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