ffmpeg/libavcodec/shorten.c

   1 /*
   2  * Shorten decoder
   3  * Copyright (c) 2005 Jeff Muizelaar
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 #include "internal.h"
  35
  36 #define MAX_CHANNELS 8
  37 #define MAX_BLOCKSIZE 65535
  38
  39 #define OUT_BUFFER_SIZE 16384
  40
  41 #define ULONGSIZE 2
  42
  43 #define WAVE_FORMAT_PCM 0x0001
  44
  45 #define DEFAULT_BLOCK_SIZE 256
  46
  47 #define TYPESIZE 4
  48 #define CHANSIZE 0
  49 #define LPCQSIZE 2
  50 #define ENERGYSIZE 3
  51 #define BITSHIFTSIZE 2
  52
  53 #define TYPE_S8    1
  54 #define TYPE_U8    2
  55 #define TYPE_S16HL 3
  56 #define TYPE_U16HL 4
  57 #define TYPE_S16LH 5
  58 #define TYPE_U16LH 6
  59
  60 #define NWRAP 3
  61 #define NSKIPSIZE 1
  62
  63 #define LPCQUANT 5
  64 #define V2LPCQOFFSET (1 << LPCQUANT)
  65
  66 #define FNSIZE 2
  67 #define FN_DIFF0        0
  68 #define FN_DIFF1        1
  69 #define FN_DIFF2        2
  70 #define FN_DIFF3        3
  71 #define FN_QUIT         4
  72 #define FN_BLOCKSIZE    5
  73 #define FN_BITSHIFT     6
  74 #define FN_QLPC         7
  75 #define FN_ZERO         8
  76 #define FN_VERBATIM     9
  77
  78 /** indicates if the FN_* command is audio or non-audio */
  79 static const uint8_t is_audio_command[10] = { 1, 1, 1, 1, 0, 0, 0, 1, 1, 0 };
  80
  81 #define VERBATIM_CKSIZE_SIZE 5
  82 #define VERBATIM_BYTE_SIZE 8
  83 #define CANONICAL_HEADER_SIZE 44
  84
  85 typedef struct ShortenContext {
  86     AVCodecContext *avctx;
  87     GetBitContext gb;
  88
  89     int min_framesize, max_framesize;
  90     unsigned channels;
  91
  92     int32_t *decoded[MAX_CHANNELS];
  93     int32_t *decoded_base[MAX_CHANNELS];
  94     int32_t *offset[MAX_CHANNELS];
  95     int *coeffs;
  96     uint8_t *bitstream;
  97     int bitstream_size;
  98     int bitstream_index;
  99     unsigned int allocated_bitstream_size;
 100     int header_size;
 101     uint8_t header[OUT_BUFFER_SIZE];
 102     int version;
 103     int cur_chan;
 104     int bitshift;
 105     int nmean;
 106     int internal_ftype;
 107     int nwrap;
 108     int blocksize;
 109     int bitindex;
 110     int32_t lpcqoffset;
 111     int got_header;
 112     int got_quit_command;
 113 } ShortenContext;
 114
 115 static av_cold int shorten_decode_init(AVCodecContext *avctx)
 116 {
 117     ShortenContext *s = avctx->priv_data;
 118     s->avctx          = avctx;
 119
 120     return 0;
 121 }
 122
 123 static int allocate_buffers(ShortenContext *s)
 124 {
 125     int i, chan, err;
 126
 127     for (chan = 0; chan < s->channels; chan++) {
 128         if (FFMAX(1, s->nmean) >= UINT_MAX / sizeof(int32_t)) {
 129             av_log(s->avctx, AV_LOG_ERROR, "nmean too large\n");
 130             return AVERROR_INVALIDDATA;
 131         }
 132         if (s->blocksize + s->nwrap >= UINT_MAX / sizeof(int32_t) ||
 133             s->blocksize + s->nwrap <= (unsigned)s->nwrap) {
 134             av_log(s->avctx, AV_LOG_ERROR,
 135                    "s->blocksize + s->nwrap too large\n");
 136             return AVERROR_INVALIDDATA;
 137         }
 138
 139         if ((err = av_reallocp(&s->offset[chan],
 140                                sizeof(int32_t) *
 141                                FFMAX(1, s->nmean))) < 0)
 142             return err;
 143
 144         if ((err = av_reallocp(&s->decoded_base[chan], (s->blocksize + s->nwrap) *
 145                                sizeof(s->decoded_base[0][0]))) < 0)
 146             return err;
 147         for (i = 0; i < s->nwrap; i++)
 148             s->decoded_base[chan][i] = 0;
 149         s->decoded[chan] = s->decoded_base[chan] + s->nwrap;
 150     }
 151
 152     if ((err = av_reallocp(&s->coeffs, s->nwrap * sizeof(*s->coeffs))) < 0)
 153         return err;
 154
 155     return 0;
 156 }
 157
 158 static inline unsigned int get_uint(ShortenContext *s, int k)
 159 {
 160     if (s->version != 0)
 161         k = get_ur_golomb_shorten(&s->gb, ULONGSIZE);
 162     return get_ur_golomb_shorten(&s->gb, k);
 163 }
 164
 165 static void fix_bitshift(ShortenContext *s, int32_t *buffer)
 166 {
 167     int i;
 168
 169     if (s->bitshift != 0)
 170         for (i = 0; i < s->blocksize; i++)
 171             buffer[i] <<= s->bitshift;
 172 }
 173
 174 static int init_offset(ShortenContext *s)
 175 {
 176     int32_t mean = 0;
 177     int chan, i;
 178     int nblock = FFMAX(1, s->nmean);
 179     /* initialise offset */
 180     switch (s->internal_ftype) {
 181     case TYPE_U8:
 182         s->avctx->sample_fmt = AV_SAMPLE_FMT_U8P;
 183         mean = 0x80;
 184         break;
 185     case TYPE_S16HL:
 186     case TYPE_S16LH:
 187         s->avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
 188         break;
 189     default:
 190         av_log(s->avctx, AV_LOG_ERROR, "unknown audio type\n");
 191         return AVERROR_PATCHWELCOME;
 192     }
 193
 194     for (chan = 0; chan < s->channels; chan++)
 195         for (i = 0; i < nblock; i++)
 196             s->offset[chan][i] = mean;
 197     return 0;
 198 }
 199
 200 static int decode_wave_header(AVCodecContext *avctx, const uint8_t *header,
 201                               int header_size)
 202 {
 203     int len, bps;
 204     short wave_format;
 205     GetByteContext gb;
 206
 207     bytestream2_init(&gb, header, header_size);
 208
 209     if (bytestream2_get_le32(&gb) != MKTAG('R', 'I', 'F', 'F')) {
 210         av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
 211         return AVERROR_INVALIDDATA;
 212     }
 213
 214     bytestream2_skip(&gb, 4); /* chunk size */
 215
 216     if (bytestream2_get_le32(&gb) != MKTAG('W', 'A', 'V', 'E')) {
 217         av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n");
 218         return AVERROR_INVALIDDATA;
 219     }
 220
 221     while (bytestream2_get_le32(&gb) != MKTAG('f', 'm', 't', ' ')) {
 222         len = bytestream2_get_le32(&gb);
 223         bytestream2_skip(&gb, len);
 224         if (len < 0 || bytestream2_get_bytes_left(&gb) < 16) {
 225             av_log(avctx, AV_LOG_ERROR, "no fmt chunk found\n");
 226             return AVERROR_INVALIDDATA;
 227         }
 228     }
 229     len = bytestream2_get_le32(&gb);
 230
 231     if (len < 16) {
 232         av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n");
 233         return AVERROR_INVALIDDATA;
 234     }
 235
 236     wave_format = bytestream2_get_le16(&gb);
 237
 238     switch (wave_format) {
 239     case WAVE_FORMAT_PCM:
 240         break;
 241     default:
 242         av_log(avctx, AV_LOG_ERROR, "unsupported wave format\n");
 243         return AVERROR(ENOSYS);
 244     }
 245
 246     bytestream2_skip(&gb, 2); // skip channels    (already got from shorten header)
 247     avctx->sample_rate = bytestream2_get_le32(&gb);
 248     bytestream2_skip(&gb, 4); // skip bit rate    (represents original uncompressed bit rate)
 249     bytestream2_skip(&gb, 2); // skip block align (not needed)
 250     bps = bytestream2_get_le16(&gb);
 251     avctx->bits_per_coded_sample = bps;
 252
 253     if (bps != 16 && bps != 8) {
 254         av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample: %d\n", bps);
 255         return AVERROR(ENOSYS);
 256     }
 257
 258     len -= 16;
 259     if (len > 0)
 260         av_log(avctx, AV_LOG_INFO, "%d header bytes unparsed\n", len);
 261
 262     return 0;
 263 }
 264
 265 static const int fixed_coeffs[][3] = {
 266     { 0,  0,  0 },
 267     { 1,  0,  0 },
 268     { 2, -1,  0 },
 269     { 3, -3,  1 }
 270 };
 271
 272 static int decode_subframe_lpc(ShortenContext *s, int command, int channel,
 273                                int residual_size, int32_t coffset)
 274 {
 275     int pred_order, sum, qshift, init_sum, i, j;
 276     const int *coeffs;
 277
 278     if (command == FN_QLPC) {
 279         /* read/validate prediction order */
 280         pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
 281         if (pred_order > s->nwrap) {
 282             av_log(s->avctx, AV_LOG_ERROR, "invalid pred_order %d\n",
 283                    pred_order);
 284             return AVERROR(EINVAL);
 285         }
 286         /* read LPC coefficients */
 287         for (i = 0; i < pred_order; i++)
 288             s->coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
 289         coeffs = s->coeffs;
 290
 291         qshift = LPCQUANT;
 292     } else {
 293         /* fixed LPC coeffs */
 294         pred_order = command;
 295         if (pred_order >= FF_ARRAY_ELEMS(fixed_coeffs)) {
 296             av_log(s->avctx, AV_LOG_ERROR, "invalid pred_order %d\n",
 297                    pred_order);
 298             return AVERROR_INVALIDDATA;
 299         }
 300         coeffs     = fixed_coeffs[pred_order];
 301         qshift     = 0;
 302     }
 303
 304     /* subtract offset from previous samples to use in prediction */
 305     if (command == FN_QLPC && coffset)
 306         for (i = -pred_order; i < 0; i++)
 307             s->decoded[channel][i] -= coffset;
 308
 309     /* decode residual and do LPC prediction */
 310     init_sum = pred_order ? (command == FN_QLPC ? s->lpcqoffset : 0) : coffset;
 311     for (i = 0; i < s->blocksize; i++) {
 312         sum = init_sum;
 313         for (j = 0; j < pred_order; j++)
 314             sum += coeffs[j] * s->decoded[channel][i - j - 1];
 315         s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) +
 316                                  (sum >> qshift);
 317     }
 318
 319     /* add offset to current samples */
 320     if (command == FN_QLPC && coffset)
 321         for (i = 0; i < s->blocksize; i++)
 322             s->decoded[channel][i] += coffset;
 323
 324     return 0;
 325 }
 326
 327 static int read_header(ShortenContext *s)
 328 {
 329     int i, ret;
 330     int maxnlpc = 0;
 331     /* shorten signature */
 332     if (get_bits_long(&s->gb, 32) != AV_RB32("ajkg")) {
 333         av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n");
 334         return AVERROR_INVALIDDATA;
 335     }
 336
 337     s->lpcqoffset     = 0;
 338     s->blocksize      = DEFAULT_BLOCK_SIZE;
 339     s->nmean          = -1;
 340     s->version        = get_bits(&s->gb, 8);
 341     s->internal_ftype = get_uint(s, TYPESIZE);
 342
 343     s->channels = get_uint(s, CHANSIZE);
 344     if (!s->channels) {
 345         av_log(s->avctx, AV_LOG_ERROR, "No channels reported\n");
 346         return AVERROR_INVALIDDATA;
 347     }
 348     if (s->channels > MAX_CHANNELS) {
 349         av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels);
 350         s->channels = 0;
 351         return AVERROR_INVALIDDATA;
 352     }
 353     s->avctx->channels = s->channels;
 354
 355     /* get blocksize if version > 0 */
 356     if (s->version > 0) {
 357         int skip_bytes;
 358         unsigned blocksize;
 359
 360         blocksize = get_uint(s, av_log2(DEFAULT_BLOCK_SIZE));
 361         if (!blocksize || blocksize > MAX_BLOCKSIZE) {
 362             av_log(s->avctx, AV_LOG_ERROR,
 363                    "invalid or unsupported block size: %d\n",
 364                    blocksize);
 365             return AVERROR(EINVAL);
 366         }
 367         s->blocksize = blocksize;
 368
 369         maxnlpc  = get_uint(s, LPCQSIZE);
 370         s->nmean = get_uint(s, 0);
 371
 372         skip_bytes = get_uint(s, NSKIPSIZE);
 373         for (i = 0; i < skip_bytes; i++)
 374             skip_bits(&s->gb, 8);
 375     }
 376     s->nwrap = FFMAX(NWRAP, maxnlpc);
 377
 378     if ((ret = allocate_buffers(s)) < 0)
 379         return ret;
 380
 381     if ((ret = init_offset(s)) < 0)
 382         return ret;
 383
 384     if (s->version > 1)
 385         s->lpcqoffset = V2LPCQOFFSET;
 386
 387     if (get_ur_golomb_shorten(&s->gb, FNSIZE) != FN_VERBATIM) {
 388         av_log(s->avctx, AV_LOG_ERROR,
 389                "missing verbatim section at beginning of stream\n");
 390         return AVERROR_INVALIDDATA;
 391     }
 392
 393     s->header_size = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
 394     if (s->header_size >= OUT_BUFFER_SIZE ||
 395         s->header_size < CANONICAL_HEADER_SIZE) {
 396         av_log(s->avctx, AV_LOG_ERROR, "header is wrong size: %d\n",
 397                s->header_size);
 398         return AVERROR_INVALIDDATA;
 399     }
 400
 401     for (i = 0; i < s->header_size; i++)
 402         s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
 403
 404     if ((ret = decode_wave_header(s->avctx, s->header, s->header_size)) < 0)
 405         return ret;
 406
 407     s->cur_chan = 0;
 408     s->bitshift = 0;
 409
 410     s->got_header = 1;
 411
 412     return 0;
 413 }
 414
 415 static int shorten_decode_frame(AVCodecContext *avctx, void *data,
 416                                 int *got_frame_ptr, AVPacket *avpkt)
 417 {
 418     AVFrame *frame     = data;
 419     const uint8_t *buf = avpkt->data;
 420     int buf_size       = avpkt->size;
 421     ShortenContext *s  = avctx->priv_data;
 422     int i, input_buf_size = 0;
 423     int ret;
 424
 425     /* allocate internal bitstream buffer */
 426     if (s->max_framesize == 0) {
 427         void *tmp_ptr;
 428         s->max_framesize = 8192; // should hopefully be enough for the first header
 429         tmp_ptr = av_fast_realloc(s->bitstream, &s->allocated_bitstream_size,
 430                                   s->max_framesize + FF_INPUT_BUFFER_PADDING_SIZE);
 431         if (!tmp_ptr) {
 432             av_log(avctx, AV_LOG_ERROR, "error allocating bitstream buffer\n");
 433             return AVERROR(ENOMEM);
 434         }
 435         memset(tmp_ptr, 0, s->allocated_bitstream_size);
 436         s->bitstream = tmp_ptr;
 437     }
 438
 439     /* append current packet data to bitstream buffer */
 440     if (1 && s->max_framesize) { //FIXME truncated
 441         buf_size       = FFMIN(buf_size, s->max_framesize - s->bitstream_size);
 442         input_buf_size = buf_size;
 443
 444         if (s->bitstream_index + s->bitstream_size + buf_size + FF_INPUT_BUFFER_PADDING_SIZE >
 445             s->allocated_bitstream_size) {
 446             memmove(s->bitstream, &s->bitstream[s->bitstream_index],
 447                     s->bitstream_size);
 448             s->bitstream_index = 0;
 449         }
 450         if (buf)
 451             memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf,
 452                    buf_size);
 453         buf               = &s->bitstream[s->bitstream_index];
 454         buf_size         += s->bitstream_size;
 455         s->bitstream_size = buf_size;
 456
 457         /* do not decode until buffer has at least max_framesize bytes or
 458          * the end of the file has been reached */
 459         if (buf_size < s->max_framesize && avpkt->data) {
 460             *got_frame_ptr = 0;
 461             return input_buf_size;
 462         }
 463     }
 464     /* init and position bitstream reader */
 465     init_get_bits(&s->gb, buf, buf_size * 8);
 466     skip_bits(&s->gb, s->bitindex);
 467
 468     /* process header or next subblock */
 469     if (!s->got_header) {
 470         if ((ret = read_header(s)) < 0)
 471             return ret;
 472         *got_frame_ptr = 0;
 473         goto finish_frame;
 474     }
 475
 476     /* if quit command was read previously, don't decode anything */
 477     if (s->got_quit_command) {
 478         *got_frame_ptr = 0;
 479         return avpkt->size;
 480     }
 481
 482     s->cur_chan = 0;
 483     while (s->cur_chan < s->channels) {
 484         unsigned cmd;
 485         int len;
 486
 487         if (get_bits_left(&s->gb) < 3 + FNSIZE) {
 488             *got_frame_ptr = 0;
 489             break;
 490         }
 491
 492         cmd = get_ur_golomb_shorten(&s->gb, FNSIZE);
 493
 494         if (cmd > FN_VERBATIM) {
 495             av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd);
 496             *got_frame_ptr = 0;
 497             break;
 498         }
 499
 500         if (!is_audio_command[cmd]) {
 501             /* process non-audio command */
 502             switch (cmd) {
 503             case FN_VERBATIM:
 504                 len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
 505                 while (len--)
 506                     get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
 507                 break;
 508             case FN_BITSHIFT: {
 509                 unsigned bitshift = get_ur_golomb_shorten(&s->gb, BITSHIFTSIZE);
 510                 if (bitshift > 31) {
 511                     av_log(avctx, AV_LOG_ERROR, "bitshift %d is invalid\n",
 512                            bitshift);
 513                     return AVERROR_PATCHWELCOME;
 514                 }
 515                 s->bitshift = bitshift;
 516                 break;
 517             }
 518             case FN_BLOCKSIZE: {
 519                 unsigned blocksize = get_uint(s, av_log2(s->blocksize));
 520                 if (blocksize > s->blocksize) {
 521                     av_log(avctx, AV_LOG_ERROR,
 522                            "Increasing block size is not supported\n");
 523                     return AVERROR_PATCHWELCOME;
 524                 }
 525                 if (!blocksize || blocksize > MAX_BLOCKSIZE) {
 526                     av_log(avctx, AV_LOG_ERROR, "invalid or unsupported "
 527                                                 "block size: %d\n", blocksize);
 528                     return AVERROR(EINVAL);
 529                 }
 530                 s->blocksize = blocksize;
 531                 break;
 532             }
 533             case FN_QUIT:
 534                 s->got_quit_command = 1;
 535                 break;
 536             }
 537             if (cmd == FN_BLOCKSIZE || cmd == FN_QUIT) {
 538                 *got_frame_ptr = 0;
 539                 break;
 540             }
 541         } else {
 542             /* process audio command */
 543             int residual_size = 0;
 544             int channel = s->cur_chan;
 545             int32_t coffset;
 546
 547             /* get Rice code for residual decoding */
 548             if (cmd != FN_ZERO) {
 549                 residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE);
 550                 /* This is a hack as version 0 differed in the definition
 551                  * of get_sr_golomb_shorten(). */
 552                 if (s->version == 0)
 553                     residual_size--;
 554             }
 555
 556             /* calculate sample offset using means from previous blocks */
 557             if (s->nmean == 0)
 558                 coffset = s->offset[channel][0];
 559             else {
 560                 int32_t sum = (s->version < 2) ? 0 : s->nmean / 2;
 561                 for (i = 0; i < s->nmean; i++)
 562                     sum += s->offset[channel][i];
 563                 coffset = sum / s->nmean;
 564                 if (s->version >= 2)
 565                     coffset = s->bitshift == 0 ? coffset : coffset >> s->bitshift - 1 >> 1;
 566             }
 567
 568             /* decode samples for this channel */
 569             if (cmd == FN_ZERO) {
 570                 for (i = 0; i < s->blocksize; i++)
 571                     s->decoded[channel][i] = 0;
 572             } else {
 573                 if ((ret = decode_subframe_lpc(s, cmd, channel,
 574                                                residual_size, coffset)) < 0)
 575                     return ret;
 576             }
 577
 578             /* update means with info from the current block */
 579             if (s->nmean > 0) {
 580                 int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
 581                 for (i = 0; i < s->blocksize; i++)
 582                     sum += s->decoded[channel][i];
 583
 584                 for (i = 1; i < s->nmean; i++)
 585                     s->offset[channel][i - 1] = s->offset[channel][i];
 586
 587                 if (s->version < 2)
 588                     s->offset[channel][s->nmean - 1] = sum / s->blocksize;
 589                 else
 590                     s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift;
 591             }
 592
 593             /* copy wrap samples for use with next block */
 594             for (i = -s->nwrap; i < 0; i++)
 595                 s->decoded[channel][i] = s->decoded[channel][i + s->blocksize];
 596
 597             /* shift samples to add in unused zero bits which were removed
 598              * during encoding */
 599             fix_bitshift(s, s->decoded[channel]);
 600
 601             /* if this is the last channel in the block, output the samples */
 602             s->cur_chan++;
 603             if (s->cur_chan == s->channels) {
 604                 uint8_t *samples_u8;
 605                 int16_t *samples_s16;
 606                 int chan;
 607
 608                 /* get output buffer */
 609                 frame->nb_samples = s->blocksize;
 610                 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
 611                     return ret;
 612
 613                 for (chan = 0; chan < s->channels; chan++) {
 614                     samples_u8  = ((uint8_t **)frame->extended_data)[chan];
 615                     samples_s16 = ((int16_t **)frame->extended_data)[chan];
 616                     for (i = 0; i < s->blocksize; i++) {
 617                         switch (s->internal_ftype) {
 618                         case TYPE_U8:
 619                             *samples_u8++ = av_clip_uint8(s->decoded[chan][i]);
 620                             break;
 621                         case TYPE_S16HL:
 622                         case TYPE_S16LH:
 623                             *samples_s16++ = av_clip_int16(s->decoded[chan][i]);
 624                             break;
 625                         }
 626                     }
 627                 }
 628
 629                 *got_frame_ptr = 1;
 630             }
 631         }
 632     }
 633     if (s->cur_chan < s->channels)
 634         *got_frame_ptr = 0;
 635
 636 finish_frame:
 637     s->bitindex = get_bits_count(&s->gb) - 8 * (get_bits_count(&s->gb) / 8);
 638     i           = get_bits_count(&s->gb) / 8;
 639     if (i > buf_size) {
 640         av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
 641         s->bitstream_size  = 0;
 642         s->bitstream_index = 0;
 643         return AVERROR_INVALIDDATA;
 644     }
 645     if (s->bitstream_size) {
 646         s->bitstream_index += i;
 647         s->bitstream_size  -= i;
 648         return input_buf_size;
 649     } else
 650         return i;
 651 }
 652
 653 static av_cold int shorten_decode_close(AVCodecContext *avctx)
 654 {
 655     ShortenContext *s = avctx->priv_data;
 656     int i;
 657
 658     for (i = 0; i < s->channels; i++) {
 659         s->decoded[i] = NULL;
 660         av_freep(&s->decoded_base[i]);
 661         av_freep(&s->offset[i]);
 662     }
 663     av_freep(&s->bitstream);
 664     av_freep(&s->coeffs);
 665
 666     return 0;
 667 }
 668
 669 AVCodec ff_shorten_decoder = {
 670     .name           = "shorten",
 671     .long_name      = NULL_IF_CONFIG_SMALL("Shorten"),
 672     .type           = AVMEDIA_TYPE_AUDIO,
 673     .id             = AV_CODEC_ID_SHORTEN,
 674     .priv_data_size = sizeof(ShortenContext),
 675     .init           = shorten_decode_init,
 676     .close          = shorten_decode_close,
 677     .decode         = shorten_decode_frame,
 678     .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
 679     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
 680                                                       AV_SAMPLE_FMT_U8P,
 681                                                       AV_SAMPLE_FMT_NONE },
 682 };