libavformat/nutenc.c

   1 /*
   2  * nut muxer
   3  * Copyright (c) 2004-2007 Michael Niedermayer
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/intreadwrite.h"
  23 #include "libavutil/tree.h"
  24 #include "libavcodec/mpegaudiodata.h"
  25 #include "nut.h"
  26
  27 static int find_expected_header(AVCodecContext *c, int size, int key_frame, uint8_t out[64]){
  28     int sample_rate= c->sample_rate;
  29
  30     if(size>4096)
  31         return 0;
  32
  33     AV_WB24(out, 1);
  34
  35     if(c->codec_id == CODEC_ID_MPEG4){
  36         if(key_frame){
  37             return 3;
  38         }else{
  39             out[3]= 0xB6;
  40             return 4;
  41         }
  42     }else if(c->codec_id == CODEC_ID_MPEG1VIDEO || c->codec_id == CODEC_ID_MPEG2VIDEO){
  43         return 3;
  44     }else if(c->codec_id == CODEC_ID_H264){
  45         return 3;
  46     }else if(c->codec_id == CODEC_ID_MP3 || c->codec_id == CODEC_ID_MP2){
  47         int lsf, mpeg25, sample_rate_index, bitrate_index, frame_size;
  48         int layer= c->codec_id == CODEC_ID_MP3 ? 3 : 2;
  49         unsigned int header= 0xFFF00000;
  50
  51         lsf     = sample_rate < (24000+32000)/2;
  52         mpeg25  = sample_rate < (12000+16000)/2;
  53         sample_rate <<= lsf + mpeg25;
  54         if     (sample_rate < (32000 + 44100)/2) sample_rate_index=2;
  55         else if(sample_rate < (44100 + 48000)/2) sample_rate_index=0;
  56         else                                     sample_rate_index=1;
  57
  58         sample_rate= ff_mpa_freq_tab[sample_rate_index] >> (lsf + mpeg25);
  59
  60         for(bitrate_index=2; bitrate_index<30; bitrate_index++){
  61             frame_size = ff_mpa_bitrate_tab[lsf][layer-1][bitrate_index>>1];
  62             frame_size = (frame_size * 144000) / (sample_rate << lsf) + (bitrate_index&1);
  63
  64             if(frame_size == size)
  65                 break;
  66         }
  67
  68         header |= (!lsf)<<19;
  69         header |= (4-layer)<<17;
  70         header |= 1<<16; //no crc
  71         AV_WB32(out, header);
  72         if(size <= 0)
  73             return 2; //we guess there is no crc, if there is one the user clearly does not care about overhead
  74         if(bitrate_index == 30)
  75             return -1; //something is wrong ...
  76
  77         header |= (bitrate_index>>1)<<12;
  78         header |= sample_rate_index<<10;
  79         header |= (bitrate_index&1)<<9;
  80
  81         return 2; //FIXME actually put the needed ones in build_elision_headers()
  82         return 3; //we guess that the private bit is not set
  83 //FIXME the above assumptions should be checked, if these turn out false too often something should be done
  84     }
  85     return 0;
  86 }
  87
  88 static int find_header_idx(AVFormatContext *s, AVCodecContext *c, int size, int frame_type){
  89     NUTContext *nut = s->priv_data;
  90     uint8_t out[64];
  91     int i;
  92     int len= find_expected_header(c, size, frame_type, out);
  93
  94 //av_log(NULL, AV_LOG_ERROR, "expected_h len=%d size=%d codec_id=%d\n", len, size, c->codec_id);
  95
  96     for(i=1; i<nut->header_count; i++){
  97         if(   len == nut->header_len[i]
  98            && !memcmp(out, nut->header[i], len)){
  99 //    av_log(NULL, AV_LOG_ERROR, "found %d\n", i);
 100             return i;
 101         }
 102     }
 103 //    av_log(NULL, AV_LOG_ERROR, "nothing found\n");
 104     return 0;
 105 }
 106
 107 static void build_elision_headers(AVFormatContext *s){
 108     NUTContext *nut = s->priv_data;
 109     int i;
 110     //FIXME this is lame
 111     //FIXME write a 2pass mode to find the maximal headers
 112     static const uint8_t headers[][5]={
 113         {3, 0x00, 0x00, 0x01},
 114         {4, 0x00, 0x00, 0x01, 0xB6},
 115         {2, 0xFF, 0xFA}, //mp3+crc
 116         {2, 0xFF, 0xFB}, //mp3
 117         {2, 0xFF, 0xFC}, //mp2+crc
 118         {2, 0xFF, 0xFD}, //mp2
 119     };
 120
 121     nut->header_count= 7;
 122     for(i=1; i<nut->header_count; i++){
 123         nut->header_len[i]=  headers[i-1][0];
 124         nut->header    [i]= &headers[i-1][1];
 125     }
 126 }
 127
 128 static void build_frame_code(AVFormatContext *s){
 129     NUTContext *nut = s->priv_data;
 130     int key_frame, index, pred, stream_id;
 131     int start=1;
 132     int end= 254;
 133     int keyframe_0_esc= s->nb_streams > 2;
 134     int pred_table[10];
 135     FrameCode *ft;
 136
 137     ft= &nut->frame_code[start];
 138     ft->flags= FLAG_CODED;
 139     ft->size_mul=1;
 140     ft->pts_delta=1;
 141     start++;
 142
 143     if(keyframe_0_esc){
 144         /* keyframe = 0 escape */
 145         FrameCode *ft= &nut->frame_code[start];
 146         ft->flags= FLAG_STREAM_ID | FLAG_SIZE_MSB | FLAG_CODED_PTS;
 147         ft->size_mul=1;
 148         start++;
 149     }
 150
 151     for(stream_id= 0; stream_id<s->nb_streams; stream_id++){
 152         int start2= start + (end-start)*stream_id / s->nb_streams;
 153         int end2  = start + (end-start)*(stream_id+1) / s->nb_streams;
 154         AVCodecContext *codec = s->streams[stream_id]->codec;
 155         int is_audio= codec->codec_type == CODEC_TYPE_AUDIO;
 156         int intra_only= /*codec->intra_only || */is_audio;
 157         int pred_count;
 158
 159         for(key_frame=0; key_frame<2; key_frame++){
 160             if(intra_only && keyframe_0_esc && key_frame==0)
 161                 continue;
 162
 163             {
 164                 FrameCode *ft= &nut->frame_code[start2];
 165                 ft->flags= FLAG_KEY*key_frame;
 166                 ft->flags|= FLAG_SIZE_MSB | FLAG_CODED_PTS;
 167                 ft->stream_id= stream_id;
 168                 ft->size_mul=1;
 169                 if(is_audio)
 170                     ft->header_idx= find_header_idx(s, codec, -1, key_frame);
 171                 start2++;
 172             }
 173         }
 174
 175         key_frame= intra_only;
 176 #if 1
 177         if(is_audio){
 178             int frame_bytes= codec->frame_size*(int64_t)codec->bit_rate / (8*codec->sample_rate);
 179             int pts;
 180             for(pts=0; pts<2; pts++){
 181                 for(pred=0; pred<2; pred++){
 182                     FrameCode *ft= &nut->frame_code[start2];
 183                     ft->flags= FLAG_KEY*key_frame;
 184                     ft->stream_id= stream_id;
 185                     ft->size_mul=frame_bytes + 2;
 186                     ft->size_lsb=frame_bytes + pred;
 187                     ft->pts_delta=pts;
 188                     ft->header_idx= find_header_idx(s, codec, frame_bytes + pred, key_frame);
 189                     start2++;
 190                 }
 191             }
 192         }else{
 193             FrameCode *ft= &nut->frame_code[start2];
 194             ft->flags= FLAG_KEY | FLAG_SIZE_MSB;
 195             ft->stream_id= stream_id;
 196             ft->size_mul=1;
 197             ft->pts_delta=1;
 198             start2++;
 199         }
 200 #endif
 201
 202         if(codec->has_b_frames){
 203             pred_count=5;
 204             pred_table[0]=-2;
 205             pred_table[1]=-1;
 206             pred_table[2]=1;
 207             pred_table[3]=3;
 208             pred_table[4]=4;
 209         }else if(codec->codec_id == CODEC_ID_VORBIS){
 210             pred_count=3;
 211             pred_table[0]=2;
 212             pred_table[1]=9;
 213             pred_table[2]=16;
 214         }else{
 215             pred_count=1;
 216             pred_table[0]=1;
 217         }
 218
 219         for(pred=0; pred<pred_count; pred++){
 220             int start3= start2 + (end2-start2)*pred / pred_count;
 221             int end3  = start2 + (end2-start2)*(pred+1) / pred_count;
 222
 223             for(index=start3; index<end3; index++){
 224                 FrameCode *ft= &nut->frame_code[index];
 225                 ft->flags= FLAG_KEY*key_frame;
 226                 ft->flags|= FLAG_SIZE_MSB;
 227                 ft->stream_id= stream_id;
 228 //FIXME use single byte size and pred from last
 229                 ft->size_mul= end3-start3;
 230                 ft->size_lsb= index - start3;
 231                 ft->pts_delta= pred_table[pred];
 232                 if(is_audio)
 233                     ft->header_idx= find_header_idx(s, codec, -1, key_frame);
 234             }
 235         }
 236     }
 237     memmove(&nut->frame_code['N'+1], &nut->frame_code['N'], sizeof(FrameCode)*(255-'N'));
 238     nut->frame_code[  0].flags=
 239     nut->frame_code[255].flags=
 240     nut->frame_code['N'].flags= FLAG_INVALID;
 241 }
 242
 243 /**
 244  * Gets the length in bytes which is needed to store val as v.
 245  */
 246 static int get_length(uint64_t val){
 247     int i=1;
 248
 249     while(val>>=7)
 250         i++;
 251
 252     return i;
 253 }
 254
 255 static void put_v(ByteIOContext *bc, uint64_t val){
 256     int i= get_length(val);
 257
 258     while(--i>0)
 259         put_byte(bc, 128 | (val>>(7*i)));
 260
 261     put_byte(bc, val&127);
 262 }
 263
 264 static void put_tt(NUTContext *nut, StreamContext *nus, ByteIOContext *bc, uint64_t val){
 265     val *= nut->time_base_count;
 266     val += nus->time_base - nut->time_base;
 267     put_v(bc, val);
 268 }
 269
 270 /**
 271  * Stores a string as vb.
 272  */
 273 static void put_str(ByteIOContext *bc, const char *string){
 274     int len= strlen(string);
 275
 276     put_v(bc, len);
 277     put_buffer(bc, string, len);
 278 }
 279
 280 static void put_s(ByteIOContext *bc, int64_t val){
 281     put_v(bc, 2*FFABS(val) - (val>0));
 282 }
 283
 284 #ifdef TRACE
 285 static inline void put_v_trace(ByteIOContext *bc, uint64_t v, char *file, char *func, int line){
 286     av_log(NULL, AV_LOG_DEBUG, "put_v %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
 287
 288     put_v(bc, v);
 289 }
 290
 291 static inline void put_s_trace(ByteIOContext *bc, int64_t v, char *file, char *func, int line){
 292     av_log(NULL, AV_LOG_DEBUG, "put_s %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
 293
 294     put_s(bc, v);
 295 }
 296 #define put_v(bc, v)  put_v_trace(bc, v, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 297 #define put_s(bc, v)  put_s_trace(bc, v, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 298 #endif
 299
 300 //FIXME remove calculate_checksum
 301 static void put_packet(NUTContext *nut, ByteIOContext *bc, ByteIOContext *dyn_bc, int calculate_checksum, uint64_t startcode){
 302     uint8_t *dyn_buf=NULL;
 303     int dyn_size= url_close_dyn_buf(dyn_bc, &dyn_buf);
 304     int forw_ptr= dyn_size + 4*calculate_checksum;
 305
 306     if(forw_ptr > 4096)
 307         init_checksum(bc, ff_crc04C11DB7_update, 0);
 308     put_be64(bc, startcode);
 309     put_v(bc, forw_ptr);
 310     if(forw_ptr > 4096)
 311         put_le32(bc, get_checksum(bc));
 312
 313     if(calculate_checksum)
 314         init_checksum(bc, ff_crc04C11DB7_update, 0);
 315     put_buffer(bc, dyn_buf, dyn_size);
 316     if(calculate_checksum)
 317         put_le32(bc, get_checksum(bc));
 318
 319     av_free(dyn_buf);
 320 }
 321
 322 static void write_mainheader(NUTContext *nut, ByteIOContext *bc){
 323     int i, j, tmp_pts, tmp_flags, tmp_stream, tmp_mul, tmp_size, tmp_fields, tmp_head_idx;
 324     int64_t tmp_match;
 325
 326     put_v(bc, 3); /* version */
 327     put_v(bc, nut->avf->nb_streams);
 328     put_v(bc, nut->max_distance);
 329     put_v(bc, nut->time_base_count);
 330
 331     for(i=0; i<nut->time_base_count; i++){
 332         put_v(bc, nut->time_base[i].num);
 333         put_v(bc, nut->time_base[i].den);
 334     }
 335
 336     tmp_pts=0;
 337     tmp_mul=1;
 338     tmp_stream=0;
 339     tmp_match= 1-(1LL<<62);
 340     tmp_head_idx= 0;
 341     for(i=0; i<256;){
 342         tmp_fields=0;
 343         tmp_size=0;
 344 //        tmp_res=0;
 345         if(tmp_pts    != nut->frame_code[i].pts_delta) tmp_fields=1;
 346         if(tmp_mul    != nut->frame_code[i].size_mul ) tmp_fields=2;
 347         if(tmp_stream != nut->frame_code[i].stream_id) tmp_fields=3;
 348         if(tmp_size   != nut->frame_code[i].size_lsb ) tmp_fields=4;
 349 //        if(tmp_res    != nut->frame_code[i].res            ) tmp_fields=5;
 350         if(tmp_head_idx!=nut->frame_code[i].header_idx)tmp_fields=8;
 351
 352         tmp_pts   = nut->frame_code[i].pts_delta;
 353         tmp_flags = nut->frame_code[i].flags;
 354         tmp_stream= nut->frame_code[i].stream_id;
 355         tmp_mul   = nut->frame_code[i].size_mul;
 356         tmp_size  = nut->frame_code[i].size_lsb;
 357 //        tmp_res   = nut->frame_code[i].res;
 358         tmp_head_idx= nut->frame_code[i].header_idx;
 359
 360         for(j=0; i<256; j++,i++){
 361             if(i == 'N'){
 362                 j--;
 363                 continue;
 364             }
 365             if(nut->frame_code[i].pts_delta != tmp_pts   ) break;
 366             if(nut->frame_code[i].flags     != tmp_flags ) break;
 367             if(nut->frame_code[i].stream_id != tmp_stream) break;
 368             if(nut->frame_code[i].size_mul  != tmp_mul   ) break;
 369             if(nut->frame_code[i].size_lsb  != tmp_size+j) break;
 370 //            if(nut->frame_code[i].res       != tmp_res   ) break;
 371             if(nut->frame_code[i].header_idx!= tmp_head_idx) break;
 372         }
 373         if(j != tmp_mul - tmp_size) tmp_fields=6;
 374
 375         put_v(bc, tmp_flags);
 376         put_v(bc, tmp_fields);
 377         if(tmp_fields>0) put_s(bc, tmp_pts);
 378         if(tmp_fields>1) put_v(bc, tmp_mul);
 379         if(tmp_fields>2) put_v(bc, tmp_stream);
 380         if(tmp_fields>3) put_v(bc, tmp_size);
 381         if(tmp_fields>4) put_v(bc, 0 /*tmp_res*/);
 382         if(tmp_fields>5) put_v(bc, j);
 383         if(tmp_fields>6) put_v(bc, tmp_match);
 384         if(tmp_fields>7) put_v(bc, tmp_head_idx);
 385     }
 386     put_v(bc, nut->header_count-1);
 387     for(i=1; i<nut->header_count; i++){
 388         put_v(bc, nut->header_len[i]);
 389         put_buffer(bc, nut->header[i], nut->header_len[i]);
 390     }
 391 }
 392
 393 static int write_streamheader(NUTContext *nut, ByteIOContext *bc, AVStream *st, int i){
 394     AVCodecContext *codec = st->codec;
 395     put_v(bc, i);
 396     switch(codec->codec_type){
 397     case CODEC_TYPE_VIDEO: put_v(bc, 0); break;
 398     case CODEC_TYPE_AUDIO: put_v(bc, 1); break;
 399     case CODEC_TYPE_SUBTITLE: put_v(bc, 2); break;
 400     default              : put_v(bc, 3); break;
 401     }
 402     put_v(bc, 4);
 403     if (codec->codec_tag){
 404         put_le32(bc, codec->codec_tag);
 405     }else
 406         return -1;
 407
 408     put_v(bc, nut->stream[i].time_base - nut->time_base);
 409     put_v(bc, nut->stream[i].msb_pts_shift);
 410     put_v(bc, nut->stream[i].max_pts_distance);
 411     put_v(bc, codec->has_b_frames);
 412     put_byte(bc, 0); /* flags: 0x1 - fixed_fps, 0x2 - index_present */
 413
 414     put_v(bc, codec->extradata_size);
 415     put_buffer(bc, codec->extradata, codec->extradata_size);
 416
 417     switch(codec->codec_type){
 418     case CODEC_TYPE_AUDIO:
 419         put_v(bc, codec->sample_rate);
 420         put_v(bc, 1);
 421         put_v(bc, codec->channels);
 422         break;
 423     case CODEC_TYPE_VIDEO:
 424         put_v(bc, codec->width);
 425         put_v(bc, codec->height);
 426
 427         if(st->sample_aspect_ratio.num<=0 || st->sample_aspect_ratio.den<=0){
 428             put_v(bc, 0);
 429             put_v(bc, 0);
 430         }else{
 431             put_v(bc, st->sample_aspect_ratio.num);
 432             put_v(bc, st->sample_aspect_ratio.den);
 433         }
 434         put_v(bc, 0); /* csp type -- unknown */
 435         break;
 436     default:
 437         break;
 438     }
 439     return 0;
 440 }
 441
 442 static int add_info(ByteIOContext *bc, const char *type, const char *value){
 443     put_str(bc, type);
 444     put_s(bc, -1);
 445     put_str(bc, value);
 446     return 1;
 447 }
 448
 449 static int write_globalinfo(NUTContext *nut, ByteIOContext *bc){
 450     AVFormatContext *s= nut->avf;
 451     AVMetadataTag *title, *author, *copyright;
 452     ByteIOContext *dyn_bc;
 453     uint8_t *dyn_buf=NULL;
 454     int count=0, dyn_size;
 455     int ret = url_open_dyn_buf(&dyn_bc);
 456     if(ret < 0)
 457         return ret;
 458
 459     title     = av_metadata_get(s->metadata, "Title"    , NULL, 0);
 460     author    = av_metadata_get(s->metadata, "Author"   , NULL, 0);
 461     copyright = av_metadata_get(s->metadata, "Copyright", NULL, 0);
 462
 463     if(title    ) count+= add_info(dyn_bc, "Title"    , title->value);
 464     if(author   ) count+= add_info(dyn_bc, "Author"   , author->value);
 465     if(copyright) count+= add_info(dyn_bc, "Copyright", copyright->value);
 466     if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
 467                         count+= add_info(dyn_bc, "Encoder"  , LIBAVFORMAT_IDENT);
 468
 469     put_v(bc, 0); //stream_if_plus1
 470     put_v(bc, 0); //chapter_id
 471     put_v(bc, 0); //timestamp_start
 472     put_v(bc, 0); //length
 473
 474     put_v(bc, count);
 475
 476     dyn_size= url_close_dyn_buf(dyn_bc, &dyn_buf);
 477     put_buffer(bc, dyn_buf, dyn_size);
 478     av_free(dyn_buf);
 479     return 0;
 480 }
 481
 482 static int write_streaminfo(NUTContext *nut, ByteIOContext *bc, int stream_id){
 483     AVFormatContext *s= nut->avf;
 484     AVStream* st = s->streams[stream_id];
 485     ByteIOContext *dyn_bc;
 486     uint8_t *dyn_buf=NULL;
 487     int count=0, dyn_size, i;
 488     int ret = url_open_dyn_buf(&dyn_bc);
 489     if(ret < 0)
 490         return ret;
 491
 492     for (i=0; ff_nut_dispositions[i].flag; ++i) {
 493         if (st->disposition & ff_nut_dispositions[i].flag)
 494             count += add_info(dyn_bc, "Disposition", ff_nut_dispositions[i].str);
 495     }
 496     dyn_size = url_close_dyn_buf(dyn_bc, &dyn_buf);
 497
 498     if (count) {
 499         put_v(bc, stream_id + 1); //stream_id_plus1
 500         put_v(bc, 0); //chapter_id
 501         put_v(bc, 0); //timestamp_start
 502         put_v(bc, 0); //length
 503
 504         put_v(bc, count);
 505
 506         put_buffer(bc, dyn_buf, dyn_size);
 507     }
 508
 509     av_free(dyn_buf);
 510     return count;
 511 }
 512
 513 static int write_headers(NUTContext *nut, ByteIOContext *bc){
 514     ByteIOContext *dyn_bc;
 515     int i, ret;
 516
 517     ret = url_open_dyn_buf(&dyn_bc);
 518     if(ret < 0)
 519         return ret;
 520     write_mainheader(nut, dyn_bc);
 521     put_packet(nut, bc, dyn_bc, 1, MAIN_STARTCODE);
 522
 523     for (i=0; i < nut->avf->nb_streams; i++){
 524         ret = url_open_dyn_buf(&dyn_bc);
 525         if(ret < 0)
 526             return ret;
 527         write_streamheader(nut, dyn_bc, nut->avf->streams[i], i);
 528         put_packet(nut, bc, dyn_bc, 1, STREAM_STARTCODE);
 529     }
 530
 531     ret = url_open_dyn_buf(&dyn_bc);
 532     if(ret < 0)
 533         return ret;
 534     write_globalinfo(nut, dyn_bc);
 535     put_packet(nut, bc, dyn_bc, 1, INFO_STARTCODE);
 536
 537     for (i = 0; i < nut->avf->nb_streams; i++) {
 538         ret = url_open_dyn_buf(&dyn_bc);
 539         if(ret < 0)
 540             return ret;
 541         ret = write_streaminfo(nut, dyn_bc, i);
 542         if (ret < 0)
 543             return ret;
 544         if (ret > 0)
 545             put_packet(nut, bc, dyn_bc, 1, INFO_STARTCODE);
 546         else {
 547             uint8_t* buf;
 548             url_close_dyn_buf(dyn_bc, &buf);
 549             av_free(buf);
 550         }
 551     }
 552
 553     nut->last_syncpoint_pos= INT_MIN;
 554     nut->header_count++;
 555     return 0;
 556 }
 557
 558 static int write_header(AVFormatContext *s){
 559     NUTContext *nut = s->priv_data;
 560     ByteIOContext *bc = s->pb;
 561     int i, j;
 562
 563     nut->avf= s;
 564
 565     nut->stream   = av_mallocz(sizeof(StreamContext)*s->nb_streams);
 566     nut->time_base= av_mallocz(sizeof(AVRational   )*s->nb_streams);
 567
 568     for(i=0; i<s->nb_streams; i++){
 569         AVStream *st= s->streams[i];
 570         int ssize;
 571         AVRational time_base;
 572         ff_parse_specific_params(st->codec, &time_base.den, &ssize, &time_base.num);
 573
 574         av_set_pts_info(st, 64, time_base.num, time_base.den);
 575
 576         for(j=0; j<nut->time_base_count; j++){
 577             if(!memcmp(&time_base, &nut->time_base[j], sizeof(AVRational))){
 578                 break;
 579             }
 580         }
 581         nut->time_base[j]= time_base;
 582         nut->stream[i].time_base= &nut->time_base[j];
 583         if(j==nut->time_base_count)
 584             nut->time_base_count++;
 585
 586         if(av_q2d(time_base) >= 0.001)
 587             nut->stream[i].msb_pts_shift = 7;
 588         else
 589             nut->stream[i].msb_pts_shift = 14;
 590         nut->stream[i].max_pts_distance= FFMAX(1/av_q2d(time_base), 1);
 591     }
 592
 593     nut->max_distance = MAX_DISTANCE;
 594     build_elision_headers(s);
 595     build_frame_code(s);
 596     assert(nut->frame_code['N'].flags == FLAG_INVALID);
 597
 598     put_buffer(bc, ID_STRING, strlen(ID_STRING));
 599     put_byte(bc, 0);
 600
 601     write_headers(nut, bc);
 602
 603     put_flush_packet(bc);
 604
 605     //FIXME index
 606
 607     return 0;
 608 }
 609
 610 static int get_needed_flags(NUTContext *nut, StreamContext *nus, FrameCode *fc, AVPacket *pkt){
 611     int flags= 0;
 612
 613     if(pkt->flags & PKT_FLAG_KEY                ) flags |= FLAG_KEY;
 614     if(pkt->stream_index != fc->stream_id       ) flags |= FLAG_STREAM_ID;
 615     if(pkt->size / fc->size_mul                 ) flags |= FLAG_SIZE_MSB;
 616     if(pkt->pts - nus->last_pts != fc->pts_delta) flags |= FLAG_CODED_PTS;
 617     if(pkt->size > 2*nut->max_distance          ) flags |= FLAG_CHECKSUM;
 618     if(FFABS(pkt->pts - nus->last_pts)
 619                          > nus->max_pts_distance) flags |= FLAG_CHECKSUM;
 620     if(   pkt->size < nut->header_len[fc->header_idx]
 621        || (pkt->size > 4096 && fc->header_idx)
 622        || memcmp(pkt->data, nut->header[fc->header_idx], nut->header_len[fc->header_idx]))
 623                                                   flags |= FLAG_HEADER_IDX;
 624
 625     return flags | (fc->flags & FLAG_CODED);
 626 }
 627
 628 static int find_best_header_idx(NUTContext *nut, AVPacket *pkt){
 629     int i;
 630     int best_i  = 0;
 631     int best_len= 0;
 632
 633     if(pkt->size > 4096)
 634         return 0;
 635
 636     for(i=1; i<nut->header_count; i++){
 637         if(   pkt->size >= nut->header_len[i]
 638            &&  nut->header_len[i] > best_len
 639            && !memcmp(pkt->data, nut->header[i], nut->header_len[i])){
 640             best_i= i;
 641             best_len= nut->header_len[i];
 642         }
 643     }
 644     return best_i;
 645 }
 646
 647 static int write_packet(AVFormatContext *s, AVPacket *pkt){
 648     NUTContext *nut = s->priv_data;
 649     StreamContext *nus= &nut->stream[pkt->stream_index];
 650     ByteIOContext *bc = s->pb, *dyn_bc;
 651     FrameCode *fc;
 652     int64_t coded_pts;
 653     int best_length, frame_code, flags, needed_flags, i, header_idx, best_header_idx;
 654     int key_frame = !!(pkt->flags & PKT_FLAG_KEY);
 655     int store_sp=0;
 656     int ret;
 657
 658     if(pkt->pts < 0)
 659         return -1;
 660
 661     if(1LL<<(20+3*nut->header_count) <= url_ftell(bc))
 662         write_headers(nut, bc);
 663
 664     if(key_frame && !(nus->last_flags & FLAG_KEY))
 665         store_sp= 1;
 666
 667     if(pkt->size + 30/*FIXME check*/ + url_ftell(bc) >= nut->last_syncpoint_pos + nut->max_distance)
 668         store_sp= 1;
 669
 670 //FIXME: Ensure store_sp is 1 in the first place.
 671
 672     if(store_sp){
 673         Syncpoint *sp, dummy= {.pos= INT64_MAX};
 674
 675         ff_nut_reset_ts(nut, *nus->time_base, pkt->dts);
 676         for(i=0; i<s->nb_streams; i++){
 677             AVStream *st= s->streams[i];
 678             int64_t dts_tb = av_rescale_rnd(pkt->dts,
 679                 nus->time_base->num * (int64_t)nut->stream[i].time_base->den,
 680                 nus->time_base->den * (int64_t)nut->stream[i].time_base->num,
 681                 AV_ROUND_DOWN);
 682             int index= av_index_search_timestamp(st, dts_tb, AVSEEK_FLAG_BACKWARD);
 683             if(index>=0) dummy.pos= FFMIN(dummy.pos, st->index_entries[index].pos);
 684         }
 685         if(dummy.pos == INT64_MAX)
 686             dummy.pos= 0;
 687         sp= av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp, NULL);
 688
 689         nut->last_syncpoint_pos= url_ftell(bc);
 690         ret = url_open_dyn_buf(&dyn_bc);
 691         if(ret < 0)
 692             return ret;
 693         put_tt(nut, nus, dyn_bc, pkt->dts);
 694         put_v(dyn_bc, sp ? (nut->last_syncpoint_pos - sp->pos)>>4 : 0);
 695         put_packet(nut, bc, dyn_bc, 1, SYNCPOINT_STARTCODE);
 696
 697         ff_nut_add_sp(nut, nut->last_syncpoint_pos, 0/*unused*/, pkt->dts);
 698     }
 699     assert(nus->last_pts != AV_NOPTS_VALUE);
 700
 701     coded_pts = pkt->pts & ((1<<nus->msb_pts_shift)-1);
 702     if(ff_lsb2full(nus, coded_pts) != pkt->pts)
 703         coded_pts= pkt->pts + (1<<nus->msb_pts_shift);
 704
 705     best_header_idx= find_best_header_idx(nut, pkt);
 706
 707     best_length=INT_MAX;
 708     frame_code= -1;
 709     for(i=0; i<256; i++){
 710         int length= 0;
 711         FrameCode *fc= &nut->frame_code[i];
 712         int flags= fc->flags;
 713
 714         if(flags & FLAG_INVALID)
 715             continue;
 716         needed_flags= get_needed_flags(nut, nus, fc, pkt);
 717
 718         if(flags & FLAG_CODED){
 719             length++;
 720             flags = needed_flags;
 721         }
 722
 723         if((flags & needed_flags) != needed_flags)
 724             continue;
 725
 726         if((flags ^ needed_flags) & FLAG_KEY)
 727             continue;
 728
 729         if(flags & FLAG_STREAM_ID)
 730             length+= get_length(pkt->stream_index);
 731
 732         if(pkt->size % fc->size_mul != fc->size_lsb)
 733             continue;
 734         if(flags & FLAG_SIZE_MSB)
 735             length += get_length(pkt->size / fc->size_mul);
 736
 737         if(flags & FLAG_CHECKSUM)
 738             length+=4;
 739
 740         if(flags & FLAG_CODED_PTS)
 741             length += get_length(coded_pts);
 742
 743         if(   (flags & FLAG_CODED)
 744            && nut->header_len[best_header_idx] > nut->header_len[fc->header_idx]+1){
 745             flags |= FLAG_HEADER_IDX;
 746         }
 747
 748         if(flags & FLAG_HEADER_IDX){
 749             length += 1 - nut->header_len[best_header_idx];
 750         }else{
 751             length -= nut->header_len[fc->header_idx];
 752         }
 753
 754         length*=4;
 755         length+= !(flags & FLAG_CODED_PTS);
 756         length+= !(flags & FLAG_CHECKSUM);
 757
 758         if(length < best_length){
 759             best_length= length;
 760             frame_code=i;
 761         }
 762     }
 763     assert(frame_code != -1);
 764     fc= &nut->frame_code[frame_code];
 765     flags= fc->flags;
 766     needed_flags= get_needed_flags(nut, nus, fc, pkt);
 767     header_idx= fc->header_idx;
 768
 769     init_checksum(bc, ff_crc04C11DB7_update, 0);
 770     put_byte(bc, frame_code);
 771     if(flags & FLAG_CODED){
 772         put_v(bc, (flags^needed_flags) & ~(FLAG_CODED));
 773         flags = needed_flags;
 774     }
 775     if(flags & FLAG_STREAM_ID)  put_v(bc, pkt->stream_index);
 776     if(flags & FLAG_CODED_PTS)  put_v(bc, coded_pts);
 777     if(flags & FLAG_SIZE_MSB)   put_v(bc, pkt->size / fc->size_mul);
 778     if(flags & FLAG_HEADER_IDX) put_v(bc, header_idx= best_header_idx);
 779
 780     if(flags & FLAG_CHECKSUM)   put_le32(bc, get_checksum(bc));
 781     else                        get_checksum(bc);
 782
 783     put_buffer(bc, pkt->data + nut->header_len[header_idx], pkt->size - nut->header_len[header_idx]);
 784     nus->last_flags= flags;
 785     nus->last_pts= pkt->pts;
 786
 787     //FIXME just store one per syncpoint
 788     if(flags & FLAG_KEY)
 789         av_add_index_entry(
 790             s->streams[pkt->stream_index],
 791             nut->last_syncpoint_pos,
 792             pkt->pts,
 793             0,
 794             0,
 795             AVINDEX_KEYFRAME);
 796
 797     return 0;
 798 }
 799
 800 static int write_trailer(AVFormatContext *s){
 801     NUTContext *nut= s->priv_data;
 802     ByteIOContext *bc= s->pb;
 803
 804     while(nut->header_count<3)
 805         write_headers(nut, bc);
 806     put_flush_packet(bc);
 807
 808     return 0;
 809 }
 810
 811 AVOutputFormat nut_muxer = {
 812     "nut",
 813     NULL_IF_CONFIG_SMALL("NUT format"),
 814     "video/x-nut",
 815     "nut",
 816     sizeof(NUTContext),
 817 #if   CONFIG_LIBVORBIS
 818     CODEC_ID_VORBIS,
 819 #elif CONFIG_LIBMP3LAME
 820     CODEC_ID_MP3,
 821 #else
 822     CODEC_ID_MP2,
 823 #endif
 824     CODEC_ID_MPEG4,
 825     write_header,
 826     write_packet,
 827     write_trailer,
 828     .flags = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS,
 829     .codec_tag= (const AVCodecTag* const []){codec_bmp_tags, codec_wav_tags, ff_nut_subtitle_tags, 0},
 830 };