git.sesse.net Git - ffmpeg/blob - 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
  24 #include "tree.h"
  25 #include "nut.h"
  26
  27 #undef NDEBUG
  28 #include <assert.h>
  29
  30 static uint64_t get_v(ByteIOContext *bc){
  31     uint64_t val = 0;
  32     int tmp;
  33
  34     do{
  35         tmp = get_byte(bc);
  36         val= (val<<7) + (tmp&127);
  37     }while(tmp&128);
  38     return val;
  39 }
  40
  41 static int get_str(ByteIOContext *bc, char *string, unsigned int maxlen){
  42     unsigned int len= get_v(bc);
  43
  44     if(len && maxlen)
  45         get_buffer(bc, string, FFMIN(len, maxlen));
  46     while(len > maxlen){
  47         get_byte(bc);
  48         len--;
  49     }
  50
  51     if(maxlen)
  52         string[FFMIN(len, maxlen-1)]= 0;
  53
  54     if(maxlen == len)
  55         return -1;
  56     else
  57         return 0;
  58 }
  59
  60 static int64_t get_s(ByteIOContext *bc){
  61     int64_t v = get_v(bc) + 1;
  62
  63     if (v&1) return -(v>>1);
  64     else     return  (v>>1);
  65 }
  66
  67 static uint64_t get_fourcc(ByteIOContext *bc){
  68     unsigned int len= get_v(bc);
  69
  70     if     (len==2) return get_le16(bc);
  71     else if(len==4) return get_le32(bc);
  72     else            return -1;
  73 }
  74
  75 #ifdef TRACE
  76 static inline uint64_t get_v_trace(ByteIOContext *bc, char *file, char *func, int line){
  77     uint64_t v= get_v(bc);
  78
  79     printf("get_v %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  80     return v;
  81 }
  82
  83 static inline int64_t get_s_trace(ByteIOContext *bc, char *file, char *func, int line){
  84     int64_t v= get_s(bc);
  85
  86     printf("get_s %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  87     return v;
  88 }
  89
  90 static inline uint64_t get_vb_trace(ByteIOContext *bc, char *file, char *func, int line){
  91     uint64_t v= get_vb(bc);
  92
  93     printf("get_vb %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  94     return v;
  95 }
  96 #define get_v(bc)  get_v_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
  97 #define get_s(bc)  get_s_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
  98 #define get_vb(bc)  get_vb_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
  99 #endif
 100
 101 static int get_packetheader(NUTContext *nut, ByteIOContext *bc, int calculate_checksum)
 102 {
 103     int64_t start, size;
 104 //    start= url_ftell(bc) - 8;
 105
 106     size= get_v(bc);
 107
 108     init_checksum(bc, calculate_checksum ? av_crc04C11DB7_update : NULL, 0);
 109
 110 //    nut->packet_start[2] = start;
 111 //    nut->written_packet_size= size;
 112
 113     return size;
 114 }
 115
 116 static uint64_t find_any_startcode(ByteIOContext *bc, int64_t pos){
 117     uint64_t state=0;
 118
 119     if(pos >= 0)
 120         url_fseek(bc, pos, SEEK_SET); //note, this may fail if the stream isnt seekable, but that shouldnt matter, as in this case we simply start where we are currently
 121
 122     while(!url_feof(bc)){
 123         state= (state<<8) | get_byte(bc);
 124         if((state>>56) != 'N')
 125             continue;
 126         switch(state){
 127         case MAIN_STARTCODE:
 128         case STREAM_STARTCODE:
 129         case SYNCPOINT_STARTCODE:
 130         case INFO_STARTCODE:
 131         case INDEX_STARTCODE:
 132             return state;
 133         }
 134     }
 135
 136     return 0;
 137 }
 138
 139 /**
 140  * find the given startcode.
 141  * @param code the startcode
 142  * @param pos the start position of the search, or -1 if the current position
 143  * @returns the position of the startcode or -1 if not found
 144  */
 145 static int64_t find_startcode(ByteIOContext *bc, uint64_t code, int64_t pos){
 146     for(;;){
 147         uint64_t startcode= find_any_startcode(bc, pos);
 148         if(startcode == code)
 149             return url_ftell(bc) - 8;
 150         else if(startcode == 0)
 151             return -1;
 152         pos=-1;
 153     }
 154 }
 155
 156 static int64_t lsb2full(StreamContext *stream, int64_t lsb){
 157     int64_t mask = (1<<stream->msb_pts_shift)-1;
 158     int64_t delta= stream->last_pts - mask/2;
 159     return  ((lsb - delta)&mask) + delta;
 160 }
 161
 162 static int nut_probe(AVProbeData *p){
 163     int i;
 164     uint64_t code= 0;
 165
 166     for (i = 0; i < p->buf_size; i++) {
 167         code = (code << 8) | p->buf[i];
 168         if (code == MAIN_STARTCODE)
 169             return AVPROBE_SCORE_MAX;
 170     }
 171     return 0;
 172 }
 173
 174 #define GET_V(dst, check) \
 175     tmp= get_v(bc);\
 176     if(!(check)){\
 177         av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp);\
 178         return -1;\
 179     }\
 180     dst= tmp;
 181
 182 static int skip_reserved(ByteIOContext *bc, int64_t pos){
 183     pos -= url_ftell(bc);
 184     if(pos<0){
 185         url_fseek(bc, pos, SEEK_CUR);
 186         return -1;
 187     }else{
 188         while(pos--)
 189             get_byte(bc);
 190         return 0;
 191     }
 192 }
 193
 194 static int decode_main_header(NUTContext *nut){
 195     AVFormatContext *s= nut->avf;
 196     ByteIOContext *bc = &s->pb;
 197     uint64_t tmp, end;
 198     unsigned int stream_count;
 199     int i, j, tmp_stream, tmp_mul, tmp_pts, tmp_size, count, tmp_res;
 200
 201     end= get_packetheader(nut, bc, 1);
 202     end += url_ftell(bc);
 203
 204     GET_V(tmp              , tmp >=2 && tmp <= 3)
 205     GET_V(stream_count     , tmp > 0 && tmp <=MAX_STREAMS)
 206
 207     nut->max_distance = get_v(bc);
 208     if(nut->max_distance > 65536){
 209         av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
 210         nut->max_distance= 65536;
 211     }
 212
 213     GET_V(nut->time_base_count, tmp>0 && tmp<INT_MAX / sizeof(AVRational))
 214     nut->time_base= av_malloc(nut->time_base_count * sizeof(AVRational));
 215
 216     for(i=0; i<nut->time_base_count; i++){
 217         GET_V(nut->time_base[i].num, tmp>0 && tmp<(1ULL<<31))
 218         GET_V(nut->time_base[i].den, tmp>0 && tmp<(1ULL<<31))
 219         if(ff_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1){
 220             av_log(s, AV_LOG_ERROR, "time base invalid\n");
 221             return -1;
 222         }
 223     }
 224     tmp_pts=0;
 225     tmp_mul=1;
 226     tmp_stream=0;
 227     for(i=0; i<256;){
 228         int tmp_flags = get_v(bc);
 229         int tmp_fields= get_v(bc);
 230         if(tmp_fields>0) tmp_pts   = get_s(bc);
 231         if(tmp_fields>1) tmp_mul   = get_v(bc);
 232         if(tmp_fields>2) tmp_stream= get_v(bc);
 233         if(tmp_fields>3) tmp_size  = get_v(bc);
 234         else             tmp_size  = 0;
 235         if(tmp_fields>4) tmp_res   = get_v(bc);
 236         else             tmp_res   = 0;
 237         if(tmp_fields>5) count     = get_v(bc);
 238         else             count     = tmp_mul - tmp_size;
 239
 240         while(tmp_fields-- > 6)
 241            get_v(bc);
 242
 243         if(count == 0 || i+count > 256){
 244             av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
 245             return -1;
 246         }
 247         if(tmp_stream >= stream_count){
 248             av_log(s, AV_LOG_ERROR, "illegal stream number\n");
 249             return -1;
 250         }
 251
 252         for(j=0; j<count; j++,i++){
 253             if (i == 'N') {
 254                 nut->frame_code[i].flags= FLAG_INVALID;
 255                 j--;
 256                 continue;
 257             }
 258             nut->frame_code[i].flags           = tmp_flags ;
 259             nut->frame_code[i].pts_delta       = tmp_pts   ;
 260             nut->frame_code[i].stream_id       = tmp_stream;
 261             nut->frame_code[i].size_mul        = tmp_mul   ;
 262             nut->frame_code[i].size_lsb        = tmp_size+j;
 263             nut->frame_code[i].reserved_count  = tmp_res   ;
 264         }
 265     }
 266     assert(nut->frame_code['N'].flags == FLAG_INVALID);
 267
 268     if(skip_reserved(bc, end) || get_checksum(bc)){
 269         av_log(s, AV_LOG_ERROR, "Main header checksum mismatch\n");
 270         return -1;
 271     }
 272
 273     nut->stream = av_mallocz(sizeof(StreamContext)*stream_count);
 274     for(i=0; i<stream_count; i++){
 275         av_new_stream(s, i);
 276     }
 277
 278     return 0;
 279 }
 280
 281 static int decode_stream_header(NUTContext *nut){
 282     AVFormatContext *s= nut->avf;
 283     ByteIOContext *bc = &s->pb;
 284     StreamContext *stc;
 285     int class, stream_id;
 286     uint64_t tmp, end;
 287     AVStream *st;
 288
 289     end= get_packetheader(nut, bc, 1);
 290     end += url_ftell(bc);
 291
 292     GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base.num);
 293     stc= &nut->stream[stream_id];
 294
 295     st = s->streams[stream_id];
 296     if (!st)
 297         return AVERROR_NOMEM;
 298
 299     class = get_v(bc);
 300     tmp = get_fourcc(bc);
 301     st->codec->codec_tag= tmp;
 302     switch(class)
 303     {
 304         case 0:
 305             st->codec->codec_type = CODEC_TYPE_VIDEO;
 306             st->codec->codec_id = codec_get_bmp_id(tmp);
 307             if (st->codec->codec_id == CODEC_ID_NONE)
 308                 av_log(s, AV_LOG_ERROR, "Unknown codec?!\n");
 309             break;
 310         case 1:
 311             st->codec->codec_type = CODEC_TYPE_AUDIO;
 312             st->codec->codec_id = codec_get_wav_id(tmp);
 313             if (st->codec->codec_id == CODEC_ID_NONE)
 314                 av_log(s, AV_LOG_ERROR, "Unknown codec?!\n");
 315             break;
 316         case 2:
 317 //            st->codec->codec_type = CODEC_TYPE_TEXT;
 318 //            break;
 319         case 3:
 320             st->codec->codec_type = CODEC_TYPE_DATA;
 321             break;
 322         default:
 323             av_log(s, AV_LOG_ERROR, "Unknown stream class (%d)\n", class);
 324             return -1;
 325     }
 326     GET_V(stc->time_base_id    , tmp < nut->time_base_count);
 327     GET_V(stc->msb_pts_shift   , tmp < 16);
 328     stc->max_pts_distance= get_v(bc);
 329     GET_V(stc->decode_delay    , tmp < 1000); //sanity limit, raise this if moors law is true
 330     st->codec->has_b_frames= stc->decode_delay;
 331     get_v(bc); //stream flags
 332
 333     GET_V(st->codec->extradata_size, tmp < (1<<30));
 334     if(st->codec->extradata_size){
 335         st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
 336         get_buffer(bc, st->codec->extradata, st->codec->extradata_size);
 337     }
 338
 339     if (st->codec->codec_type == CODEC_TYPE_VIDEO){
 340         GET_V(st->codec->width , tmp > 0)
 341         GET_V(st->codec->height, tmp > 0)
 342         st->codec->sample_aspect_ratio.num= get_v(bc);
 343         st->codec->sample_aspect_ratio.den= get_v(bc);
 344         if((!st->codec->sample_aspect_ratio.num) != (!st->codec->sample_aspect_ratio.den)){
 345             av_log(s, AV_LOG_ERROR, "invalid aspect ratio\n");
 346             return -1;
 347         }
 348         get_v(bc); /* csp type */
 349     }else if (st->codec->codec_type == CODEC_TYPE_AUDIO){
 350         GET_V(st->codec->sample_rate , tmp > 0)
 351         tmp= get_v(bc); // samplerate_den
 352         if(tmp > st->codec->sample_rate){
 353             av_log(s, AV_LOG_ERROR, "bleh, libnut muxed this ;)\n");
 354             st->codec->sample_rate= tmp;
 355         }
 356         GET_V(st->codec->channels, tmp > 0)
 357     }
 358     if(skip_reserved(bc, end) || get_checksum(bc)){
 359         av_log(s, AV_LOG_ERROR, "Stream header %d checksum mismatch\n", stream_id);
 360         return -1;
 361     }
 362     stc->time_base= nut->time_base[stc->time_base_id];
 363     av_set_pts_info(s->streams[stream_id], 63, stc->time_base.num, stc->time_base.den);
 364     return 0;
 365 }
 366
 367 static int decode_info_header(NUTContext *nut){
 368     AVFormatContext *s= nut->avf;
 369     ByteIOContext *bc = &s->pb;
 370     uint64_t tmp;
 371     unsigned int stream_id_plus1, chapter_start, chapter_len, count;
 372     int chapter_id, i;
 373     int64_t value, end;
 374     char name[256], str_value[1024], type_str[256], *type= type_str;
 375
 376     end= get_packetheader(nut, bc, 1);
 377     end += url_ftell(bc);
 378
 379     GET_V(stream_id_plus1, tmp <= s->nb_streams)
 380     chapter_id   = get_s(bc);
 381     chapter_start= get_v(bc);
 382     chapter_len  = get_v(bc);
 383     count        = get_v(bc);
 384     for(i=0; i<count; i++){
 385         get_str(bc, name, sizeof(name));
 386         value= get_s(bc);
 387         if(value == -1){
 388             type= "UTF-8";
 389             get_str(bc, str_value, sizeof(str_value));
 390         }else if(value == -2){
 391             get_str(bc, type, sizeof(type));
 392             get_str(bc, str_value, sizeof(str_value));
 393         }else if(value == -3){
 394             type= "s";
 395             value= get_s(bc);
 396         }else if(value == -4){
 397             type= "t";
 398             value= get_v(bc);
 399         }else if(value < -4){
 400             type= "r";
 401             get_s(bc);
 402         }else{
 403             type= "v";
 404         }
 405
 406         if(chapter_id==0 && !strcmp(type, "UTF-8")){
 407             if     (!strcmp(name, "Author"))
 408                 pstrcpy(s->author   , sizeof(s->author)   , str_value);
 409             else if(!strcmp(name, "Title"))
 410                 pstrcpy(s->title    , sizeof(s->title)    , str_value);
 411             else if(!strcmp(name, "Copyright"))
 412                 pstrcpy(s->copyright, sizeof(s->copyright), str_value);
 413             else if(!strcmp(name, "Description"))
 414                 pstrcpy(s->comment  , sizeof(s->comment)  , str_value);
 415         }
 416     }
 417
 418     if(skip_reserved(bc, end) || get_checksum(bc)){
 419         av_log(s, AV_LOG_ERROR, "Info header checksum mismatch\n");
 420         return -1;
 421     }
 422     return 0;
 423 }
 424
 425 int sp_pos_cmp(syncpoint_t *a, syncpoint_t *b){
 426     return (a->pos - b->pos>>32) - (b->pos - a->pos>>32);
 427 }
 428
 429 int sp_pts_cmp(syncpoint_t *a, syncpoint_t *b){
 430     return (a->ts - b->ts>>32) - (b->ts - a->ts>>32);
 431 }
 432
 433 static void add_sp(NUTContext *nut, int64_t pos, int64_t back_ptr, int64_t ts){
 434     syncpoint_t *sp2, *sp= av_mallocz(sizeof(syncpoint_t));
 435
 436     sp->pos= pos;
 437     sp->back_ptr= back_ptr;
 438     sp->ts= ts;
 439     sp2= av_tree_insert(&nut->syncpoints, sp, sp_pos_cmp);
 440     if(sp2 && sp2 != sp)
 441         av_free(sp);
 442 }
 443
 444 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr){
 445     AVFormatContext *s= nut->avf;
 446     ByteIOContext *bc = &s->pb;
 447     int64_t end, tmp;
 448     int i;
 449     AVRational time_base;
 450
 451     nut->last_syncpoint_pos= url_ftell(bc)-8;
 452
 453     end= get_packetheader(nut, bc, 1);
 454     end += url_ftell(bc);
 455
 456     tmp= get_v(bc);
 457     *back_ptr= nut->last_syncpoint_pos - 16*get_v(bc);
 458     if(*back_ptr < 0)
 459         return -1;
 460
 461     time_base= nut->time_base[tmp % nut->time_base_count];
 462     for(i=0; i<s->nb_streams; i++){
 463         nut->stream[i].last_pts= av_rescale_rnd(
 464             tmp / nut->time_base_count,
 465             time_base.num * (int64_t)nut->stream[i].time_base.den,
 466             time_base.den * (int64_t)nut->stream[i].time_base.num,
 467             AV_ROUND_DOWN);
 468         //last_key_frame ?
 469     }
 470     //FIXME put this in a reset func maybe
 471
 472     if(skip_reserved(bc, end) || get_checksum(bc)){
 473         av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
 474         return -1;
 475     }
 476
 477     *ts= tmp / s->nb_streams * av_q2d(nut->time_base[tmp % s->nb_streams])*AV_TIME_BASE;
 478     add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts);
 479
 480     return 0;
 481 }
 482
 483 static int find_and_decode_index(NUTContext *nut){
 484     AVFormatContext *s= nut->avf;
 485     ByteIOContext *bc = &s->pb;
 486     uint64_t tmp, end;
 487     int i, j, syncpoint_count;
 488     int64_t filesize= url_fsize(bc);
 489     int64_t *syncpoints;
 490     int8_t *has_keyframe;
 491
 492     url_fseek(bc, filesize-12, SEEK_SET);
 493     url_fseek(bc, filesize-get_be64(bc), SEEK_SET);
 494     if(get_be64(bc) != INDEX_STARTCODE){
 495         av_log(s, AV_LOG_ERROR, "no index at the end\n");
 496         return -1;
 497     }
 498
 499     end= get_packetheader(nut, bc, 1);
 500     end += url_ftell(bc);
 501
 502     get_v(bc); //max_pts
 503     GET_V(syncpoint_count, tmp < INT_MAX/8 && tmp > 0)
 504     syncpoints= av_malloc(sizeof(int64_t)*syncpoint_count);
 505     has_keyframe= av_malloc(sizeof(int8_t)*(syncpoint_count+1));
 506     for(i=0; i<syncpoint_count; i++){
 507         GET_V(syncpoints[i], tmp>0)
 508         if(i)
 509             syncpoints[i] += syncpoints[i-1];
 510     }
 511
 512     for(i=0; i<s->nb_streams; i++){
 513         int64_t last_pts= -1;
 514         for(j=0; j<syncpoint_count;){
 515             uint64_t x= get_v(bc);
 516             int type= x&1;
 517             int n= j;
 518             x>>=1;
 519             if(type){
 520                 int flag= x&1;
 521                 x>>=1;
 522                 if(n+x >= syncpoint_count + 1){
 523                     av_log(s, AV_LOG_ERROR, "index overflow A\n");
 524                     return -1;
 525                 }
 526                 while(x--)
 527                     has_keyframe[n++]= flag;
 528                 has_keyframe[n++]= !flag;
 529             }else{
 530                 while(x != 1){
 531                     if(n>=syncpoint_count + 1){
 532                         av_log(s, AV_LOG_ERROR, "index overflow B\n");
 533                         return -1;
 534                     }
 535                     has_keyframe[n++]= x&1;
 536                     x>>=1;
 537                 }
 538             }
 539             if(has_keyframe[0]){
 540                 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
 541                 return -1;
 542             }
 543             assert(n<=syncpoint_count+1);
 544             for(; j<n; j++){
 545                 if(has_keyframe[j]){
 546                     uint64_t B, A= get_v(bc);
 547                     if(!A){
 548                         A= get_v(bc);
 549                         B= get_v(bc);
 550                         //eor_pts[j][i] = last_pts + A + B
 551                     }else
 552                         B= 0;
 553                     av_add_index_entry(
 554                         s->streams[i],
 555                         16*syncpoints[j-1],
 556                         last_pts + A,
 557                         0,
 558                         0,
 559                         AVINDEX_KEYFRAME);
 560                     last_pts += A + B;
 561                 }
 562             }
 563         }
 564     }
 565
 566     if(skip_reserved(bc, end) || get_checksum(bc)){
 567         av_log(s, AV_LOG_ERROR, "Index checksum mismatch\n");
 568         return -1;
 569     }
 570     return 0;
 571 }
 572
 573 static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)
 574 {
 575     NUTContext *nut = s->priv_data;
 576     ByteIOContext *bc = &s->pb;
 577     int64_t pos;
 578     int inited_stream_count;
 579
 580     nut->avf= s;
 581
 582     /* main header */
 583     pos=0;
 584     do{
 585         pos= find_startcode(bc, MAIN_STARTCODE, pos)+1;
 586         if (pos<0+1){
 587             av_log(s, AV_LOG_ERROR, "no main startcode found\n");
 588             return -1;
 589         }
 590     }while(decode_main_header(nut) < 0);
 591
 592     /* stream headers */
 593     pos=0;
 594     for(inited_stream_count=0; inited_stream_count < s->nb_streams;){
 595         pos= find_startcode(bc, STREAM_STARTCODE, pos)+1;
 596         if (pos<0+1){
 597             av_log(s, AV_LOG_ERROR, "not all stream headers found\n");
 598             return -1;
 599         }
 600         if(decode_stream_header(nut) >= 0)
 601             inited_stream_count++;
 602     }
 603
 604     /* info headers */
 605     pos=0;
 606     for(;;){
 607         uint64_t startcode= find_any_startcode(bc, pos);
 608         pos= url_ftell(bc);
 609
 610         if(startcode==0){
 611             av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
 612             return -1;
 613         }else if(startcode == SYNCPOINT_STARTCODE){
 614             nut->next_startcode= startcode;
 615             break;
 616         }else if(startcode != INFO_STARTCODE){
 617             continue;
 618         }
 619
 620         decode_info_header(nut);
 621     }
 622
 623     s->data_offset= pos-8;
 624
 625     if(!url_is_streamed(bc)){
 626         int64_t orig_pos= url_ftell(bc);
 627         find_and_decode_index(nut);
 628         url_fseek(bc, orig_pos, SEEK_SET);
 629     }
 630     assert(nut->next_startcode == SYNCPOINT_STARTCODE);
 631
 632     return 0;
 633 }
 634
 635 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id, int frame_code){
 636     AVFormatContext *s= nut->avf;
 637     ByteIOContext *bc = &s->pb;
 638     StreamContext *stc;
 639     int size, flags, size_mul, pts_delta, i, reserved_count;
 640     uint64_t tmp;
 641
 642     if(url_ftell(bc) > nut->last_syncpoint_pos + nut->max_distance){
 643         av_log(s, AV_LOG_ERROR, "last frame must have been damaged %Ld > %Ld + %d\n", url_ftell(bc), nut->last_syncpoint_pos, nut->max_distance);
 644         return -1;
 645     }
 646
 647     flags          = nut->frame_code[frame_code].flags;
 648     size_mul       = nut->frame_code[frame_code].size_mul;
 649     size           = nut->frame_code[frame_code].size_lsb;
 650     *stream_id     = nut->frame_code[frame_code].stream_id;
 651     pts_delta      = nut->frame_code[frame_code].pts_delta;
 652     reserved_count = nut->frame_code[frame_code].reserved_count;
 653
 654     if(flags & FLAG_INVALID)
 655         return -1;
 656     if(flags & FLAG_CODED)
 657         flags ^= get_v(bc);
 658     if(flags & FLAG_STREAM_ID){
 659         GET_V(*stream_id, tmp < s->nb_streams)
 660     }
 661     stc= &nut->stream[*stream_id];
 662     if(flags&FLAG_CODED_PTS){
 663         int coded_pts= get_v(bc);
 664 //FIXME check last_pts validity?
 665         if(coded_pts < (1<<stc->msb_pts_shift)){
 666             *pts=lsb2full(stc, coded_pts);
 667         }else
 668             *pts=coded_pts - (1<<stc->msb_pts_shift);
 669     }else
 670         *pts= stc->last_pts + pts_delta;
 671     if(flags&FLAG_SIZE_MSB){
 672         size += size_mul*get_v(bc);
 673     }
 674     if(flags&FLAG_RESERVED)
 675         reserved_count= get_v(bc);
 676     for(i=0; i<reserved_count; i++)
 677         get_v(bc);
 678     if(flags&FLAG_CHECKSUM){
 679         get_be32(bc); //FIXME check this
 680     }else if(size > 2*nut->max_distance || FFABS(stc->last_pts - *pts) > stc->max_pts_distance){
 681         av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
 682         return -1;
 683     }
 684
 685     stc->last_pts= *pts;
 686     stc->last_flags= flags;
 687
 688     return size;
 689 }
 690
 691 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code){
 692     AVFormatContext *s= nut->avf;
 693     ByteIOContext *bc = &s->pb;
 694     int size, stream_id, discard;
 695     int64_t pts, last_IP_pts;
 696     StreamContext *stc;
 697
 698     size= decode_frame_header(nut, &pts, &stream_id, frame_code);
 699     if(size < 0)
 700         return -1;
 701
 702     stc= &nut->stream[stream_id];
 703
 704     if (stc->last_flags & FLAG_KEY)
 705         stc->skip_until_key_frame=0;
 706
 707     discard= s->streams[ stream_id ]->discard;
 708     last_IP_pts= s->streams[ stream_id ]->last_IP_pts;
 709     if(  (discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY))
 710        ||(discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE && last_IP_pts > pts)
 711        || discard >= AVDISCARD_ALL
 712        || stc->skip_until_key_frame){
 713         url_fskip(bc, size);
 714         return 1;
 715     }
 716
 717     av_get_packet(bc, pkt, size);
 718     pkt->stream_index = stream_id;
 719     if (stc->last_flags & FLAG_KEY)
 720         pkt->flags |= PKT_FLAG_KEY;
 721     pkt->pts = pts;
 722
 723     return 0;
 724 }
 725
 726 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
 727 {
 728     NUTContext *nut = s->priv_data;
 729     ByteIOContext *bc = &s->pb;
 730     int i, frame_code=0, ret, skip;
 731     int64_t ts, back_ptr;
 732
 733     for(;;){
 734         int64_t pos= url_ftell(bc);
 735         uint64_t tmp= nut->next_startcode;
 736         nut->next_startcode=0;
 737
 738         if (url_feof(bc))
 739             return -1;
 740
 741         if(tmp){
 742             pos-=8;
 743         }else{
 744             frame_code = get_byte(bc);
 745             if(frame_code == 'N'){
 746                 tmp= frame_code;
 747                 for(i=1; i<8; i++)
 748                     tmp = (tmp<<8) + get_byte(bc);
 749             }
 750         }
 751         switch(tmp){
 752         case MAIN_STARTCODE:
 753         case STREAM_STARTCODE:
 754         case INDEX_STARTCODE:
 755             skip= get_packetheader(nut, bc, 0);
 756             url_fseek(bc, skip, SEEK_CUR);
 757             break;
 758         case INFO_STARTCODE:
 759             if(decode_info_header(nut)<0)
 760                 goto resync;
 761             break;
 762         case SYNCPOINT_STARTCODE:
 763             if(decode_syncpoint(nut, &ts, &back_ptr)<0)
 764                 goto resync;
 765             frame_code = get_byte(bc);
 766         case 0:
 767             ret= decode_frame(nut, pkt, frame_code);
 768             if(ret==0)
 769                 return 0;
 770             else if(ret==1) //ok but discard packet
 771                 break;
 772         default:
 773 resync:
 774 av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
 775             tmp= find_any_startcode(bc, nut->last_syncpoint_pos+1);
 776             if(tmp==0)
 777                 return -1;
 778 av_log(s, AV_LOG_DEBUG, "sync\n");
 779             nut->next_startcode= tmp;
 780         }
 781     }
 782 }
 783
 784 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index, int64_t *pos_arg, int64_t pos_limit){
 785     NUTContext *nut = s->priv_data;
 786     ByteIOContext *bc = &s->pb;
 787     int64_t pos, pts, back_ptr;
 788 av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n", stream_index, *pos_arg, pos_limit);
 789
 790     pos= *pos_arg;
 791 resync:
 792     do{
 793         pos= find_startcode(bc, SYNCPOINT_STARTCODE, pos)+1;
 794         if(pos < 1){
 795             assert(nut->next_startcode == 0);
 796             av_log(s, AV_LOG_ERROR, "read_timestamp failed\n");
 797             return AV_NOPTS_VALUE;
 798         }
 799     }while(decode_syncpoint(nut, &pts, &back_ptr) < 0);
 800     *pos_arg = pos-1;
 801     assert(nut->last_syncpoint_pos == *pos_arg);
 802
 803     av_log(s, AV_LOG_DEBUG, "return %Ld %Ld\n", pts,back_ptr );
 804     if     (stream_index == -1) return pts;
 805     else if(stream_index == -2) return back_ptr;
 806
 807 assert(0);
 808 }
 809
 810 static int read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags){
 811     NUTContext *nut = s->priv_data;
 812     AVStream *st= s->streams[stream_index];
 813     syncpoint_t dummy={.ts= pts*av_q2d(st->time_base)*AV_TIME_BASE};
 814     syncpoint_t nopts_sp= {.ts= AV_NOPTS_VALUE, .back_ptr= AV_NOPTS_VALUE};
 815     syncpoint_t *sp, *next_node[2]= {&nopts_sp, &nopts_sp};
 816     int64_t pos, pos2, ts;
 817     int i;
 818
 819     if(st->index_entries){
 820         int index= av_index_search_timestamp(st, pts, flags);
 821         if(index<0)
 822             return -1;
 823
 824         pos2= st->index_entries[index].pos;
 825         ts  = st->index_entries[index].timestamp;
 826     }else{
 827         av_tree_find(nut->syncpoints, &dummy, sp_pts_cmp, next_node);
 828         av_log(s, AV_LOG_DEBUG, "%Ld-%Ld %Ld-%Ld\n", next_node[0]->pos, next_node[1]->pos,
 829                                                     next_node[0]->ts , next_node[1]->ts);
 830         pos= av_gen_search(s, -1, dummy.ts, next_node[0]->pos, next_node[1]->pos, next_node[1]->pos,
 831                                             next_node[0]->ts , next_node[1]->ts, AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
 832
 833         if(!(flags & AVSEEK_FLAG_BACKWARD)){
 834             dummy.pos= pos+16;
 835             next_node[1]= &nopts_sp;
 836             av_tree_find(nut->syncpoints, &dummy, sp_pos_cmp, next_node);
 837             pos2= av_gen_search(s, -2, dummy.pos, next_node[0]->pos     , next_node[1]->pos, next_node[1]->pos,
 838                                                 next_node[0]->back_ptr, next_node[1]->back_ptr, flags, &ts, nut_read_timestamp);
 839             if(pos2>=0)
 840                 pos= pos2;
 841             //FIXME dir but i think it doesnt matter
 842         }
 843         dummy.pos= pos;
 844         sp= av_tree_find(nut->syncpoints, &dummy, sp_pos_cmp, NULL);
 845
 846         assert(sp);
 847         pos2= sp->back_ptr  - 15;
 848     }
 849     av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
 850     pos= find_startcode(&s->pb, SYNCPOINT_STARTCODE, pos2);
 851     url_fseek(&s->pb, pos, SEEK_SET);
 852     av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
 853     if(pos2 > pos || pos2 + 15 < pos){
 854         av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
 855     }
 856     for(i=0; i<s->nb_streams; i++)
 857         nut->stream[i].skip_until_key_frame=1;
 858
 859     return 0;
 860 }
 861
 862 static int nut_read_close(AVFormatContext *s)
 863 {
 864     NUTContext *nut = s->priv_data;
 865
 866     av_freep(&nut->time_base);
 867     av_freep(&nut->stream);
 868
 869     return 0;
 870 }
 871
 872 #ifdef CONFIG_NUT_DEMUXER
 873 AVInputFormat nut_demuxer = {
 874     "nut",
 875     "nut format",
 876     sizeof(NUTContext),
 877     nut_probe,
 878     nut_read_header,
 879     nut_read_packet,
 880     nut_read_close,
 881     read_seek,
 882     .extensions = "nut",
 883 };
 884 #endif