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 "libavutil/avstring.h"
  24 #include "libavutil/bswap.h"
  25 #include "libavutil/tree.h"
  26 #include "nut.h"
  27
  28 #undef NDEBUG
  29 #include <assert.h>
  30
  31 static int get_str(ByteIOContext *bc, char *string, unsigned int maxlen){
  32     unsigned int len= ff_get_v(bc);
  33
  34     if(len && maxlen)
  35         get_buffer(bc, string, FFMIN(len, maxlen));
  36     while(len > maxlen){
  37         get_byte(bc);
  38         len--;
  39     }
  40
  41     if(maxlen)
  42         string[FFMIN(len, maxlen-1)]= 0;
  43
  44     if(maxlen == len)
  45         return -1;
  46     else
  47         return 0;
  48 }
  49
  50 static int64_t get_s(ByteIOContext *bc){
  51     int64_t v = ff_get_v(bc) + 1;
  52
  53     if (v&1) return -(v>>1);
  54     else     return  (v>>1);
  55 }
  56
  57 static uint64_t get_fourcc(ByteIOContext *bc){
  58     unsigned int len= ff_get_v(bc);
  59
  60     if     (len==2) return get_le16(bc);
  61     else if(len==4) return get_le32(bc);
  62     else            return -1;
  63 }
  64
  65 #ifdef TRACE
  66 static inline uint64_t get_v_trace(ByteIOContext *bc, char *file, char *func, int line){
  67     uint64_t v= ff_get_v(bc);
  68
  69     av_log(NULL, AV_LOG_DEBUG, "get_v %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  70     return v;
  71 }
  72
  73 static inline int64_t get_s_trace(ByteIOContext *bc, char *file, char *func, int line){
  74     int64_t v= get_s(bc);
  75
  76     av_log(NULL, AV_LOG_DEBUG, "get_s %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  77     return v;
  78 }
  79
  80 static inline uint64_t get_vb_trace(ByteIOContext *bc, char *file, char *func, int line){
  81     uint64_t v= get_vb(bc);
  82
  83     av_log(NULL, AV_LOG_DEBUG, "get_vb %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  84     return v;
  85 }
  86 #define ff_get_v(bc)  get_v_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
  87 #define get_s(bc)  get_s_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
  88 #define get_vb(bc)  get_vb_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
  89 #endif
  90
  91 static int get_packetheader(NUTContext *nut, ByteIOContext *bc, int calculate_checksum, uint64_t startcode)
  92 {
  93     int64_t size;
  94 //    start= url_ftell(bc) - 8;
  95
  96     startcode= be2me_64(startcode);
  97     startcode= ff_crc04C11DB7_update(0, &startcode, 8);
  98
  99     init_checksum(bc, ff_crc04C11DB7_update, startcode);
 100     size= ff_get_v(bc);
 101     if(size > 4096)
 102         get_be32(bc);
 103     if(get_checksum(bc) && size > 4096)
 104         return -1;
 105
 106     init_checksum(bc, calculate_checksum ? ff_crc04C11DB7_update : NULL, 0);
 107
 108     return size;
 109 }
 110
 111 static uint64_t find_any_startcode(ByteIOContext *bc, int64_t pos){
 112     uint64_t state=0;
 113
 114     if(pos >= 0)
 115         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
 116
 117     while(!url_feof(bc)){
 118         state= (state<<8) | get_byte(bc);
 119         if((state>>56) != 'N')
 120             continue;
 121         switch(state){
 122         case MAIN_STARTCODE:
 123         case STREAM_STARTCODE:
 124         case SYNCPOINT_STARTCODE:
 125         case INFO_STARTCODE:
 126         case INDEX_STARTCODE:
 127             return state;
 128         }
 129     }
 130
 131     return 0;
 132 }
 133
 134 /**
 135  * Find the given startcode.
 136  * @param code the startcode
 137  * @param pos the start position of the search, or -1 if the current position
 138  * @returns the position of the startcode or -1 if not found
 139  */
 140 static int64_t find_startcode(ByteIOContext *bc, uint64_t code, int64_t pos){
 141     for(;;){
 142         uint64_t startcode= find_any_startcode(bc, pos);
 143         if(startcode == code)
 144             return url_ftell(bc) - 8;
 145         else if(startcode == 0)
 146             return -1;
 147         pos=-1;
 148     }
 149 }
 150
 151 static int nut_probe(AVProbeData *p){
 152     int i;
 153     uint64_t code= 0;
 154
 155     for (i = 0; i < p->buf_size; i++) {
 156         code = (code << 8) | p->buf[i];
 157         if (code == MAIN_STARTCODE)
 158             return AVPROBE_SCORE_MAX;
 159     }
 160     return 0;
 161 }
 162
 163 #define GET_V(dst, check) \
 164     tmp= ff_get_v(bc);\
 165     if(!(check)){\
 166         av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp);\
 167         return -1;\
 168     }\
 169     dst= tmp;
 170
 171 static int skip_reserved(ByteIOContext *bc, int64_t pos){
 172     pos -= url_ftell(bc);
 173     if(pos<0){
 174         url_fseek(bc, pos, SEEK_CUR);
 175         return -1;
 176     }else{
 177         while(pos--)
 178             get_byte(bc);
 179         return 0;
 180     }
 181 }
 182
 183 static int decode_main_header(NUTContext *nut){
 184     AVFormatContext *s= nut->avf;
 185     ByteIOContext *bc = s->pb;
 186     uint64_t tmp, end;
 187     unsigned int stream_count;
 188     int i, j, tmp_stream, tmp_mul, tmp_pts, tmp_size, count, tmp_res, tmp_head_idx;
 189     int64_t tmp_match;
 190
 191     end= get_packetheader(nut, bc, 1, MAIN_STARTCODE);
 192     end += url_ftell(bc);
 193
 194     GET_V(tmp              , tmp >=2 && tmp <= 3)
 195     GET_V(stream_count     , tmp > 0 && tmp <=MAX_STREAMS)
 196
 197     nut->max_distance = ff_get_v(bc);
 198     if(nut->max_distance > 65536){
 199         av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
 200         nut->max_distance= 65536;
 201     }
 202
 203     GET_V(nut->time_base_count, tmp>0 && tmp<INT_MAX / sizeof(AVRational))
 204     nut->time_base= av_malloc(nut->time_base_count * sizeof(AVRational));
 205
 206     for(i=0; i<nut->time_base_count; i++){
 207         GET_V(nut->time_base[i].num, tmp>0 && tmp<(1ULL<<31))
 208         GET_V(nut->time_base[i].den, tmp>0 && tmp<(1ULL<<31))
 209         if(av_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1){
 210             av_log(s, AV_LOG_ERROR, "time base invalid\n");
 211             return -1;
 212         }
 213     }
 214     tmp_pts=0;
 215     tmp_mul=1;
 216     tmp_stream=0;
 217     tmp_match= 1-(1LL<<62);
 218     tmp_head_idx= 0;
 219     for(i=0; i<256;){
 220         int tmp_flags = ff_get_v(bc);
 221         int tmp_fields= ff_get_v(bc);
 222         if(tmp_fields>0) tmp_pts   = get_s(bc);
 223         if(tmp_fields>1) tmp_mul   = ff_get_v(bc);
 224         if(tmp_fields>2) tmp_stream= ff_get_v(bc);
 225         if(tmp_fields>3) tmp_size  = ff_get_v(bc);
 226         else             tmp_size  = 0;
 227         if(tmp_fields>4) tmp_res   = ff_get_v(bc);
 228         else             tmp_res   = 0;
 229         if(tmp_fields>5) count     = ff_get_v(bc);
 230         else             count     = tmp_mul - tmp_size;
 231         if(tmp_fields>6) tmp_match = get_s(bc);
 232         if(tmp_fields>7) tmp_head_idx= ff_get_v(bc);
 233
 234         while(tmp_fields-- > 8)
 235            ff_get_v(bc);
 236
 237         if(count == 0 || i+count > 256){
 238             av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
 239             return -1;
 240         }
 241         if(tmp_stream >= stream_count){
 242             av_log(s, AV_LOG_ERROR, "illegal stream number\n");
 243             return -1;
 244         }
 245
 246         for(j=0; j<count; j++,i++){
 247             if (i == 'N') {
 248                 nut->frame_code[i].flags= FLAG_INVALID;
 249                 j--;
 250                 continue;
 251             }
 252             nut->frame_code[i].flags           = tmp_flags ;
 253             nut->frame_code[i].pts_delta       = tmp_pts   ;
 254             nut->frame_code[i].stream_id       = tmp_stream;
 255             nut->frame_code[i].size_mul        = tmp_mul   ;
 256             nut->frame_code[i].size_lsb        = tmp_size+j;
 257             nut->frame_code[i].reserved_count  = tmp_res   ;
 258             nut->frame_code[i].header_idx      = tmp_head_idx;
 259         }
 260     }
 261     assert(nut->frame_code['N'].flags == FLAG_INVALID);
 262
 263     if(end > url_ftell(bc) + 4){
 264         int rem= 1024;
 265         GET_V(nut->header_count, tmp<128U)
 266         nut->header_count++;
 267         for(i=1; i<nut->header_count; i++){
 268             GET_V(nut->header_len[i], tmp>0 && tmp<256);
 269             rem -= nut->header_len[i];
 270             if(rem < 0){
 271                 av_log(s, AV_LOG_ERROR, "invalid elision header\n");
 272                 return -1;
 273             }
 274             nut->header[i]= av_malloc(nut->header_len[i]);
 275             get_buffer(bc, nut->header[i], nut->header_len[i]);
 276         }
 277         assert(nut->header_len[0]==0);
 278     }
 279
 280     if(skip_reserved(bc, end) || get_checksum(bc)){
 281         av_log(s, AV_LOG_ERROR, "main header checksum mismatch\n");
 282         return -1;
 283     }
 284
 285     nut->stream = av_mallocz(sizeof(StreamContext)*stream_count);
 286     for(i=0; i<stream_count; i++){
 287         av_new_stream(s, i);
 288     }
 289
 290     return 0;
 291 }
 292
 293 static int decode_stream_header(NUTContext *nut){
 294     AVFormatContext *s= nut->avf;
 295     ByteIOContext *bc = s->pb;
 296     StreamContext *stc;
 297     int class, stream_id;
 298     uint64_t tmp, end;
 299     AVStream *st;
 300
 301     end= get_packetheader(nut, bc, 1, STREAM_STARTCODE);
 302     end += url_ftell(bc);
 303
 304     GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base);
 305     stc= &nut->stream[stream_id];
 306
 307     st = s->streams[stream_id];
 308     if (!st)
 309         return AVERROR(ENOMEM);
 310
 311     class = ff_get_v(bc);
 312     tmp = get_fourcc(bc);
 313     st->codec->codec_tag= tmp;
 314     switch(class)
 315     {
 316         case 0:
 317             st->codec->codec_type = CODEC_TYPE_VIDEO;
 318             st->codec->codec_id = codec_get_id(codec_bmp_tags, tmp);
 319             break;
 320         case 1:
 321             st->codec->codec_type = CODEC_TYPE_AUDIO;
 322             st->codec->codec_id = codec_get_id(codec_wav_tags, tmp);
 323             break;
 324         case 2:
 325             st->codec->codec_type = CODEC_TYPE_SUBTITLE;
 326             st->codec->codec_id = codec_get_id(ff_nut_subtitle_tags, tmp);
 327             break;
 328         case 3:
 329             st->codec->codec_type = CODEC_TYPE_DATA;
 330             break;
 331         default:
 332             av_log(s, AV_LOG_ERROR, "unknown stream class (%d)\n", class);
 333             return -1;
 334     }
 335     if(class<3 && st->codec->codec_id == CODEC_ID_NONE)
 336         av_log(s, AV_LOG_ERROR, "Unknown codec?!\n");
 337
 338     GET_V(stc->time_base_id    , tmp < nut->time_base_count);
 339     GET_V(stc->msb_pts_shift   , tmp < 16);
 340     stc->max_pts_distance= ff_get_v(bc);
 341     GET_V(stc->decode_delay    , tmp < 1000); //sanity limit, raise this if Moore's law is true
 342     st->codec->has_b_frames= stc->decode_delay;
 343     ff_get_v(bc); //stream flags
 344
 345     GET_V(st->codec->extradata_size, tmp < (1<<30));
 346     if(st->codec->extradata_size){
 347         st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
 348         get_buffer(bc, st->codec->extradata, st->codec->extradata_size);
 349     }
 350
 351     if (st->codec->codec_type == CODEC_TYPE_VIDEO){
 352         GET_V(st->codec->width , tmp > 0)
 353         GET_V(st->codec->height, tmp > 0)
 354         st->sample_aspect_ratio.num= ff_get_v(bc);
 355         st->sample_aspect_ratio.den= ff_get_v(bc);
 356         if((!st->sample_aspect_ratio.num) != (!st->sample_aspect_ratio.den)){
 357             av_log(s, AV_LOG_ERROR, "invalid aspect ratio %d/%d\n", st->sample_aspect_ratio.num, st->sample_aspect_ratio.den);
 358             return -1;
 359         }
 360         ff_get_v(bc); /* csp type */
 361     }else if (st->codec->codec_type == CODEC_TYPE_AUDIO){
 362         GET_V(st->codec->sample_rate , tmp > 0)
 363         ff_get_v(bc); // samplerate_den
 364         GET_V(st->codec->channels, tmp > 0)
 365     }
 366     if(skip_reserved(bc, end) || get_checksum(bc)){
 367         av_log(s, AV_LOG_ERROR, "stream header %d checksum mismatch\n", stream_id);
 368         return -1;
 369     }
 370     stc->time_base= &nut->time_base[stc->time_base_id];
 371     av_set_pts_info(s->streams[stream_id], 63, stc->time_base->num, stc->time_base->den);
 372     return 0;
 373 }
 374
 375 static void set_disposition_bits(AVFormatContext* avf, char* value, int stream_id){
 376     int flag = 0, i;
 377     for (i=0; ff_nut_dispositions[i].flag; ++i) {
 378         if (!strcmp(ff_nut_dispositions[i].str, value))
 379             flag = ff_nut_dispositions[i].flag;
 380     }
 381     if (!flag)
 382         av_log(avf, AV_LOG_INFO, "unknown disposition type '%s'\n", value);
 383     for (i = 0; i < avf->nb_streams; ++i)
 384         if (stream_id == i || stream_id == -1)
 385             avf->streams[i]->disposition |= flag;
 386 }
 387
 388 static int decode_info_header(NUTContext *nut){
 389     AVFormatContext *s= nut->avf;
 390     ByteIOContext *bc = s->pb;
 391     uint64_t tmp;
 392     unsigned int stream_id_plus1, chapter_start, chapter_len, count;
 393     int chapter_id, i;
 394     int64_t value, end;
 395     char name[256], str_value[1024], type_str[256];
 396     const char *type;
 397     AVChapter *chapter= NULL;
 398
 399     end= get_packetheader(nut, bc, 1, INFO_STARTCODE);
 400     end += url_ftell(bc);
 401
 402     GET_V(stream_id_plus1, tmp <= s->nb_streams)
 403     chapter_id   = get_s(bc);
 404     chapter_start= ff_get_v(bc);
 405     chapter_len  = ff_get_v(bc);
 406     count        = ff_get_v(bc);
 407
 408     if(chapter_id && !stream_id_plus1){
 409         int64_t start= chapter_start / nut->time_base_count;
 410         chapter= ff_new_chapter(s, chapter_id,
 411                                 nut->time_base[chapter_start % nut->time_base_count],
 412                                 start, start + chapter_len, NULL);
 413     }
 414
 415     for(i=0; i<count; i++){
 416         get_str(bc, name, sizeof(name));
 417         value= get_s(bc);
 418         if(value == -1){
 419             type= "UTF-8";
 420             get_str(bc, str_value, sizeof(str_value));
 421         }else if(value == -2){
 422             get_str(bc, type_str, sizeof(type_str));
 423             type= type_str;
 424             get_str(bc, str_value, sizeof(str_value));
 425         }else if(value == -3){
 426             type= "s";
 427             value= get_s(bc);
 428         }else if(value == -4){
 429             type= "t";
 430             value= ff_get_v(bc);
 431         }else if(value < -4){
 432             type= "r";
 433             get_s(bc);
 434         }else{
 435             type= "v";
 436         }
 437
 438         if (stream_id_plus1 > s->nb_streams) {
 439             av_log(s, AV_LOG_ERROR, "invalid stream id for info packet\n");
 440             continue;
 441         }
 442
 443         if(chapter_id==0 && !strcmp(type, "UTF-8")){
 444             if     (!strcmp(name, "Author"))
 445                 av_strlcpy(s->author   , str_value, sizeof(s->author));
 446             else if(!strcmp(name, "Title"))
 447                 av_strlcpy(s->title    , str_value, sizeof(s->title));
 448             else if(!strcmp(name, "Copyright"))
 449                 av_strlcpy(s->copyright, str_value, sizeof(s->copyright));
 450             else if(!strcmp(name, "Description"))
 451                 av_strlcpy(s->comment  , str_value, sizeof(s->comment));
 452             else if(!strcmp(name, "Disposition"))
 453                 set_disposition_bits(s, str_value, stream_id_plus1 - 1);
 454         }
 455         if(chapter && !strcmp(type, "UTF-8")){
 456             if(!strcmp(name, "Title"))
 457                 chapter->title= av_strdup(str_value);
 458         }
 459     }
 460
 461     if(skip_reserved(bc, end) || get_checksum(bc)){
 462         av_log(s, AV_LOG_ERROR, "info header checksum mismatch\n");
 463         return -1;
 464     }
 465     return 0;
 466 }
 467
 468 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr){
 469     AVFormatContext *s= nut->avf;
 470     ByteIOContext *bc = s->pb;
 471     int64_t end, tmp;
 472
 473     nut->last_syncpoint_pos= url_ftell(bc)-8;
 474
 475     end= get_packetheader(nut, bc, 1, SYNCPOINT_STARTCODE);
 476     end += url_ftell(bc);
 477
 478     tmp= ff_get_v(bc);
 479     *back_ptr= nut->last_syncpoint_pos - 16*ff_get_v(bc);
 480     if(*back_ptr < 0)
 481         return -1;
 482
 483     ff_nut_reset_ts(nut, nut->time_base[tmp % nut->time_base_count], tmp / nut->time_base_count);
 484
 485     if(skip_reserved(bc, end) || get_checksum(bc)){
 486         av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
 487         return -1;
 488     }
 489
 490     *ts= tmp / s->nb_streams * av_q2d(nut->time_base[tmp % s->nb_streams])*AV_TIME_BASE;
 491     ff_nut_add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts);
 492
 493     return 0;
 494 }
 495
 496 static int find_and_decode_index(NUTContext *nut){
 497     AVFormatContext *s= nut->avf;
 498     ByteIOContext *bc = s->pb;
 499     uint64_t tmp, end;
 500     int i, j, syncpoint_count;
 501     int64_t filesize= url_fsize(bc);
 502     int64_t *syncpoints;
 503     int8_t *has_keyframe;
 504     int ret= -1;
 505
 506     url_fseek(bc, filesize-12, SEEK_SET);
 507     url_fseek(bc, filesize-get_be64(bc), SEEK_SET);
 508     if(get_be64(bc) != INDEX_STARTCODE){
 509         av_log(s, AV_LOG_ERROR, "no index at the end\n");
 510         return -1;
 511     }
 512
 513     end= get_packetheader(nut, bc, 1, INDEX_STARTCODE);
 514     end += url_ftell(bc);
 515
 516     ff_get_v(bc); //max_pts
 517     GET_V(syncpoint_count, tmp < INT_MAX/8 && tmp > 0)
 518     syncpoints= av_malloc(sizeof(int64_t)*syncpoint_count);
 519     has_keyframe= av_malloc(sizeof(int8_t)*(syncpoint_count+1));
 520     for(i=0; i<syncpoint_count; i++){
 521         syncpoints[i] = ff_get_v(bc);
 522         if(syncpoints[i] <= 0)
 523             goto fail;
 524         if(i)
 525             syncpoints[i] += syncpoints[i-1];
 526     }
 527
 528     for(i=0; i<s->nb_streams; i++){
 529         int64_t last_pts= -1;
 530         for(j=0; j<syncpoint_count;){
 531             uint64_t x= ff_get_v(bc);
 532             int type= x&1;
 533             int n= j;
 534             x>>=1;
 535             if(type){
 536                 int flag= x&1;
 537                 x>>=1;
 538                 if(n+x >= syncpoint_count + 1){
 539                     av_log(s, AV_LOG_ERROR, "index overflow A\n");
 540                     goto fail;
 541                 }
 542                 while(x--)
 543                     has_keyframe[n++]= flag;
 544                 has_keyframe[n++]= !flag;
 545             }else{
 546                 while(x != 1){
 547                     if(n>=syncpoint_count + 1){
 548                         av_log(s, AV_LOG_ERROR, "index overflow B\n");
 549                         goto fail;
 550                     }
 551                     has_keyframe[n++]= x&1;
 552                     x>>=1;
 553                 }
 554             }
 555             if(has_keyframe[0]){
 556                 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
 557                 goto fail;
 558             }
 559             assert(n<=syncpoint_count+1);
 560             for(; j<n && j<syncpoint_count; j++){
 561                 if(has_keyframe[j]){
 562                     uint64_t B, A= ff_get_v(bc);
 563                     if(!A){
 564                         A= ff_get_v(bc);
 565                         B= ff_get_v(bc);
 566                         //eor_pts[j][i] = last_pts + A + B
 567                     }else
 568                         B= 0;
 569                     av_add_index_entry(
 570                         s->streams[i],
 571                         16*syncpoints[j-1],
 572                         last_pts + A,
 573                         0,
 574                         0,
 575                         AVINDEX_KEYFRAME);
 576                     last_pts += A + B;
 577                 }
 578             }
 579         }
 580     }
 581
 582     if(skip_reserved(bc, end) || get_checksum(bc)){
 583         av_log(s, AV_LOG_ERROR, "index checksum mismatch\n");
 584         goto fail;
 585     }
 586     ret= 0;
 587 fail:
 588     av_free(syncpoints);
 589     av_free(has_keyframe);
 590     return ret;
 591 }
 592
 593 static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)
 594 {
 595     NUTContext *nut = s->priv_data;
 596     ByteIOContext *bc = s->pb;
 597     int64_t pos;
 598     int initialized_stream_count;
 599
 600     nut->avf= s;
 601
 602     /* main header */
 603     pos=0;
 604     do{
 605         pos= find_startcode(bc, MAIN_STARTCODE, pos)+1;
 606         if (pos<0+1){
 607             av_log(s, AV_LOG_ERROR, "No main startcode found.\n");
 608             return -1;
 609         }
 610     }while(decode_main_header(nut) < 0);
 611
 612     /* stream headers */
 613     pos=0;
 614     for(initialized_stream_count=0; initialized_stream_count < s->nb_streams;){
 615         pos= find_startcode(bc, STREAM_STARTCODE, pos)+1;
 616         if (pos<0+1){
 617             av_log(s, AV_LOG_ERROR, "Not all stream headers found.\n");
 618             return -1;
 619         }
 620         if(decode_stream_header(nut) >= 0)
 621             initialized_stream_count++;
 622     }
 623
 624     /* info headers */
 625     pos=0;
 626     for(;;){
 627         uint64_t startcode= find_any_startcode(bc, pos);
 628         pos= url_ftell(bc);
 629
 630         if(startcode==0){
 631             av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
 632             return -1;
 633         }else if(startcode == SYNCPOINT_STARTCODE){
 634             nut->next_startcode= startcode;
 635             break;
 636         }else if(startcode != INFO_STARTCODE){
 637             continue;
 638         }
 639
 640         decode_info_header(nut);
 641     }
 642
 643     s->data_offset= pos-8;
 644
 645     if(!url_is_streamed(bc)){
 646         int64_t orig_pos= url_ftell(bc);
 647         find_and_decode_index(nut);
 648         url_fseek(bc, orig_pos, SEEK_SET);
 649     }
 650     assert(nut->next_startcode == SYNCPOINT_STARTCODE);
 651
 652     return 0;
 653 }
 654
 655 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id, uint8_t *header_idx, int frame_code){
 656     AVFormatContext *s= nut->avf;
 657     ByteIOContext *bc = s->pb;
 658     StreamContext *stc;
 659     int size, flags, size_mul, pts_delta, i, reserved_count;
 660     uint64_t tmp;
 661
 662     if(url_ftell(bc) > nut->last_syncpoint_pos + nut->max_distance){
 663         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);
 664         return -1;
 665     }
 666
 667     flags          = nut->frame_code[frame_code].flags;
 668     size_mul       = nut->frame_code[frame_code].size_mul;
 669     size           = nut->frame_code[frame_code].size_lsb;
 670     *stream_id     = nut->frame_code[frame_code].stream_id;
 671     pts_delta      = nut->frame_code[frame_code].pts_delta;
 672     reserved_count = nut->frame_code[frame_code].reserved_count;
 673     *header_idx    = nut->frame_code[frame_code].header_idx;
 674
 675     if(flags & FLAG_INVALID)
 676         return -1;
 677     if(flags & FLAG_CODED)
 678         flags ^= ff_get_v(bc);
 679     if(flags & FLAG_STREAM_ID){
 680         GET_V(*stream_id, tmp < s->nb_streams)
 681     }
 682     stc= &nut->stream[*stream_id];
 683     if(flags&FLAG_CODED_PTS){
 684         int coded_pts= ff_get_v(bc);
 685 //FIXME check last_pts validity?
 686         if(coded_pts < (1<<stc->msb_pts_shift)){
 687             *pts=ff_lsb2full(stc, coded_pts);
 688         }else
 689             *pts=coded_pts - (1<<stc->msb_pts_shift);
 690     }else
 691         *pts= stc->last_pts + pts_delta;
 692     if(flags&FLAG_SIZE_MSB){
 693         size += size_mul*ff_get_v(bc);
 694     }
 695     if(flags&FLAG_MATCH_TIME)
 696         get_s(bc);
 697     if(flags&FLAG_HEADER_IDX)
 698         *header_idx= ff_get_v(bc);
 699     if(flags&FLAG_RESERVED)
 700         reserved_count= ff_get_v(bc);
 701     for(i=0; i<reserved_count; i++)
 702         ff_get_v(bc);
 703
 704     if(*header_idx >= (unsigned)nut->header_count){
 705         av_log(s, AV_LOG_ERROR, "header_idx invalid\n");
 706         return -1;
 707     }
 708     if(size > 4096)
 709         *header_idx=0;
 710     size -= nut->header_len[*header_idx];
 711
 712     if(flags&FLAG_CHECKSUM){
 713         get_be32(bc); //FIXME check this
 714     }else if(size > 2*nut->max_distance || FFABS(stc->last_pts - *pts) > stc->max_pts_distance){
 715         av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
 716         return -1;
 717     }
 718
 719     stc->last_pts= *pts;
 720     stc->last_flags= flags;
 721
 722     return size;
 723 }
 724
 725 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code){
 726     AVFormatContext *s= nut->avf;
 727     ByteIOContext *bc = s->pb;
 728     int size, stream_id, discard;
 729     int64_t pts, last_IP_pts;
 730     StreamContext *stc;
 731     uint8_t header_idx;
 732
 733     size= decode_frame_header(nut, &pts, &stream_id, &header_idx, frame_code);
 734     if(size < 0)
 735         return -1;
 736
 737     stc= &nut->stream[stream_id];
 738
 739     if (stc->last_flags & FLAG_KEY)
 740         stc->skip_until_key_frame=0;
 741
 742     discard= s->streams[ stream_id ]->discard;
 743     last_IP_pts= s->streams[ stream_id ]->last_IP_pts;
 744     if(  (discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY))
 745        ||(discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE && last_IP_pts > pts)
 746        || discard >= AVDISCARD_ALL
 747        || stc->skip_until_key_frame){
 748         url_fskip(bc, size);
 749         return 1;
 750     }
 751
 752     av_new_packet(pkt, size + nut->header_len[header_idx]);
 753     memcpy(pkt->data, nut->header[header_idx], nut->header_len[header_idx]);
 754     pkt->pos= url_ftell(bc); //FIXME
 755     get_buffer(bc, pkt->data + nut->header_len[header_idx], size);
 756
 757     pkt->stream_index = stream_id;
 758     if (stc->last_flags & FLAG_KEY)
 759         pkt->flags |= PKT_FLAG_KEY;
 760     pkt->pts = pts;
 761
 762     return 0;
 763 }
 764
 765 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
 766 {
 767     NUTContext *nut = s->priv_data;
 768     ByteIOContext *bc = s->pb;
 769     int i, frame_code=0, ret, skip;
 770     int64_t ts, back_ptr;
 771
 772     for(;;){
 773         int64_t pos= url_ftell(bc);
 774         uint64_t tmp= nut->next_startcode;
 775         nut->next_startcode=0;
 776
 777         if(tmp){
 778             pos-=8;
 779         }else{
 780             frame_code = get_byte(bc);
 781             if(url_feof(bc))
 782                 return -1;
 783             if(frame_code == 'N'){
 784                 tmp= frame_code;
 785                 for(i=1; i<8; i++)
 786                     tmp = (tmp<<8) + get_byte(bc);
 787             }
 788         }
 789         switch(tmp){
 790         case MAIN_STARTCODE:
 791         case STREAM_STARTCODE:
 792         case INDEX_STARTCODE:
 793             skip= get_packetheader(nut, bc, 0, tmp);
 794             url_fseek(bc, skip, SEEK_CUR);
 795             break;
 796         case INFO_STARTCODE:
 797             if(decode_info_header(nut)<0)
 798                 goto resync;
 799             break;
 800         case SYNCPOINT_STARTCODE:
 801             if(decode_syncpoint(nut, &ts, &back_ptr)<0)
 802                 goto resync;
 803             frame_code = get_byte(bc);
 804         case 0:
 805             ret= decode_frame(nut, pkt, frame_code);
 806             if(ret==0)
 807                 return 0;
 808             else if(ret==1) //ok but discard packet
 809                 break;
 810         default:
 811 resync:
 812 av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
 813             tmp= find_any_startcode(bc, nut->last_syncpoint_pos+1);
 814             if(tmp==0)
 815                 return -1;
 816 av_log(s, AV_LOG_DEBUG, "sync\n");
 817             nut->next_startcode= tmp;
 818         }
 819     }
 820 }
 821
 822 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index, int64_t *pos_arg, int64_t pos_limit){
 823     NUTContext *nut = s->priv_data;
 824     ByteIOContext *bc = s->pb;
 825     int64_t pos, pts, back_ptr;
 826 av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n", stream_index, *pos_arg, pos_limit);
 827
 828     pos= *pos_arg;
 829     do{
 830         pos= find_startcode(bc, SYNCPOINT_STARTCODE, pos)+1;
 831         if(pos < 1){
 832             assert(nut->next_startcode == 0);
 833             av_log(s, AV_LOG_ERROR, "read_timestamp failed.\n");
 834             return AV_NOPTS_VALUE;
 835         }
 836     }while(decode_syncpoint(nut, &pts, &back_ptr) < 0);
 837     *pos_arg = pos-1;
 838     assert(nut->last_syncpoint_pos == *pos_arg);
 839
 840     av_log(s, AV_LOG_DEBUG, "return %"PRId64" %"PRId64"\n", pts,back_ptr );
 841     if     (stream_index == -1) return pts;
 842     else if(stream_index == -2) return back_ptr;
 843
 844 assert(0);
 845 }
 846
 847 static int read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags){
 848     NUTContext *nut = s->priv_data;
 849     AVStream *st= s->streams[stream_index];
 850     Syncpoint dummy={.ts= pts*av_q2d(st->time_base)*AV_TIME_BASE};
 851     Syncpoint nopts_sp= {.ts= AV_NOPTS_VALUE, .back_ptr= AV_NOPTS_VALUE};
 852     Syncpoint *sp, *next_node[2]= {&nopts_sp, &nopts_sp};
 853     int64_t pos, pos2, ts;
 854     int i;
 855
 856     if(st->index_entries){
 857         int index= av_index_search_timestamp(st, pts, flags);
 858         if(index<0)
 859             return -1;
 860
 861         pos2= st->index_entries[index].pos;
 862         ts  = st->index_entries[index].timestamp;
 863     }else{
 864         av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pts_cmp, next_node);
 865         av_log(s, AV_LOG_DEBUG, "%"PRIu64"-%"PRIu64" %"PRId64"-%"PRId64"\n", next_node[0]->pos, next_node[1]->pos,
 866                                                     next_node[0]->ts , next_node[1]->ts);
 867         pos= av_gen_search(s, -1, dummy.ts, next_node[0]->pos, next_node[1]->pos, next_node[1]->pos,
 868                                             next_node[0]->ts , next_node[1]->ts, AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
 869
 870         if(!(flags & AVSEEK_FLAG_BACKWARD)){
 871             dummy.pos= pos+16;
 872             next_node[1]= &nopts_sp;
 873             av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp, next_node);
 874             pos2= av_gen_search(s, -2, dummy.pos, next_node[0]->pos     , next_node[1]->pos, next_node[1]->pos,
 875                                                 next_node[0]->back_ptr, next_node[1]->back_ptr, flags, &ts, nut_read_timestamp);
 876             if(pos2>=0)
 877                 pos= pos2;
 878             //FIXME dir but I think it does not matter
 879         }
 880         dummy.pos= pos;
 881         sp= av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp, NULL);
 882
 883         assert(sp);
 884         pos2= sp->back_ptr  - 15;
 885     }
 886     av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
 887     pos= find_startcode(s->pb, SYNCPOINT_STARTCODE, pos2);
 888     url_fseek(s->pb, pos, SEEK_SET);
 889     av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
 890     if(pos2 > pos || pos2 + 15 < pos){
 891         av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
 892     }
 893     for(i=0; i<s->nb_streams; i++)
 894         nut->stream[i].skip_until_key_frame=1;
 895
 896     return 0;
 897 }
 898
 899 static int nut_read_close(AVFormatContext *s)
 900 {
 901     NUTContext *nut = s->priv_data;
 902
 903     av_freep(&nut->time_base);
 904     av_freep(&nut->stream);
 905
 906     return 0;
 907 }
 908
 909 #if CONFIG_NUT_DEMUXER
 910 AVInputFormat nut_demuxer = {
 911     "nut",
 912     NULL_IF_CONFIG_SMALL("NUT format"),
 913     sizeof(NUTContext),
 914     nut_probe,
 915     nut_read_header,
 916     nut_read_packet,
 917     nut_read_close,
 918     read_seek,
 919     .extensions = "nut",
 920 };
 921 #endif