ffmpeg/libavcodec/ralf.c

   1 /*
   2  * RealAudio Lossless decoder
   3  *
   4  * Copyright (c) 2012 Konstantin Shishkov
   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 /**
  24  * @file
  25  * This is a decoder for Real Audio Lossless format.
  26  * Dedicated to the mastermind behind it, Ralph Wiggum.
  27  */
  28
  29 #include "libavutil/attributes.h"
  30 #include "libavutil/channel_layout.h"
  31 #include "avcodec.h"
  32 #include "get_bits.h"
  33 #include "golomb.h"
  34 #include "internal.h"
  35 #include "unary.h"
  36 #include "ralfdata.h"
  37
  38 #define FILTER_NONE 0
  39 #define FILTER_RAW  642
  40
  41 typedef struct VLCSet {
  42     VLC filter_params;
  43     VLC bias;
  44     VLC coding_mode;
  45     VLC filter_coeffs[10][11];
  46     VLC short_codes[15];
  47     VLC long_codes[125];
  48 } VLCSet;
  49
  50 #define RALF_MAX_PKT_SIZE 8192
  51
  52 typedef struct RALFContext {
  53     int version;
  54     int max_frame_size;
  55     VLCSet sets[3];
  56     int32_t channel_data[2][4096];
  57
  58     int     filter_params;   ///< combined filter parameters for the current channel data
  59     int     filter_length;   ///< length of the filter for the current channel data
  60     int     filter_bits;     ///< filter precision for the current channel data
  61     int32_t filter[64];
  62
  63     int     bias[2];         ///< a constant value added to channel data after filtering
  64
  65     int num_blocks;          ///< number of blocks inside the frame
  66     int sample_offset;
  67     int block_size[1 << 12]; ///< size of the blocks
  68     int block_pts[1 << 12];  ///< block start time (in milliseconds)
  69
  70     uint8_t pkt[16384];
  71     int     has_pkt;
  72 } RALFContext;
  73
  74 #define MAX_ELEMS 644 // no RALF table uses more than that
  75
  76 static av_cold int init_ralf_vlc(VLC *vlc, const uint8_t *data, int elems)
  77 {
  78     uint8_t  lens[MAX_ELEMS];
  79     uint16_t codes[MAX_ELEMS];
  80     int counts[17], prefixes[18];
  81     int i, cur_len;
  82     int max_bits = 0;
  83     int nb = 0;
  84
  85     for (i = 0; i <= 16; i++)
  86         counts[i] = 0;
  87     for (i = 0; i < elems; i++) {
  88         cur_len  = (nb ? *data & 0xF : *data >> 4) + 1;
  89         counts[cur_len]++;
  90         max_bits = FFMAX(max_bits, cur_len);
  91         lens[i]  = cur_len;
  92         data    += nb;
  93         nb      ^= 1;
  94     }
  95     prefixes[1] = 0;
  96     for (i = 1; i <= 16; i++)
  97         prefixes[i + 1] = (prefixes[i] + counts[i]) << 1;
  98
  99     for (i = 0; i < elems; i++)
 100         codes[i] = prefixes[lens[i]]++;
 101
 102     return ff_init_vlc_sparse(vlc, FFMIN(max_bits, 9), elems,
 103                               lens, 1, 1, codes, 2, 2, NULL, 0, 0, 0);
 104 }
 105
 106 static av_cold int decode_close(AVCodecContext *avctx)
 107 {
 108     RALFContext *ctx = avctx->priv_data;
 109     int i, j, k;
 110
 111     for (i = 0; i < 3; i++) {
 112         ff_free_vlc(&ctx->sets[i].filter_params);
 113         ff_free_vlc(&ctx->sets[i].bias);
 114         ff_free_vlc(&ctx->sets[i].coding_mode);
 115         for (j = 0; j < 10; j++)
 116             for (k = 0; k < 11; k++)
 117                 ff_free_vlc(&ctx->sets[i].filter_coeffs[j][k]);
 118         for (j = 0; j < 15; j++)
 119             ff_free_vlc(&ctx->sets[i].short_codes[j]);
 120         for (j = 0; j < 125; j++)
 121             ff_free_vlc(&ctx->sets[i].long_codes[j]);
 122     }
 123
 124     return 0;
 125 }
 126
 127 static av_cold int decode_init(AVCodecContext *avctx)
 128 {
 129     RALFContext *ctx = avctx->priv_data;
 130     int i, j, k;
 131     int ret;
 132
 133     if (avctx->extradata_size < 24 || memcmp(avctx->extradata, "LSD:", 4)) {
 134         av_log(avctx, AV_LOG_ERROR, "Extradata is not groovy, dude\n");
 135         return AVERROR_INVALIDDATA;
 136     }
 137
 138     ctx->version = AV_RB16(avctx->extradata + 4);
 139     if (ctx->version != 0x103) {
 140         avpriv_request_sample(avctx, "Unknown version %X", ctx->version);
 141         return AVERROR_PATCHWELCOME;
 142     }
 143
 144     avctx->channels    = AV_RB16(avctx->extradata + 8);
 145     avctx->sample_rate = AV_RB32(avctx->extradata + 12);
 146     if (avctx->channels < 1 || avctx->channels > 2
 147         || avctx->sample_rate < 8000 || avctx->sample_rate > 96000) {
 148         av_log(avctx, AV_LOG_ERROR, "Invalid coding parameters %d Hz %d ch\n",
 149                avctx->sample_rate, avctx->channels);
 150         return AVERROR_INVALIDDATA;
 151     }
 152     avctx->sample_fmt     = AV_SAMPLE_FMT_S16P;
 153     avctx->channel_layout = (avctx->channels == 2) ? AV_CH_LAYOUT_STEREO
 154                                                    : AV_CH_LAYOUT_MONO;
 155
 156     ctx->max_frame_size = AV_RB32(avctx->extradata + 16);
 157     if (ctx->max_frame_size > (1 << 20) || !ctx->max_frame_size) {
 158         av_log(avctx, AV_LOG_ERROR, "invalid frame size %d\n",
 159                ctx->max_frame_size);
 160     }
 161     ctx->max_frame_size = FFMAX(ctx->max_frame_size, avctx->sample_rate);
 162
 163     for (i = 0; i < 3; i++) {
 164         ret = init_ralf_vlc(&ctx->sets[i].filter_params, filter_param_def[i],
 165                             FILTERPARAM_ELEMENTS);
 166         if (ret < 0) {
 167             decode_close(avctx);
 168             return ret;
 169         }
 170         ret = init_ralf_vlc(&ctx->sets[i].bias, bias_def[i], BIAS_ELEMENTS);
 171         if (ret < 0) {
 172             decode_close(avctx);
 173             return ret;
 174         }
 175         ret = init_ralf_vlc(&ctx->sets[i].coding_mode, coding_mode_def[i],
 176                             CODING_MODE_ELEMENTS);
 177         if (ret < 0) {
 178             decode_close(avctx);
 179             return ret;
 180         }
 181         for (j = 0; j < 10; j++) {
 182             for (k = 0; k < 11; k++) {
 183                 ret = init_ralf_vlc(&ctx->sets[i].filter_coeffs[j][k],
 184                                     filter_coeffs_def[i][j][k],
 185                                     FILTER_COEFFS_ELEMENTS);
 186                 if (ret < 0) {
 187                     decode_close(avctx);
 188                     return ret;
 189                 }
 190             }
 191         }
 192         for (j = 0; j < 15; j++) {
 193             ret = init_ralf_vlc(&ctx->sets[i].short_codes[j],
 194                                 short_codes_def[i][j], SHORT_CODES_ELEMENTS);
 195             if (ret < 0) {
 196                 decode_close(avctx);
 197                 return ret;
 198             }
 199         }
 200         for (j = 0; j < 125; j++) {
 201             ret = init_ralf_vlc(&ctx->sets[i].long_codes[j],
 202                                 long_codes_def[i][j], LONG_CODES_ELEMENTS);
 203             if (ret < 0) {
 204                 decode_close(avctx);
 205                 return ret;
 206             }
 207         }
 208     }
 209
 210     return 0;
 211 }
 212
 213 static inline int extend_code(GetBitContext *gb, int val, int range, int bits)
 214 {
 215     if (val == 0) {
 216         val = -range - get_ue_golomb(gb);
 217     } else if (val == range * 2) {
 218         val =  range + get_ue_golomb(gb);
 219     } else {
 220         val -= range;
 221     }
 222     if (bits)
 223         val = (val << bits) | get_bits(gb, bits);
 224     return val;
 225 }
 226
 227 static int decode_channel(RALFContext *ctx, GetBitContext *gb, int ch,
 228                           int length, int mode, int bits)
 229 {
 230     int i, t;
 231     int code_params;
 232     VLCSet *set = ctx->sets + mode;
 233     VLC *code_vlc; int range, range2, add_bits;
 234     int *dst = ctx->channel_data[ch];
 235
 236     ctx->filter_params = get_vlc2(gb, set->filter_params.table, 9, 2);
 237     ctx->filter_bits   = (ctx->filter_params - 2) >> 6;
 238     ctx->filter_length = ctx->filter_params - (ctx->filter_bits << 6) - 1;
 239
 240     if (ctx->filter_params == FILTER_RAW) {
 241         for (i = 0; i < length; i++)
 242             dst[i] = get_bits(gb, bits);
 243         ctx->bias[ch] = 0;
 244         return 0;
 245     }
 246
 247     ctx->bias[ch] = get_vlc2(gb, set->bias.table, 9, 2);
 248     ctx->bias[ch] = extend_code(gb, ctx->bias[ch], 127, 4);
 249
 250     if (ctx->filter_params == FILTER_NONE) {
 251         memset(dst, 0, sizeof(*dst) * length);
 252         return 0;
 253     }
 254
 255     if (ctx->filter_params > 1) {
 256         int cmode = 0, coeff = 0;
 257         VLC *vlc = set->filter_coeffs[ctx->filter_bits] + 5;
 258
 259         add_bits = ctx->filter_bits;
 260
 261         for (i = 0; i < ctx->filter_length; i++) {
 262             t = get_vlc2(gb, vlc[cmode].table, vlc[cmode].bits, 2);
 263             t = extend_code(gb, t, 21, add_bits);
 264             if (!cmode)
 265                 coeff -= 12 << add_bits;
 266             coeff = t - coeff;
 267             ctx->filter[i] = coeff;
 268
 269             cmode = coeff >> add_bits;
 270             if (cmode < 0) {
 271                 cmode = -1 - av_log2(-cmode);
 272                 if (cmode < -5)
 273                     cmode = -5;
 274             } else if (cmode > 0) {
 275                 cmode =  1 + av_log2(cmode);
 276                 if (cmode > 5)
 277                     cmode = 5;
 278             }
 279         }
 280     }
 281
 282     code_params = get_vlc2(gb, set->coding_mode.table, set->coding_mode.bits, 2);
 283     if (code_params >= 15) {
 284         add_bits = av_clip((code_params / 5 - 3) / 2, 0, 10);
 285         if (add_bits > 9 && (code_params % 5) != 2)
 286             add_bits--;
 287         range    = 10;
 288         range2   = 21;
 289         code_vlc = set->long_codes + code_params - 15;
 290     } else {
 291         add_bits = 0;
 292         range    = 6;
 293         range2   = 13;
 294         code_vlc = set->short_codes + code_params;
 295     }
 296
 297     for (i = 0; i < length; i += 2) {
 298         int code1, code2;
 299
 300         t = get_vlc2(gb, code_vlc->table, code_vlc->bits, 2);
 301         code1 = t / range2;
 302         code2 = t % range2;
 303         dst[i]     = extend_code(gb, code1, range, 0) << add_bits;
 304         dst[i + 1] = extend_code(gb, code2, range, 0) << add_bits;
 305         if (add_bits) {
 306             dst[i]     |= get_bits(gb, add_bits);
 307             dst[i + 1] |= get_bits(gb, add_bits);
 308         }
 309     }
 310
 311     return 0;
 312 }
 313
 314 static void apply_lpc(RALFContext *ctx, int ch, int length, int bits)
 315 {
 316     int i, j, acc;
 317     int *audio = ctx->channel_data[ch];
 318     int bias = 1 << (ctx->filter_bits - 1);
 319     int max_clip = (1 << bits) - 1, min_clip = -max_clip - 1;
 320
 321     for (i = 1; i < length; i++) {
 322         int flen = FFMIN(ctx->filter_length, i);
 323
 324         acc = 0;
 325         for (j = 0; j < flen; j++)
 326             acc += ctx->filter[j] * audio[i - j - 1];
 327         if (acc < 0) {
 328             acc = (acc + bias - 1) >> ctx->filter_bits;
 329             acc = FFMAX(acc, min_clip);
 330         } else {
 331             acc = (acc + bias) >> ctx->filter_bits;
 332             acc = FFMIN(acc, max_clip);
 333         }
 334         audio[i] += acc;
 335     }
 336 }
 337
 338 static int decode_block(AVCodecContext *avctx, GetBitContext *gb,
 339                         int16_t *dst0, int16_t *dst1)
 340 {
 341     RALFContext *ctx = avctx->priv_data;
 342     int len, ch, ret;
 343     int dmode, mode[2], bits[2];
 344     int *ch0, *ch1;
 345     int i, t, t2;
 346
 347     len = 12 - get_unary(gb, 0, 6);
 348
 349     if (len <= 7) len ^= 1; // codes for length = 6 and 7 are swapped
 350     len = 1 << len;
 351
 352     if (ctx->sample_offset + len > ctx->max_frame_size) {
 353         av_log(avctx, AV_LOG_ERROR,
 354                "Decoder's stomach is crying, it ate too many samples\n");
 355         return AVERROR_INVALIDDATA;
 356     }
 357
 358     if (avctx->channels > 1)
 359         dmode = get_bits(gb, 2) + 1;
 360     else
 361         dmode = 0;
 362
 363     mode[0] = (dmode == 4) ? 1 : 0;
 364     mode[1] = (dmode >= 2) ? 2 : 0;
 365     bits[0] = 16;
 366     bits[1] = (mode[1] == 2) ? 17 : 16;
 367
 368     for (ch = 0; ch < avctx->channels; ch++) {
 369         if ((ret = decode_channel(ctx, gb, ch, len, mode[ch], bits[ch])) < 0)
 370             return ret;
 371         if (ctx->filter_params > 1 && ctx->filter_params != FILTER_RAW) {
 372             ctx->filter_bits += 3;
 373             apply_lpc(ctx, ch, len, bits[ch]);
 374         }
 375         if (get_bits_left(gb) < 0)
 376             return AVERROR_INVALIDDATA;
 377     }
 378     ch0 = ctx->channel_data[0];
 379     ch1 = ctx->channel_data[1];
 380     switch (dmode) {
 381     case 0:
 382         for (i = 0; i < len; i++)
 383             dst0[i] = ch0[i] + ctx->bias[0];
 384         break;
 385     case 1:
 386         for (i = 0; i < len; i++) {
 387             dst0[i] = ch0[i] + ctx->bias[0];
 388             dst1[i] = ch1[i] + ctx->bias[1];
 389         }
 390         break;
 391     case 2:
 392         for (i = 0; i < len; i++) {
 393             ch0[i] += ctx->bias[0];
 394             dst0[i] = ch0[i];
 395             dst1[i] = ch0[i] - (ch1[i] + ctx->bias[1]);
 396         }
 397         break;
 398     case 3:
 399         for (i = 0; i < len; i++) {
 400             t  = ch0[i] + ctx->bias[0];
 401             t2 = ch1[i] + ctx->bias[1];
 402             dst0[i] = t + t2;
 403             dst1[i] = t;
 404         }
 405         break;
 406     case 4:
 407         for (i = 0; i < len; i++) {
 408             t  =   ch1[i] + ctx->bias[1];
 409             t2 = ((ch0[i] + ctx->bias[0]) << 1) | (t & 1);
 410             dst0[i] = (t2 + t) / 2;
 411             dst1[i] = (t2 - t) / 2;
 412         }
 413         break;
 414     }
 415
 416     ctx->sample_offset += len;
 417
 418     return 0;
 419 }
 420
 421 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,
 422                         AVPacket *avpkt)
 423 {
 424     RALFContext *ctx = avctx->priv_data;
 425     AVFrame *frame   = data;
 426     int16_t *samples0;
 427     int16_t *samples1;
 428     int ret;
 429     GetBitContext gb;
 430     int table_size, table_bytes, i;
 431     const uint8_t *src, *block_pointer;
 432     int src_size;
 433     int bytes_left;
 434
 435     if (ctx->has_pkt) {
 436         ctx->has_pkt = 0;
 437         table_bytes = (AV_RB16(avpkt->data) + 7) >> 3;
 438         if (table_bytes + 3 > avpkt->size || avpkt->size > RALF_MAX_PKT_SIZE) {
 439             av_log(avctx, AV_LOG_ERROR, "Wrong packet's breath smells of wrong data!\n");
 440             return AVERROR_INVALIDDATA;
 441         }
 442         if (memcmp(ctx->pkt, avpkt->data, 2 + table_bytes)) {
 443             av_log(avctx, AV_LOG_ERROR, "Wrong packet tails are wrong!\n");
 444             return AVERROR_INVALIDDATA;
 445         }
 446
 447         src      = ctx->pkt;
 448         src_size = RALF_MAX_PKT_SIZE + avpkt->size;
 449         memcpy(ctx->pkt + RALF_MAX_PKT_SIZE, avpkt->data + 2 + table_bytes,
 450                avpkt->size - 2 - table_bytes);
 451     } else {
 452         if (avpkt->size == RALF_MAX_PKT_SIZE) {
 453             memcpy(ctx->pkt, avpkt->data, avpkt->size);
 454             ctx->has_pkt   = 1;
 455             *got_frame_ptr = 0;
 456
 457             return avpkt->size;
 458         }
 459         src      = avpkt->data;
 460         src_size = avpkt->size;
 461     }
 462
 463     frame->nb_samples = ctx->max_frame_size;
 464     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
 465         return ret;
 466     samples0 = (int16_t *)frame->data[0];
 467     samples1 = (int16_t *)frame->data[1];
 468
 469     if (src_size < 5) {
 470         av_log(avctx, AV_LOG_ERROR, "too short packets are too short!\n");
 471         return AVERROR_INVALIDDATA;
 472     }
 473     table_size  = AV_RB16(src);
 474     table_bytes = (table_size + 7) >> 3;
 475     if (src_size < table_bytes + 3) {
 476         av_log(avctx, AV_LOG_ERROR, "short packets are short!\n");
 477         return AVERROR_INVALIDDATA;
 478     }
 479     init_get_bits(&gb, src + 2, table_size);
 480     ctx->num_blocks = 0;
 481     while (get_bits_left(&gb) > 0) {
 482         ctx->block_size[ctx->num_blocks] = get_bits(&gb, 15);
 483         if (get_bits1(&gb)) {
 484             ctx->block_pts[ctx->num_blocks] = get_bits(&gb, 9);
 485         } else {
 486             ctx->block_pts[ctx->num_blocks] = 0;
 487         }
 488         ctx->num_blocks++;
 489     }
 490
 491     block_pointer = src      + table_bytes + 2;
 492     bytes_left    = src_size - table_bytes - 2;
 493     ctx->sample_offset = 0;
 494     for (i = 0; i < ctx->num_blocks; i++) {
 495         if (bytes_left < ctx->block_size[i]) {
 496             av_log(avctx, AV_LOG_ERROR, "I'm pedaling backwards\n");
 497             break;
 498         }
 499         init_get_bits(&gb, block_pointer, ctx->block_size[i] * 8);
 500         if (decode_block(avctx, &gb, samples0 + ctx->sample_offset,
 501                                      samples1 + ctx->sample_offset) < 0) {
 502             av_log(avctx, AV_LOG_ERROR, "Sir, I got carsick in your office. Not decoding the rest of packet.\n");
 503             break;
 504         }
 505         block_pointer += ctx->block_size[i];
 506         bytes_left    -= ctx->block_size[i];
 507     }
 508
 509     frame->nb_samples = ctx->sample_offset;
 510     *got_frame_ptr    = ctx->sample_offset > 0;
 511
 512     return avpkt->size;
 513 }
 514
 515 static void decode_flush(AVCodecContext *avctx)
 516 {
 517     RALFContext *ctx = avctx->priv_data;
 518
 519     ctx->has_pkt = 0;
 520 }
 521
 522
 523 AVCodec ff_ralf_decoder = {
 524     .name           = "ralf",
 525     .long_name      = NULL_IF_CONFIG_SMALL("RealAudio Lossless"),
 526     .type           = AVMEDIA_TYPE_AUDIO,
 527     .id             = AV_CODEC_ID_RALF,
 528     .priv_data_size = sizeof(RALFContext),
 529     .init           = decode_init,
 530     .close          = decode_close,
 531     .decode         = decode_frame,
 532     .flush          = decode_flush,
 533     .capabilities   = CODEC_CAP_DR1,
 534     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
 535                                                       AV_SAMPLE_FMT_NONE },
 536 };