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 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 #include <strings.h>
  24 #include "libavutil/avstring.h"
  25 #include "libavutil/bswap.h"
  26 #include "libavutil/tree.h"
  27 #include "nut.h"
  28
  29 #undef NDEBUG
  30 #include <assert.h>
  31
  32 static int get_str(ByteIOContext *bc, char *string, unsigned int maxlen){
  33     unsigned int len= ff_get_v(bc);
  34
  35     if(len && maxlen)
  36         get_buffer(bc, string, FFMIN(len, maxlen));
  37     while(len > maxlen){
  38         get_byte(bc);
  39         len--;
  40     }
  41
  42     if(maxlen)
  43         string[FFMIN(len, maxlen-1)]= 0;
  44
  45     if(maxlen == len)
  46         return -1;
  47     else
  48         return 0;
  49 }
  50
  51 static int64_t get_s(ByteIOContext *bc){
  52     int64_t v = ff_get_v(bc) + 1;
  53
  54     if (v&1) return -(v>>1);
  55     else     return  (v>>1);
  56 }
  57
  58 static uint64_t get_fourcc(ByteIOContext *bc){
  59     unsigned int len= ff_get_v(bc);
  60
  61     if     (len==2) return get_le16(bc);
  62     else if(len==4) return get_le32(bc);
  63     else            return -1;
  64 }
  65
  66 #ifdef TRACE
  67 static inline uint64_t get_v_trace(ByteIOContext *bc, char *file, char *func, int line){
  68     uint64_t v= ff_get_v(bc);
  69
  70     av_log(NULL, AV_LOG_DEBUG, "get_v %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  71     return v;
  72 }
  73
  74 static inline int64_t get_s_trace(ByteIOContext *bc, char *file, char *func, int line){
  75     int64_t v= get_s(bc);
  76
  77     av_log(NULL, AV_LOG_DEBUG, "get_s %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  78     return v;
  79 }
  80
  81 static inline uint64_t get_vb_trace(ByteIOContext *bc, char *file, char *func, int line){
  82     uint64_t v= get_vb(bc);
  83
  84     av_log(NULL, AV_LOG_DEBUG, "get_vb %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  85     return v;
  86 }
  87 #define ff_get_v(bc)  get_v_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
  88 #define get_s(bc)  get_s_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
  89 #define get_vb(bc)  get_vb_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
  90 #endif
  91
  92 static int get_packetheader(NUTContext *nut, ByteIOContext *bc, int calculate_checksum, uint64_t startcode)
  93 {
  94     int64_t size;
  95 //    start= url_ftell(bc) - 8;
  96
  97     startcode= be2me_64(startcode);
  98     startcode= ff_crc04C11DB7_update(0, &startcode, 8);
  99
 100     init_checksum(bc, ff_crc04C11DB7_update, startcode);
 101     size= ff_get_v(bc);
 102     if(size > 4096)
 103         get_be32(bc);
 104     if(get_checksum(bc) && size > 4096)
 105         return -1;
 106
 107     init_checksum(bc, calculate_checksum ? ff_crc04C11DB7_update : NULL, 0);
 108
 109     return size;
 110 }
 111
 112 static uint64_t find_any_startcode(ByteIOContext *bc, int64_t pos){
 113     uint64_t state=0;
 114
 115     if(pos >= 0)
 116         url_fseek(bc, pos, SEEK_SET); //note, this may fail if the stream is not seekable, but that should not matter, as in this case we simply start where we currently are
 117
 118     while(!url_feof(bc)){
 119         state= (state<<8) | get_byte(bc);
 120         if((state>>56) != 'N')
 121             continue;
 122         switch(state){
 123         case MAIN_STARTCODE:
 124         case STREAM_STARTCODE:
 125         case SYNCPOINT_STARTCODE:
 126         case INFO_STARTCODE:
 127         case INDEX_STARTCODE:
 128             return state;
 129         }
 130     }
 131
 132     return 0;
 133 }
 134
 135 /**
 136  * Find the given startcode.
 137  * @param code the startcode
 138  * @param pos the start position of the search, or -1 if the current position
 139  * @returns the position of the startcode or -1 if not found
 140  */
 141 static int64_t find_startcode(ByteIOContext *bc, uint64_t code, int64_t pos){
 142     for(;;){
 143         uint64_t startcode= find_any_startcode(bc, pos);
 144         if(startcode == code)
 145             return url_ftell(bc) - 8;
 146         else if(startcode == 0)
 147             return -1;
 148         pos=-1;
 149     }
 150 }
 151
 152 static int nut_probe(AVProbeData *p){
 153     int i;
 154     uint64_t code= 0;
 155
 156     for (i = 0; i < p->buf_size; i++) {
 157         code = (code << 8) | p->buf[i];
 158         if (code == MAIN_STARTCODE)
 159             return AVPROBE_SCORE_MAX;
 160     }
 161     return 0;
 162 }
 163
 164 #define GET_V(dst, check) \
 165     tmp= ff_get_v(bc);\
 166     if(!(check)){\
 167         av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp);\
 168         return -1;\
 169     }\
 170     dst= tmp;
 171
 172 static int skip_reserved(ByteIOContext *bc, int64_t pos){
 173     pos -= url_ftell(bc);
 174     if(pos<0){
 175         url_fseek(bc, pos, SEEK_CUR);
 176         return -1;
 177     }else{
 178         while(pos--)
 179             get_byte(bc);
 180         return 0;
 181     }
 182 }
 183
 184 static int decode_main_header(NUTContext *nut){
 185     AVFormatContext *s= nut->avf;
 186     ByteIOContext *bc = s->pb;
 187     uint64_t tmp, end;
 188     unsigned int stream_count;
 189     int i, j, tmp_stream, tmp_mul, tmp_pts, tmp_size, count, tmp_res, tmp_head_idx;
 190     int64_t tmp_match;
 191
 192     end= get_packetheader(nut, bc, 1, MAIN_STARTCODE);
 193     end += url_ftell(bc);
 194
 195     GET_V(tmp              , tmp >=2 && tmp <= 3)
 196     GET_V(stream_count     , tmp > 0 && tmp <=MAX_STREAMS)
 197
 198     nut->max_distance = ff_get_v(bc);
 199     if(nut->max_distance > 65536){
 200         av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
 201         nut->max_distance= 65536;
 202     }
 203
 204     GET_V(nut->time_base_count, tmp>0 && tmp<INT_MAX / sizeof(AVRational))
 205     nut->time_base= av_malloc(nut->time_base_count * sizeof(AVRational));
 206
 207     for(i=0; i<nut->time_base_count; i++){
 208         GET_V(nut->time_base[i].num, tmp>0 && tmp<(1ULL<<31))
 209         GET_V(nut->time_base[i].den, tmp>0 && tmp<(1ULL<<31))
 210         if(av_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1){
 211             av_log(s, AV_LOG_ERROR, "time base invalid\n");
 212             return -1;
 213         }
 214     }
 215     tmp_pts=0;
 216     tmp_mul=1;
 217     tmp_stream=0;
 218     tmp_match= 1-(1LL<<62);
 219     tmp_head_idx= 0;
 220     for(i=0; i<256;){
 221         int tmp_flags = ff_get_v(bc);
 222         int tmp_fields= ff_get_v(bc);
 223         if(tmp_fields>0) tmp_pts   = get_s(bc);
 224         if(tmp_fields>1) tmp_mul   = ff_get_v(bc);
 225         if(tmp_fields>2) tmp_stream= ff_get_v(bc);
 226         if(tmp_fields>3) tmp_size  = ff_get_v(bc);
 227         else             tmp_size  = 0;
 228         if(tmp_fields>4) tmp_res   = ff_get_v(bc);
 229         else             tmp_res   = 0;
 230         if(tmp_fields>5) count     = ff_get_v(bc);
 231         else             count     = tmp_mul - tmp_size;
 232         if(tmp_fields>6) tmp_match = get_s(bc);
 233         if(tmp_fields>7) tmp_head_idx= ff_get_v(bc);
 234
 235         while(tmp_fields-- > 8)
 236            ff_get_v(bc);
 237
 238         if(count == 0 || i+count > 256){
 239             av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
 240             return -1;
 241         }
 242         if(tmp_stream >= stream_count){
 243             av_log(s, AV_LOG_ERROR, "illegal stream number\n");
 244             return -1;
 245         }
 246
 247         for(j=0; j<count; j++,i++){
 248             if (i == 'N') {
 249                 nut->frame_code[i].flags= FLAG_INVALID;
 250                 j--;
 251                 continue;
 252             }
 253             nut->frame_code[i].flags           = tmp_flags ;
 254             nut->frame_code[i].pts_delta       = tmp_pts   ;
 255             nut->frame_code[i].stream_id       = tmp_stream;
 256             nut->frame_code[i].size_mul        = tmp_mul   ;
 257             nut->frame_code[i].size_lsb        = tmp_size+j;
 258             nut->frame_code[i].reserved_count  = tmp_res   ;
 259             nut->frame_code[i].header_idx      = tmp_head_idx;
 260         }
 261     }
 262     assert(nut->frame_code['N'].flags == FLAG_INVALID);
 263
 264     if(end > url_ftell(bc) + 4){
 265         int rem= 1024;
 266         GET_V(nut->header_count, tmp<128U)
 267         nut->header_count++;
 268         for(i=1; i<nut->header_count; i++){
 269             GET_V(nut->header_len[i], tmp>0 && tmp<256);
 270             rem -= nut->header_len[i];
 271             if(rem < 0){
 272                 av_log(s, AV_LOG_ERROR, "invalid elision header\n");
 273                 return -1;
 274             }
 275             nut->header[i]= av_malloc(nut->header_len[i]);
 276             get_buffer(bc, nut->header[i], nut->header_len[i]);
 277         }
 278         assert(nut->header_len[0]==0);
 279     }
 280
 281     if(skip_reserved(bc, end) || get_checksum(bc)){
 282         av_log(s, AV_LOG_ERROR, "main header checksum mismatch\n");
 283         return -1;
 284     }
 285
 286     nut->stream = av_mallocz(sizeof(StreamContext)*stream_count);
 287     for(i=0; i<stream_count; i++){
 288         av_new_stream(s, i);
 289     }
 290
 291     return 0;
 292 }
 293
 294 static int decode_stream_header(NUTContext *nut){
 295     AVFormatContext *s= nut->avf;
 296     ByteIOContext *bc = s->pb;
 297     StreamContext *stc;
 298     int class, stream_id;
 299     uint64_t tmp, end;
 300     AVStream *st;
 301
 302     end= get_packetheader(nut, bc, 1, STREAM_STARTCODE);
 303     end += url_ftell(bc);
 304
 305     GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base);
 306     stc= &nut->stream[stream_id];
 307
 308     st = s->streams[stream_id];
 309     if (!st)
 310         return AVERROR(ENOMEM);
 311
 312     class = ff_get_v(bc);
 313     tmp = get_fourcc(bc);
 314     st->codec->codec_tag= tmp;
 315     switch(class)
 316     {
 317         case 0:
 318             st->codec->codec_type = CODEC_TYPE_VIDEO;
 319             st->codec->codec_id = codec_get_id(codec_bmp_tags, tmp);
 320             break;
 321         case 1:
 322             st->codec->codec_type = CODEC_TYPE_AUDIO;
 323             st->codec->codec_id = codec_get_id(codec_wav_tags, tmp);
 324             break;
 325         case 2:
 326             st->codec->codec_type = CODEC_TYPE_SUBTITLE;
 327             st->codec->codec_id = codec_get_id(ff_nut_subtitle_tags, tmp);
 328             break;
 329         case 3:
 330             st->codec->codec_type = CODEC_TYPE_DATA;
 331             break;
 332         default:
 333             av_log(s, AV_LOG_ERROR, "unknown stream class (%d)\n", class);
 334             return -1;
 335     }
 336     if(class<3 && st->codec->codec_id == CODEC_ID_NONE)
 337         av_log(s, AV_LOG_ERROR, "Unknown codec?!\n");
 338
 339     GET_V(stc->time_base_id    , tmp < nut->time_base_count);
 340     GET_V(stc->msb_pts_shift   , tmp < 16);
 341     stc->max_pts_distance= ff_get_v(bc);
 342     GET_V(stc->decode_delay    , tmp < 1000); //sanity limit, raise this if Moore's law is true
 343     st->codec->has_b_frames= stc->decode_delay;
 344     ff_get_v(bc); //stream flags
 345
 346     GET_V(st->codec->extradata_size, tmp < (1<<30));
 347     if(st->codec->extradata_size){
 348         st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
 349         get_buffer(bc, st->codec->extradata, st->codec->extradata_size);
 350     }
 351
 352     if (st->codec->codec_type == CODEC_TYPE_VIDEO){
 353         GET_V(st->codec->width , tmp > 0)
 354         GET_V(st->codec->height, tmp > 0)
 355         st->sample_aspect_ratio.num= ff_get_v(bc);
 356         st->sample_aspect_ratio.den= ff_get_v(bc);
 357         if((!st->sample_aspect_ratio.num) != (!st->sample_aspect_ratio.den)){
 358             av_log(s, AV_LOG_ERROR, "invalid aspect ratio %d/%d\n", st->sample_aspect_ratio.num, st->sample_aspect_ratio.den);
 359             return -1;
 360         }
 361         ff_get_v(bc); /* csp type */
 362     }else if (st->codec->codec_type == CODEC_TYPE_AUDIO){
 363         GET_V(st->codec->sample_rate , tmp > 0)
 364         ff_get_v(bc); // samplerate_den
 365         GET_V(st->codec->channels, tmp > 0)
 366     }
 367     if(skip_reserved(bc, end) || get_checksum(bc)){
 368         av_log(s, AV_LOG_ERROR, "stream header %d checksum mismatch\n", stream_id);
 369         return -1;
 370     }
 371     stc->time_base= &nut->time_base[stc->time_base_id];
 372     av_set_pts_info(s->streams[stream_id], 63, stc->time_base->num, stc->time_base->den);
 373     return 0;
 374 }
 375
 376 static void set_disposition_bits(AVFormatContext* avf, char* value, int stream_id){
 377     int flag = 0, i;
 378     for (i=0; ff_nut_dispositions[i].flag; ++i) {
 379         if (!strcmp(ff_nut_dispositions[i].str, value))
 380             flag = ff_nut_dispositions[i].flag;
 381     }
 382     if (!flag)
 383         av_log(avf, AV_LOG_INFO, "unknown disposition type '%s'\n", value);
 384     for (i = 0; i < avf->nb_streams; ++i)
 385         if (stream_id == i || stream_id == -1)
 386             avf->streams[i]->disposition |= flag;
 387 }
 388
 389 static int decode_info_header(NUTContext *nut){
 390     AVFormatContext *s= nut->avf;
 391     ByteIOContext *bc = s->pb;
 392     uint64_t tmp;
 393     unsigned int stream_id_plus1, chapter_start, chapter_len, count;
 394     int chapter_id, i;
 395     int64_t value, end;
 396     char name[256], str_value[1024], type_str[256];
 397     const char *type;
 398     AVChapter *chapter= NULL;
 399     AVStream *st= NULL;
 400
 401     end= get_packetheader(nut, bc, 1, INFO_STARTCODE);
 402     end += url_ftell(bc);
 403
 404     GET_V(stream_id_plus1, tmp <= s->nb_streams)
 405     chapter_id   = get_s(bc);
 406     chapter_start= ff_get_v(bc);
 407     chapter_len  = ff_get_v(bc);
 408     count        = ff_get_v(bc);
 409
 410     if(chapter_id && !stream_id_plus1){
 411         int64_t start= chapter_start / nut->time_base_count;
 412         chapter= ff_new_chapter(s, chapter_id,
 413                                 nut->time_base[chapter_start % nut->time_base_count],
 414                                 start, start + chapter_len, NULL);
 415     } else if(stream_id_plus1)
 416         st= s->streams[stream_id_plus1 - 1];
 417
 418     for(i=0; i<count; i++){
 419         get_str(bc, name, sizeof(name));
 420         value= get_s(bc);
 421         if(value == -1){
 422             type= "UTF-8";
 423             get_str(bc, str_value, sizeof(str_value));
 424         }else if(value == -2){
 425             get_str(bc, type_str, sizeof(type_str));
 426             type= type_str;
 427             get_str(bc, str_value, sizeof(str_value));
 428         }else if(value == -3){
 429             type= "s";
 430             value= get_s(bc);
 431         }else if(value == -4){
 432             type= "t";
 433             value= ff_get_v(bc);
 434         }else if(value < -4){
 435             type= "r";
 436             get_s(bc);
 437         }else{
 438             type= "v";
 439         }
 440
 441         if (stream_id_plus1 > s->nb_streams) {
 442             av_log(s, AV_LOG_ERROR, "invalid stream id for info packet\n");
 443             continue;
 444         }
 445
 446         if(!strcmp(type, "UTF-8")){
 447             AVMetadata **metadata = NULL;
 448             if(chapter_id==0 && !strcmp(name, "Disposition"))
 449                 set_disposition_bits(s, str_value, stream_id_plus1 - 1);
 450             else if(chapter)          metadata= &chapter->metadata;
 451             else if(stream_id_plus1)  metadata= &st->metadata;
 452             else                      metadata= &s->metadata;
 453             if(metadata && strcasecmp(name,"Uses")
 454                && strcasecmp(name,"Depends") && strcasecmp(name,"Replaces"))
 455                 av_metadata_set(metadata, name, str_value);
 456         }
 457     }
 458
 459     if(skip_reserved(bc, end) || get_checksum(bc)){
 460         av_log(s, AV_LOG_ERROR, "info header checksum mismatch\n");
 461         return -1;
 462     }
 463     return 0;
 464 }
 465
 466 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr){
 467     AVFormatContext *s= nut->avf;
 468     ByteIOContext *bc = s->pb;
 469     int64_t end, tmp;
 470
 471     nut->last_syncpoint_pos= url_ftell(bc)-8;
 472
 473     end= get_packetheader(nut, bc, 1, SYNCPOINT_STARTCODE);
 474     end += url_ftell(bc);
 475
 476     tmp= ff_get_v(bc);
 477     *back_ptr= nut->last_syncpoint_pos - 16*ff_get_v(bc);
 478     if(*back_ptr < 0)
 479         return -1;
 480
 481     ff_nut_reset_ts(nut, nut->time_base[tmp % nut->time_base_count], tmp / nut->time_base_count);
 482
 483     if(skip_reserved(bc, end) || get_checksum(bc)){
 484         av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
 485         return -1;
 486     }
 487
 488     *ts= tmp / s->nb_streams * av_q2d(nut->time_base[tmp % s->nb_streams])*AV_TIME_BASE;
 489     ff_nut_add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts);
 490
 491     return 0;
 492 }
 493
 494 static int find_and_decode_index(NUTContext *nut){
 495     AVFormatContext *s= nut->avf;
 496     ByteIOContext *bc = s->pb;
 497     uint64_t tmp, end;
 498     int i, j, syncpoint_count;
 499     int64_t filesize= url_fsize(bc);
 500     int64_t *syncpoints;
 501     int8_t *has_keyframe;
 502     int ret= -1;
 503
 504     url_fseek(bc, filesize-12, SEEK_SET);
 505     url_fseek(bc, filesize-get_be64(bc), SEEK_SET);
 506     if(get_be64(bc) != INDEX_STARTCODE){
 507         av_log(s, AV_LOG_ERROR, "no index at the end\n");
 508         return -1;
 509     }
 510
 511     end= get_packetheader(nut, bc, 1, INDEX_STARTCODE);
 512     end += url_ftell(bc);
 513
 514     ff_get_v(bc); //max_pts
 515     GET_V(syncpoint_count, tmp < INT_MAX/8 && tmp > 0)
 516     syncpoints= av_malloc(sizeof(int64_t)*syncpoint_count);
 517     has_keyframe= av_malloc(sizeof(int8_t)*(syncpoint_count+1));
 518     for(i=0; i<syncpoint_count; i++){
 519         syncpoints[i] = ff_get_v(bc);
 520         if(syncpoints[i] <= 0)
 521             goto fail;
 522         if(i)
 523             syncpoints[i] += syncpoints[i-1];
 524     }
 525
 526     for(i=0; i<s->nb_streams; i++){
 527         int64_t last_pts= -1;
 528         for(j=0; j<syncpoint_count;){
 529             uint64_t x= ff_get_v(bc);
 530             int type= x&1;
 531             int n= j;
 532             x>>=1;
 533             if(type){
 534                 int flag= x&1;
 535                 x>>=1;
 536                 if(n+x >= syncpoint_count + 1){
 537                     av_log(s, AV_LOG_ERROR, "index overflow A\n");
 538                     goto fail;
 539                 }
 540                 while(x--)
 541                     has_keyframe[n++]= flag;
 542                 has_keyframe[n++]= !flag;
 543             }else{
 544                 while(x != 1){
 545                     if(n>=syncpoint_count + 1){
 546                         av_log(s, AV_LOG_ERROR, "index overflow B\n");
 547                         goto fail;
 548                     }
 549                     has_keyframe[n++]= x&1;
 550                     x>>=1;
 551                 }
 552             }
 553             if(has_keyframe[0]){
 554                 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
 555                 goto fail;
 556             }
 557             assert(n<=syncpoint_count+1);
 558             for(; j<n && j<syncpoint_count; j++){
 559                 if(has_keyframe[j]){
 560                     uint64_t B, A= ff_get_v(bc);
 561                     if(!A){
 562                         A= ff_get_v(bc);
 563                         B= ff_get_v(bc);
 564                         //eor_pts[j][i] = last_pts + A + B
 565                     }else
 566                         B= 0;
 567                     av_add_index_entry(
 568                         s->streams[i],
 569                         16*syncpoints[j-1],
 570                         last_pts + A,
 571                         0,
 572                         0,
 573                         AVINDEX_KEYFRAME);
 574                     last_pts += A + B;
 575                 }
 576             }
 577         }
 578     }
 579
 580     if(skip_reserved(bc, end) || get_checksum(bc)){
 581         av_log(s, AV_LOG_ERROR, "index checksum mismatch\n");
 582         goto fail;
 583     }
 584     ret= 0;
 585 fail:
 586     av_free(syncpoints);
 587     av_free(has_keyframe);
 588     return ret;
 589 }
 590
 591 static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)
 592 {
 593     NUTContext *nut = s->priv_data;
 594     ByteIOContext *bc = s->pb;
 595     int64_t pos;
 596     int initialized_stream_count;
 597
 598     nut->avf= s;
 599
 600     /* main header */
 601     pos=0;
 602     do{
 603         pos= find_startcode(bc, MAIN_STARTCODE, pos)+1;
 604         if (pos<0+1){
 605             av_log(s, AV_LOG_ERROR, "No main startcode found.\n");
 606             return -1;
 607         }
 608     }while(decode_main_header(nut) < 0);
 609
 610     /* stream headers */
 611     pos=0;
 612     for(initialized_stream_count=0; initialized_stream_count < s->nb_streams;){
 613         pos= find_startcode(bc, STREAM_STARTCODE, pos)+1;
 614         if (pos<0+1){
 615             av_log(s, AV_LOG_ERROR, "Not all stream headers found.\n");
 616             return -1;
 617         }
 618         if(decode_stream_header(nut) >= 0)
 619             initialized_stream_count++;
 620     }
 621
 622     /* info headers */
 623     pos=0;
 624     for(;;){
 625         uint64_t startcode= find_any_startcode(bc, pos);
 626         pos= url_ftell(bc);
 627
 628         if(startcode==0){
 629             av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
 630             return -1;
 631         }else if(startcode == SYNCPOINT_STARTCODE){
 632             nut->next_startcode= startcode;
 633             break;
 634         }else if(startcode != INFO_STARTCODE){
 635             continue;
 636         }
 637
 638         decode_info_header(nut);
 639     }
 640
 641     s->data_offset= pos-8;
 642
 643     if(!url_is_streamed(bc)){
 644         int64_t orig_pos= url_ftell(bc);
 645         find_and_decode_index(nut);
 646         url_fseek(bc, orig_pos, SEEK_SET);
 647     }
 648     assert(nut->next_startcode == SYNCPOINT_STARTCODE);
 649
 650     return 0;
 651 }
 652
 653 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id, uint8_t *header_idx, int frame_code){
 654     AVFormatContext *s= nut->avf;
 655     ByteIOContext *bc = s->pb;
 656     StreamContext *stc;
 657     int size, flags, size_mul, pts_delta, i, reserved_count;
 658     uint64_t tmp;
 659
 660     if(url_ftell(bc) > nut->last_syncpoint_pos + nut->max_distance){
 661         av_log(s, AV_LOG_ERROR, "Last frame must have been damaged %"PRId64" > %"PRId64" + %d\n", url_ftell(bc), nut->last_syncpoint_pos, nut->max_distance);
 662         return -1;
 663     }
 664
 665     flags          = nut->frame_code[frame_code].flags;
 666     size_mul       = nut->frame_code[frame_code].size_mul;
 667     size           = nut->frame_code[frame_code].size_lsb;
 668     *stream_id     = nut->frame_code[frame_code].stream_id;
 669     pts_delta      = nut->frame_code[frame_code].pts_delta;
 670     reserved_count = nut->frame_code[frame_code].reserved_count;
 671     *header_idx    = nut->frame_code[frame_code].header_idx;
 672
 673     if(flags & FLAG_INVALID)
 674         return -1;
 675     if(flags & FLAG_CODED)
 676         flags ^= ff_get_v(bc);
 677     if(flags & FLAG_STREAM_ID){
 678         GET_V(*stream_id, tmp < s->nb_streams)
 679     }
 680     stc= &nut->stream[*stream_id];
 681     if(flags&FLAG_CODED_PTS){
 682         int coded_pts= ff_get_v(bc);
 683 //FIXME check last_pts validity?
 684         if(coded_pts < (1<<stc->msb_pts_shift)){
 685             *pts=ff_lsb2full(stc, coded_pts);
 686         }else
 687             *pts=coded_pts - (1<<stc->msb_pts_shift);
 688     }else
 689         *pts= stc->last_pts + pts_delta;
 690     if(flags&FLAG_SIZE_MSB){
 691         size += size_mul*ff_get_v(bc);
 692     }
 693     if(flags&FLAG_MATCH_TIME)
 694         get_s(bc);
 695     if(flags&FLAG_HEADER_IDX)
 696         *header_idx= ff_get_v(bc);
 697     if(flags&FLAG_RESERVED)
 698         reserved_count= ff_get_v(bc);
 699     for(i=0; i<reserved_count; i++)
 700         ff_get_v(bc);
 701
 702     if(*header_idx >= (unsigned)nut->header_count){
 703         av_log(s, AV_LOG_ERROR, "header_idx invalid\n");
 704         return -1;
 705     }
 706     if(size > 4096)
 707         *header_idx=0;
 708     size -= nut->header_len[*header_idx];
 709
 710     if(flags&FLAG_CHECKSUM){
 711         get_be32(bc); //FIXME check this
 712     }else if(size > 2*nut->max_distance || FFABS(stc->last_pts - *pts) > stc->max_pts_distance){
 713         av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
 714         return -1;
 715     }
 716
 717     stc->last_pts= *pts;
 718     stc->last_flags= flags;
 719
 720     return size;
 721 }
 722
 723 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code){
 724     AVFormatContext *s= nut->avf;
 725     ByteIOContext *bc = s->pb;
 726     int size, stream_id, discard;
 727     int64_t pts, last_IP_pts;
 728     StreamContext *stc;
 729     uint8_t header_idx;
 730
 731     size= decode_frame_header(nut, &pts, &stream_id, &header_idx, frame_code);
 732     if(size < 0)
 733         return -1;
 734
 735     stc= &nut->stream[stream_id];
 736
 737     if (stc->last_flags & FLAG_KEY)
 738         stc->skip_until_key_frame=0;
 739
 740     discard= s->streams[ stream_id ]->discard;
 741     last_IP_pts= s->streams[ stream_id ]->last_IP_pts;
 742     if(  (discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY))
 743        ||(discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE && last_IP_pts > pts)
 744        || discard >= AVDISCARD_ALL
 745        || stc->skip_until_key_frame){
 746         url_fskip(bc, size);
 747         return 1;
 748     }
 749
 750     av_new_packet(pkt, size + nut->header_len[header_idx]);
 751     memcpy(pkt->data, nut->header[header_idx], nut->header_len[header_idx]);
 752     pkt->pos= url_ftell(bc); //FIXME
 753     get_buffer(bc, pkt->data + nut->header_len[header_idx], size);
 754
 755     pkt->stream_index = stream_id;
 756     if (stc->last_flags & FLAG_KEY)
 757         pkt->flags |= PKT_FLAG_KEY;
 758     pkt->pts = pts;
 759
 760     return 0;
 761 }
 762
 763 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
 764 {
 765     NUTContext *nut = s->priv_data;
 766     ByteIOContext *bc = s->pb;
 767     int i, frame_code=0, ret, skip;
 768     int64_t ts, back_ptr;
 769
 770     for(;;){
 771         int64_t pos= url_ftell(bc);
 772         uint64_t tmp= nut->next_startcode;
 773         nut->next_startcode=0;
 774
 775         if(tmp){
 776             pos-=8;
 777         }else{
 778             frame_code = get_byte(bc);
 779             if(url_feof(bc))
 780                 return -1;
 781             if(frame_code == 'N'){
 782                 tmp= frame_code;
 783                 for(i=1; i<8; i++)
 784                     tmp = (tmp<<8) + get_byte(bc);
 785             }
 786         }
 787         switch(tmp){
 788         case MAIN_STARTCODE:
 789         case STREAM_STARTCODE:
 790         case INDEX_STARTCODE:
 791             skip= get_packetheader(nut, bc, 0, tmp);
 792             url_fseek(bc, skip, SEEK_CUR);
 793             break;
 794         case INFO_STARTCODE:
 795             if(decode_info_header(nut)<0)
 796                 goto resync;
 797             break;
 798         case SYNCPOINT_STARTCODE:
 799             if(decode_syncpoint(nut, &ts, &back_ptr)<0)
 800                 goto resync;
 801             frame_code = get_byte(bc);
 802         case 0:
 803             ret= decode_frame(nut, pkt, frame_code);
 804             if(ret==0)
 805                 return 0;
 806             else if(ret==1) //ok but discard packet
 807                 break;
 808         default:
 809 resync:
 810 av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
 811             tmp= find_any_startcode(bc, nut->last_syncpoint_pos+1);
 812             if(tmp==0)
 813                 return -1;
 814 av_log(s, AV_LOG_DEBUG, "sync\n");
 815             nut->next_startcode= tmp;
 816         }
 817     }
 818 }
 819
 820 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index, int64_t *pos_arg, int64_t pos_limit){
 821     NUTContext *nut = s->priv_data;
 822     ByteIOContext *bc = s->pb;
 823     int64_t pos, pts, back_ptr;
 824 av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n", stream_index, *pos_arg, pos_limit);
 825
 826     pos= *pos_arg;
 827     do{
 828         pos= find_startcode(bc, SYNCPOINT_STARTCODE, pos)+1;
 829         if(pos < 1){
 830             assert(nut->next_startcode == 0);
 831             av_log(s, AV_LOG_ERROR, "read_timestamp failed.\n");
 832             return AV_NOPTS_VALUE;
 833         }
 834     }while(decode_syncpoint(nut, &pts, &back_ptr) < 0);
 835     *pos_arg = pos-1;
 836     assert(nut->last_syncpoint_pos == *pos_arg);
 837
 838     av_log(s, AV_LOG_DEBUG, "return %"PRId64" %"PRId64"\n", pts,back_ptr );
 839     if     (stream_index == -1) return pts;
 840     else if(stream_index == -2) return back_ptr;
 841
 842 assert(0);
 843 }
 844
 845 static int read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags){
 846     NUTContext *nut = s->priv_data;
 847     AVStream *st= s->streams[stream_index];
 848     Syncpoint dummy={.ts= pts*av_q2d(st->time_base)*AV_TIME_BASE};
 849     Syncpoint nopts_sp= {.ts= AV_NOPTS_VALUE, .back_ptr= AV_NOPTS_VALUE};
 850     Syncpoint *sp, *next_node[2]= {&nopts_sp, &nopts_sp};
 851     int64_t pos, pos2, ts;
 852     int i;
 853
 854     if(st->index_entries){
 855         int index= av_index_search_timestamp(st, pts, flags);
 856         if(index<0)
 857             return -1;
 858
 859         pos2= st->index_entries[index].pos;
 860         ts  = st->index_entries[index].timestamp;
 861     }else{
 862         av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pts_cmp, next_node);
 863         av_log(s, AV_LOG_DEBUG, "%"PRIu64"-%"PRIu64" %"PRId64"-%"PRId64"\n", next_node[0]->pos, next_node[1]->pos,
 864                                                     next_node[0]->ts , next_node[1]->ts);
 865         pos= av_gen_search(s, -1, dummy.ts, next_node[0]->pos, next_node[1]->pos, next_node[1]->pos,
 866                                             next_node[0]->ts , next_node[1]->ts, AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
 867
 868         if(!(flags & AVSEEK_FLAG_BACKWARD)){
 869             dummy.pos= pos+16;
 870             next_node[1]= &nopts_sp;
 871             av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp, next_node);
 872             pos2= av_gen_search(s, -2, dummy.pos, next_node[0]->pos     , next_node[1]->pos, next_node[1]->pos,
 873                                                 next_node[0]->back_ptr, next_node[1]->back_ptr, flags, &ts, nut_read_timestamp);
 874             if(pos2>=0)
 875                 pos= pos2;
 876             //FIXME dir but I think it does not matter
 877         }
 878         dummy.pos= pos;
 879         sp= av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp, NULL);
 880
 881         assert(sp);
 882         pos2= sp->back_ptr  - 15;
 883     }
 884     av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
 885     pos= find_startcode(s->pb, SYNCPOINT_STARTCODE, pos2);
 886     url_fseek(s->pb, pos, SEEK_SET);
 887     av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
 888     if(pos2 > pos || pos2 + 15 < pos){
 889         av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
 890     }
 891     for(i=0; i<s->nb_streams; i++)
 892         nut->stream[i].skip_until_key_frame=1;
 893
 894     return 0;
 895 }
 896
 897 static int nut_read_close(AVFormatContext *s)
 898 {
 899     NUTContext *nut = s->priv_data;
 900
 901     av_freep(&nut->time_base);
 902     av_freep(&nut->stream);
 903
 904     return 0;
 905 }
 906
 907 #if CONFIG_NUT_DEMUXER
 908 AVInputFormat nut_demuxer = {
 909     "nut",
 910     NULL_IF_CONFIG_SMALL("NUT format"),
 911     sizeof(NUTContext),
 912     nut_probe,
 913     nut_read_header,
 914     nut_read_packet,
 915     nut_read_close,
 916     read_seek,
 917     .extensions = "nut",
 918 };
 919 #endif