; 470 471 /* The first 8 bits of input are ignored. */ 472 ctx->ptr++; 473 474 range_start_decoding(ctx); 475} 476 477static const int32_t initial_coeffs[4] = { 478 360, 317, -109, 98 479}; 480 481static void init_predictor_decoder(APEContext * ctx) 482{ 483 APEPredictor *p = &ctx->predictor; 484 485 /* Zero the history buffers */ 486 memset(p->historybuffer, 0, PREDICTOR_SIZE * sizeof(int32_t)); 487 p->buf = p->historybuffer; 488 489 /* Initialize and zero the coefficients */ 490 memcpy(p->coeffsA[0], initial_coeffs, sizeof(initial_coeffs)); 491 memcpy(p->coeffsA[1], initial_coeffs, sizeof(initial_coeffs)); 492 memset(p->coeffsB, 0, sizeof(p->coeffsB)); 493 494 p->filterA[0] = p->filterA[1] = 0; 495 p->filterB[0] = p->filterB[1] = 0; 496 p->lastA[0] = p->lastA[1] = 0; 497} 498 499/** Get inverse sign of integer (-1 for positive, 1 for negative and 0 for zero) */ 500static inline int APESIGN(int32_t x) { 501 return (x < 0) - (x > 0); 502} 503 504static int predictor_update_filter(APEPredictor *p, const int decoded, const int filter, const int delayA, const int delayB, const int adaptA, const int adaptB) 505{ 506 int32_t predictionA, predictionB; 507 508 p->buf[delayA] = p->lastA[filter]; 509 p->buf[adaptA] = APESIGN(p->buf[delayA]); 510 p->buf[delayA - 1] = p->buf[delayA] - p->buf[delayA - 1]; 511 p->buf[adaptA - 1] = APESIGN(p->buf[delayA - 1]); 512 513 predictionA = p->buf[delayA ] * p->coeffsA[filter][0] + 514 p->buf[delayA - 1] * p->coeffsA[filter][1] + 515 p->buf[delayA - 2] * p->coeffsA[filter][2] + 516 p->buf[delayA - 3] * p->coeffsA[filter][3]; 517 518 /* Apply a scaled first-order filter compression */ 519 p->buf[delayB] = p->filterA[filter ^ 1] - ((p->filterB[filter] * 31) >> 5); 520 p->buf[adaptB] = APESIGN(p->buf[delayB]); 521 p->buf[delayB - 1] = p->buf[delayB] - p->buf[delayB - 1]; 522 p->buf[adaptB - 1] = APESIGN(p->buf[delayB - 1]); 523 p->filterB[filter] = p->filterA[filter ^ 1]; 524 525 predictionB = p->buf[delayB ] * p->coeffsB[filter][0] + 526 p->buf[delayB - 1] * p->coeffsB[filter][1] + 527 p->buf[delayB - 2] * p->coeffsB[filter][2] + 528 p->buf[delayB - 3] * p->coeffsB[filter][3] + 529 p->buf[delayB - 4] * p->coeffsB[filter][4]; 530 531 p->lastA[filter] = decoded + ((predictionA + (predictionB >> 1)) >> 10); 532 p->filterA[filter] = p->lastA[filter] + ((p->filterA[filter] * 31) >> 5); 533 534 if (!decoded) // no need updating filter coefficients 535 return p->filterA[filter]; 536 537 if (decoded > 0) { 538 p->coeffsA[filter][0] -= p->buf[adaptA ]; 539 p->coeffsA[filter][1] -= p->buf[adaptA - 1]; 540 p->coeffsA[filter][2] -= p->buf[adaptA - 2]; 541 p->coeffsA[filter][3] -= p->buf[adaptA - 3]; 542 543 p->coeffsB[filter][0] -= p->buf[adaptB ]; 544 p->coeffsB[filter][1] -= p->buf[adaptB - 1]; 545 p->coeffsB[filter][2] -= p->buf[adaptB - 2]; 546 p->coeffsB[filter][3] -= p->buf[adaptB - 3]; 547 p->coeffsB[filter][4] -= p->buf[adaptB - 4]; 548 } else { 549 p->coeffsA[filter][0] += p->buf[adaptA ]; 550 p->coeffsA[filter][1] += p->buf[adaptA - 1]; 551 p->coeffsA[filter][2] += p->buf[adaptA - 2]; 552 p->coeffsA[filter][3] += p->buf[adaptA - 3]; 553 554 p->coeffsB[filter][0] += p->buf[adaptB ]; 555 p->coeffsB[filter][1] += p->buf[adaptB - 1]; 556 p->coeffsB[filter][2] += p->buf[adaptB - 2]; 557 p->coeffsB[filter][3] += p->buf[adaptB - 3]; 558 p->coeffsB[filter][4] += p->buf[adaptB - 4]; 559 } 560 return p->filterA[filter]; 561} 562 563static void predictor_decode_stereo(APEContext * ctx, int count) 564{ 565 int32_t predictionA, predictionB; 566 APEPredictor *p = &ctx->predictor; 567 int32_t *decoded0 = ctx->decoded0; 568 int32_t *decoded1 = ctx->decoded1; 569 570 while (count--) { 571 /* Predictor Y */ 572 predictionA = predictor_update_filter(p, *decoded0, 0, YDELAYA, YDELAYB, YADAPTCOEFFSA, YADAPTCOEFFSB); 573 predictionB = predictor_update_filter(p, *decoded1, 1, XDELAYA, XDELAYB, XADAPTCOEFFSA, XADAPTCOEFFSB); 574 *(decoded0++) = predictionA; 575 *(decoded1++) = predictionB; 576 577 /* Combined */ 578 p->buf++; 579 580 /* Have we filled the history buffer? */ 581 if (p->buf == p->historybuffer + HISTORY_SIZE) { 582 memmove(p->historybuffer, p->buf, PREDICTOR_SIZE * sizeof(int32_t)); 583 p->buf = p->historybuffer; 584 } 585 } 586} 587 588static void predictor_decode_mono(APEContext * ctx, int count) 589{ 590 APEPredictor *p = &ctx->predictor; 591 int32_t *decoded0 = ctx->decoded0; 592 int32_t predictionA, currentA, A; 593 594 currentA = p->lastA[0]; 595 596 while (count--) { 597 A = *decoded0; 598 599 p->buf[YDELAYA] = currentA; 600 p->buf[YDELAYA - 1] = p->buf[YDELAYA] - p->buf[YDELAYA - 1]; 601 602 predictionA = p->buf[YDELAYA ] * p->coeffsA[0][0] + 603 p->buf[YDELAYA - 1] * p->coeffsA[0][1] + 604 p->buf[YDELAYA - 2] * p->coeffsA[0][2] + 605 p->buf[YDELAYA - 3] * p->coeffsA[0][3]; 606 607 currentA = A + (predictionA >> 10); 608 609 p->buf[YADAPTCOEFFSA] = APESIGN(p->buf[YDELAYA ]); 610 p->buf[YADAPTCOEFFSA - 1] = APESIGN(p->buf[YDELAYA - 1]); 611 612 if (A > 0) { 613 p->coeffsA[0][0] -= p->buf[YADAPTCOEFFSA ]; 614 p->coeffsA[0][1] -= p->buf[YADAPTCOEFFSA - 1]; 615 p->coeffsA[0][2] -= p->buf[YADAPTCOEFFSA - 2]; 616 p->coeffsA[0][3] -= p->buf[YADAPTCOEFFSA - 3]; 617 } else if (A < 0) { 618 p->coeffsA[0][0] += p->buf[YADAPTCOEFFSA ]; 619 p->coeffsA[0][1] += p->buf[YADAPTCOEFFSA - 1]; 620 p->coeffsA[0][2] += p->buf[YADAPTCOEFFSA - 2]; 621 p->coeffsA[0][3] += p->buf[YADAPTCOEFFSA - 3]; 622 } 623 624 p->buf++; 625 626 /* Have we filled the history buffer? */ 627 if (p->buf == p->historybuffer + HISTORY_SIZE) { 628 memmove(p->historybuffer, p->buf, PREDICTOR_SIZE * sizeof(int32_t)); 629 p->buf = p->historybuffer; 630 } 631 632 p->filterA[0] = currentA + ((p->filterA[0] * 31) >> 5); 633 *(decoded0++) = p->filterA[0]; 634 } 635 636 p->lastA[0] = currentA; 637} 638 639static void do_init_filter(APEFilter *f, int16_t * buf, int order) 640{ 641 f->coeffs = buf; 642 f->historybuffer = buf + order; 643 f->delay = f->historybuffer + order * 2; 644 f->adaptcoeffs = f->historybuffer + order; 645 646 memset(f->historybuffer, 0, (order * 2) * sizeof(int16_t)); 647 memset(f->coeffs, 0, order * sizeof(int16_t)); 648 f->avg = 0; 649} 650 651static void init_filter(APEContext * ctx, APEFilter *f, int16_t * buf, int order) 652{ 653 do_init_filter(&f[0], buf, order); 654 do_init_filter(&f[1], buf + order * 3 + HISTORY_SIZE, order); 655} 656 657static inline void do_apply_filter(APEContext * ctx, int version, APEFilter *f, int32_t *data, int count, int order, int fracbits) 658{ 659 int res; 660 int absres; 661 662 while (count--) { 663 /* round fixedpoint scalar product */ 664 res = (ctx->dsp.scalarproduct_int16(f->delay - order, f->coeffs, order, 0) + (1 << (fracbits - 1))) >> fracbits; 665 666 if (*data < 0) 667 ctx->dsp.add_int16(f->coeffs, f->adaptcoeffs - order, order); 668 else if (*data > 0) 669 ctx->dsp.sub_int16(f->coeffs, f->adaptcoeffs - order, order); 670 671 res += *data; 672 673 *data++ = res; 674 675 /* Update the output history */ 676 *f->delay++ = av_clip_int16(res); 677 678 if (version < 3980) { 679 /* Version ??? to < 3.98 files (untested) */ 680 f->adaptcoeffs[0] = (res == 0) ? 0 : ((res >> 28) & 8) - 4; 681 f->adaptcoeffs[-4] >>= 1; 682 f->adaptcoeffs[-8] >>= 1; 683 } else { 684 /* Version 3.98 and later files */ 685 686 /* Update the adaption coefficients */ 687 absres = (res < 0 ? -res : res); 688 689 if (absres > (f->avg * 3)) 690 *f->adaptcoeffs = ((res >> 25) & 64) - 32; 691 else if (absres > (f->avg * 4) / 3) 692 *f->adaptcoeffs = ((res >> 26) & 32) - 16; 693 else if (absres > 0) 694 *f->adaptcoeffs = ((res >> 27) & 16) - 8; 695 else 696 *f->adaptcoeffs = 0; 697 698 f->avg += (absres - f->avg) / 16; 699 700 f->adaptcoeffs[-1] >>= 1; 701 f->adaptcoeffs[-2] >>= 1; 702 f->adaptcoeffs[-8] >>= 1; 703 } 704 705 f->adaptcoeffs++; 706 707 /* Have we filled the history buffer? */ 708 if (f->delay == f->historybuffer + HISTORY_SIZE + (order * 2)) { 709 memmove(f->historybuffer, f->delay - (order * 2), 710 (order * 2) * sizeof(int16_t)); 711 f->delay = f->historybuffer + order * 2; 712 f->adaptcoeffs = f->historybuffer + order; 713 } 714 } 715} 716 717static void apply_filter(APEContext * ctx, APEFilter *f, 718 int32_t * data0, int32_t * data1, 719 int count, int order, int fracbits) 720{ 721 do_apply_filter(ctx, ctx->fileversion, &f[0], data0, count, order, fracbits); 722 if (data1) 723 do_apply_filter(ctx, ctx->fileversion, &f[1], data1, count, order, fracbits); 724} 725 726static void ape_apply_filters(APEContext * ctx, int32_t * decoded0, 727 int32_t * decoded1, int count) 728{ 729 int i; 730 731 for (i = 0; i < APE_FILTER_LEVELS; i++) { 732 if (!ape_filter_orders[ctx->fset][i]) 733 break; 734 apply_filter(ctx, ctx->filters[i], decoded0, decoded1, count, ape_filter_orders[ctx->fset][i], ape_filter_fracbits[ctx->fset][i]); 735 } 736} 737 738static void init_frame_decoder(APEContext * ctx) 739{ 740 int i; 741 init_entropy_decoder(ctx); 742 init_predictor_decoder(ctx); 743 744 for (i = 0; i < APE_FILTER_LEVELS; i++) { 745 if (!ape_filter_orders[ctx->fset][i]) 746 break; 747 init_filter(ctx, ctx->filters[i], ctx->filterbuf[i], ape_filter_orders[ctx->fset][i]); 748 } 749} 750 751static void ape_unpack_mono(APEContext * ctx, int count) 752{ 753 int32_t left; 754 int32_t *decoded0 = ctx->decoded0; 755 int32_t *decoded1 = ctx->decoded1; 756 757 if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) { 758 entropy_decode(ctx, count, 0); 759 /* We are pure silence, so we're done. */ 760 av_log(ctx->avctx, AV_LOG_DEBUG, "pure silence mono\n"); 761 return; 762 } 763 764 entropy_decode(ctx, count, 0); 765 ape_apply_filters(ctx, decoded0, NULL, count); 766 767 /* Now apply the predictor decoding */ 768 predictor_decode_mono(ctx, count); 769 770 /* Pseudo-stereo - just copy left channel to right channel */ 771 if (ctx->channels == 2) { 772 while (count--) { 773 left = *decoded0; 774 *(decoded1++) = *(decoded0++) = left; 775 } 776 } 777} 778 779static void ape_unpack_stereo(APEContext * ctx, int count) 780{ 781 int32_t left, right; 782 int32_t *decoded0 = ctx->decoded0; 783 int32_t *decoded1 = ctx->decoded1; 784 785 if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) { 786 /* We are pure silence, so we're done. */ 787 av_log(ctx->avctx, AV_LOG_DEBUG, "pure silence stereo\n"); 788 return; 789 } 790 791 entropy_decode(ctx, count, 1); 792 ape_apply_filters(ctx, decoded0, decoded1, count); 793 794 /* Now apply the predictor decoding */ 795 predictor_decode_stereo(ctx, count); 796 797 /* Decorrelate and scale to output depth */ 798 while (count--) { 799 left = *decoded1 - (*decoded0 / 2); 800 right = left + *decoded0; 801 802 *(decoded0++) = left; 803 *(decoded1++) = right; 804 } 805} 806 807static int ape_decode_frame(AVCodecContext * avctx, 808 void *data, int *data_size, 809 const uint8_t * buf, int buf_size) 810{ 811 APEContext *s = avctx->priv_data; 812 int16_t *samples = data; 813 int nblocks; 814 int i, n; 815 int blockstodecode; 816 int bytes_used; 817 818 if (buf_size == 0 && !s->samples) { 819 *data_size = 0; 820 return 0; 821 } 822 823 /* should not happen but who knows */ 824 if (BLOCKS_PER_LOOP * 2 * avctx->channels > *data_size) { 825 av_log (avctx, AV_LOG_ERROR, "Packet size is too big to be handled in lavc! (max is %d where you have %d)\n", *data_size, s->samples * 2 * avctx->channels); 826 return -1; 827 } 828 829 if(!s->samples){ 830 s->data = av_realloc(s->data, (buf_size + 3) & ~3); 831 s->dsp.bswap_buf((uint32_t*)s->data, (const uint32_t*)buf, buf_size >> 2); 832 s->ptr = s->last_ptr = s->data; 833 s->data_end = s->data + buf_size; 834 835 nblocks = s->samples = bytestream_get_be32(&s->ptr); 836 n = bytestream_get_be32(&s->ptr); 837 if(n < 0 || n > 3){ 838 av_log(avctx, AV_LOG_ERROR, "Incorrect offset passed\n"); 839 s->data = NULL; 840 return -1; 841 } 842 s->ptr += n; 843 844 s->currentframeblocks = nblocks; 845 buf += 4; 846 if (s->samples <= 0) { 847 *data_size = 0; 848 return buf_size; 849 } 850 851 memset(s->decoded0, 0, sizeof(s->decoded0)); 852 memset(s->decoded1, 0, sizeof(s->decoded1)); 853 854 /* Initialize the frame decoder */ 855 init_frame_decoder(s); 856 } 857 858 if (!s->data) { 859 *data_size = 0; 860 return buf_size; 861 } 862 863 nblocks = s->samples; 864 blockstodecode = FFMIN(BLOCKS_PER_LOOP, nblocks); 865 866 s->error=0; 867 868 if ((s->channels == 1) || (s->frameflags & APE_FRAMECODE_PSEUDO_STEREO)) 869 ape_unpack_mono(s, blockstodecode); 870 else 871 ape_unpack_stereo(s, blockstodecode); 872 873 if(s->error || s->ptr > s->data_end){ 874 s->samples=0; 875 av_log(avctx, AV_LOG_ERROR, "Error decoding frame\n"); 876 return -1; 877 } 878 879 for (i = 0; i < blockstodecode; i++) { 880 *samples++ = s->decoded0[i]; 881 if(s->channels == 2) 882 *samples++ = s->decoded1[i]; 883 } 884 885 s->samples -= blockstodecode; 886 887 *data_size = blockstodecode * 2 * s->channels; 888 bytes_used = s->samples ? s->ptr - s->last_ptr : buf_size; 889 s->last_ptr = s->ptr; 890 return bytes_used; 891} 892 893AVCodec ape_decoder = { 894 "ape", 895 CODEC_TYPE_AUDIO, 896 CODEC_ID_APE, 897 sizeof(APEContext), 898 ape_decode_init, 899 NULL, 900 ape_decode_close, 901 ape_decode_frame, 902 .long_name = NULL_IF_CONFIG_SMALL("Monkey's Audio"), 903}; 904