FFmpeg: libavformat/nutenc.c Source File

00001 /*
00002  * nut muxer
00003  * Copyright (c) 2004-2007 Michael Niedermayer
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "libavutil/intreadwrite.h"
00023 #include "libavutil/tree.h"
00024 #include "libavcodec/mpegaudiodata.h"
00025 #include "nut.h"
00026 
00027 static int find_expected_header(AVCodecContext *c, int size, int key_frame, uint8_t out[64]){
00028     int sample_rate= c->sample_rate;
00029 
00030     if(size>4096)
00031         return 0;
00032 
00033     AV_WB24(out, 1);
00034 
00035     if(c->codec_id == CODEC_ID_MPEG4){
00036         if(key_frame){
00037             return 3;
00038         }else{
00039             out[3]= 0xB6;
00040             return 4;
00041         }
00042     }else if(c->codec_id == CODEC_ID_MPEG1VIDEO || c->codec_id == CODEC_ID_MPEG2VIDEO){
00043         return 3;
00044     }else if(c->codec_id == CODEC_ID_H264){
00045         return 3;
00046     }else if(c->codec_id == CODEC_ID_MP3 || c->codec_id == CODEC_ID_MP2){
00047         int lsf, mpeg25, sample_rate_index, bitrate_index, frame_size;
00048         int layer= c->codec_id == CODEC_ID_MP3 ? 3 : 2;
00049         unsigned int header= 0xFFF00000;
00050 
00051         lsf     = sample_rate < (24000+32000)/2;
00052         mpeg25  = sample_rate < (12000+16000)/2;
00053         sample_rate <<= lsf + mpeg25;
00054         if     (sample_rate < (32000 + 44100)/2) sample_rate_index=2;
00055         else if(sample_rate < (44100 + 48000)/2) sample_rate_index=0;
00056         else                                     sample_rate_index=1;
00057 
00058         sample_rate= ff_mpa_freq_tab[sample_rate_index] >> (lsf + mpeg25);
00059 
00060         for(bitrate_index=2; bitrate_index<30; bitrate_index++){
00061             frame_size = ff_mpa_bitrate_tab[lsf][layer-1][bitrate_index>>1];
00062             frame_size = (frame_size * 144000) / (sample_rate << lsf) + (bitrate_index&1);
00063 
00064             if(frame_size == size)
00065                 break;
00066         }
00067 
00068         header |= (!lsf)<<19;
00069         header |= (4-layer)<<17;
00070         header |= 1<<16; //no crc
00071         AV_WB32(out, header);
00072         if(size <= 0)
00073             return 2; //we guess there is no crc, if there is one the user clearly does not care about overhead
00074         if(bitrate_index == 30)
00075             return -1; //something is wrong ...
00076 
00077         header |= (bitrate_index>>1)<<12;
00078         header |= sample_rate_index<<10;
00079         header |= (bitrate_index&1)<<9;
00080 
00081         return 2; //FIXME actually put the needed ones in build_elision_headers()
00082         return 3; //we guess that the private bit is not set
00083 //FIXME the above assumptions should be checked, if these turn out false too often something should be done
00084     }
00085     return 0;
00086 }
00087 
00088 static int find_header_idx(AVFormatContext *s, AVCodecContext *c, int size, int frame_type){
00089     NUTContext *nut = s->priv_data;
00090     uint8_t out[64];
00091     int i;
00092     int len= find_expected_header(c, size, frame_type, out);
00093 
00094 //av_log(NULL, AV_LOG_ERROR, "expected_h len=%d size=%d codec_id=%d\n", len, size, c->codec_id);
00095 
00096     for(i=1; i<nut->header_count; i++){
00097         if(   len == nut->header_len[i]
00098            && !memcmp(out, nut->header[i], len)){
00099 //    av_log(NULL, AV_LOG_ERROR, "found %d\n", i);
00100             return i;
00101         }
00102     }
00103 //    av_log(NULL, AV_LOG_ERROR, "nothing found\n");
00104     return 0;
00105 }
00106 
00107 static void build_elision_headers(AVFormatContext *s){
00108     NUTContext *nut = s->priv_data;
00109     int i;
00110     //FIXME this is lame
00111     //FIXME write a 2pass mode to find the maximal headers
00112     static const uint8_t headers[][5]={
00113         {3, 0x00, 0x00, 0x01},
00114         {4, 0x00, 0x00, 0x01, 0xB6},
00115         {2, 0xFF, 0xFA}, //mp3+crc
00116         {2, 0xFF, 0xFB}, //mp3
00117         {2, 0xFF, 0xFC}, //mp2+crc
00118         {2, 0xFF, 0xFD}, //mp2
00119     };
00120 
00121     nut->header_count= 7;
00122     for(i=1; i<nut->header_count; i++){
00123         nut->header_len[i]=  headers[i-1][0];
00124         nut->header    [i]= &headers[i-1][1];
00125     }
00126 }
00127 
00128 static void build_frame_code(AVFormatContext *s){
00129     NUTContext *nut = s->priv_data;
00130     int key_frame, index, pred, stream_id;
00131     int start=1;
00132     int end= 254;
00133     int keyframe_0_esc= s->nb_streams > 2;
00134     int pred_table[10];
00135     FrameCode *ft;
00136 
00137     ft= &nut->frame_code[start];
00138     ft->flags= FLAG_CODED;
00139     ft->size_mul=1;
00140     ft->pts_delta=1;
00141     start++;
00142 
00143     if(keyframe_0_esc){
00144         /* keyframe = 0 escape */
00145         FrameCode *ft= &nut->frame_code[start];
00146         ft->flags= FLAG_STREAM_ID | FLAG_SIZE_MSB | FLAG_CODED_PTS;
00147         ft->size_mul=1;
00148         start++;
00149     }
00150 
00151     for(stream_id= 0; stream_id<s->nb_streams; stream_id++){
00152         int start2= start + (end-start)*stream_id / s->nb_streams;
00153         int end2  = start + (end-start)*(stream_id+1) / s->nb_streams;
00154         AVCodecContext *codec = s->streams[stream_id]->codec;
00155         int is_audio= codec->codec_type == AVMEDIA_TYPE_AUDIO;
00156         int intra_only= /*codec->intra_only || */is_audio;
00157         int pred_count;
00158 
00159         for(key_frame=0; key_frame<2; key_frame++){
00160             if(intra_only && keyframe_0_esc && key_frame==0)
00161                 continue;
00162 
00163             {
00164                 FrameCode *ft= &nut->frame_code[start2];
00165                 ft->flags= FLAG_KEY*key_frame;
00166                 ft->flags|= FLAG_SIZE_MSB | FLAG_CODED_PTS;
00167                 ft->stream_id= stream_id;
00168                 ft->size_mul=1;
00169                 if(is_audio)
00170                     ft->header_idx= find_header_idx(s, codec, -1, key_frame);
00171                 start2++;
00172             }
00173         }
00174 
00175         key_frame= intra_only;
00176 #if 1
00177         if(is_audio){
00178             int frame_bytes= codec->frame_size*(int64_t)codec->bit_rate / (8*codec->sample_rate);
00179             int pts;
00180             for(pts=0; pts<2; pts++){
00181                 for(pred=0; pred<2; pred++){
00182                     FrameCode *ft= &nut->frame_code[start2];
00183                     ft->flags= FLAG_KEY*key_frame;
00184                     ft->stream_id= stream_id;
00185                     ft->size_mul=frame_bytes + 2;
00186                     ft->size_lsb=frame_bytes + pred;
00187                     ft->pts_delta=pts;
00188                     ft->header_idx= find_header_idx(s, codec, frame_bytes + pred, key_frame);
00189                     start2++;
00190                 }
00191             }
00192         }else{
00193             FrameCode *ft= &nut->frame_code[start2];
00194             ft->flags= FLAG_KEY | FLAG_SIZE_MSB;
00195             ft->stream_id= stream_id;
00196             ft->size_mul=1;
00197             ft->pts_delta=1;
00198             start2++;
00199         }
00200 #endif
00201 
00202         if(codec->has_b_frames){
00203             pred_count=5;
00204             pred_table[0]=-2;
00205             pred_table[1]=-1;
00206             pred_table[2]=1;
00207             pred_table[3]=3;
00208             pred_table[4]=4;
00209         }else if(codec->codec_id == CODEC_ID_VORBIS){
00210             pred_count=3;
00211             pred_table[0]=2;
00212             pred_table[1]=9;
00213             pred_table[2]=16;
00214         }else{
00215             pred_count=1;
00216             pred_table[0]=1;
00217         }
00218 
00219         for(pred=0; pred<pred_count; pred++){
00220             int start3= start2 + (end2-start2)*pred / pred_count;
00221             int end3  = start2 + (end2-start2)*(pred+1) / pred_count;
00222 
00223             for(index=start3; index<end3; index++){
00224                 FrameCode *ft= &nut->frame_code[index];
00225                 ft->flags= FLAG_KEY*key_frame;
00226                 ft->flags|= FLAG_SIZE_MSB;
00227                 ft->stream_id= stream_id;
00228 //FIXME use single byte size and pred from last
00229                 ft->size_mul= end3-start3;
00230                 ft->size_lsb= index - start3;
00231                 ft->pts_delta= pred_table[pred];
00232                 if(is_audio)
00233                     ft->header_idx= find_header_idx(s, codec, -1, key_frame);
00234             }
00235         }
00236     }
00237     memmove(&nut->frame_code['N'+1], &nut->frame_code['N'], sizeof(FrameCode)*(255-'N'));
00238     nut->frame_code[  0].flags=
00239     nut->frame_code[255].flags=
00240     nut->frame_code['N'].flags= FLAG_INVALID;
00241 }
00242 
00246 static int get_length(uint64_t val){
00247     int i=1;
00248 
00249     while(val>>=7)
00250         i++;
00251 
00252     return i;
00253 }
00254 
00255 static void put_v(ByteIOContext *bc, uint64_t val){
00256     int i= get_length(val);
00257 
00258     while(--i>0)
00259         put_byte(bc, 128 | (val>>(7*i)));
00260 
00261     put_byte(bc, val&127);
00262 }
00263 
00264 static void put_tt(NUTContext *nut, StreamContext *nus, ByteIOContext *bc, uint64_t val){
00265     val *= nut->time_base_count;
00266     val += nus->time_base - nut->time_base;
00267     put_v(bc, val);
00268 }
00269 
00273 static void put_str(ByteIOContext *bc, const char *string){
00274     int len= strlen(string);
00275 
00276     put_v(bc, len);
00277     put_buffer(bc, string, len);
00278 }
00279 
00280 static void put_s(ByteIOContext *bc, int64_t val){
00281     put_v(bc, 2*FFABS(val) - (val>0));
00282 }
00283 
00284 #ifdef TRACE
00285 static inline void put_v_trace(ByteIOContext *bc, uint64_t v, char *file, char *func, int line){
00286     av_log(NULL, AV_LOG_DEBUG, "put_v %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
00287 
00288     put_v(bc, v);
00289 }
00290 
00291 static inline void put_s_trace(ByteIOContext *bc, int64_t v, char *file, char *func, int line){
00292     av_log(NULL, AV_LOG_DEBUG, "put_s %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
00293 
00294     put_s(bc, v);
00295 }
00296 #define put_v(bc, v)  put_v_trace(bc, v, __FILE__, __PRETTY_FUNCTION__, __LINE__)
00297 #define put_s(bc, v)  put_s_trace(bc, v, __FILE__, __PRETTY_FUNCTION__, __LINE__)
00298 #endif
00299 
00300 //FIXME remove calculate_checksum
00301 static void put_packet(NUTContext *nut, ByteIOContext *bc, ByteIOContext *dyn_bc, int calculate_checksum, uint64_t startcode){
00302     uint8_t *dyn_buf=NULL;
00303     int dyn_size= url_close_dyn_buf(dyn_bc, &dyn_buf);
00304     int forw_ptr= dyn_size + 4*calculate_checksum;
00305 
00306     if(forw_ptr > 4096)
00307         init_checksum(bc, ff_crc04C11DB7_update, 0);
00308     put_be64(bc, startcode);
00309     put_v(bc, forw_ptr);
00310     if(forw_ptr > 4096)
00311         put_le32(bc, get_checksum(bc));
00312 
00313     if(calculate_checksum)
00314         init_checksum(bc, ff_crc04C11DB7_update, 0);
00315     put_buffer(bc, dyn_buf, dyn_size);
00316     if(calculate_checksum)
00317         put_le32(bc, get_checksum(bc));
00318 
00319     av_free(dyn_buf);
00320 }
00321 
00322 static void write_mainheader(NUTContext *nut, ByteIOContext *bc){
00323     int i, j, tmp_pts, tmp_flags, tmp_stream, tmp_mul, tmp_size, tmp_fields, tmp_head_idx;
00324     int64_t tmp_match;
00325 
00326     put_v(bc, 3); /* version */
00327     put_v(bc, nut->avf->nb_streams);
00328     put_v(bc, nut->max_distance);
00329     put_v(bc, nut->time_base_count);
00330 
00331     for(i=0; i<nut->time_base_count; i++){
00332         put_v(bc, nut->time_base[i].num);
00333         put_v(bc, nut->time_base[i].den);
00334     }
00335 
00336     tmp_pts=0;
00337     tmp_mul=1;
00338     tmp_stream=0;
00339     tmp_match= 1-(1LL<<62);
00340     tmp_head_idx= 0;
00341     for(i=0; i<256;){
00342         tmp_fields=0;
00343         tmp_size=0;
00344 //        tmp_res=0;
00345         if(tmp_pts    != nut->frame_code[i].pts_delta) tmp_fields=1;
00346         if(tmp_mul    != nut->frame_code[i].size_mul ) tmp_fields=2;
00347         if(tmp_stream != nut->frame_code[i].stream_id) tmp_fields=3;
00348         if(tmp_size   != nut->frame_code[i].size_lsb ) tmp_fields=4;
00349 //        if(tmp_res    != nut->frame_code[i].res            ) tmp_fields=5;
00350         if(tmp_head_idx!=nut->frame_code[i].header_idx)tmp_fields=8;
00351 
00352         tmp_pts   = nut->frame_code[i].pts_delta;
00353         tmp_flags = nut->frame_code[i].flags;
00354         tmp_stream= nut->frame_code[i].stream_id;
00355         tmp_mul   = nut->frame_code[i].size_mul;
00356         tmp_size  = nut->frame_code[i].size_lsb;
00357 //        tmp_res   = nut->frame_code[i].res;
00358         tmp_head_idx= nut->frame_code[i].header_idx;
00359 
00360         for(j=0; i<256; j++,i++){
00361             if(i == 'N'){
00362                 j--;
00363                 continue;
00364             }
00365             if(nut->frame_code[i].pts_delta != tmp_pts   ) break;
00366             if(nut->frame_code[i].flags     != tmp_flags ) break;
00367             if(nut->frame_code[i].stream_id != tmp_stream) break;
00368             if(nut->frame_code[i].size_mul  != tmp_mul   ) break;
00369             if(nut->frame_code[i].size_lsb  != tmp_size+j) break;
00370 //            if(nut->frame_code[i].res       != tmp_res   ) break;
00371             if(nut->frame_code[i].header_idx!= tmp_head_idx) break;
00372         }
00373         if(j != tmp_mul - tmp_size) tmp_fields=6;
00374 
00375         put_v(bc, tmp_flags);
00376         put_v(bc, tmp_fields);
00377         if(tmp_fields>0) put_s(bc, tmp_pts);
00378         if(tmp_fields>1) put_v(bc, tmp_mul);
00379         if(tmp_fields>2) put_v(bc, tmp_stream);
00380         if(tmp_fields>3) put_v(bc, tmp_size);
00381         if(tmp_fields>4) put_v(bc, 0 /*tmp_res*/);
00382         if(tmp_fields>5) put_v(bc, j);
00383         if(tmp_fields>6) put_v(bc, tmp_match);
00384         if(tmp_fields>7) put_v(bc, tmp_head_idx);
00385     }
00386     put_v(bc, nut->header_count-1);
00387     for(i=1; i<nut->header_count; i++){
00388         put_v(bc, nut->header_len[i]);
00389         put_buffer(bc, nut->header[i], nut->header_len[i]);
00390     }
00391 }
00392 
00393 static int write_streamheader(NUTContext *nut, ByteIOContext *bc, AVStream *st, int i){
00394     AVCodecContext *codec = st->codec;
00395     put_v(bc, i);
00396     switch(codec->codec_type){
00397     case AVMEDIA_TYPE_VIDEO: put_v(bc, 0); break;
00398     case AVMEDIA_TYPE_AUDIO: put_v(bc, 1); break;
00399     case AVMEDIA_TYPE_SUBTITLE: put_v(bc, 2); break;
00400     default              : put_v(bc, 3); break;
00401     }
00402     put_v(bc, 4);
00403     if (codec->codec_tag){
00404         put_le32(bc, codec->codec_tag);
00405     }else
00406         return -1;
00407 
00408     put_v(bc, nut->stream[i].time_base - nut->time_base);
00409     put_v(bc, nut->stream[i].msb_pts_shift);
00410     put_v(bc, nut->stream[i].max_pts_distance);
00411     put_v(bc, codec->has_b_frames);
00412     put_byte(bc, 0); /* flags: 0x1 - fixed_fps, 0x2 - index_present */
00413 
00414     put_v(bc, codec->extradata_size);
00415     put_buffer(bc, codec->extradata, codec->extradata_size);
00416 
00417     switch(codec->codec_type){
00418     case AVMEDIA_TYPE_AUDIO:
00419         put_v(bc, codec->sample_rate);
00420         put_v(bc, 1);
00421         put_v(bc, codec->channels);
00422         break;
00423     case AVMEDIA_TYPE_VIDEO:
00424         put_v(bc, codec->width);
00425         put_v(bc, codec->height);
00426 
00427         if(st->sample_aspect_ratio.num<=0 || st->sample_aspect_ratio.den<=0){
00428             put_v(bc, 0);
00429             put_v(bc, 0);
00430         }else{
00431             put_v(bc, st->sample_aspect_ratio.num);
00432             put_v(bc, st->sample_aspect_ratio.den);
00433         }
00434         put_v(bc, 0); /* csp type -- unknown */
00435         break;
00436     default:
00437         break;
00438     }
00439     return 0;
00440 }
00441 
00442 static int add_info(ByteIOContext *bc, const char *type, const char *value){
00443     put_str(bc, type);
00444     put_s(bc, -1);
00445     put_str(bc, value);
00446     return 1;
00447 }
00448 
00449 static int write_globalinfo(NUTContext *nut, ByteIOContext *bc){
00450     AVFormatContext *s= nut->avf;
00451     AVMetadataTag *t = NULL;
00452     ByteIOContext *dyn_bc;
00453     uint8_t *dyn_buf=NULL;
00454     int count=0, dyn_size;
00455     int ret = url_open_dyn_buf(&dyn_bc);
00456     if(ret < 0)
00457         return ret;
00458 
00459     while ((t = av_metadata_get(s->metadata, "", t, AV_METADATA_IGNORE_SUFFIX)))
00460         count += add_info(dyn_bc, t->key, t->value);
00461 
00462     put_v(bc, 0); //stream_if_plus1
00463     put_v(bc, 0); //chapter_id
00464     put_v(bc, 0); //timestamp_start
00465     put_v(bc, 0); //length
00466 
00467     put_v(bc, count);
00468 
00469     dyn_size= url_close_dyn_buf(dyn_bc, &dyn_buf);
00470     put_buffer(bc, dyn_buf, dyn_size);
00471     av_free(dyn_buf);
00472     return 0;
00473 }
00474 
00475 static int write_streaminfo(NUTContext *nut, ByteIOContext *bc, int stream_id){
00476     AVFormatContext *s= nut->avf;
00477     AVStream* st = s->streams[stream_id];
00478     ByteIOContext *dyn_bc;
00479     uint8_t *dyn_buf=NULL;
00480     int count=0, dyn_size, i;
00481     int ret = url_open_dyn_buf(&dyn_bc);
00482     if(ret < 0)
00483         return ret;
00484 
00485     for (i=0; ff_nut_dispositions[i].flag; ++i) {
00486         if (st->disposition & ff_nut_dispositions[i].flag)
00487             count += add_info(dyn_bc, "Disposition", ff_nut_dispositions[i].str);
00488     }
00489     dyn_size = url_close_dyn_buf(dyn_bc, &dyn_buf);
00490 
00491     if (count) {
00492         put_v(bc, stream_id + 1); //stream_id_plus1
00493         put_v(bc, 0); //chapter_id
00494         put_v(bc, 0); //timestamp_start
00495         put_v(bc, 0); //length
00496 
00497         put_v(bc, count);
00498 
00499         put_buffer(bc, dyn_buf, dyn_size);
00500     }
00501 
00502     av_free(dyn_buf);
00503     return count;
00504 }
00505 
00506 static int write_headers(NUTContext *nut, ByteIOContext *bc){
00507     ByteIOContext *dyn_bc;
00508     int i, ret;
00509 
00510     ret = url_open_dyn_buf(&dyn_bc);
00511     if(ret < 0)
00512         return ret;
00513     write_mainheader(nut, dyn_bc);
00514     put_packet(nut, bc, dyn_bc, 1, MAIN_STARTCODE);
00515 
00516     for (i=0; i < nut->avf->nb_streams; i++){
00517         ret = url_open_dyn_buf(&dyn_bc);
00518         if(ret < 0)
00519             return ret;
00520         write_streamheader(nut, dyn_bc, nut->avf->streams[i], i);
00521         put_packet(nut, bc, dyn_bc, 1, STREAM_STARTCODE);
00522     }
00523 
00524     ret = url_open_dyn_buf(&dyn_bc);
00525     if(ret < 0)
00526         return ret;
00527     write_globalinfo(nut, dyn_bc);
00528     put_packet(nut, bc, dyn_bc, 1, INFO_STARTCODE);
00529 
00530     for (i = 0; i < nut->avf->nb_streams; i++) {
00531         ret = url_open_dyn_buf(&dyn_bc);
00532         if(ret < 0)
00533             return ret;
00534         ret = write_streaminfo(nut, dyn_bc, i);
00535         if (ret < 0)
00536             return ret;
00537         if (ret > 0)
00538             put_packet(nut, bc, dyn_bc, 1, INFO_STARTCODE);
00539         else {
00540             uint8_t* buf;
00541             url_close_dyn_buf(dyn_bc, &buf);
00542             av_free(buf);
00543         }
00544     }
00545 
00546     nut->last_syncpoint_pos= INT_MIN;
00547     nut->header_count++;
00548     return 0;
00549 }
00550 
00551 static int write_header(AVFormatContext *s){
00552     NUTContext *nut = s->priv_data;
00553     ByteIOContext *bc = s->pb;
00554     int i, j;
00555 
00556     nut->avf= s;
00557 
00558     nut->stream   = av_mallocz(sizeof(StreamContext)*s->nb_streams);
00559     nut->time_base= av_mallocz(sizeof(AVRational   )*s->nb_streams);
00560 
00561     for(i=0; i<s->nb_streams; i++){
00562         AVStream *st= s->streams[i];
00563         int ssize;
00564         AVRational time_base;
00565         ff_parse_specific_params(st->codec, &time_base.den, &ssize, &time_base.num);
00566 
00567         av_set_pts_info(st, 64, time_base.num, time_base.den);
00568 
00569         for(j=0; j<nut->time_base_count; j++){
00570             if(!memcmp(&time_base, &nut->time_base[j], sizeof(AVRational))){
00571                 break;
00572             }
00573         }
00574         nut->time_base[j]= time_base;
00575         nut->stream[i].time_base= &nut->time_base[j];
00576         if(j==nut->time_base_count)
00577             nut->time_base_count++;
00578 
00579         if(av_q2d(time_base) >= 0.001)
00580             nut->stream[i].msb_pts_shift = 7;
00581         else
00582             nut->stream[i].msb_pts_shift = 14;
00583         nut->stream[i].max_pts_distance= FFMAX(1/av_q2d(time_base), 1);
00584     }
00585 
00586     nut->max_distance = MAX_DISTANCE;
00587     build_elision_headers(s);
00588     build_frame_code(s);
00589     assert(nut->frame_code['N'].flags == FLAG_INVALID);
00590 
00591     put_buffer(bc, ID_STRING, strlen(ID_STRING));
00592     put_byte(bc, 0);
00593 
00594     write_headers(nut, bc);
00595 
00596     put_flush_packet(bc);
00597 
00598     //FIXME index
00599 
00600     return 0;
00601 }
00602 
00603 static int get_needed_flags(NUTContext *nut, StreamContext *nus, FrameCode *fc, AVPacket *pkt){
00604     int flags= 0;
00605 
00606     if(pkt->flags & AV_PKT_FLAG_KEY             ) flags |= FLAG_KEY;
00607     if(pkt->stream_index != fc->stream_id       ) flags |= FLAG_STREAM_ID;
00608     if(pkt->size / fc->size_mul                 ) flags |= FLAG_SIZE_MSB;
00609     if(pkt->pts - nus->last_pts != fc->pts_delta) flags |= FLAG_CODED_PTS;
00610     if(pkt->size > 2*nut->max_distance          ) flags |= FLAG_CHECKSUM;
00611     if(FFABS(pkt->pts - nus->last_pts)
00612                          > nus->max_pts_distance) flags |= FLAG_CHECKSUM;
00613     if(   pkt->size < nut->header_len[fc->header_idx]
00614        || (pkt->size > 4096 && fc->header_idx)
00615        || memcmp(pkt->data, nut->header[fc->header_idx], nut->header_len[fc->header_idx]))
00616                                                   flags |= FLAG_HEADER_IDX;
00617 
00618     return flags | (fc->flags & FLAG_CODED);
00619 }
00620 
00621 static int find_best_header_idx(NUTContext *nut, AVPacket *pkt){
00622     int i;
00623     int best_i  = 0;
00624     int best_len= 0;
00625 
00626     if(pkt->size > 4096)
00627         return 0;
00628 
00629     for(i=1; i<nut->header_count; i++){
00630         if(   pkt->size >= nut->header_len[i]
00631            &&  nut->header_len[i] > best_len
00632            && !memcmp(pkt->data, nut->header[i], nut->header_len[i])){
00633             best_i= i;
00634             best_len= nut->header_len[i];
00635         }
00636     }
00637     return best_i;
00638 }
00639 
00640 static int write_packet(AVFormatContext *s, AVPacket *pkt){
00641     NUTContext *nut = s->priv_data;
00642     StreamContext *nus= &nut->stream[pkt->stream_index];
00643     ByteIOContext *bc = s->pb, *dyn_bc;
00644     FrameCode *fc;
00645     int64_t coded_pts;
00646     int best_length, frame_code, flags, needed_flags, i, header_idx, best_header_idx;
00647     int key_frame = !!(pkt->flags & AV_PKT_FLAG_KEY);
00648     int store_sp=0;
00649     int ret;
00650 
00651     if(pkt->pts < 0)
00652         return -1;
00653 
00654     if(1LL<<(20+3*nut->header_count) <= url_ftell(bc))
00655         write_headers(nut, bc);
00656 
00657     if(key_frame && !(nus->last_flags & FLAG_KEY))
00658         store_sp= 1;
00659 
00660     if(pkt->size + 30/*FIXME check*/ + url_ftell(bc) >= nut->last_syncpoint_pos + nut->max_distance)
00661         store_sp= 1;
00662 
00663 //FIXME: Ensure store_sp is 1 in the first place.
00664 
00665     if(store_sp){
00666         Syncpoint *sp, dummy= {.pos= INT64_MAX};
00667 
00668         ff_nut_reset_ts(nut, *nus->time_base, pkt->dts);
00669         for(i=0; i<s->nb_streams; i++){
00670             AVStream *st= s->streams[i];
00671             int64_t dts_tb = av_rescale_rnd(pkt->dts,
00672                 nus->time_base->num * (int64_t)nut->stream[i].time_base->den,
00673                 nus->time_base->den * (int64_t)nut->stream[i].time_base->num,
00674                 AV_ROUND_DOWN);
00675             int index= av_index_search_timestamp(st, dts_tb, AVSEEK_FLAG_BACKWARD);
00676             if(index>=0) dummy.pos= FFMIN(dummy.pos, st->index_entries[index].pos);
00677         }
00678         if(dummy.pos == INT64_MAX)
00679             dummy.pos= 0;
00680         sp= av_tree_find(nut->syncpoints, &dummy, (void *) ff_nut_sp_pos_cmp,
00681                          NULL);
00682 
00683         nut->last_syncpoint_pos= url_ftell(bc);
00684         ret = url_open_dyn_buf(&dyn_bc);
00685         if(ret < 0)
00686             return ret;
00687         put_tt(nut, nus, dyn_bc, pkt->dts);
00688         put_v(dyn_bc, sp ? (nut->last_syncpoint_pos - sp->pos)>>4 : 0);
00689         put_packet(nut, bc, dyn_bc, 1, SYNCPOINT_STARTCODE);
00690 
00691         ff_nut_add_sp(nut, nut->last_syncpoint_pos, 0/*unused*/, pkt->dts);
00692     }
00693     assert(nus->last_pts != AV_NOPTS_VALUE);
00694 
00695     coded_pts = pkt->pts & ((1<<nus->msb_pts_shift)-1);
00696     if(ff_lsb2full(nus, coded_pts) != pkt->pts)
00697         coded_pts= pkt->pts + (1<<nus->msb_pts_shift);
00698 
00699     best_header_idx= find_best_header_idx(nut, pkt);
00700 
00701     best_length=INT_MAX;
00702     frame_code= -1;
00703     for(i=0; i<256; i++){
00704         int length= 0;
00705         FrameCode *fc= &nut->frame_code[i];
00706         int flags= fc->flags;
00707 
00708         if(flags & FLAG_INVALID)
00709             continue;
00710         needed_flags= get_needed_flags(nut, nus, fc, pkt);
00711 
00712         if(flags & FLAG_CODED){
00713             length++;
00714             flags = needed_flags;
00715         }
00716 
00717         if((flags & needed_flags) != needed_flags)
00718             continue;
00719 
00720         if((flags ^ needed_flags) & FLAG_KEY)
00721             continue;
00722 
00723         if(flags & FLAG_STREAM_ID)
00724             length+= get_length(pkt->stream_index);
00725 
00726         if(pkt->size % fc->size_mul != fc->size_lsb)
00727             continue;
00728         if(flags & FLAG_SIZE_MSB)
00729             length += get_length(pkt->size / fc->size_mul);
00730 
00731         if(flags & FLAG_CHECKSUM)
00732             length+=4;
00733 
00734         if(flags & FLAG_CODED_PTS)
00735             length += get_length(coded_pts);
00736 
00737         if(   (flags & FLAG_CODED)
00738            && nut->header_len[best_header_idx] > nut->header_len[fc->header_idx]+1){
00739             flags |= FLAG_HEADER_IDX;
00740         }
00741 
00742         if(flags & FLAG_HEADER_IDX){
00743             length += 1 - nut->header_len[best_header_idx];
00744         }else{
00745             length -= nut->header_len[fc->header_idx];
00746         }
00747 
00748         length*=4;
00749         length+= !(flags & FLAG_CODED_PTS);
00750         length+= !(flags & FLAG_CHECKSUM);
00751 
00752         if(length < best_length){
00753             best_length= length;
00754             frame_code=i;
00755         }
00756     }
00757     assert(frame_code != -1);
00758     fc= &nut->frame_code[frame_code];
00759     flags= fc->flags;
00760     needed_flags= get_needed_flags(nut, nus, fc, pkt);
00761     header_idx= fc->header_idx;
00762 
00763     init_checksum(bc, ff_crc04C11DB7_update, 0);
00764     put_byte(bc, frame_code);
00765     if(flags & FLAG_CODED){
00766         put_v(bc, (flags^needed_flags) & ~(FLAG_CODED));
00767         flags = needed_flags;
00768     }
00769     if(flags & FLAG_STREAM_ID)  put_v(bc, pkt->stream_index);
00770     if(flags & FLAG_CODED_PTS)  put_v(bc, coded_pts);
00771     if(flags & FLAG_SIZE_MSB)   put_v(bc, pkt->size / fc->size_mul);
00772     if(flags & FLAG_HEADER_IDX) put_v(bc, header_idx= best_header_idx);
00773 
00774     if(flags & FLAG_CHECKSUM)   put_le32(bc, get_checksum(bc));
00775     else                        get_checksum(bc);
00776 
00777     put_buffer(bc, pkt->data + nut->header_len[header_idx], pkt->size - nut->header_len[header_idx]);
00778     nus->last_flags= flags;
00779     nus->last_pts= pkt->pts;
00780 
00781     //FIXME just store one per syncpoint
00782     if(flags & FLAG_KEY)
00783         av_add_index_entry(
00784             s->streams[pkt->stream_index],
00785             nut->last_syncpoint_pos,
00786             pkt->pts,
00787             0,
00788             0,
00789             AVINDEX_KEYFRAME);
00790 
00791     return 0;
00792 }
00793 
00794 static int write_trailer(AVFormatContext *s){
00795     NUTContext *nut= s->priv_data;
00796     ByteIOContext *bc= s->pb;
00797 
00798     while(nut->header_count<3)
00799         write_headers(nut, bc);
00800     put_flush_packet(bc);
00801     ff_nut_free_sp(nut);
00802     av_freep(&nut->stream);
00803     av_freep(&nut->time_base);
00804 
00805     return 0;
00806 }
00807 
00808 AVOutputFormat nut_muxer = {
00809     "nut",
00810     NULL_IF_CONFIG_SMALL("NUT format"),
00811     "video/x-nut",
00812     "nut",
00813     sizeof(NUTContext),
00814 #if   CONFIG_LIBVORBIS
00815     CODEC_ID_VORBIS,
00816 #elif CONFIG_LIBMP3LAME
00817     CODEC_ID_MP3,
00818 #else
00819     CODEC_ID_MP2,
00820 #endif
00821     CODEC_ID_MPEG4,
00822     write_header,
00823     write_packet,
00824     write_trailer,
00825     .flags = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS,
00826     .codec_tag= (const AVCodecTag* const []){ff_codec_bmp_tags, ff_codec_wav_tags, ff_nut_subtitle_tags, 0},
00827     .metadata_conv = ff_nut_metadata_conv,
00828 };