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 #include <strings.h>
  24 #include "libavutil/avstring.h"
  25 #include "libavutil/bswap.h"
  26 #include "libavutil/tree.h"
  27 #include "nut.h"
  28
  29 #undef NDEBUG
  30 #include <assert.h>
  31
  32 #if FF_API_MAX_STREAMS
  33 #define NUT_MAX_STREAMS MAX_STREAMS
  34 #else
  35 #define NUT_MAX_STREAMS 256    /* arbitrary sanity check value */
  36 #endif
  37
  38 static int get_str(ByteIOContext *bc, char *string, unsigned int maxlen){
  39     unsigned int len= ff_get_v(bc);
  40
  41     if(len && maxlen)
  42         get_buffer(bc, string, FFMIN(len, maxlen));
  43     while(len > maxlen){
  44         get_byte(bc);
  45         len--;
  46     }
  47
  48     if(maxlen)
  49         string[FFMIN(len, maxlen-1)]= 0;
  50
  51     if(maxlen == len)
  52         return -1;
  53     else
  54         return 0;
  55 }
  56
  57 static int64_t get_s(ByteIOContext *bc){
  58     int64_t v = ff_get_v(bc) + 1;
  59
  60     if (v&1) return -(v>>1);
  61     else     return  (v>>1);
  62 }
  63
  64 static uint64_t get_fourcc(ByteIOContext *bc){
  65     unsigned int len= ff_get_v(bc);
  66
  67     if     (len==2) return get_le16(bc);
  68     else if(len==4) return get_le32(bc);
  69     else            return -1;
  70 }
  71
  72 #ifdef TRACE
  73 static inline uint64_t get_v_trace(ByteIOContext *bc, char *file, char *func, int line){
  74     uint64_t v= ff_get_v(bc);
  75
  76     av_log(NULL, AV_LOG_DEBUG, "get_v %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  77     return v;
  78 }
  79
  80 static inline int64_t get_s_trace(ByteIOContext *bc, char *file, char *func, int line){
  81     int64_t v= get_s(bc);
  82
  83     av_log(NULL, AV_LOG_DEBUG, "get_s %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  84     return v;
  85 }
  86
  87 static inline uint64_t get_vb_trace(ByteIOContext *bc, char *file, char *func, int line){
  88     uint64_t v= get_vb(bc);
  89
  90     av_log(NULL, AV_LOG_DEBUG, "get_vb %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
  91     return v;
  92 }
  93 #define ff_get_v(bc)  get_v_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
  94 #define get_s(bc)  get_s_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
  95 #define get_vb(bc)  get_vb_trace(bc, __FILE__, __PRETTY_FUNCTION__, __LINE__)
  96 #endif
  97
  98 static int get_packetheader(NUTContext *nut, ByteIOContext *bc, int calculate_checksum, uint64_t startcode)
  99 {
 100     int64_t size;
 101 //    start= url_ftell(bc) - 8;
 102
 103     startcode= av_be2ne64(startcode);
 104     startcode= ff_crc04C11DB7_update(0, (uint8_t*)&startcode, 8);
 105
 106     init_checksum(bc, ff_crc04C11DB7_update, startcode);
 107     size= ff_get_v(bc);
 108     if(size > 4096)
 109         get_be32(bc);
 110     if(get_checksum(bc) && size > 4096)
 111         return -1;
 112
 113     init_checksum(bc, calculate_checksum ? ff_crc04C11DB7_update : NULL, 0);
 114
 115     return size;
 116 }
 117
 118 static uint64_t find_any_startcode(ByteIOContext *bc, int64_t pos){
 119     uint64_t state=0;
 120
 121     if(pos >= 0)
 122         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
 123
 124     while(!url_feof(bc)){
 125         state= (state<<8) | get_byte(bc);
 126         if((state>>56) != 'N')
 127             continue;
 128         switch(state){
 129         case MAIN_STARTCODE:
 130         case STREAM_STARTCODE:
 131         case SYNCPOINT_STARTCODE:
 132         case INFO_STARTCODE:
 133         case INDEX_STARTCODE:
 134             return state;
 135         }
 136     }
 137
 138     return 0;
 139 }
 140
 141 /**
 142  * Find the given startcode.
 143  * @param code the startcode
 144  * @param pos the start position of the search, or -1 if the current position
 145  * @return the position of the startcode or -1 if not found
 146  */
 147 static int64_t find_startcode(ByteIOContext *bc, uint64_t code, int64_t pos){
 148     for(;;){
 149         uint64_t startcode= find_any_startcode(bc, pos);
 150         if(startcode == code)
 151             return url_ftell(bc) - 8;
 152         else if(startcode == 0)
 153             return -1;
 154         pos=-1;
 155     }
 156 }
 157
 158 static int nut_probe(AVProbeData *p){
 159     int i;
 160     uint64_t code= 0;
 161
 162     for (i = 0; i < p->buf_size; i++) {
 163         code = (code << 8) | p->buf[i];
 164         if (code == MAIN_STARTCODE)
 165             return AVPROBE_SCORE_MAX;
 166     }
 167     return 0;
 168 }
 169
 170 #define GET_V(dst, check) \
 171     tmp= ff_get_v(bc);\
 172     if(!(check)){\
 173         av_log(s, AV_LOG_ERROR, "Error " #dst " is (%"PRId64")\n", tmp);\
 174         return -1;\
 175     }\
 176     dst= tmp;
 177
 178 static int skip_reserved(ByteIOContext *bc, int64_t pos){
 179     pos -= url_ftell(bc);
 180     if(pos<0){
 181         url_fseek(bc, pos, SEEK_CUR);
 182         return -1;
 183     }else{
 184         while(pos--)
 185             get_byte(bc);
 186         return 0;
 187     }
 188 }
 189
 190 static int decode_main_header(NUTContext *nut){
 191     AVFormatContext *s= nut->avf;
 192     ByteIOContext *bc = s->pb;
 193     uint64_t tmp, end;
 194     unsigned int stream_count;
 195     int i, j, tmp_stream, tmp_mul, tmp_pts, tmp_size, count, tmp_res, tmp_head_idx;
 196     int64_t tmp_match;
 197
 198     end= get_packetheader(nut, bc, 1, MAIN_STARTCODE);
 199     end += url_ftell(bc);
 200
 201     GET_V(tmp              , tmp >=2 && tmp <= 3)
 202     GET_V(stream_count     , tmp > 0 && tmp <= NUT_MAX_STREAMS)
 203
 204     nut->max_distance = ff_get_v(bc);
 205     if(nut->max_distance > 65536){
 206         av_log(s, AV_LOG_DEBUG, "max_distance %d\n", nut->max_distance);
 207         nut->max_distance= 65536;
 208     }
 209
 210     GET_V(nut->time_base_count, tmp>0 && tmp<INT_MAX / sizeof(AVRational))
 211     nut->time_base= av_malloc(nut->time_base_count * sizeof(AVRational));
 212
 213     for(i=0; i<nut->time_base_count; i++){
 214         GET_V(nut->time_base[i].num, tmp>0 && tmp<(1ULL<<31))
 215         GET_V(nut->time_base[i].den, tmp>0 && tmp<(1ULL<<31))
 216         if(av_gcd(nut->time_base[i].num, nut->time_base[i].den) != 1){
 217             av_log(s, AV_LOG_ERROR, "time base invalid\n");
 218             return -1;
 219         }
 220     }
 221     tmp_pts=0;
 222     tmp_mul=1;
 223     tmp_stream=0;
 224     tmp_match= 1-(1LL<<62);
 225     tmp_head_idx= 0;
 226     for(i=0; i<256;){
 227         int tmp_flags = ff_get_v(bc);
 228         int tmp_fields= ff_get_v(bc);
 229         if(tmp_fields>0) tmp_pts   = get_s(bc);
 230         if(tmp_fields>1) tmp_mul   = ff_get_v(bc);
 231         if(tmp_fields>2) tmp_stream= ff_get_v(bc);
 232         if(tmp_fields>3) tmp_size  = ff_get_v(bc);
 233         else             tmp_size  = 0;
 234         if(tmp_fields>4) tmp_res   = ff_get_v(bc);
 235         else             tmp_res   = 0;
 236         if(tmp_fields>5) count     = ff_get_v(bc);
 237         else             count     = tmp_mul - tmp_size;
 238         if(tmp_fields>6) tmp_match = get_s(bc);
 239         if(tmp_fields>7) tmp_head_idx= ff_get_v(bc);
 240
 241         while(tmp_fields-- > 8)
 242            ff_get_v(bc);
 243
 244         if(count == 0 || i+count > 256){
 245             av_log(s, AV_LOG_ERROR, "illegal count %d at %d\n", count, i);
 246             return -1;
 247         }
 248         if(tmp_stream >= stream_count){
 249             av_log(s, AV_LOG_ERROR, "illegal stream number\n");
 250             return -1;
 251         }
 252
 253         for(j=0; j<count; j++,i++){
 254             if (i == 'N') {
 255                 nut->frame_code[i].flags= FLAG_INVALID;
 256                 j--;
 257                 continue;
 258             }
 259             nut->frame_code[i].flags           = tmp_flags ;
 260             nut->frame_code[i].pts_delta       = tmp_pts   ;
 261             nut->frame_code[i].stream_id       = tmp_stream;
 262             nut->frame_code[i].size_mul        = tmp_mul   ;
 263             nut->frame_code[i].size_lsb        = tmp_size+j;
 264             nut->frame_code[i].reserved_count  = tmp_res   ;
 265             nut->frame_code[i].header_idx      = tmp_head_idx;
 266         }
 267     }
 268     assert(nut->frame_code['N'].flags == FLAG_INVALID);
 269
 270     if(end > url_ftell(bc) + 4){
 271         int rem= 1024;
 272         GET_V(nut->header_count, tmp<128U)
 273         nut->header_count++;
 274         for(i=1; i<nut->header_count; i++){
 275             GET_V(nut->header_len[i], tmp>0 && tmp<256);
 276             rem -= nut->header_len[i];
 277             if(rem < 0){
 278                 av_log(s, AV_LOG_ERROR, "invalid elision header\n");
 279                 return -1;
 280             }
 281             nut->header[i]= av_malloc(nut->header_len[i]);
 282             get_buffer(bc, nut->header[i], nut->header_len[i]);
 283         }
 284         assert(nut->header_len[0]==0);
 285     }
 286
 287     if(skip_reserved(bc, end) || get_checksum(bc)){
 288         av_log(s, AV_LOG_ERROR, "main header checksum mismatch\n");
 289         return -1;
 290     }
 291
 292     nut->stream = av_mallocz(sizeof(StreamContext)*stream_count);
 293     for(i=0; i<stream_count; i++){
 294         av_new_stream(s, i);
 295     }
 296
 297     return 0;
 298 }
 299
 300 static int decode_stream_header(NUTContext *nut){
 301     AVFormatContext *s= nut->avf;
 302     ByteIOContext *bc = s->pb;
 303     StreamContext *stc;
 304     int class, stream_id;
 305     uint64_t tmp, end;
 306     AVStream *st;
 307
 308     end= get_packetheader(nut, bc, 1, STREAM_STARTCODE);
 309     end += url_ftell(bc);
 310
 311     GET_V(stream_id, tmp < s->nb_streams && !nut->stream[tmp].time_base);
 312     stc= &nut->stream[stream_id];
 313
 314     st = s->streams[stream_id];
 315     if (!st)
 316         return AVERROR(ENOMEM);
 317
 318     class = ff_get_v(bc);
 319     tmp = get_fourcc(bc);
 320     st->codec->codec_tag= tmp;
 321     switch(class)
 322     {
 323         case 0:
 324             st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
 325             st->codec->codec_id = av_codec_get_id(
 326                 (const AVCodecTag * const []) { ff_codec_bmp_tags, ff_nut_video_tags, 0 },
 327                 tmp);
 328             break;
 329         case 1:
 330             st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
 331             st->codec->codec_id = ff_codec_get_id(ff_codec_wav_tags, tmp);
 332             break;
 333         case 2:
 334             st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
 335             st->codec->codec_id = ff_codec_get_id(ff_nut_subtitle_tags, tmp);
 336             break;
 337         case 3:
 338             st->codec->codec_type = AVMEDIA_TYPE_DATA;
 339             break;
 340         default:
 341             av_log(s, AV_LOG_ERROR, "unknown stream class (%d)\n", class);
 342             return -1;
 343     }
 344     if(class<3 && st->codec->codec_id == CODEC_ID_NONE)
 345         av_log(s, AV_LOG_ERROR, "Unknown codec tag '0x%04x' for stream number %d\n",
 346                (unsigned int)tmp, stream_id);
 347
 348     GET_V(stc->time_base_id    , tmp < nut->time_base_count);
 349     GET_V(stc->msb_pts_shift   , tmp < 16);
 350     stc->max_pts_distance= ff_get_v(bc);
 351     GET_V(stc->decode_delay    , tmp < 1000); //sanity limit, raise this if Moore's law is true
 352     st->codec->has_b_frames= stc->decode_delay;
 353     ff_get_v(bc); //stream flags
 354
 355     GET_V(st->codec->extradata_size, tmp < (1<<30));
 356     if(st->codec->extradata_size){
 357         st->codec->extradata= av_mallocz(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
 358         get_buffer(bc, st->codec->extradata, st->codec->extradata_size);
 359     }
 360
 361     if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO){
 362         GET_V(st->codec->width , tmp > 0)
 363         GET_V(st->codec->height, tmp > 0)
 364         st->sample_aspect_ratio.num= ff_get_v(bc);
 365         st->sample_aspect_ratio.den= ff_get_v(bc);
 366         if((!st->sample_aspect_ratio.num) != (!st->sample_aspect_ratio.den)){
 367             av_log(s, AV_LOG_ERROR, "invalid aspect ratio %d/%d\n", st->sample_aspect_ratio.num, st->sample_aspect_ratio.den);
 368             return -1;
 369         }
 370         ff_get_v(bc); /* csp type */
 371     }else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO){
 372         GET_V(st->codec->sample_rate , tmp > 0)
 373         ff_get_v(bc); // samplerate_den
 374         GET_V(st->codec->channels, tmp > 0)
 375     }
 376     if(skip_reserved(bc, end) || get_checksum(bc)){
 377         av_log(s, AV_LOG_ERROR, "stream header %d checksum mismatch\n", stream_id);
 378         return -1;
 379     }
 380     stc->time_base= &nut->time_base[stc->time_base_id];
 381     av_set_pts_info(s->streams[stream_id], 63, stc->time_base->num, stc->time_base->den);
 382     return 0;
 383 }
 384
 385 static void set_disposition_bits(AVFormatContext* avf, char* value, int stream_id){
 386     int flag = 0, i;
 387     for (i=0; ff_nut_dispositions[i].flag; ++i) {
 388         if (!strcmp(ff_nut_dispositions[i].str, value))
 389             flag = ff_nut_dispositions[i].flag;
 390     }
 391     if (!flag)
 392         av_log(avf, AV_LOG_INFO, "unknown disposition type '%s'\n", value);
 393     for (i = 0; i < avf->nb_streams; ++i)
 394         if (stream_id == i || stream_id == -1)
 395             avf->streams[i]->disposition |= flag;
 396 }
 397
 398 static int decode_info_header(NUTContext *nut){
 399     AVFormatContext *s= nut->avf;
 400     ByteIOContext *bc = s->pb;
 401     uint64_t tmp, chapter_start, chapter_len;
 402     unsigned int stream_id_plus1, count;
 403     int chapter_id, i;
 404     int64_t value, end;
 405     char name[256], str_value[1024], type_str[256];
 406     const char *type;
 407     AVChapter *chapter= NULL;
 408     AVStream *st= NULL;
 409
 410     end= get_packetheader(nut, bc, 1, INFO_STARTCODE);
 411     end += url_ftell(bc);
 412
 413     GET_V(stream_id_plus1, tmp <= s->nb_streams)
 414     chapter_id   = get_s(bc);
 415     chapter_start= ff_get_v(bc);
 416     chapter_len  = ff_get_v(bc);
 417     count        = ff_get_v(bc);
 418
 419     if(chapter_id && !stream_id_plus1){
 420         int64_t start= chapter_start / nut->time_base_count;
 421         chapter= ff_new_chapter(s, chapter_id,
 422                                 nut->time_base[chapter_start % nut->time_base_count],
 423                                 start, start + chapter_len, NULL);
 424     } else if(stream_id_plus1)
 425         st= s->streams[stream_id_plus1 - 1];
 426
 427     for(i=0; i<count; i++){
 428         get_str(bc, name, sizeof(name));
 429         value= get_s(bc);
 430         if(value == -1){
 431             type= "UTF-8";
 432             get_str(bc, str_value, sizeof(str_value));
 433         }else if(value == -2){
 434             get_str(bc, type_str, sizeof(type_str));
 435             type= type_str;
 436             get_str(bc, str_value, sizeof(str_value));
 437         }else if(value == -3){
 438             type= "s";
 439             value= get_s(bc);
 440         }else if(value == -4){
 441             type= "t";
 442             value= ff_get_v(bc);
 443         }else if(value < -4){
 444             type= "r";
 445             get_s(bc);
 446         }else{
 447             type= "v";
 448         }
 449
 450         if (stream_id_plus1 > s->nb_streams) {
 451             av_log(s, AV_LOG_ERROR, "invalid stream id for info packet\n");
 452             continue;
 453         }
 454
 455         if(!strcmp(type, "UTF-8")){
 456             AVMetadata **metadata = NULL;
 457             if(chapter_id==0 && !strcmp(name, "Disposition"))
 458                 set_disposition_bits(s, str_value, stream_id_plus1 - 1);
 459             else if(chapter)          metadata= &chapter->metadata;
 460             else if(stream_id_plus1)  metadata= &st->metadata;
 461             else                      metadata= &s->metadata;
 462             if(metadata && strcasecmp(name,"Uses")
 463                && strcasecmp(name,"Depends") && strcasecmp(name,"Replaces"))
 464                 av_metadata_set2(metadata, name, str_value, 0);
 465         }
 466     }
 467
 468     if(skip_reserved(bc, end) || get_checksum(bc)){
 469         av_log(s, AV_LOG_ERROR, "info header checksum mismatch\n");
 470         return -1;
 471     }
 472     return 0;
 473 }
 474
 475 static int decode_syncpoint(NUTContext *nut, int64_t *ts, int64_t *back_ptr){
 476     AVFormatContext *s= nut->avf;
 477     ByteIOContext *bc = s->pb;
 478     int64_t end, tmp;
 479
 480     nut->last_syncpoint_pos= url_ftell(bc)-8;
 481
 482     end= get_packetheader(nut, bc, 1, SYNCPOINT_STARTCODE);
 483     end += url_ftell(bc);
 484
 485     tmp= ff_get_v(bc);
 486     *back_ptr= nut->last_syncpoint_pos - 16*ff_get_v(bc);
 487     if(*back_ptr < 0)
 488         return -1;
 489
 490     ff_nut_reset_ts(nut, nut->time_base[tmp % nut->time_base_count], tmp / nut->time_base_count);
 491
 492     if(skip_reserved(bc, end) || get_checksum(bc)){
 493         av_log(s, AV_LOG_ERROR, "sync point checksum mismatch\n");
 494         return -1;
 495     }
 496
 497     *ts= tmp / s->nb_streams * av_q2d(nut->time_base[tmp % s->nb_streams])*AV_TIME_BASE;
 498     ff_nut_add_sp(nut, nut->last_syncpoint_pos, *back_ptr, *ts);
 499
 500     return 0;
 501 }
 502
 503 static int find_and_decode_index(NUTContext *nut){
 504     AVFormatContext *s= nut->avf;
 505     ByteIOContext *bc = s->pb;
 506     uint64_t tmp, end;
 507     int i, j, syncpoint_count;
 508     int64_t filesize= url_fsize(bc);
 509     int64_t *syncpoints;
 510     int8_t *has_keyframe;
 511     int ret= -1;
 512
 513     url_fseek(bc, filesize-12, SEEK_SET);
 514     url_fseek(bc, filesize-get_be64(bc), SEEK_SET);
 515     if(get_be64(bc) != INDEX_STARTCODE){
 516         av_log(s, AV_LOG_ERROR, "no index at the end\n");
 517         return -1;
 518     }
 519
 520     end= get_packetheader(nut, bc, 1, INDEX_STARTCODE);
 521     end += url_ftell(bc);
 522
 523     ff_get_v(bc); //max_pts
 524     GET_V(syncpoint_count, tmp < INT_MAX/8 && tmp > 0)
 525     syncpoints= av_malloc(sizeof(int64_t)*syncpoint_count);
 526     has_keyframe= av_malloc(sizeof(int8_t)*(syncpoint_count+1));
 527     for(i=0; i<syncpoint_count; i++){
 528         syncpoints[i] = ff_get_v(bc);
 529         if(syncpoints[i] <= 0)
 530             goto fail;
 531         if(i)
 532             syncpoints[i] += syncpoints[i-1];
 533     }
 534
 535     for(i=0; i<s->nb_streams; i++){
 536         int64_t last_pts= -1;
 537         for(j=0; j<syncpoint_count;){
 538             uint64_t x= ff_get_v(bc);
 539             int type= x&1;
 540             int n= j;
 541             x>>=1;
 542             if(type){
 543                 int flag= x&1;
 544                 x>>=1;
 545                 if(n+x >= syncpoint_count + 1){
 546                     av_log(s, AV_LOG_ERROR, "index overflow A\n");
 547                     goto fail;
 548                 }
 549                 while(x--)
 550                     has_keyframe[n++]= flag;
 551                 has_keyframe[n++]= !flag;
 552             }else{
 553                 while(x != 1){
 554                     if(n>=syncpoint_count + 1){
 555                         av_log(s, AV_LOG_ERROR, "index overflow B\n");
 556                         goto fail;
 557                     }
 558                     has_keyframe[n++]= x&1;
 559                     x>>=1;
 560                 }
 561             }
 562             if(has_keyframe[0]){
 563                 av_log(s, AV_LOG_ERROR, "keyframe before first syncpoint in index\n");
 564                 goto fail;
 565             }
 566             assert(n<=syncpoint_count+1);
 567             for(; j<n && j<syncpoint_count; j++){
 568                 if(has_keyframe[j]){
 569                     uint64_t B, A= ff_get_v(bc);
 570                     if(!A){
 571                         A= ff_get_v(bc);
 572                         B= ff_get_v(bc);
 573                         //eor_pts[j][i] = last_pts + A + B
 574                     }else
 575                         B= 0;
 576                     av_add_index_entry(
 577                         s->streams[i],
 578                         16*syncpoints[j-1],
 579                         last_pts + A,
 580                         0,
 581                         0,
 582                         AVINDEX_KEYFRAME);
 583                     last_pts += A + B;
 584                 }
 585             }
 586         }
 587     }
 588
 589     if(skip_reserved(bc, end) || get_checksum(bc)){
 590         av_log(s, AV_LOG_ERROR, "index checksum mismatch\n");
 591         goto fail;
 592     }
 593     ret= 0;
 594 fail:
 595     av_free(syncpoints);
 596     av_free(has_keyframe);
 597     return ret;
 598 }
 599
 600 static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)
 601 {
 602     NUTContext *nut = s->priv_data;
 603     ByteIOContext *bc = s->pb;
 604     int64_t pos;
 605     int initialized_stream_count;
 606
 607     nut->avf= s;
 608
 609     /* main header */
 610     pos=0;
 611     do{
 612         pos= find_startcode(bc, MAIN_STARTCODE, pos)+1;
 613         if (pos<0+1){
 614             av_log(s, AV_LOG_ERROR, "No main startcode found.\n");
 615             return -1;
 616         }
 617     }while(decode_main_header(nut) < 0);
 618
 619     /* stream headers */
 620     pos=0;
 621     for(initialized_stream_count=0; initialized_stream_count < s->nb_streams;){
 622         pos= find_startcode(bc, STREAM_STARTCODE, pos)+1;
 623         if (pos<0+1){
 624             av_log(s, AV_LOG_ERROR, "Not all stream headers found.\n");
 625             return -1;
 626         }
 627         if(decode_stream_header(nut) >= 0)
 628             initialized_stream_count++;
 629     }
 630
 631     /* info headers */
 632     pos=0;
 633     for(;;){
 634         uint64_t startcode= find_any_startcode(bc, pos);
 635         pos= url_ftell(bc);
 636
 637         if(startcode==0){
 638             av_log(s, AV_LOG_ERROR, "EOF before video frames\n");
 639             return -1;
 640         }else if(startcode == SYNCPOINT_STARTCODE){
 641             nut->next_startcode= startcode;
 642             break;
 643         }else if(startcode != INFO_STARTCODE){
 644             continue;
 645         }
 646
 647         decode_info_header(nut);
 648     }
 649
 650     s->data_offset= pos-8;
 651
 652     if(!url_is_streamed(bc)){
 653         int64_t orig_pos= url_ftell(bc);
 654         find_and_decode_index(nut);
 655         url_fseek(bc, orig_pos, SEEK_SET);
 656     }
 657     assert(nut->next_startcode == SYNCPOINT_STARTCODE);
 658
 659     return 0;
 660 }
 661
 662 static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id, uint8_t *header_idx, int frame_code){
 663     AVFormatContext *s= nut->avf;
 664     ByteIOContext *bc = s->pb;
 665     StreamContext *stc;
 666     int size, flags, size_mul, pts_delta, i, reserved_count;
 667     uint64_t tmp;
 668
 669     if(url_ftell(bc) > nut->last_syncpoint_pos + nut->max_distance){
 670         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);
 671         return -1;
 672     }
 673
 674     flags          = nut->frame_code[frame_code].flags;
 675     size_mul       = nut->frame_code[frame_code].size_mul;
 676     size           = nut->frame_code[frame_code].size_lsb;
 677     *stream_id     = nut->frame_code[frame_code].stream_id;
 678     pts_delta      = nut->frame_code[frame_code].pts_delta;
 679     reserved_count = nut->frame_code[frame_code].reserved_count;
 680     *header_idx    = nut->frame_code[frame_code].header_idx;
 681
 682     if(flags & FLAG_INVALID)
 683         return -1;
 684     if(flags & FLAG_CODED)
 685         flags ^= ff_get_v(bc);
 686     if(flags & FLAG_STREAM_ID){
 687         GET_V(*stream_id, tmp < s->nb_streams)
 688     }
 689     stc= &nut->stream[*stream_id];
 690     if(flags&FLAG_CODED_PTS){
 691         int coded_pts= ff_get_v(bc);
 692 //FIXME check last_pts validity?
 693         if(coded_pts < (1<<stc->msb_pts_shift)){
 694             *pts=ff_lsb2full(stc, coded_pts);
 695         }else
 696             *pts=coded_pts - (1<<stc->msb_pts_shift);
 697     }else
 698         *pts= stc->last_pts + pts_delta;
 699     if(flags&FLAG_SIZE_MSB){
 700         size += size_mul*ff_get_v(bc);
 701     }
 702     if(flags&FLAG_MATCH_TIME)
 703         get_s(bc);
 704     if(flags&FLAG_HEADER_IDX)
 705         *header_idx= ff_get_v(bc);
 706     if(flags&FLAG_RESERVED)
 707         reserved_count= ff_get_v(bc);
 708     for(i=0; i<reserved_count; i++)
 709         ff_get_v(bc);
 710
 711     if(*header_idx >= (unsigned)nut->header_count){
 712         av_log(s, AV_LOG_ERROR, "header_idx invalid\n");
 713         return -1;
 714     }
 715     if(size > 4096)
 716         *header_idx=0;
 717     size -= nut->header_len[*header_idx];
 718
 719     if(flags&FLAG_CHECKSUM){
 720         get_be32(bc); //FIXME check this
 721     }else if(size > 2*nut->max_distance || FFABS(stc->last_pts - *pts) > stc->max_pts_distance){
 722         av_log(s, AV_LOG_ERROR, "frame size > 2max_distance and no checksum\n");
 723         return -1;
 724     }
 725
 726     stc->last_pts= *pts;
 727     stc->last_flags= flags;
 728
 729     return size;
 730 }
 731
 732 static int decode_frame(NUTContext *nut, AVPacket *pkt, int frame_code){
 733     AVFormatContext *s= nut->avf;
 734     ByteIOContext *bc = s->pb;
 735     int size, stream_id, discard;
 736     int64_t pts, last_IP_pts;
 737     StreamContext *stc;
 738     uint8_t header_idx;
 739
 740     size= decode_frame_header(nut, &pts, &stream_id, &header_idx, frame_code);
 741     if(size < 0)
 742         return -1;
 743
 744     stc= &nut->stream[stream_id];
 745
 746     if (stc->last_flags & FLAG_KEY)
 747         stc->skip_until_key_frame=0;
 748
 749     discard= s->streams[ stream_id ]->discard;
 750     last_IP_pts= s->streams[ stream_id ]->last_IP_pts;
 751     if(  (discard >= AVDISCARD_NONKEY && !(stc->last_flags & FLAG_KEY))
 752        ||(discard >= AVDISCARD_BIDIR && last_IP_pts != AV_NOPTS_VALUE && last_IP_pts > pts)
 753        || discard >= AVDISCARD_ALL
 754        || stc->skip_until_key_frame){
 755         url_fskip(bc, size);
 756         return 1;
 757     }
 758
 759     av_new_packet(pkt, size + nut->header_len[header_idx]);
 760     memcpy(pkt->data, nut->header[header_idx], nut->header_len[header_idx]);
 761     pkt->pos= url_ftell(bc); //FIXME
 762     get_buffer(bc, pkt->data + nut->header_len[header_idx], size);
 763
 764     pkt->stream_index = stream_id;
 765     if (stc->last_flags & FLAG_KEY)
 766         pkt->flags |= AV_PKT_FLAG_KEY;
 767     pkt->pts = pts;
 768
 769     return 0;
 770 }
 771
 772 static int nut_read_packet(AVFormatContext *s, AVPacket *pkt)
 773 {
 774     NUTContext *nut = s->priv_data;
 775     ByteIOContext *bc = s->pb;
 776     int i, frame_code=0, ret, skip;
 777     int64_t ts, back_ptr;
 778
 779     for(;;){
 780         int64_t pos= url_ftell(bc);
 781         uint64_t tmp= nut->next_startcode;
 782         nut->next_startcode=0;
 783
 784         if(tmp){
 785             pos-=8;
 786         }else{
 787             frame_code = get_byte(bc);
 788             if(url_feof(bc))
 789                 return -1;
 790             if(frame_code == 'N'){
 791                 tmp= frame_code;
 792                 for(i=1; i<8; i++)
 793                     tmp = (tmp<<8) + get_byte(bc);
 794             }
 795         }
 796         switch(tmp){
 797         case MAIN_STARTCODE:
 798         case STREAM_STARTCODE:
 799         case INDEX_STARTCODE:
 800             skip= get_packetheader(nut, bc, 0, tmp);
 801             url_fseek(bc, skip, SEEK_CUR);
 802             break;
 803         case INFO_STARTCODE:
 804             if(decode_info_header(nut)<0)
 805                 goto resync;
 806             break;
 807         case SYNCPOINT_STARTCODE:
 808             if(decode_syncpoint(nut, &ts, &back_ptr)<0)
 809                 goto resync;
 810             frame_code = get_byte(bc);
 811         case 0:
 812             ret= decode_frame(nut, pkt, frame_code);
 813             if(ret==0)
 814                 return 0;
 815             else if(ret==1) //ok but discard packet
 816                 break;
 817         default:
 818 resync:
 819 av_log(s, AV_LOG_DEBUG, "syncing from %"PRId64"\n", pos);
 820             tmp= find_any_startcode(bc, nut->last_syncpoint_pos+1);
 821             if(tmp==0)
 822                 return -1;
 823 av_log(s, AV_LOG_DEBUG, "sync\n");
 824             nut->next_startcode= tmp;
 825         }
 826     }
 827 }
 828
 829 static int64_t nut_read_timestamp(AVFormatContext *s, int stream_index, int64_t *pos_arg, int64_t pos_limit){
 830     NUTContext *nut = s->priv_data;
 831     ByteIOContext *bc = s->pb;
 832     int64_t pos, pts, back_ptr;
 833 av_log(s, AV_LOG_DEBUG, "read_timestamp(X,%d,%"PRId64",%"PRId64")\n", stream_index, *pos_arg, pos_limit);
 834
 835     pos= *pos_arg;
 836     do{
 837         pos= find_startcode(bc, SYNCPOINT_STARTCODE, pos)+1;
 838         if(pos < 1){
 839             assert(nut->next_startcode == 0);
 840             av_log(s, AV_LOG_ERROR, "read_timestamp failed.\n");
 841             return AV_NOPTS_VALUE;
 842         }
 843     }while(decode_syncpoint(nut, &pts, &back_ptr) < 0);
 844     *pos_arg = pos-1;
 845     assert(nut->last_syncpoint_pos == *pos_arg);
 846
 847     av_log(s, AV_LOG_DEBUG, "return %"PRId64" %"PRId64"\n", pts,back_ptr );
 848     if     (stream_index == -1) return pts;
 849     else if(stream_index == -2) return back_ptr;
 850
 851 assert(0);
 852 }
 853
 854 static int read_seek(AVFormatContext *s, int stream_index, int64_t pts, int flags){
 855     NUTContext *nut = s->priv_data;
 856     AVStream *st= s->streams[stream_index];
 857     Syncpoint dummy={.ts= pts*av_q2d(st->time_base)*AV_TIME_BASE};
 858     Syncpoint nopts_sp= {.ts= AV_NOPTS_VALUE, .back_ptr= AV_NOPTS_VALUE};
 859     Syncpoint *sp, *next_node[2]= {&nopts_sp, &nopts_sp};
 860     int64_t pos, pos2, ts;
 861     int i;
 862
 863     if(st->index_entries){
 864         int index= av_index_search_timestamp(st, pts, flags);
 865         if(index<0)
 866             return -1;
 867
 868         pos2= st->index_entries[index].pos;
 869         ts  = st->index_entries[index].timestamp;
 870     }else{
 871         av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pts_cmp,
 872                      (void **) next_node);
 873         av_log(s, AV_LOG_DEBUG, "%"PRIu64"-%"PRIu64" %"PRId64"-%"PRId64"\n", next_node[0]->pos, next_node[1]->pos,
 874                                                     next_node[0]->ts , next_node[1]->ts);
 875         pos= av_gen_search(s, -1, dummy.ts, next_node[0]->pos, next_node[1]->pos, next_node[1]->pos,
 876                                             next_node[0]->ts , next_node[1]->ts, AVSEEK_FLAG_BACKWARD, &ts, nut_read_timestamp);
 877
 878         if(!(flags & AVSEEK_FLAG_BACKWARD)){
 879             dummy.pos= pos+16;
 880             next_node[1]= &nopts_sp;
 881             av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
 882                          (void **) next_node);
 883             pos2= av_gen_search(s, -2, dummy.pos, next_node[0]->pos     , next_node[1]->pos, next_node[1]->pos,
 884                                                 next_node[0]->back_ptr, next_node[1]->back_ptr, flags, &ts, nut_read_timestamp);
 885             if(pos2>=0)
 886                 pos= pos2;
 887             //FIXME dir but I think it does not matter
 888         }
 889         dummy.pos= pos;
 890         sp= av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
 891                          NULL);
 892
 893         assert(sp);
 894         pos2= sp->back_ptr  - 15;
 895     }
 896     av_log(NULL, AV_LOG_DEBUG, "SEEKTO: %"PRId64"\n", pos2);
 897     pos= find_startcode(s->pb, SYNCPOINT_STARTCODE, pos2);
 898     url_fseek(s->pb, pos, SEEK_SET);
 899     av_log(NULL, AV_LOG_DEBUG, "SP: %"PRId64"\n", pos);
 900     if(pos2 > pos || pos2 + 15 < pos){
 901         av_log(NULL, AV_LOG_ERROR, "no syncpoint at backptr pos\n");
 902     }
 903     for(i=0; i<s->nb_streams; i++)
 904         nut->stream[i].skip_until_key_frame=1;
 905
 906     return 0;
 907 }
 908
 909 static int nut_read_close(AVFormatContext *s)
 910 {
 911     NUTContext *nut = s->priv_data;
 912     int i;
 913
 914     av_freep(&nut->time_base);
 915     av_freep(&nut->stream);
 916     ff_nut_free_sp(nut);
 917     for(i = 1; i < nut->header_count; i++)
 918         av_freep(&nut->header[i]);
 919
 920     return 0;
 921 }
 922
 923 #if CONFIG_NUT_DEMUXER
 924 AVInputFormat nut_demuxer = {
 925     "nut",
 926     NULL_IF_CONFIG_SMALL("NUT format"),
 927     sizeof(NUTContext),
 928     nut_probe,
 929     nut_read_header,
 930     nut_read_packet,
 931     nut_read_close,
 932     read_seek,
 933     .extensions = "nut",
 934     .metadata_conv = ff_nut_metadata_conv,
 935     .codec_tag = (const AVCodecTag * const []) { ff_codec_bmp_tags, ff_nut_video_tags, ff_codec_wav_tags, ff_nut_subtitle_tags, 0 },
 936 };
 937 #endif