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
  33     for(;;)
  34     {
  35         int tmp = get_byte(bc);
  36
  37         if (tmp&0x80)
  38             val= (val<<7) + tmp - 0x80;
  39         else{
  40             return (val<<7) + tmp;
  41         }
  42     }
  43     return -1;
  44 }
  45
  46 static int get_str(ByteIOContext *bc, char *string, unsigned int maxlen){
  47     unsigned int len= get_v(bc);
  48
  49     if(len && maxlen)
  50         get_buffer(bc, string, FFMIN(len, maxlen));
  51     while(len > maxlen){
  52         get_byte(bc);
  53         len--;
  54     }
  55
  56     if(maxlen)
  57         string[FFMIN(len, maxlen-1)]= 0;
  58
  59     if(maxlen == len)
  60         return -1;
  61     else
  62         return 0;
  63 }
  64
  65 static int64_t get_s(ByteIOContext *bc){
  66     int64_t v = get_v(bc) + 1;
  67
  68     if (v&1) return -(v>>1);
  69     else     return  (v>>1);
  70 }
  71
  72 static uint64_t get_fourcc(ByteIOContext *bc){
  73     unsigned int len= get_v(bc);
  74
  75     if     (len==2) return get_le16(bc);
  76     else if(len==4) return get_le32(bc);
  77     else            return -1;
  78 }
  79
  80 #ifdef TRACE
  81 static inline uint64_t get_v_trace(ByteIOContext *bc, char *file, char *func, int line){
  82     uint64_t v= get_v(bc);
  83
  84     printf("get_v %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  85     return v;
  86 }
  87
  88 static inline int64_t get_s_trace(ByteIOContext *bc, char *file, char *func, int line){
  89     int64_t v= get_s(bc);
  90
  91     printf("get_s %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  92     return v;
  93 }
  94
  95 static inline uint64_t get_vb_trace(ByteIOContext *bc, char *file, char *func, int line){
  96     uint64_t v= get_vb(bc);
  97
  98     printf("get_vb %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  99     return v;
 100 }
 101 #define get_v(bc)  get_v_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 102 #define get_s(bc)  get_s_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 103 #define get_vb(bc)  get_vb_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 104 #endif
 105
 106 static int get_packetheader(NUTContext *nut, ByteIOContext *bc, int calculate_checksum)
 107 {
 108     int64_t start, size;
 109 //    start= url_ftell(bc) - 8;
 110
 111     size= get_v(bc);
 112
 113     init_checksum(bc, calculate_checksum ? av_crc04C11DB7_update : NULL, 0);
 114
 115 //    nut->packet_start[2] = start;
 116 //    nut->written_packet_size= size;
 117
 118     return size;
 119 }
 120
 121 static uint64_t find_any_startcode(ByteIOContext *bc, int64_t pos){
 122     uint64_t state=0;
 123
 124     if(pos >= 0)
 125         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
 126
 127     while(!url_feof(bc)){
 128         state= (state<<8) | get_byte(bc);
 129         if((state>>56) != 'N')
 130             continue;
 131         switch(state){
 132         case MAIN_STARTCODE:
 133         case STREAM_STARTCODE:
 134         case SYNCPOINT_STARTCODE:
 135         case INFO_STARTCODE:
 136         case INDEX_STARTCODE:
 137             return state;
 138         }
 139     }
 140
 141     return 0;
 142 }
 143
 144 /**
 145  * find the given startcode.
 146  * @param code the startcode
 147  * @param pos the start position of the search, or -1 if the current position
 148  * @returns the position of the startcode or -1 if not found
 149  */
 150 static int64_t find_startcode(ByteIOContext *bc, uint64_t code, int64_t pos){
 151     for(;;){
 152         uint64_t startcode= find_any_startcode(bc, pos);
 153         if(startcode == code)
 154             return url_ftell(bc) - 8;
 155         else if(startcode == 0)
 156             return -1;
 157         pos=-1;
 158     }
 159 }
 160
 161 static int64_t lsb2full(StreamContext *stream, int64_t lsb){
 162     int64_t mask = (1<<stream->msb_pts_shift)-1;
 163     int64_t delta= stream->last_pts - mask/2;
 164     return  ((lsb - delta)&mask) + delta;
 165 }
 166
 167 static int nut_probe(AVProbeData *p){
 168     int i;
 169     uint64_t code= 0;
 170
 171     for (i = 0; i < p->buf_size; i++) {
 172         code = (code << 8) | p->buf[i];
 173         if (code == MAIN_STARTCODE)
 174             return AVPROBE_SCORE_MAX;
 175     }
 176     return 0;
 177 }
 178
 179 #define GET_V(dst, check) \
 180     tmp= get_v(bc);\
 181     if(!(check)){\
 182         av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp);\
 183         return -1;\
 184     }\
 185     dst= tmp;
 186
 187 static int skip_reserved(ByteIOContext *bc, int64_t pos){
 188     pos -= url_ftell(bc);
 189     if(pos<0){
 190         url_fseek(bc, pos, SEEK_CUR);
 191         return -1;
 192     }else{
 193         while(pos--)
 194             get_byte(bc);
 195         return 0;
 196     }
 197 }
 198
 199 static int decode_main_header(NUTContext *nut){
 200     AVFormatContext *s= nut->avf;
 201     ByteIOContext *bc = &s->pb;
 202     uint64_t tmp, end;
 203     unsigned int stream_count;
 204     int i, j, tmp_stream, tmp_mul, tmp_pts, tmp_size, count, tmp_res;
 205
 206     end= get_packetheader(nut, bc, 1);
 207     end += url_ftell(bc);
 208
 209     GET_V(tmp              , tmp >=2 && tmp <= 3)
 210     GET_V(stream_count     , tmp > 0 && tmp <=MAX_STREAMS)
 211
 212     nut->max_distance = get_v(bc);
 213     if(nut->max_distance > 65536){
 214         av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
 215         nut->max_distance= 65536;
 216     }
 217
 218     GET_V(nut->time_base_count, tmp>0 && tmp<INT_MAX / sizeof(AVRational))
 219     nut->time_base= av_malloc(nut->time_base_count * sizeof(AVRational));
 220
 221     for(i=0; i<nut->time_base_count; i++){
 222         GET_V(nut->time_base[i].num, tmp>0 && tmp<(1ULL<<31))
 223         GET_V(nut->time_base[i].den, tmp>0 && tmp<(1ULL<<31))
 224         if(ff_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1){
 225             av_log(s, AV_LOG_ERROR, "time base invalid\n");
 226             return -1;
 227         }
 228     }
 229     tmp_pts=0;
 230     tmp_mul=1;
 231     tmp_stream=0;
 232     for(i=0; i<256;){
 233         int tmp_flags = get_v(bc);
 234         int tmp_fields= get_v(bc);
 235         if(tmp_fields>0) tmp_pts   = get_s(bc);
 236         if(tmp_fields>1) tmp_mul   = get_v(bc);
 237         if(tmp_fields>2) tmp_stream= get_v(bc);
 238         if(tmp_fields>3) tmp_size  = get_v(bc);
 239         else             tmp_size  = 0;
 240         if(tmp_fields>4) tmp_res   = get_v(bc);
 241         else             tmp_res   = 0;
 242         if(tmp_fields>5) count     = get_v(bc);
 243         else             count     = tmp_mul - tmp_size;
 244
 245         while(tmp_fields-- > 6)
 246            get_v(bc);
 247
 248         if(count == 0 || i+count > 256){
 249             av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
 250             return -1;
 251         }
 252         if(tmp_stream >= stream_count){
 253             av_log(s, AV_LOG_ERROR, "illegal stream number\n");
 254             return -1;
 255         }
 256
 257         for(j=0; j<count; j++,i++){
 258             if (i == 'N') {
 259                 nut->frame_code[i].flags= FLAG_INVALID;
 260                 j--;
 261                 continue;
 262             }
 263             nut->frame_code[i].flags           = tmp_flags ;
 264             nut->frame_code[i].pts_delta       = tmp_pts   ;
 265             nut->frame_code[i].stream_id       = tmp_stream;
 266             nut->frame_code[i].size_mul        = tmp_mul   ;
 267             nut->frame_code[i].size_lsb        = tmp_size+j;
 268             nut->frame_code[i].reserved_count  = tmp_res   ;
 269         }
 270     }
 271     assert(nut->frame_code['N'].flags == FLAG_INVALID);
 272
 273     if(skip_reserved(bc, end) || get_checksum(bc)){
 274         av_log(s, AV_LOG_ERROR, "Main header checksum mismatch\n");
 275         return -1;
 276     }
 277
 278     nut->stream = av_mallocz(sizeof(StreamContext)*stream_count);
 279     for(i=0; i<stream_count; i++){
 280         av_new_stream(s, i);
 281     }
 282
 283     return 0;
 284 }
 285
 286 static int decode_stream_header(NUTContext *nut){
 287     AVFormatContext *s= nut->avf;
 288     ByteIOContext *bc = &s->pb;
 289     StreamContext *stc;
 290     int class, stream_id;
 291     uint64_t tmp, end;
 292     AVStream *st;
 293
 294     end= get_packetheader(nut, bc, 1);
 295     end += url_ftell(bc);
 296
 297     GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base.num);
 298     stc= &nut->stream[stream_id];
 299
 300     st = s->streams[stream_id];
 301     if (!st)
 302         return AVERROR_NOMEM;
 303
 304     class = get_v(bc);
 305     tmp = get_fourcc(bc);
 306     st->codec->codec_tag= tmp;
 307     switch(class)
 308     {
 309         case 0:
 310             st->codec->codec_type = CODEC_TYPE_VIDEO;
 311             st->codec->codec_id = codec_get_bmp_id(tmp);
 312             if (st->codec->codec_id == CODEC_ID_NONE)
 313                 av_log(s, AV_LOG_ERROR, "Unknown codec?!\n");
 314             break;
 315         case 1:
 316             st->codec->codec_type = CODEC_TYPE_AUDIO;
 317             st->codec->codec_id = codec_get_wav_id(tmp);
 318             if (st->codec->codec_id == CODEC_ID_NONE)
 319                 av_log(s, AV_LOG_ERROR, "Unknown codec?!\n");
 320             break;
 321         case 2:
 322 //            st->codec->codec_type = CODEC_TYPE_TEXT;
 323 //            break;
 324         case 3:
 325             st->codec->codec_type = CODEC_TYPE_DATA;
 326             break;
 327         default:
 328             av_log(s, AV_LOG_ERROR, "Unknown stream class (%d)\n", class);
 329             return -1;
 330     }
 331     GET_V(stc->time_base_id    , tmp < nut->time_base_count);
 332     GET_V(stc->msb_pts_shift   , tmp < 16);
 333     stc->max_pts_distance= get_v(bc);
 334     GET_V(stc->decode_delay    , tmp < 1000); //sanity limit, raise this if moors law is true
 335     st->codec->has_b_frames= stc->decode_delay;
 336     get_v(bc); //stream flags
 337
 338     GET_V(st->codec->extradata_size, tmp < (1<<30));
 339     if(st->codec->extradata_size){
 340         st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
 341         get_buffer(bc, st->codec->extradata, st->codec->extradata_size);
 342     }
 343
 344     if (st->codec->codec_type == CODEC_TYPE_VIDEO){
 345         GET_V(st->codec->width , tmp > 0)
 346         GET_V(st->codec->height, tmp > 0)
 347         st->codec->sample_aspect_ratio.num= get_v(bc);
 348         st->codec->sample_aspect_ratio.den= get_v(bc);
 349         if((!st->codec->sample_aspect_ratio.num) != (!st->codec->sample_aspect_ratio.den)){
 350             av_log(s, AV_LOG_ERROR, "invalid aspect ratio\n");
 351             return -1;
 352         }
 353         get_v(bc); /* csp type */
 354     }else if (st->codec->codec_type == CODEC_TYPE_AUDIO){
 355         GET_V(st->codec->sample_rate , tmp > 0)
 356         tmp= get_v(bc); // samplerate_den
 357         if(tmp > st->codec->sample_rate){
 358             av_log(s, AV_LOG_ERROR, "bleh, libnut muxed this ;)\n");
 359             st->codec->sample_rate= tmp;
 360         }
 361         GET_V(st->codec->channels, tmp > 0)
 362     }
 363     if(skip_reserved(bc, end) || get_checksum(bc)){
 364         av_log(s, AV_LOG_ERROR, "Stream header %d checksum mismatch\n", stream_id);
 365         return -1;
 366     }
 367     stc->time_base= nut->time_base[stc->time_base_id];
 368     av_set_pts_info(s->streams[stream_id], 63, stc->time_base.num, stc->time_base.den);
 369     return 0;
 370 }
 371
 372 static int decode_info_header(NUTContext *nut){
 373     AVFormatContext *s= nut->avf;
 374     ByteIOContext *bc = &s->pb;
 375     uint64_t tmp;
 376     unsigned int stream_id_plus1, chapter_start, chapter_len, count;
 377     int chapter_id, i;
 378     int64_t value, end;
 379     char name[256], str_value[1024], type_str[256], *type= type_str;
 380
 381     end= get_packetheader(nut, bc, 1);
 382     end += url_ftell(bc);
 383
 384     GET_V(stream_id_plus1, tmp <= s->nb_streams)
 385     chapter_id   = get_s(bc);
 386     chapter_start= get_v(bc);
 387     chapter_len  = get_v(bc);
 388     count        = get_v(bc);
 389     for(i=0; i<count; i++){
 390         get_str(bc, name, sizeof(name));
 391         value= get_s(bc);
 392         if(value == -1){
 393             type= "UTF-8";
 394             get_str(bc, str_value, sizeof(str_value));
 395         }else if(value == -2){
 396             get_str(bc, type, sizeof(type));
 397             get_str(bc, str_value, sizeof(str_value));
 398         }else if(value == -3){
 399             type= "s";
 400             value= get_s(bc);
 401         }else if(value == -4){
 402             type= "t";
 403             value= get_v(bc);
 404         }else if(value < -4){
 405             type= "r";
 406             get_s(bc);
 407         }else{
 408             type= "v";
 409         }
 410
 411         if(chapter_id==0 && !strcmp(type, "UTF-8")){
 412             if     (!strcmp(name, "Author"))
 413                 pstrcpy(s->author   , sizeof(s->author)   , str_value);
 414             else if(!strcmp(name, "Title"))
 415                 pstrcpy(s->title    , sizeof(s->title)    , str_value);
 416             else if(!strcmp(name, "Copyright"))
 417                 pstrcpy(s->copyright, sizeof(s->copyright), str_value);
 418             else if(!strcmp(name, "Description"))
 419                 pstrcpy(s->comment  , sizeof(s->comment)  , str_value);
 420         }
 421     }
 422
 423     if(skip_reserved(bc, end) || get_checksum(bc)){
 424         av_log(s, AV_LOG_ERROR, "Info header checksum mismatch\n");
 425         return -1;
 426     }
 427     return 0;
 428 }
 429
 430 int sp_pos_cmp(syncpoint_t *a, syncpoint_t *b){
 431     return (a->pos - b->pos>>32) - (b->pos - a->pos>>32);
 432 }
 433
 434 int sp_pts_cmp(syncpoint_t *a, syncpoint_t *b){
 435     return (a->ts - b->ts>>32) - (b->ts - a->ts>>32);
 436 }
 437
 438 static void add_sp(NUTContext *nut, int64_t pos, int64_t back_ptr, int64_t ts){
 439     syncpoint_t *sp2, *sp= av_mallocz(sizeof(syncpoint_t));
 440
 441     sp->pos= pos;
 442     sp->back_ptr= back_ptr;
 443     sp->ts= ts;
 444     sp2= av_tree_insert(&nut->syncpoints, sp, sp_pos_cmp);
 445     if(sp2 && sp2 != sp)
 446         av_free(sp);
 447 }
 448
 449 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr){
 450     AVFormatContext *s= nut->avf;
 451     ByteIOContext *bc = &s->pb;
 452     int64_t end, tmp;
 453     int i;
 454     AVRational time_base;
 455
 456     nut->last_syncpoint_pos= url_ftell(bc)-8;
 457
 458     end= get_packetheader(nut, bc, 1);
 459     end += url_ftell(bc);
 460
 461     tmp= get_v(bc);
 462     *back_ptr= nut->last_syncpoint_pos - 16*get_v(bc);
 463     if(*back_ptr < 0)
 464         return -1;
 465
 466     time_base= nut->time_base[tmp % nut->time_base_count];
 467     for(i=0; i<s->nb_streams; i++){
 468         nut->stream[i].last_pts= av_rescale_rnd(
 469             tmp / nut->time_base_count,
 470             time_base.num * (int64_t)nut->stream[i].time_base.den,
 471             time_base.den * (int64_t)nut->stream[i].time_base.num,
 472             AV_ROUND_DOWN);
 473         //last_key_frame ?
 474     }
 475     //FIXME put this in a reset func maybe
 476
 477     if(skip_reserved(bc, end) || get_checksum(bc)){
 478         av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
 479         return -1;
 480     }
 481
 482     *ts= tmp / s->nb_streams * av_q2d(nut->time_base[tmp % s->nb_streams])*AV_TIME_BASE;
 483     add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts);
 484
 485     return 0;
 486 }
 487
 488 static int find_and_decode_index(NUTContext *nut){
 489     AVFormatContext *s= nut->avf;
 490     ByteIOContext *bc = &s->pb;
 491     uint64_t tmp, end;
 492     int i, j, syncpoint_count;
 493     int64_t filesize= url_fsize(bc);
 494     int64_t *syncpoints;
 495     int8_t *has_keyframe;
 496
 497     url_fseek(bc, filesize-12, SEEK_SET);
 498     url_fseek(bc, filesize-get_be64(bc), SEEK_SET);
 499     if(get_be64(bc) != INDEX_STARTCODE){
 500         av_log(s, AV_LOG_ERROR, "no index at the end\n");
 501         return -1;
 502     }
 503
 504     end= get_packetheader(nut, bc, 1);
 505     end += url_ftell(bc);
 506
 507     get_v(bc); //max_pts
 508     GET_V(syncpoint_count, tmp < INT_MAX/8 && tmp > 0)
 509     syncpoints= av_malloc(sizeof(int64_t)*syncpoint_count);
 510     has_keyframe= av_malloc(sizeof(int8_t)*(syncpoint_count+1));
 511     for(i=0; i<syncpoint_count; i++){
 512         GET_V(syncpoints[i], tmp>0)
 513         if(i)
 514             syncpoints[i] += syncpoints[i-1];
 515     }
 516
 517     for(i=0; i<s->nb_streams; i++){
 518         int64_t last_pts= -1;
 519         for(j=0; j<syncpoint_count;){
 520             uint64_t x= get_v(bc);
 521             int type= x&1;
 522             int n= j;
 523             x>>=1;
 524             if(type){
 525                 int flag= x&1;
 526                 x>>=1;
 527                 if(n+x >= syncpoint_count + 1){
 528                     av_log(s, AV_LOG_ERROR, "index overflow A\n");
 529                     return -1;
 530                 }
 531                 while(x--)
 532                     has_keyframe[n++]= flag;
 533                 has_keyframe[n++]= !flag;
 534             }else{
 535                 while(x != 1){
 536                     if(n>=syncpoint_count + 1){
 537                         av_log(s, AV_LOG_ERROR, "index overflow B\n");
 538                         return -1;
 539                     }
 540                     has_keyframe[n++]= x&1;
 541                     x>>=1;
 542                 }
 543             }
 544             if(has_keyframe[0]){
 545                 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
 546                 return -1;
 547             }
 548             assert(n<=syncpoint_count+1);
 549             for(; j<n; j++){
 550                 if(has_keyframe[j]){
 551                     uint64_t B, A= get_v(bc);
 552                     if(!A){
 553                         A= get_v(bc);
 554                         B= get_v(bc);
 555                         //eor_pts[j][i] = last_pts + A + B
 556                     }else
 557                         B= 0;
 558                     av_add_index_entry(
 559                         s->streams[i],
 560                         16*syncpoints[j-1],
 561                         last_pts + A,
 562                         0,
 563                         0,
 564                         AVINDEX_KEYFRAME);
 565                     last_pts += A + B;
 566                 }
 567             }
 568         }
 569     }
 570
 571     if(skip_reserved(bc, end) || get_checksum(bc)){
 572         av_log(s, AV_LOG_ERROR, "Index checksum mismatch\n");
 573         return -1;
 574     }
 575     return 0;
 576 }
 577
 578 static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)
 579 {
 580     NUTContext *nut = s->priv_data;
 581     ByteIOContext *bc = &s->pb;
 582     int64_t pos;
 583     int inited_stream_count;
 584
 585     nut->avf= s;
 586
 587     /* main header */
 588     pos=0;
 589     do{
 590         pos= find_startcode(bc, MAIN_STARTCODE, pos)+1;
 591         if (pos<0+1){
 592             av_log(s, AV_LOG_ERROR, "no main startcode found\n");
 593             return -1;
 594         }
 595     }while(decode_main_header(nut) < 0);
 596
 597     /* stream headers */
 598     pos=0;
 599     for(inited_stream_count=0; inited_stream_count < s->nb_streams;){
 600         pos= find_startcode(bc, STREAM_STARTCODE, pos)+1;
 601         if (pos<0+1){
 602             av_log(s, AV_LOG_ERROR, "not all stream headers found\n");
 603             return -1;
 604         }
 605         if(decode_stream_header(nut) >= 0)
 606             inited_stream_count++;
 607     }
 608
 609     /* info headers */
 610     pos=0;
 611     for(;;){
 612         uint64_t startcode= find_any_startcode(bc, pos);
 613         pos= url_ftell(bc);
 614
 615         if(startcode==0){
 616             av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
 617             return -1;
 618         }else if(startcode == SYNCPOINT_STARTCODE){
 619             nut->next_startcode= startcode;
 620             break;
 621         }else if(startcode != INFO_STARTCODE){
 622             continue;
 623         }
 624
 625         decode_info_header(nut);
 626     }
 627
 628     s->data_offset= pos-8;
 629
 630     if(!url_is_streamed(bc)){
 631         int64_t orig_pos= url_ftell(bc);
 632         find_and_decode_index(nut);
 633         url_fseek(bc, orig_pos, SEEK_SET);
 634     }
 635     assert(nut->next_startcode == SYNCPOINT_STARTCODE);
 636
 637     return 0;
 638 }
 639
 640 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id, int frame_code){
 641     AVFormatContext *s= nut->avf;
 642     ByteIOContext *bc = &s->pb;
 643     StreamContext *stc;
 644     int size, flags, size_mul, pts_delta, i, reserved_count;
 645     uint64_t tmp;
 646
 647     if(url_ftell(bc) > nut->last_syncpoint_pos + nut->max_distance){
 648         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);
 649         return -1;
 650     }
 651
 652     flags          = nut->frame_code[frame_code].flags;
 653     size_mul       = nut->frame_code[frame_code].size_mul;
 654     size           = nut->frame_code[frame_code].size_lsb;
 655     *stream_id     = nut->frame_code[frame_code].stream_id;
 656     pts_delta      = nut->frame_code[frame_code].pts_delta;
 657     reserved_count = nut->frame_code[frame_code].reserved_count;
 658
 659     if(flags & FLAG_INVALID)
 660         return -1;
 661     if(flags & FLAG_CODED)
 662         flags ^= get_v(bc);
 663     if(flags & FLAG_STREAM_ID){
 664         GET_V(*stream_id, tmp < s->nb_streams)
 665     }
 666     stc= &nut->stream[*stream_id];
 667     if(flags&FLAG_CODED_PTS){
 668         int coded_pts= get_v(bc);
 669 //FIXME check last_pts validity?
 670         if(coded_pts < (1<<stc->msb_pts_shift)){
 671             *pts=lsb2full(stc, coded_pts);
 672         }else
 673             *pts=coded_pts - (1<<stc->msb_pts_shift);
 674     }else
 675         *pts= stc->last_pts + pts_delta;
 676     if(flags&FLAG_SIZE_MSB){
 677         size += size_mul*get_v(bc);
 678     }
 679     if(flags&FLAG_RESERVED)
 680         reserved_count= get_v(bc);
 681     for(i=0; i<reserved_count; i++)
 682         get_v(bc);
 683     if(flags&FLAG_CHECKSUM){
 684         get_be32(bc); //FIXME check this
 685     }else if(size > 2*nut->max_distance || FFABS(stc->last_pts - *pts) > stc->max_pts_distance){
 686         av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
 687         return -1;
 688     }
 689
 690     stc->last_pts= *pts;
 691     stc->last_flags= flags;
 692
 693     return size;
 694 }
 695
 696 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code){
 697     AVFormatContext *s= nut->avf;
 698     ByteIOContext *bc = &s->pb;
 699     int size, stream_id, discard;
 700     int64_t pts, last_IP_pts;
 701     StreamContext *stc;
 702
 703     size= decode_frame_header(nut, &pts, &stream_id, frame_code);
 704     if(size < 0)
 705         return -1;
 706
 707     stc= &nut->stream[stream_id];
 708
 709     if (stc->last_flags & FLAG_KEY)
 710         stc->skip_until_key_frame=0;
 711
 712     discard= s->streams[ stream_id ]->discard;
 713     last_IP_pts= s->streams[ stream_id ]->last_IP_pts;
 714     if(  (discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY))
 715        ||(discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE && last_IP_pts > pts)
 716        || discard >= AVDISCARD_ALL
 717        || stc->skip_until_key_frame){
 718         url_fskip(bc, size);
 719         return 1;
 720     }
 721
 722     av_get_packet(bc, pkt, size);
 723     pkt->stream_index = stream_id;
 724     if (stc->last_flags & FLAG_KEY)
 725         pkt->flags |= PKT_FLAG_KEY;
 726     pkt->pts = pts;
 727
 728     return 0;
 729 }
 730
 731 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
 732 {
 733     NUTContext *nut = s->priv_data;
 734     ByteIOContext *bc = &s->pb;
 735     int i, frame_code=0, ret, skip;
 736     int64_t ts, back_ptr;
 737
 738     for(;;){
 739         int64_t pos= url_ftell(bc);
 740         uint64_t tmp= nut->next_startcode;
 741         nut->next_startcode=0;
 742
 743         if (url_feof(bc))
 744             return -1;
 745
 746         if(tmp){
 747             pos-=8;
 748         }else{
 749             frame_code = get_byte(bc);
 750             if(frame_code == 'N'){
 751                 tmp= frame_code;
 752                 for(i=1; i<8; i++)
 753                     tmp = (tmp<<8) + get_byte(bc);
 754             }
 755         }
 756         switch(tmp){
 757         case MAIN_STARTCODE:
 758         case STREAM_STARTCODE:
 759         case INDEX_STARTCODE:
 760             skip= get_packetheader(nut, bc, 0);
 761             url_fseek(bc, skip, SEEK_CUR);
 762             break;
 763         case INFO_STARTCODE:
 764             if(decode_info_header(nut)<0)
 765                 goto resync;
 766             break;
 767         case SYNCPOINT_STARTCODE:
 768             if(decode_syncpoint(nut, &ts, &back_ptr)<0)
 769                 goto resync;
 770             frame_code = get_byte(bc);
 771         case 0:
 772             ret= decode_frame(nut, pkt, frame_code);
 773             if(ret==0)
 774                 return 0;
 775             else if(ret==1) //ok but discard packet
 776                 break;
 777         default:
 778 resync:
 779 av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
 780             tmp= find_any_startcode(bc, nut->last_syncpoint_pos+1);
 781             if(tmp==0)
 782                 return -1;
 783 av_log(s, AV_LOG_DEBUG, "sync\n");
 784             nut->next_startcode= tmp;
 785         }
 786     }
 787 }
 788
 789 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index, int64_t *pos_arg, int64_t pos_limit){
 790     NUTContext *nut = s->priv_data;
 791     ByteIOContext *bc = &s->pb;
 792     int64_t pos, pts, back_ptr;
 793 av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n", stream_index, *pos_arg, pos_limit);
 794
 795     pos= *pos_arg;
 796 resync:
 797     do{
 798         pos= find_startcode(bc, SYNCPOINT_STARTCODE, pos)+1;
 799         if(pos < 1){
 800             assert(nut->next_startcode == 0);
 801             av_log(s, AV_LOG_ERROR, "read_timestamp failed\n");
 802             return AV_NOPTS_VALUE;
 803         }
 804     }while(decode_syncpoint(nut, &pts, &back_ptr) < 0);
 805     *pos_arg = pos-1;
 806     assert(nut->last_syncpoint_pos == *pos_arg);
 807
 808     av_log(s, AV_LOG_DEBUG, "return %Ld %Ld\n", pts,back_ptr );
 809     if     (stream_index == -1) return pts;
 810     else if(stream_index == -2) return back_ptr;
 811
 812 assert(0);
 813 }
 814
 815 static int read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags){
 816     NUTContext *nut = s->priv_data;
 817     AVStream *st= s->streams[stream_index];
 818     syncpoint_t dummy={.ts= pts*av_q2d(st->time_base)*AV_TIME_BASE};
 819     syncpoint_t nopts_sp= {.ts= AV_NOPTS_VALUE, .back_ptr= AV_NOPTS_VALUE};
 820     syncpoint_t *sp, *next_node[2]= {&nopts_sp, &nopts_sp};
 821     int64_t pos, pos2, ts;
 822     int i;
 823
 824     if(st->index_entries){
 825         int index= av_index_search_timestamp(st, pts, flags);
 826         if(index<0)
 827             return -1;
 828
 829         pos2= st->index_entries[index].pos;
 830         ts  = st->index_entries[index].timestamp;
 831     }else{
 832         av_tree_find(nut->syncpoints, &dummy, sp_pts_cmp, next_node);
 833         av_log(s, AV_LOG_DEBUG, "%Ld-%Ld %Ld-%Ld\n", next_node[0]->pos, next_node[1]->pos,
 834                                                     next_node[0]->ts , next_node[1]->ts);
 835         pos= av_gen_search(s, -1, dummy.ts, next_node[0]->pos, next_node[1]->pos, next_node[1]->pos,
 836                                             next_node[0]->ts , next_node[1]->ts, AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
 837
 838         if(!(flags & AVSEEK_FLAG_BACKWARD)){
 839             dummy.pos= pos+16;
 840             next_node[1]= &nopts_sp;
 841             av_tree_find(nut->syncpoints, &dummy, sp_pos_cmp, next_node);
 842             pos2= av_gen_search(s, -2, dummy.pos, next_node[0]->pos     , next_node[1]->pos, next_node[1]->pos,
 843                                                 next_node[0]->back_ptr, next_node[1]->back_ptr, flags, &ts, nut_read_timestamp);
 844             if(pos2>=0)
 845                 pos= pos2;
 846             //FIXME dir but i think it doesnt matter
 847         }
 848         dummy.pos= pos;
 849         sp= av_tree_find(nut->syncpoints, &dummy, sp_pos_cmp, NULL);
 850
 851         assert(sp);
 852         pos2= sp->back_ptr  - 15;
 853     }
 854     av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
 855     pos= find_startcode(&s->pb, SYNCPOINT_STARTCODE, pos2);
 856     url_fseek(&s->pb, pos, SEEK_SET);
 857     av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
 858     if(pos2 > pos || pos2 + 15 < pos){
 859         av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
 860     }
 861     for(i=0; i<s->nb_streams; i++)
 862         nut->stream[i].skip_until_key_frame=1;
 863
 864     return 0;
 865 }
 866
 867 static int nut_read_close(AVFormatContext *s)
 868 {
 869     NUTContext *nut = s->priv_data;
 870
 871     av_freep(&nut->time_base);
 872     av_freep(&nut->stream);
 873
 874     return 0;
 875 }
 876
 877 #ifdef CONFIG_NUT_DEMUXER
 878 AVInputFormat nut_demuxer = {
 879     "nut",
 880     "nut format",
 881     sizeof(NUTContext),
 882     nut_probe,
 883     nut_read_header,
 884     nut_read_packet,
 885     nut_read_close,
 886     read_seek,
 887     .extensions = "nut",
 888 };
 889 #endif