1/* 2 * Shorten decoder 3 * Copyright (c) 2005 Jeff Muizelaar 4 * 5 * This file is part of Libav. 6 * 7 * Libav is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * Libav is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with Libav; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22/** 23 * @file 24 * Shorten decoder 25 * @author Jeff Muizelaar 26 * 27 */ 28 29#include <limits.h> 30#include "avcodec.h" 31#include "bytestream.h" 32#include "get_bits.h" 33#include "golomb.h" 34 35#define MAX_CHANNELS 8 36#define MAX_BLOCKSIZE 65535 37 38#define OUT_BUFFER_SIZE 16384 39 40#define ULONGSIZE 2 41 42#define WAVE_FORMAT_PCM 0x0001 43 44#define DEFAULT_BLOCK_SIZE 256 45 46#define TYPESIZE 4 47#define CHANSIZE 0 48#define LPCQSIZE 2 49#define ENERGYSIZE 3 50#define BITSHIFTSIZE 2 51 52#define TYPE_S16HL 3 53#define TYPE_S16LH 5 54 55#define NWRAP 3 56#define NSKIPSIZE 1 57 58#define LPCQUANT 5 59#define V2LPCQOFFSET (1 << LPCQUANT) 60 61#define FNSIZE 2 62#define FN_DIFF0 0 63#define FN_DIFF1 1 64#define FN_DIFF2 2 65#define FN_DIFF3 3 66#define FN_QUIT 4 67#define FN_BLOCKSIZE 5 68#define FN_BITSHIFT 6 69#define FN_QLPC 7 70#define FN_ZERO 8 71#define FN_VERBATIM 9 72 73/** indicates if the FN_* command is audio or non-audio */ 74static const uint8_t is_audio_command[10] = { 1, 1, 1, 1, 0, 0, 0, 1, 1, 0 }; 75 76#define VERBATIM_CKSIZE_SIZE 5 77#define VERBATIM_BYTE_SIZE 8 78#define CANONICAL_HEADER_SIZE 44 79 80typedef struct ShortenContext { 81 AVCodecContext *avctx; 82 AVFrame frame; 83 GetBitContext gb; 84 85 int min_framesize, max_framesize; 86 unsigned channels; 87 88 int32_t *decoded[MAX_CHANNELS]; 89 int32_t *decoded_base[MAX_CHANNELS]; 90 int32_t *offset[MAX_CHANNELS]; 91 int *coeffs; 92 uint8_t *bitstream; 93 int bitstream_size; 94 int bitstream_index; 95 unsigned int allocated_bitstream_size; 96 int header_size; 97 uint8_t header[OUT_BUFFER_SIZE]; 98 int version; 99 int cur_chan; 100 int bitshift; 101 int nmean; 102 int internal_ftype; 103 int nwrap; 104 int blocksize; 105 int bitindex; 106 int32_t lpcqoffset; 107 int got_header; 108 int got_quit_command; 109} ShortenContext; 110 111static av_cold int shorten_decode_init(AVCodecContext *avctx) 112{ 113 ShortenContext *s = avctx->priv_data; 114 s->avctx = avctx; 115 avctx->sample_fmt = AV_SAMPLE_FMT_S16; 116 117 avcodec_get_frame_defaults(&s->frame); 118 avctx->coded_frame = &s->frame; 119 120 return 0; 121} 122 123static int allocate_buffers(ShortenContext *s) 124{ 125 int i, chan; 126 int *coeffs; 127 void *tmp_ptr; 128 129 for (chan = 0; chan < s->channels; chan++) { 130 if (FFMAX(1, s->nmean) >= UINT_MAX / sizeof(int32_t)) { 131 av_log(s->avctx, AV_LOG_ERROR, "nmean too large\n"); 132 return AVERROR_INVALIDDATA; 133 } 134 if (s->blocksize + s->nwrap >= UINT_MAX / sizeof(int32_t) || 135 s->blocksize + s->nwrap <= (unsigned)s->nwrap) { 136 av_log(s->avctx, AV_LOG_ERROR, 137 "s->blocksize + s->nwrap too large\n"); 138 return AVERROR_INVALIDDATA; 139 } 140 141 tmp_ptr = 142 av_realloc(s->offset[chan], sizeof(int32_t) * FFMAX(1, s->nmean)); 143 if (!tmp_ptr) 144 return AVERROR(ENOMEM); 145 s->offset[chan] = tmp_ptr; 146 147 tmp_ptr = av_realloc(s->decoded_base[chan], (s->blocksize + s->nwrap) * 148 sizeof(s->decoded_base[0][0])); 149 if (!tmp_ptr) 150 return AVERROR(ENOMEM); 151 s->decoded_base[chan] = tmp_ptr; 152 for (i = 0; i < s->nwrap; i++) 153 s->decoded_base[chan][i] = 0; 154 s->decoded[chan] = s->decoded_base[chan] + s->nwrap; 155 } 156 157 coeffs = av_realloc(s->coeffs, s->nwrap * sizeof(*s->coeffs)); 158 if (!coeffs) 159 return AVERROR(ENOMEM); 160 s->coeffs = coeffs; 161 162 return 0; 163} 164 165static inline unsigned int get_uint(ShortenContext *s, int k) 166{ 167 if (s->version != 0) 168 k = get_ur_golomb_shorten(&s->gb, ULONGSIZE); 169 return get_ur_golomb_shorten(&s->gb, k); 170} 171 172static void fix_bitshift(ShortenContext *s, int32_t *buffer) 173{ 174 int i; 175 176 if (s->bitshift != 0) 177 for (i = 0; i < s->blocksize; i++) 178 buffer[i] <<= s->bitshift; 179} 180 181static int init_offset(ShortenContext *s) 182{ 183 int32_t mean = 0; 184 int chan, i; 185 int nblock = FFMAX(1, s->nmean); 186 /* initialise offset */ 187 switch (s->internal_ftype) { 188 case TYPE_S16HL: 189 case TYPE_S16LH: 190 mean = 0; 191 break; 192 default: 193 av_log(s->avctx, AV_LOG_ERROR, "unknown audio type"); 194 return AVERROR_INVALIDDATA; 195 } 196 197 for (chan = 0; chan < s->channels; chan++) 198 for (i = 0; i < nblock; i++) 199 s->offset[chan][i] = mean; 200 return 0; 201} 202 203static int decode_wave_header(AVCodecContext *avctx, const uint8_t *header, 204 int header_size) 205{ 206 int len; 207 short wave_format; 208 209 if (bytestream_get_le32(&header) != MKTAG('R', 'I', 'F', 'F')) { 210 av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n"); 211 return AVERROR_INVALIDDATA; 212 } 213 214 header += 4; /* chunk size */ 215 216 if (bytestream_get_le32(&header) != MKTAG('W', 'A', 'V', 'E')) { 217 av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n"); 218 return AVERROR_INVALIDDATA; 219 } 220 221 while (bytestream_get_le32(&header) != MKTAG('f', 'm', 't', ' ')) { 222 len = bytestream_get_le32(&header); 223 header += len; 224 } 225 len = bytestream_get_le32(&header); 226 227 if (len < 16) { 228 av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n"); 229 return AVERROR_INVALIDDATA; 230 } 231 232 wave_format = bytestream_get_le16(&header); 233 234 switch (wave_format) { 235 case WAVE_FORMAT_PCM: 236 break; 237 default: 238 av_log(avctx, AV_LOG_ERROR, "unsupported wave format\n"); 239 return AVERROR(ENOSYS); 240 } 241 242 header += 2; // skip channels (already got from shorten header) 243 avctx->sample_rate = bytestream_get_le32(&header); 244 header += 4; // skip bit rate (represents original uncompressed bit rate) 245 header += 2; // skip block align (not needed) 246 avctx->bits_per_coded_sample = bytestream_get_le16(&header); 247 248 if (avctx->bits_per_coded_sample != 16) { 249 av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample\n"); 250 return AVERROR(ENOSYS); 251 } 252 253 len -= 16; 254 if (len > 0) 255 av_log(avctx, AV_LOG_INFO, "%d header bytes unparsed\n", len); 256 257 return 0; 258} 259 260static void interleave_buffer(int16_t *samples, int nchan, int blocksize, 261 int32_t **buffer) 262{ 263 int i, chan; 264 for (i=0; i<blocksize; i++) 265 for (chan=0; chan < nchan; chan++) 266 *samples++ = av_clip_int16(buffer[chan][i]); 267} 268 269static const int fixed_coeffs[3][3] = { 270 { 1, 0, 0 }, 271 { 2, -1, 0 }, 272 { 3, -3, 1 } 273}; 274 275static int decode_subframe_lpc(ShortenContext *s, int command, int channel, 276 int residual_size, int32_t coffset) 277{ 278 int pred_order, sum, qshift, init_sum, i, j; 279 const int *coeffs; 280 281 if (command == FN_QLPC) { 282 /* read/validate prediction order */ 283 pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE); 284 if (pred_order > s->nwrap) { 285 av_log(s->avctx, AV_LOG_ERROR, "invalid pred_order %d\n", 286 pred_order); 287 return AVERROR(EINVAL); 288 } 289 /* read LPC coefficients */ 290 for (i = 0; i < pred_order; i++) 291 s->coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT); 292 coeffs = s->coeffs; 293 294 qshift = LPCQUANT; 295 } else { 296 /* fixed LPC coeffs */ 297 pred_order = command; 298 coeffs = fixed_coeffs[pred_order - 1]; 299 qshift = 0; 300 } 301 302 /* subtract offset from previous samples to use in prediction */ 303 if (command == FN_QLPC && coffset) 304 for (i = -pred_order; i < 0; i++) 305 s->decoded[channel][i] -= coffset; 306 307 /* decode residual and do LPC prediction */ 308 init_sum = pred_order ? (command == FN_QLPC ? s->lpcqoffset : 0) : coffset; 309 for (i = 0; i < s->blocksize; i++) { 310 sum = init_sum; 311 for (j = 0; j < pred_order; j++) 312 sum += coeffs[j] * s->decoded[channel][i - j - 1]; 313 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 314 (sum >> qshift); 315 } 316 317 /* add offset to current samples */ 318 if (command == FN_QLPC && coffset) 319 for (i = 0; i < s->blocksize; i++) 320 s->decoded[channel][i] += coffset; 321 322 return 0; 323} 324 325static int read_header(ShortenContext *s) 326{ 327 int i, ret; 328 int maxnlpc = 0; 329 /* shorten signature */ 330 if (get_bits_long(&s->gb, 32) != AV_RB32("ajkg")) { 331 av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n"); 332 return AVERROR_INVALIDDATA; 333 } 334 335 s->lpcqoffset = 0; 336 s->blocksize = DEFAULT_BLOCK_SIZE; 337 s->nmean = -1; 338 s->version = get_bits(&s->gb, 8); 339 s->internal_ftype = get_uint(s, TYPESIZE); 340 341 s->channels = get_uint(s, CHANSIZE); 342 if (!s->channels) { 343 av_log(s->avctx, AV_LOG_ERROR, "No channels reported\n"); 344 return AVERROR_INVALIDDATA; 345 } 346 if (s->channels > MAX_CHANNELS) { 347 av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels); 348 s->channels = 0; 349 return AVERROR_INVALIDDATA; 350 } 351 s->avctx->channels = s->channels; 352 353 /* get blocksize if version > 0 */ 354 if (s->version > 0) { 355 int skip_bytes; 356 unsigned blocksize; 357 358 blocksize = get_uint(s, av_log2(DEFAULT_BLOCK_SIZE)); 359 if (!blocksize || blocksize > MAX_BLOCKSIZE) { 360 av_log(s->avctx, AV_LOG_ERROR, 361 "invalid or unsupported block size: %d\n", 362 blocksize); 363 return AVERROR(EINVAL); 364 } 365 s->blocksize = blocksize; 366 367 maxnlpc = get_uint(s, LPCQSIZE); 368 s->nmean = get_uint(s, 0); 369 370 skip_bytes = get_uint(s, NSKIPSIZE); 371 for (i = 0; i < skip_bytes; i++) 372 skip_bits(&s->gb, 8); 373 } 374 s->nwrap = FFMAX(NWRAP, maxnlpc); 375 376 if ((ret = allocate_buffers(s)) < 0) 377 return ret; 378 379 if ((ret = init_offset(s)) < 0) 380 return ret; 381 382 if (s->version > 1) 383 s->lpcqoffset = V2LPCQOFFSET; 384 385 if (get_ur_golomb_shorten(&s->gb, FNSIZE) != FN_VERBATIM) { 386 av_log(s->avctx, AV_LOG_ERROR, 387 "missing verbatim section at beginning of stream\n"); 388 return AVERROR_INVALIDDATA; 389 } 390 391 s->header_size = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE); 392 if (s->header_size >= OUT_BUFFER_SIZE || 393 s->header_size < CANONICAL_HEADER_SIZE) { 394 av_log(s->avctx, AV_LOG_ERROR, "header is wrong size: %d\n", 395 s->header_size); 396 return AVERROR_INVALIDDATA; 397 } 398 399 for (i = 0; i < s->header_size; i++) 400 s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE); 401 402 if ((ret = decode_wave_header(s->avctx, s->header, s->header_size)) < 0) 403 return ret; 404 405 s->cur_chan = 0; 406 s->bitshift = 0; 407 408 s->got_header = 1; 409 410 return 0; 411} 412 413static int shorten_decode_frame(AVCodecContext *avctx, void *data, 414 int *got_frame_ptr, AVPacket *avpkt) 415{ 416 const uint8_t *buf = avpkt->data; 417 int buf_size = avpkt->size; 418 ShortenContext *s = avctx->priv_data; 419 int i, input_buf_size = 0; 420 int ret; 421 422 /* allocate internal bitstream buffer */ 423 if (s->max_framesize == 0) { 424 void *tmp_ptr; 425 s->max_framesize = 1024; // should hopefully be enough for the first header 426 tmp_ptr = av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, 427 s->max_framesize); 428 if (!tmp_ptr) { 429 av_log(avctx, AV_LOG_ERROR, "error allocating bitstream buffer\n"); 430 return AVERROR(ENOMEM); 431 } 432 s->bitstream = tmp_ptr; 433 } 434 435 /* append current packet data to bitstream buffer */ 436 if (1 && s->max_framesize) { //FIXME truncated 437 buf_size = FFMIN(buf_size, s->max_framesize - s->bitstream_size); 438 input_buf_size = buf_size; 439 440 if (s->bitstream_index + s->bitstream_size + buf_size > 441 s->allocated_bitstream_size) { 442 memmove(s->bitstream, &s->bitstream[s->bitstream_index], 443 s->bitstream_size); 444 s->bitstream_index = 0; 445 } 446 if (buf) 447 memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, 448 buf_size); 449 buf = &s->bitstream[s->bitstream_index]; 450 buf_size += s->bitstream_size; 451 s->bitstream_size = buf_size; 452 453 /* do not decode until buffer has at least max_framesize bytes or 454 * the end of the file has been reached */ 455 if (buf_size < s->max_framesize && avpkt->data) { 456 *got_frame_ptr = 0; 457 return input_buf_size; 458 } 459 } 460 /* init and position bitstream reader */ 461 init_get_bits(&s->gb, buf, buf_size * 8); 462 skip_bits(&s->gb, s->bitindex); 463 464 /* process header or next subblock */ 465 if (!s->got_header) { 466 if ((ret = read_header(s)) < 0) 467 return ret; 468 *got_frame_ptr = 0; 469 goto finish_frame; 470 } 471 472 /* if quit command was read previously, don't decode anything */ 473 if (s->got_quit_command) { 474 *got_frame_ptr = 0; 475 return avpkt->size; 476 } 477 478 s->cur_chan = 0; 479 while (s->cur_chan < s->channels) { 480 int cmd; 481 int len; 482 483 if (get_bits_left(&s->gb) < 3 + FNSIZE) { 484 *got_frame_ptr = 0; 485 break; 486 } 487 488 cmd = get_ur_golomb_shorten(&s->gb, FNSIZE); 489 490 if (cmd > FN_VERBATIM) { 491 av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd); 492 *got_frame_ptr = 0; 493 break; 494 } 495 496 if (!is_audio_command[cmd]) { 497 /* process non-audio command */ 498 switch (cmd) { 499 case FN_VERBATIM: 500 len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE); 501 while (len--) 502 get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE); 503 break; 504 case FN_BITSHIFT: 505 s->bitshift = get_ur_golomb_shorten(&s->gb, BITSHIFTSIZE); 506 break; 507 case FN_BLOCKSIZE: { 508 unsigned blocksize = get_uint(s, av_log2(s->blocksize)); 509 if (blocksize > s->blocksize) { 510 av_log(avctx, AV_LOG_ERROR, 511 "Increasing block size is not supported\n"); 512 return AVERROR_PATCHWELCOME; 513 } 514 if (!blocksize || blocksize > MAX_BLOCKSIZE) { 515 av_log(avctx, AV_LOG_ERROR, "invalid or unsupported " 516 "block size: %d\n", blocksize); 517 return AVERROR(EINVAL); 518 } 519 s->blocksize = blocksize; 520 break; 521 } 522 case FN_QUIT: 523 s->got_quit_command = 1; 524 break; 525 } 526 if (cmd == FN_BLOCKSIZE || cmd == FN_QUIT) { 527 *got_frame_ptr = 0; 528 break; 529 } 530 } else { 531 /* process audio command */ 532 int residual_size = 0; 533 int channel = s->cur_chan; 534 int32_t coffset; 535 536 /* get Rice code for residual decoding */ 537 if (cmd != FN_ZERO) { 538 residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE); 539 /* this is a hack as version 0 differed in defintion of get_sr_golomb_shorten */ 540 if (s->version == 0) 541 residual_size--; 542 } 543 544 /* calculate sample offset using means from previous blocks */ 545 if (s->nmean == 0) 546 coffset = s->offset[channel][0]; 547 else { 548 int32_t sum = (s->version < 2) ? 0 : s->nmean / 2; 549 for (i = 0; i < s->nmean; i++) 550 sum += s->offset[channel][i]; 551 coffset = sum / s->nmean; 552 if (s->version >= 2) 553 coffset >>= FFMIN(1, s->bitshift); 554 } 555 556 /* decode samples for this channel */ 557 if (cmd == FN_ZERO) { 558 for (i = 0; i < s->blocksize; i++) 559 s->decoded[channel][i] = 0; 560 } else { 561 if ((ret = decode_subframe_lpc(s, cmd, channel, 562 residual_size, coffset)) < 0) 563 return ret; 564 } 565 566 /* update means with info from the current block */ 567 if (s->nmean > 0) { 568 int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2; 569 for (i = 0; i < s->blocksize; i++) 570 sum += s->decoded[channel][i]; 571 572 for (i = 1; i < s->nmean; i++) 573 s->offset[channel][i - 1] = s->offset[channel][i]; 574 575 if (s->version < 2) 576 s->offset[channel][s->nmean - 1] = sum / s->blocksize; 577 else 578 s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift; 579 } 580 581 /* copy wrap samples for use with next block */ 582 for (i = -s->nwrap; i < 0; i++) 583 s->decoded[channel][i] = s->decoded[channel][i + s->blocksize]; 584 585 /* shift samples to add in unused zero bits which were removed 586 * during encoding */ 587 fix_bitshift(s, s->decoded[channel]); 588 589 /* if this is the last channel in the block, output the samples */ 590 s->cur_chan++; 591 if (s->cur_chan == s->channels) { 592 /* get output buffer */ 593 s->frame.nb_samples = s->blocksize; 594 if ((ret = avctx->get_buffer(avctx, &s->frame)) < 0) { 595 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 596 return ret; 597 } 598 /* interleave output */ 599 interleave_buffer((int16_t *)s->frame.data[0], s->channels, 600 s->blocksize, s->decoded); 601 602 *got_frame_ptr = 1; 603 *(AVFrame *)data = s->frame; 604 } 605 } 606 } 607 if (s->cur_chan < s->channels) 608 *got_frame_ptr = 0; 609 610finish_frame: 611 s->bitindex = get_bits_count(&s->gb) - 8 * (get_bits_count(&s->gb) / 8); 612 i = get_bits_count(&s->gb) / 8; 613 if (i > buf_size) { 614 av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size); 615 s->bitstream_size = 0; 616 s->bitstream_index = 0; 617 return AVERROR_INVALIDDATA; 618 } 619 if (s->bitstream_size) { 620 s->bitstream_index += i; 621 s->bitstream_size -= i; 622 return input_buf_size; 623 } else 624 return i; 625} 626 627static av_cold int shorten_decode_close(AVCodecContext *avctx) 628{ 629 ShortenContext *s = avctx->priv_data; 630 int i; 631 632 for (i = 0; i < s->channels; i++) { 633 s->decoded[i] = NULL; 634 av_freep(&s->decoded_base[i]); 635 av_freep(&s->offset[i]); 636 } 637 av_freep(&s->bitstream); 638 av_freep(&s->coeffs); 639 640 return 0; 641} 642 643AVCodec ff_shorten_decoder = { 644 .name = "shorten", 645 .type = AVMEDIA_TYPE_AUDIO, 646 .id = CODEC_ID_SHORTEN, 647 .priv_data_size = sizeof(ShortenContext), 648 .init = shorten_decode_init, 649 .close = shorten_decode_close, 650 .decode = shorten_decode_frame, 651 .capabilities = CODEC_CAP_DELAY | CODEC_CAP_DR1, 652 .long_name= NULL_IF_CONFIG_SMALL("Shorten"), 653}; 654