libavformat/nutdec.c

   1 /*
   2  * "NUT" Container Format demuxer
   3  * Copyright (c) 2004-2006 Michael Niedermayer
   4  * Copyright (c) 2003 Alex Beregszaszi
   5  *
   6  * This file is part of Libav.
   7  *
   8  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include "libavutil/avstring.h"
  24 #include "libavutil/bswap.h"
  25 #include "libavutil/dict.h"
  26 #include "libavutil/mathematics.h"
  27 #include "libavutil/tree.h"
  28 #include "avio_internal.h"
  29 #include "nut.h"
  30 #include "riff.h"
  31
  32 #undef NDEBUG
  33 #include <assert.h>
  34
  35 #define NUT_MAX_STREAMS 256    /* arbitrary sanity check value */
  36
  37 static int get_str(AVIOContext *bc, char *string, unsigned int maxlen)
  38 {
  39     unsigned int len = ffio_read_varlen(bc);
  40
  41     if (len && maxlen)
  42         avio_read(bc, string, FFMIN(len, maxlen));
  43     while (len > maxlen) {
  44         avio_r8(bc);
  45         len--;
  46     }
  47
  48     if (maxlen)
  49         string[FFMIN(len, maxlen - 1)] = 0;
  50
  51     if (maxlen == len)
  52         return -1;
  53     else
  54         return 0;
  55 }
  56
  57 static int64_t get_s(AVIOContext *bc)
  58 {
  59     int64_t v = ffio_read_varlen(bc) + 1;
  60
  61     if (v & 1)
  62         return -(v >> 1);
  63     else
  64         return  (v >> 1);
  65 }
  66
  67 static uint64_t get_fourcc(AVIOContext *bc)
  68 {
  69     unsigned int len = ffio_read_varlen(bc);
  70
  71     if (len == 2)
  72         return avio_rl16(bc);
  73     else if (len == 4)
  74         return avio_rl32(bc);
  75     else
  76         return -1;
  77 }
  78
  79 #ifdef TRACE
  80 static inline uint64_t get_v_trace(AVIOContext *bc, const char *file,
  81                                    const char *func, int line)
  82 {
  83     uint64_t v = ffio_read_varlen(bc);
  84
  85     av_log(NULL, AV_LOG_DEBUG, "get_v %5"PRId64" / %"PRIX64" in %s %s:%d\n",
  86            v, v, file, func, line);
  87     return v;
  88 }
  89
  90 static inline int64_t get_s_trace(AVIOContext *bc, const char *file,
  91                                   const char *func, int line)
  92 {
  93     int64_t v = get_s(bc);
  94
  95     av_log(NULL, AV_LOG_DEBUG, "get_s %5"PRId64" / %"PRIX64" in %s %s:%d\n",
  96            v, v, file, func, line);
  97     return v;
  98 }
  99
 100 #define ffio_read_varlen(bc) get_v_trace(bc,  __FILE__, __PRETTY_FUNCTION__, __LINE__)
 101 #define get_s(bc)            get_s_trace(bc,  __FILE__, __PRETTY_FUNCTION__, __LINE__)
 102 #endif
 103
 104 static int get_packetheader(NUTContext *nut, AVIOContext *bc,
 105                             int calculate_checksum, uint64_t startcode)
 106 {
 107     int64_t size;
 108 //    start = avio_tell(bc) - 8;
 109
 110     startcode = av_be2ne64(startcode);
 111     startcode = ff_crc04C11DB7_update(0, (uint8_t*) &startcode, 8);
 112
 113     ffio_init_checksum(bc, ff_crc04C11DB7_update, startcode);
 114     size = ffio_read_varlen(bc);
 115     if (size > 4096)
 116         avio_rb32(bc);
 117     if (ffio_get_checksum(bc) && size > 4096)
 118         return -1;
 119
 120     ffio_init_checksum(bc, calculate_checksum ? ff_crc04C11DB7_update : NULL, 0);
 121
 122     return size;
 123 }
 124
 125 static uint64_t find_any_startcode(AVIOContext *bc, int64_t pos)
 126 {
 127     uint64_t state = 0;
 128
 129     if (pos >= 0)
 130         /* Note, this may fail if the stream is not seekable, but that should
 131          * not matter, as in this case we simply start where we currently are */
 132         avio_seek(bc, pos, SEEK_SET);
 133     while (!bc->eof_reached) {
 134         state = (state << 8) | avio_r8(bc);
 135         if ((state >> 56) != 'N')
 136             continue;
 137         switch (state) {
 138         case MAIN_STARTCODE:
 139         case STREAM_STARTCODE:
 140         case SYNCPOINT_STARTCODE:
 141         case INFO_STARTCODE:
 142         case INDEX_STARTCODE:
 143             return state;
 144         }
 145     }
 146
 147     return 0;
 148 }
 149
 150 /**
 151  * Find the given startcode.
 152  * @param code the startcode
 153  * @param pos the start position of the search, or -1 if the current position
 154  * @return the position of the startcode or -1 if not found
 155  */
 156 static int64_t find_startcode(AVIOContext *bc, uint64_t code, int64_t pos)
 157 {
 158     for (;;) {
 159         uint64_t startcode = find_any_startcode(bc, pos);
 160         if (startcode == code)
 161             return avio_tell(bc) - 8;
 162         else if (startcode == 0)
 163             return -1;
 164         pos = -1;
 165     }
 166 }
 167
 168 static int nut_probe(AVProbeData *p)
 169 {
 170     int i;
 171     uint64_t code = 0;
 172
 173     for (i = 0; i < p->buf_size; i++) {
 174         code = (code << 8) | p->buf[i];
 175         if (code == MAIN_STARTCODE)
 176             return AVPROBE_SCORE_MAX;
 177     }
 178     return 0;
 179 }
 180
 181 #define GET_V(dst, check)                                                     \
 182     do {                                                                      \
 183         tmp = ffio_read_varlen(bc);                                           \
 184         if (!(check)) {                                                       \
 185             av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp);  \
 186             return -1;                                                        \
 187         }                                                                     \
 188         dst = tmp;                                                            \
 189     } while (0)
 190
 191 static int skip_reserved(AVIOContext *bc, int64_t pos)
 192 {
 193     pos -= avio_tell(bc);
 194     if (pos < 0) {
 195         avio_seek(bc, pos, SEEK_CUR);
 196         return -1;
 197     } else {
 198         while (pos--)
 199             avio_r8(bc);
 200         return 0;
 201     }
 202 }
 203
 204 static int decode_main_header(NUTContext *nut)
 205 {
 206     AVFormatContext *s = nut->avf;
 207     AVIOContext *bc    = s->pb;
 208     uint64_t tmp, end;
 209     unsigned int stream_count;
 210     int i, j, count;
 211     int tmp_stream, tmp_mul, tmp_pts, tmp_size, tmp_res, tmp_head_idx;
 212
 213     end  = get_packetheader(nut, bc, 1, MAIN_STARTCODE);
 214     end += avio_tell(bc);
 215
 216     GET_V(tmp, tmp >= 2 && tmp <= 3);
 217     GET_V(stream_count, tmp > 0 && tmp <= NUT_MAX_STREAMS);
 218
 219     nut->max_distance = ffio_read_varlen(bc);
 220     if (nut->max_distance > 65536) {
 221         av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
 222         nut->max_distance = 65536;
 223     }
 224
 225     GET_V(nut->time_base_count, tmp > 0 && tmp < INT_MAX / sizeof(AVRational));
 226     nut->time_base = av_malloc(nut->time_base_count * sizeof(AVRational));
 227
 228     for (i = 0; i < nut->time_base_count; i++) {
 229         GET_V(nut->time_base[i].num, tmp > 0 && tmp < (1ULL << 31));
 230         GET_V(nut->time_base[i].den, tmp > 0 && tmp < (1ULL << 31));
 231         if (av_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1) {
 232             av_log(s, AV_LOG_ERROR, "time base invalid\n");
 233             return AVERROR_INVALIDDATA;
 234         }
 235     }
 236     tmp_pts      = 0;
 237     tmp_mul      = 1;
 238     tmp_stream   = 0;
 239     tmp_head_idx = 0;
 240     for (i = 0; i < 256;) {
 241         int tmp_flags  = ffio_read_varlen(bc);
 242         int tmp_fields = ffio_read_varlen(bc);
 243
 244         if (tmp_fields > 0)
 245             tmp_pts = get_s(bc);
 246         if (tmp_fields > 1)
 247             tmp_mul = ffio_read_varlen(bc);
 248         if (tmp_fields > 2)
 249             tmp_stream = ffio_read_varlen(bc);
 250         if (tmp_fields > 3)
 251             tmp_size = ffio_read_varlen(bc);
 252         else
 253             tmp_size = 0;
 254         if (tmp_fields > 4)
 255             tmp_res = ffio_read_varlen(bc);
 256         else
 257             tmp_res = 0;
 258         if (tmp_fields > 5)
 259             count = ffio_read_varlen(bc);
 260         else
 261             count = tmp_mul - tmp_size;
 262         if (tmp_fields > 6)
 263             get_s(bc);
 264         if (tmp_fields > 7)
 265             tmp_head_idx = ffio_read_varlen(bc);
 266
 267         while (tmp_fields-- > 8)
 268             ffio_read_varlen(bc);
 269
 270         if (count == 0 || i + count > 256) {
 271             av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
 272             return AVERROR_INVALIDDATA;
 273         }
 274         if (tmp_stream >= stream_count) {
 275             av_log(s, AV_LOG_ERROR, "illegal stream number\n");
 276             return AVERROR_INVALIDDATA;
 277         }
 278
 279         for (j = 0; j < count; j++, i++) {
 280             if (i == 'N') {
 281                 nut->frame_code[i].flags = FLAG_INVALID;
 282                 j--;
 283                 continue;
 284             }
 285             nut->frame_code[i].flags          = tmp_flags;
 286             nut->frame_code[i].pts_delta      = tmp_pts;
 287             nut->frame_code[i].stream_id      = tmp_stream;
 288             nut->frame_code[i].size_mul       = tmp_mul;
 289             nut->frame_code[i].size_lsb       = tmp_size + j;
 290             nut->frame_code[i].reserved_count = tmp_res;
 291             nut->frame_code[i].header_idx     = tmp_head_idx;
 292         }
 293     }
 294     assert(nut->frame_code['N'].flags == FLAG_INVALID);
 295
 296     if (end > avio_tell(bc) + 4) {
 297         int rem = 1024;
 298         GET_V(nut->header_count, tmp < 128U);
 299         nut->header_count++;
 300         for (i = 1; i < nut->header_count; i++) {
 301             uint8_t *hdr;
 302             GET_V(nut->header_len[i], tmp > 0 && tmp < 256);
 303             rem -= nut->header_len[i];
 304             if (rem < 0) {
 305                 av_log(s, AV_LOG_ERROR, "invalid elision header\n");
 306                 return AVERROR_INVALIDDATA;
 307             }
 308             hdr = av_malloc(nut->header_len[i]);
 309             if (!hdr)
 310                 return AVERROR(ENOMEM);
 311             avio_read(bc, hdr, nut->header_len[i]);
 312             nut->header[i] = hdr;
 313         }
 314         assert(nut->header_len[0] == 0);
 315     }
 316
 317     if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
 318         av_log(s, AV_LOG_ERROR, "main header checksum mismatch\n");
 319         return AVERROR_INVALIDDATA;
 320     }
 321
 322     nut->stream = av_mallocz(sizeof(StreamContext) * stream_count);
 323     for (i = 0; i < stream_count; i++)
 324         avformat_new_stream(s, NULL);
 325
 326     return 0;
 327 }
 328
 329 static int decode_stream_header(NUTContext *nut)
 330 {
 331     AVFormatContext *s = nut->avf;
 332     AVIOContext *bc    = s->pb;
 333     StreamContext *stc;
 334     int class, stream_id;
 335     uint64_t tmp, end;
 336     AVStream *st;
 337
 338     end  = get_packetheader(nut, bc, 1, STREAM_STARTCODE);
 339     end += avio_tell(bc);
 340
 341     GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base);
 342     stc = &nut->stream[stream_id];
 343     st  = s->streams[stream_id];
 344     if (!st)
 345         return AVERROR(ENOMEM);
 346
 347     class                = ffio_read_varlen(bc);
 348     tmp                  = get_fourcc(bc);
 349     st->codec->codec_tag = tmp;
 350     switch (class) {
 351     case 0:
 352         st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
 353         st->codec->codec_id   = av_codec_get_id((const AVCodecTag * const []) {
 354                                                     ff_nut_video_tags,
 355                                                     ff_codec_bmp_tags,
 356                                                     0
 357                                                 },
 358                                                 tmp);
 359         break;
 360     case 1:
 361         st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
 362         st->codec->codec_id   = av_codec_get_id((const AVCodecTag * const []) {
 363                                                     ff_nut_audio_tags,
 364                                                     ff_codec_wav_tags,
 365                                                     0
 366                                                 },
 367                                                 tmp);
 368         break;
 369     case 2:
 370         st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
 371         st->codec->codec_id   = ff_codec_get_id(ff_nut_subtitle_tags, tmp);
 372         break;
 373     case 3:
 374         st->codec->codec_type = AVMEDIA_TYPE_DATA;
 375         st->codec->codec_id   = ff_codec_get_id(ff_nut_data_tags, tmp);
 376         break;
 377     default:
 378         av_log(s, AV_LOG_ERROR, "unknown stream class (%d)\n", class);
 379         return -1;
 380     }
 381     if (class < 3 && st->codec->codec_id == AV_CODEC_ID_NONE)
 382         av_log(s, AV_LOG_ERROR,
 383                "Unknown codec tag '0x%04x' for stream number %d\n",
 384                (unsigned int) tmp, stream_id);
 385
 386     GET_V(stc->time_base_id, tmp < nut->time_base_count);
 387     GET_V(stc->msb_pts_shift, tmp < 16);
 388     stc->max_pts_distance = ffio_read_varlen(bc);
 389     GET_V(stc->decode_delay, tmp < 1000); // sanity limit, raise this if Moore's law is true
 390     st->codec->has_b_frames = stc->decode_delay;
 391     ffio_read_varlen(bc); // stream flags
 392
 393     GET_V(st->codec->extradata_size, tmp < (1 << 30));
 394     if (st->codec->extradata_size) {
 395         st->codec->extradata = av_mallocz(st->codec->extradata_size +
 396                                           FF_INPUT_BUFFER_PADDING_SIZE);
 397         avio_read(bc, st->codec->extradata, st->codec->extradata_size);
 398     }
 399
 400     if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
 401         GET_V(st->codec->width,  tmp > 0);
 402         GET_V(st->codec->height, tmp > 0);
 403         st->sample_aspect_ratio.num = ffio_read_varlen(bc);
 404         st->sample_aspect_ratio.den = ffio_read_varlen(bc);
 405         if ((!st->sample_aspect_ratio.num) != (!st->sample_aspect_ratio.den)) {
 406             av_log(s, AV_LOG_ERROR, "invalid aspect ratio %d/%d\n",
 407                    st->sample_aspect_ratio.num, st->sample_aspect_ratio.den);
 408             return -1;
 409         }
 410         ffio_read_varlen(bc); /* csp type */
 411     } else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
 412         GET_V(st->codec->sample_rate, tmp > 0);
 413         ffio_read_varlen(bc); // samplerate_den
 414         GET_V(st->codec->channels, tmp > 0);
 415     }
 416     if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
 417         av_log(s, AV_LOG_ERROR,
 418                "stream header %d checksum mismatch\n", stream_id);
 419         return -1;
 420     }
 421     stc->time_base = &nut->time_base[stc->time_base_id];
 422     avpriv_set_pts_info(s->streams[stream_id], 63, stc->time_base->num,
 423                         stc->time_base->den);
 424     return 0;
 425 }
 426
 427 static void set_disposition_bits(AVFormatContext *avf, char *value,
 428                                  int stream_id)
 429 {
 430     int flag = 0, i;
 431
 432     for (i = 0; ff_nut_dispositions[i].flag; ++i)
 433         if (!strcmp(ff_nut_dispositions[i].str, value))
 434             flag = ff_nut_dispositions[i].flag;
 435     if (!flag)
 436         av_log(avf, AV_LOG_INFO, "unknown disposition type '%s'\n", value);
 437     for (i = 0; i < avf->nb_streams; ++i)
 438         if (stream_id == i || stream_id == -1)
 439             avf->streams[i]->disposition |= flag;
 440 }
 441
 442 static int decode_info_header(NUTContext *nut)
 443 {
 444     AVFormatContext *s = nut->avf;
 445     AVIOContext *bc    = s->pb;
 446     uint64_t tmp, chapter_start, chapter_len;
 447     unsigned int stream_id_plus1, count;
 448     int chapter_id, i;
 449     int64_t value, end;
 450     char name[256], str_value[1024], type_str[256];
 451     const char *type;
 452     AVChapter *chapter      = NULL;
 453     AVStream *st            = NULL;
 454     AVDictionary **metadata = NULL;
 455
 456     end  = get_packetheader(nut, bc, 1, INFO_STARTCODE);
 457     end += avio_tell(bc);
 458
 459     GET_V(stream_id_plus1, tmp <= s->nb_streams);
 460     chapter_id    = get_s(bc);
 461     chapter_start = ffio_read_varlen(bc);
 462     chapter_len   = ffio_read_varlen(bc);
 463     count         = ffio_read_varlen(bc);
 464
 465     if (chapter_id && !stream_id_plus1) {
 466         int64_t start = chapter_start / nut->time_base_count;
 467         chapter = avpriv_new_chapter(s, chapter_id,
 468                                      nut->time_base[chapter_start %
 469                                                     nut->time_base_count],
 470                                      start, start + chapter_len, NULL);
 471         metadata = &chapter->metadata;
 472     } else if (stream_id_plus1) {
 473         st       = s->streams[stream_id_plus1 - 1];
 474         metadata = &st->metadata;
 475     } else
 476         metadata = &s->metadata;
 477
 478     for (i = 0; i < count; i++) {
 479         get_str(bc, name, sizeof(name));
 480         value = get_s(bc);
 481         if (value == -1) {
 482             type = "UTF-8";
 483             get_str(bc, str_value, sizeof(str_value));
 484         } else if (value == -2) {
 485             get_str(bc, type_str, sizeof(type_str));
 486             type = type_str;
 487             get_str(bc, str_value, sizeof(str_value));
 488         } else if (value == -3) {
 489             type  = "s";
 490             value = get_s(bc);
 491         } else if (value == -4) {
 492             type  = "t";
 493             value = ffio_read_varlen(bc);
 494         } else if (value < -4) {
 495             type = "r";
 496             get_s(bc);
 497         } else {
 498             type = "v";
 499         }
 500
 501         if (stream_id_plus1 > s->nb_streams) {
 502             av_log(s, AV_LOG_ERROR, "invalid stream id for info packet\n");
 503             continue;
 504         }
 505
 506         if (!strcmp(type, "UTF-8")) {
 507             if (chapter_id == 0 && !strcmp(name, "Disposition")) {
 508                 set_disposition_bits(s, str_value, stream_id_plus1 - 1);
 509                 continue;
 510             }
 511             if (metadata && av_strcasecmp(name, "Uses") &&
 512                 av_strcasecmp(name, "Depends") && av_strcasecmp(name, "Replaces"))
 513                 av_dict_set(metadata, name, str_value, 0);
 514         }
 515     }
 516
 517     if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
 518         av_log(s, AV_LOG_ERROR, "info header checksum mismatch\n");
 519         return -1;
 520     }
 521     return 0;
 522 }
 523
 524 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr)
 525 {
 526     AVFormatContext *s = nut->avf;
 527     AVIOContext *bc    = s->pb;
 528     int64_t end, tmp;
 529
 530     nut->last_syncpoint_pos = avio_tell(bc) - 8;
 531
 532     end  = get_packetheader(nut, bc, 1, SYNCPOINT_STARTCODE);
 533     end += avio_tell(bc);
 534
 535     tmp       = ffio_read_varlen(bc);
 536     *back_ptr = nut->last_syncpoint_pos - 16 * ffio_read_varlen(bc);
 537     if (*back_ptr < 0)
 538         return -1;
 539
 540     ff_nut_reset_ts(nut, nut->time_base[tmp % nut->time_base_count],
 541                     tmp / nut->time_base_count);
 542
 543     if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
 544         av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
 545         return -1;
 546     }
 547
 548     *ts = tmp / s->nb_streams *
 549           av_q2d(nut->time_base[tmp % s->nb_streams]) * AV_TIME_BASE;
 550     ff_nut_add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts);
 551
 552     return 0;
 553 }
 554
 555 static int find_and_decode_index(NUTContext *nut)
 556 {
 557     AVFormatContext *s = nut->avf;
 558     AVIOContext *bc    = s->pb;
 559     uint64_t tmp, end;
 560     int i, j, syncpoint_count;
 561     int64_t filesize = avio_size(bc);
 562     int64_t *syncpoints;
 563     int8_t *has_keyframe;
 564     int ret = -1;
 565
 566     avio_seek(bc, filesize - 12, SEEK_SET);
 567     avio_seek(bc, filesize - avio_rb64(bc), SEEK_SET);
 568     if (avio_rb64(bc) != INDEX_STARTCODE) {
 569         av_log(s, AV_LOG_ERROR, "no index at the end\n");
 570         return -1;
 571     }
 572
 573     end  = get_packetheader(nut, bc, 1, INDEX_STARTCODE);
 574     end += avio_tell(bc);
 575
 576     ffio_read_varlen(bc); // max_pts
 577     GET_V(syncpoint_count, tmp < INT_MAX / 8 && tmp > 0);
 578     syncpoints   = av_malloc(sizeof(int64_t) *  syncpoint_count);
 579     has_keyframe = av_malloc(sizeof(int8_t)  * (syncpoint_count + 1));
 580     for (i = 0; i < syncpoint_count; i++) {
 581         syncpoints[i] = ffio_read_varlen(bc);
 582         if (syncpoints[i] <= 0)
 583             goto fail;
 584         if (i)
 585             syncpoints[i] += syncpoints[i - 1];
 586     }
 587
 588     for (i = 0; i < s->nb_streams; i++) {
 589         int64_t last_pts = -1;
 590         for (j = 0; j < syncpoint_count;) {
 591             uint64_t x = ffio_read_varlen(bc);
 592             int type   = x & 1;
 593             int n      = j;
 594             x >>= 1;
 595             if (type) {
 596                 int flag = x & 1;
 597                 x >>= 1;
 598                 if (n + x >= syncpoint_count + 1) {
 599                     av_log(s, AV_LOG_ERROR, "index overflow A\n");
 600                     goto fail;
 601                 }
 602                 while (x--)
 603                     has_keyframe[n++] = flag;
 604                 has_keyframe[n++] = !flag;
 605             } else {
 606                 while (x != 1) {
 607                     if (n >= syncpoint_count + 1) {
 608                         av_log(s, AV_LOG_ERROR, "index overflow B\n");
 609                         goto fail;
 610                     }
 611                     has_keyframe[n++] = x & 1;
 612                     x >>= 1;
 613                 }
 614             }
 615             if (has_keyframe[0]) {
 616                 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
 617                 goto fail;
 618             }
 619             assert(n <= syncpoint_count + 1);
 620             for (; j < n && j < syncpoint_count; j++) {
 621                 if (has_keyframe[j]) {
 622                     uint64_t B, A = ffio_read_varlen(bc);
 623                     if (!A) {
 624                         A = ffio_read_varlen(bc);
 625                         B = ffio_read_varlen(bc);
 626                         // eor_pts[j][i] = last_pts + A + B
 627                     } else
 628                         B = 0;
 629                     av_add_index_entry(s->streams[i], 16 * syncpoints[j - 1],
 630                                        last_pts + A, 0, 0, AVINDEX_KEYFRAME);
 631                     last_pts += A + B;
 632                 }
 633             }
 634         }
 635     }
 636
 637     if (skip_reserved(bc, end) || ffio_get_checksum(bc)) {
 638         av_log(s, AV_LOG_ERROR, "index checksum mismatch\n");
 639         goto fail;
 640     }
 641     ret = 0;
 642
 643 fail:
 644     av_free(syncpoints);
 645     av_free(has_keyframe);
 646     return ret;
 647 }
 648
 649 static int nut_read_header(AVFormatContext *s)
 650 {
 651     NUTContext *nut = s->priv_data;
 652     AVIOContext *bc = s->pb;
 653     int64_t pos;
 654     int initialized_stream_count;
 655
 656     nut->avf = s;
 657
 658     /* main header */
 659     pos = 0;
 660     do {
 661         pos = find_startcode(bc, MAIN_STARTCODE, pos) + 1;
 662         if (pos < 0 + 1) {
 663             av_log(s, AV_LOG_ERROR, "No main startcode found.\n");
 664             return AVERROR_INVALIDDATA;
 665         }
 666     } while (decode_main_header(nut) < 0);
 667
 668     /* stream headers */
 669     pos = 0;
 670     for (initialized_stream_count = 0; initialized_stream_count < s->nb_streams;) {
 671         pos = find_startcode(bc, STREAM_STARTCODE, pos) + 1;
 672         if (pos < 0 + 1) {
 673             av_log(s, AV_LOG_ERROR, "Not all stream headers found.\n");
 674             return AVERROR_INVALIDDATA;
 675         }
 676         if (decode_stream_header(nut) >= 0)
 677             initialized_stream_count++;
 678     }
 679
 680     /* info headers */
 681     pos = 0;
 682     for (;;) {
 683         uint64_t startcode = find_any_startcode(bc, pos);
 684         pos = avio_tell(bc);
 685
 686         if (startcode == 0) {
 687             av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
 688             return AVERROR_INVALIDDATA;
 689         } else if (startcode == SYNCPOINT_STARTCODE) {
 690             nut->next_startcode = startcode;
 691             break;
 692         } else if (startcode != INFO_STARTCODE) {
 693             continue;
 694         }
 695
 696         decode_info_header(nut);
 697     }
 698
 699     s->data_offset = pos - 8;
 700
 701     if (bc->seekable) {
 702         int64_t orig_pos = avio_tell(bc);
 703         find_and_decode_index(nut);
 704         avio_seek(bc, orig_pos, SEEK_SET);
 705     }
 706     assert(nut->next_startcode == SYNCPOINT_STARTCODE);
 707
 708     ff_metadata_conv_ctx(s, NULL, ff_nut_metadata_conv);
 709
 710     return 0;
 711 }
 712
 713 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id,
 714                                uint8_t *header_idx, int frame_code)
 715 {
 716     AVFormatContext *s = nut->avf;
 717     AVIOContext *bc    = s->pb;
 718     StreamContext *stc;
 719     int size, flags, size_mul, pts_delta, i, reserved_count;
 720     uint64_t tmp;
 721
 722     if (avio_tell(bc) > nut->last_syncpoint_pos + nut->max_distance) {
 723         av_log(s, AV_LOG_ERROR,
 724                "Last frame must have been damaged %"PRId64" > %"PRId64" + %d\n",
 725                avio_tell(bc), nut->last_syncpoint_pos, nut->max_distance);
 726         return AVERROR_INVALIDDATA;
 727     }
 728
 729     flags          = nut->frame_code[frame_code].flags;
 730     size_mul       = nut->frame_code[frame_code].size_mul;
 731     size           = nut->frame_code[frame_code].size_lsb;
 732     *stream_id     = nut->frame_code[frame_code].stream_id;
 733     pts_delta      = nut->frame_code[frame_code].pts_delta;
 734     reserved_count = nut->frame_code[frame_code].reserved_count;
 735     *header_idx    = nut->frame_code[frame_code].header_idx;
 736
 737     if (flags & FLAG_INVALID)
 738         return AVERROR_INVALIDDATA;
 739     if (flags & FLAG_CODED)
 740         flags ^= ffio_read_varlen(bc);
 741     if (flags & FLAG_STREAM_ID) {
 742         GET_V(*stream_id, tmp < s->nb_streams);
 743     }
 744     stc = &nut->stream[*stream_id];
 745     if (flags & FLAG_CODED_PTS) {
 746         int coded_pts = ffio_read_varlen(bc);
 747         // FIXME check last_pts validity?
 748         if (coded_pts < (1 << stc->msb_pts_shift)) {
 749             *pts = ff_lsb2full(stc, coded_pts);
 750         } else
 751             *pts = coded_pts - (1 << stc->msb_pts_shift);
 752     } else
 753         *pts = stc->last_pts + pts_delta;
 754     if (flags & FLAG_SIZE_MSB)
 755         size += size_mul * ffio_read_varlen(bc);
 756     if (flags & FLAG_MATCH_TIME)
 757         get_s(bc);
 758     if (flags & FLAG_HEADER_IDX)
 759         *header_idx = ffio_read_varlen(bc);
 760     if (flags & FLAG_RESERVED)
 761         reserved_count = ffio_read_varlen(bc);
 762     for (i = 0; i < reserved_count; i++)
 763         ffio_read_varlen(bc);
 764
 765     if (*header_idx >= (unsigned)nut->header_count) {
 766         av_log(s, AV_LOG_ERROR, "header_idx invalid\n");
 767         return AVERROR_INVALIDDATA;
 768     }
 769     if (size > 4096)
 770         *header_idx = 0;
 771     size -= nut->header_len[*header_idx];
 772
 773     if (flags & FLAG_CHECKSUM) {
 774         avio_rb32(bc); // FIXME check this
 775     } else if (size > 2 * nut->max_distance || FFABS(stc->last_pts - *pts) >
 776                stc->max_pts_distance) {
 777         av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
 778         return AVERROR_INVALIDDATA;
 779     }
 780
 781     stc->last_pts   = *pts;
 782     stc->last_flags = flags;
 783
 784     return size;
 785 }
 786
 787 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code)
 788 {
 789     AVFormatContext *s = nut->avf;
 790     AVIOContext *bc    = s->pb;
 791     int size, stream_id, discard;
 792     int64_t pts, last_IP_pts;
 793     StreamContext *stc;
 794     uint8_t header_idx;
 795
 796     size = decode_frame_header(nut, &pts, &stream_id, &header_idx, frame_code);
 797     if (size < 0)
 798         return size;
 799
 800     stc = &nut->stream[stream_id];
 801
 802     if (stc->last_flags & FLAG_KEY)
 803         stc->skip_until_key_frame = 0;
 804
 805     discard     = s->streams[stream_id]->discard;
 806     last_IP_pts = s->streams[stream_id]->last_IP_pts;
 807     if ((discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY)) ||
 808         (discard >= AVDISCARD_BIDIR  && last_IP_pts != AV_NOPTS_VALUE &&
 809          last_IP_pts > pts) ||
 810         discard >= AVDISCARD_ALL ||
 811         stc->skip_until_key_frame) {
 812         avio_skip(bc, size);
 813         return 1;
 814     }
 815
 816     av_new_packet(pkt, size + nut->header_len[header_idx]);
 817     memcpy(pkt->data, nut->header[header_idx], nut->header_len[header_idx]);
 818     pkt->pos = avio_tell(bc); // FIXME
 819     avio_read(bc, pkt->data + nut->header_len[header_idx], size);
 820
 821     pkt->stream_index = stream_id;
 822     if (stc->last_flags & FLAG_KEY)
 823         pkt->flags |= AV_PKT_FLAG_KEY;
 824     pkt->pts = pts;
 825
 826     return 0;
 827 }
 828
 829 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
 830 {
 831     NUTContext *nut = s->priv_data;
 832     AVIOContext *bc = s->pb;
 833     int i, frame_code = 0, ret, skip;
 834     int64_t ts, back_ptr;
 835
 836     for (;;) {
 837         int64_t pos  = avio_tell(bc);
 838         uint64_t tmp = nut->next_startcode;
 839         nut->next_startcode = 0;
 840
 841         if (tmp) {
 842             pos -= 8;
 843         } else {
 844             frame_code = avio_r8(bc);
 845             if (bc->eof_reached)
 846                 return -1;
 847             if (frame_code == 'N') {
 848                 tmp = frame_code;
 849                 for (i = 1; i < 8; i++)
 850                     tmp = (tmp << 8) + avio_r8(bc);
 851             }
 852         }
 853         switch (tmp) {
 854         case MAIN_STARTCODE:
 855         case STREAM_STARTCODE:
 856         case INDEX_STARTCODE:
 857             skip = get_packetheader(nut, bc, 0, tmp);
 858             avio_skip(bc, skip);
 859             break;
 860         case INFO_STARTCODE:
 861             if (decode_info_header(nut) < 0)
 862                 goto resync;
 863             break;
 864         case SYNCPOINT_STARTCODE:
 865             if (decode_syncpoint(nut, &ts, &back_ptr) < 0)
 866                 goto resync;
 867             frame_code = avio_r8(bc);
 868         case 0:
 869             ret = decode_frame(nut, pkt, frame_code);
 870             if (ret == 0)
 871                 return 0;
 872             else if (ret == 1) // OK but discard packet
 873                 break;
 874         default:
 875 resync:
 876             av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
 877             tmp = find_any_startcode(bc, nut->last_syncpoint_pos + 1);
 878             if (tmp == 0)
 879                 return AVERROR_INVALIDDATA;
 880             av_log(s, AV_LOG_DEBUG, "sync\n");
 881             nut->next_startcode = tmp;
 882         }
 883     }
 884 }
 885
 886 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index,
 887                                   int64_t *pos_arg, int64_t pos_limit)
 888 {
 889     NUTContext *nut = s->priv_data;
 890     AVIOContext *bc = s->pb;
 891     int64_t pos, pts, back_ptr;
 892     av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n",
 893            stream_index, *pos_arg, pos_limit);
 894
 895     pos = *pos_arg;
 896     do {
 897         pos = find_startcode(bc, SYNCPOINT_STARTCODE, pos) + 1;
 898         if (pos < 1) {
 899             assert(nut->next_startcode == 0);
 900             av_log(s, AV_LOG_ERROR, "read_timestamp failed.\n");
 901             return AV_NOPTS_VALUE;
 902         }
 903     } while (decode_syncpoint(nut, &pts, &back_ptr) < 0);
 904     *pos_arg = pos - 1;
 905     assert(nut->last_syncpoint_pos == *pos_arg);
 906
 907     av_log(s, AV_LOG_DEBUG, "return %"PRId64" %"PRId64"\n", pts, back_ptr);
 908     if (stream_index == -1)
 909         return pts;
 910     else if (stream_index == -2)
 911         return back_ptr;
 912
 913     return AV_NOPTS_VALUE;
 914 }
 915
 916 static int read_seek(AVFormatContext *s, int stream_index,
 917                      int64_t pts, int flags)
 918 {
 919     NUTContext *nut    = s->priv_data;
 920     AVStream *st       = s->streams[stream_index];
 921     Syncpoint dummy    = { .ts = pts * av_q2d(st->time_base) * AV_TIME_BASE };
 922     Syncpoint nopts_sp = { .ts = AV_NOPTS_VALUE, .back_ptr = AV_NOPTS_VALUE };
 923     Syncpoint *sp, *next_node[2] = { &nopts_sp, &nopts_sp };
 924     int64_t pos, pos2, ts;
 925     int i;
 926
 927     if (st->index_entries) {
 928         int index = av_index_search_timestamp(st, pts, flags);
 929         if (index < 0)
 930             return -1;
 931
 932         pos2 = st->index_entries[index].pos;
 933         ts   = st->index_entries[index].timestamp;
 934     } else {
 935         av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pts_cmp,
 936                      (void **) next_node);
 937         av_log(s, AV_LOG_DEBUG, "%"PRIu64"-%"PRIu64" %"PRId64"-%"PRId64"\n",
 938                next_node[0]->pos, next_node[1]->pos, next_node[0]->ts,
 939                next_node[1]->ts);
 940         pos = ff_gen_search(s, -1, dummy.ts, next_node[0]->pos,
 941                             next_node[1]->pos, next_node[1]->pos,
 942                             next_node[0]->ts, next_node[1]->ts,
 943                             AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
 944
 945         if (!(flags & AVSEEK_FLAG_BACKWARD)) {
 946             dummy.pos    = pos + 16;
 947             next_node[1] = &nopts_sp;
 948             av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
 949                          (void **) next_node);
 950             pos2 = ff_gen_search(s, -2, dummy.pos, next_node[0]->pos,
 951                                  next_node[1]->pos, next_node[1]->pos,
 952                                  next_node[0]->back_ptr, next_node[1]->back_ptr,
 953                                  flags, &ts, nut_read_timestamp);
 954             if (pos2 >= 0)
 955                 pos = pos2;
 956             // FIXME dir but I think it does not matter
 957         }
 958         dummy.pos = pos;
 959         sp = av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
 960                           NULL);
 961
 962         assert(sp);
 963         pos2 = sp->back_ptr - 15;
 964     }
 965     av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
 966     pos = find_startcode(s->pb, SYNCPOINT_STARTCODE, pos2);
 967     avio_seek(s->pb, pos, SEEK_SET);
 968     av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
 969     if (pos2 > pos || pos2 + 15 < pos)
 970         av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
 971     for (i = 0; i < s->nb_streams; i++)
 972         nut->stream[i].skip_until_key_frame = 1;
 973
 974     return 0;
 975 }
 976
 977 static int nut_read_close(AVFormatContext *s)
 978 {
 979     NUTContext *nut = s->priv_data;
 980     int i;
 981
 982     av_freep(&nut->time_base);
 983     av_freep(&nut->stream);
 984     ff_nut_free_sp(nut);
 985     for (i = 1; i < nut->header_count; i++)
 986         av_freep(&nut->header[i]);
 987
 988     return 0;
 989 }
 990
 991 AVInputFormat ff_nut_demuxer = {
 992     .name           = "nut",
 993     .long_name      = NULL_IF_CONFIG_SMALL("NUT"),
 994     .priv_data_size = sizeof(NUTContext),
 995     .read_probe     = nut_probe,
 996     .read_header    = nut_read_header,
 997     .read_packet    = nut_read_packet,
 998     .read_close     = nut_read_close,
 999     .read_seek      = read_seek,
1000     .extensions     = "nut",
1001     .codec_tag      = ff_nut_codec_tags,
1002 };