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FFmpeg/libavformat/flvdec.c

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  1. /*

  2.  * FLV demuxer

  3.  * Copyright (c) 2003 The FFmpeg Project

  4.  *

  5.  * This demuxer will generate a 1 byte extradata for VP6F content.

  6.  * It is composed of:

  7.  *  - upper 4bits: difference between encoded width and visible width

  8.  *  - lower 4bits: difference between encoded height and visible height

  9.  *

  10.  * This file is part of FFmpeg.

  11.  *

  12.  * FFmpeg is free software; you can redistribute it and/or

  13.  * modify it under the terms of the GNU Lesser General Public

  14.  * License as published by the Free Software Foundation; either

  15.  * version 2.1 of the License, or (at your option) any later version.

  16.  *

  17.  * FFmpeg is distributed in the hope that it will be useful,

  18.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  19.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

  20.  * Lesser General Public License for more details.

  21.  *

  22.  * You should have received a copy of the GNU Lesser General Public

  23.  * License along with FFmpeg; if not, write to the Free Software

  24.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  25.  */

  26. 

  27. #include "libavutil/avstring.h"

  28. #include "libavutil/dict.h"

  29. #include "libavutil/intfloat_readwrite.h"

  30. #include "libavutil/mathematics.h"

  31. #include "libavcodec/bytestream.h"

  32. #include "libavcodec/mpeg4audio.h"

  33. #include "avformat.h"

  34. #include "avio_internal.h"

  35. #include "flv.h"

  36. 

  37. typedef struct {

  38.     int wrong_dts; ///< wrong dts due to negative cts

  39. } FLVContext;

  40. 

  41. static int flv_probe(AVProbeData *p)

  42. {

  43.     const uint8_t *d;

  44. 

  45.     d = p->buf;

  46.     if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V' && d[3] < 5 && d[5]==0 && AV_RB32(d+5)>8) {

  47.         return AVPROBE_SCORE_MAX;

  48.     }

  49.     return 0;

  50. }

  51. 

  52. static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, int flv_codecid) {

  53.     AVCodecContext *acodec = astream->codec;

  54.     switch(flv_codecid) {

  55.         //no distinction between S16 and S8 PCM codec flags

  56.         case FLV_CODECID_PCM:

  57.             acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_U8 :

  58. #if HAVE_BIGENDIAN

  59.                                 CODEC_ID_PCM_S16BE;

  60. #else

  61.                                 CODEC_ID_PCM_S16LE;

  62. #endif

  63.             break;

  64.         case FLV_CODECID_PCM_LE:

  65.             acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_U8 : CODEC_ID_PCM_S16LE; break;

  66.         case FLV_CODECID_AAC  : acodec->codec_id = CODEC_ID_AAC;                                    break;

  67.         case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF;                              break;

  68.         case FLV_CODECID_SPEEX:

  69.             acodec->codec_id = CODEC_ID_SPEEX;

  70.             acodec->sample_rate = 16000;

  71.             break;

  72.         case FLV_CODECID_MP3  : acodec->codec_id = CODEC_ID_MP3      ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;

  73.         case FLV_CODECID_NELLYMOSER_8KHZ_MONO:

  74.             acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate

  75.             acodec->codec_id = CODEC_ID_NELLYMOSER;

  76.             break;

  77.         case FLV_CODECID_NELLYMOSER_16KHZ_MONO:

  78.             acodec->sample_rate = 16000;

  79.             acodec->codec_id = CODEC_ID_NELLYMOSER;

  80.             break;

  81.         case FLV_CODECID_NELLYMOSER:

  82.             acodec->codec_id = CODEC_ID_NELLYMOSER;

  83.             break;

  84.         default:

  85.             av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);

  86.             acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;

  87.     }

  88. }

  89. 

  90. static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {

  91.     AVCodecContext *vcodec = vstream->codec;

  92.     switch(flv_codecid) {

  93.         case FLV_CODECID_H263  : vcodec->codec_id = CODEC_ID_FLV1   ; break;

  94.         case FLV_CODECID_REALH263: vcodec->codec_id = CODEC_ID_H263 ; break; // Really mean it this time

  95.         case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;

  96.         case FLV_CODECID_SCREEN2: vcodec->codec_id = CODEC_ID_FLASHSV2; break;

  97.         case FLV_CODECID_VP6   : vcodec->codec_id = CODEC_ID_VP6F   ;

  98.         case FLV_CODECID_VP6A  :

  99.             if(flv_codecid == FLV_CODECID_VP6A)

  100.                 vcodec->codec_id = CODEC_ID_VP6A;

  101.             if(vcodec->extradata_size != 1) {

  102.                 vcodec->extradata_size = 1;

  103.                 vcodec->extradata = av_malloc(1);

  104.             }

  105.             vcodec->extradata[0] = avio_r8(s->pb);

  106.             return 1; // 1 byte body size adjustment for flv_read_packet()

  107.         case FLV_CODECID_H264:

  108.             vcodec->codec_id = CODEC_ID_H264;

  109.             return 3; // not 4, reading packet type will consume one byte

  110.         case FLV_CODECID_MPEG4:

  111.             vcodec->codec_id = CODEC_ID_MPEG4;

  112.             return 3;

  113.         default:

  114.             av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);

  115.             vcodec->codec_tag = flv_codecid;

  116.     }

  117. 

  118.     return 0;

  119. }

  120. 

  121. static int amf_get_string(AVIOContext *ioc, char *buffer, int buffsize) {

  122.     int length = avio_rb16(ioc);

  123.     if(length >= buffsize) {

  124.         avio_skip(ioc, length);

  125.         return -1;

  126.     }

  127. 

  128.     avio_read(ioc, buffer, length);

  129. 

  130.     buffer[length] = '\0';

  131. 

  132.     return length;

  133. }

  134. 

  135. static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, AVStream *vstream, int64_t max_pos) {

  136.     unsigned int timeslen = 0, fileposlen = 0, i;

  137.     char str_val[256];

  138.     int64_t *times = NULL;

  139.     int64_t *filepositions = NULL;

  140.     int ret = AVERROR(ENOSYS);

  141.     int64_t initial_pos = avio_tell(ioc);

  142.     AVDictionaryEntry *creator = av_dict_get(s->metadata, "metadatacreator",

  143.                                              NULL, 0);

  144. 

  145.     if (creator && !strcmp(creator->value, "MEGA")) {

  146.         /* Files with this metadatacreator tag seem to have filepositions

  147.          * pointing at the 4 trailer bytes of the previous packet,

  148.          * which isn't the norm (nor what we expect here, nor what

  149.          * jwplayer + lighttpd expect, nor what flvtool2 produces).

  150.          * Just ignore the index in this case, instead of risking trying

  151.          * to adjust it to something that might or might not work. */

  152.         return 0;

  153.     }

  154. 

  155.     while (avio_tell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {

  156.         int64_t** current_array;

  157.         unsigned int arraylen;

  158. 

  159.         // Expect array object in context

  160.         if (avio_r8(ioc) != AMF_DATA_TYPE_ARRAY)

  161.             break;

  162. 

  163.         arraylen = avio_rb32(ioc);

  164.         if(arraylen>>28)

  165.             break;

  166. 

  167.         if       (!strcmp(KEYFRAMES_TIMESTAMP_TAG , str_val) && !times){

  168.             current_array= &times;

  169.             timeslen= arraylen;

  170.         }else if (!strcmp(KEYFRAMES_BYTEOFFSET_TAG, str_val) && !filepositions){

  171.             current_array= &filepositions;

  172.             fileposlen= arraylen;

  173.         }else // unexpected metatag inside keyframes, will not use such metadata for indexing

  174.             break;

  175. 

  176.         if (!(*current_array = av_mallocz(sizeof(**current_array) * arraylen))) {

  177.             ret = AVERROR(ENOMEM);

  178.             goto finish;

  179.         }

  180. 

  181.         for (i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {

  182.             if (avio_r8(ioc) != AMF_DATA_TYPE_NUMBER)

  183.                 goto finish;

  184.             current_array[0][i] = av_int2dbl(avio_rb64(ioc));

  185.         }

  186.         if (times && filepositions) {

  187.             // All done, exiting at a position allowing amf_parse_object

  188.             // to finish parsing the object

  189.             ret = 0;

  190.             break;

  191.         }

  192.     }

  193. 

  194.     if (timeslen == fileposlen) {

  195.          for(i = 0; i < timeslen; i++)

  196.              av_add_index_entry(vstream, filepositions[i], times[i]*1000, 0, 0, AVINDEX_KEYFRAME);

  197.     } else

  198.         av_log(s, AV_LOG_WARNING, "Invalid keyframes object, skipping.\n");

  199. 

  200. finish:

  201.     av_freep(&times);

  202.     av_freep(&filepositions);

  203.     avio_seek(ioc, initial_pos, SEEK_SET);

  204.     return ret;

  205. }

  206. 

  207. static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, int64_t max_pos, int depth) {

  208.     AVCodecContext *acodec, *vcodec;

  209.     AVIOContext *ioc;

  210.     AMFDataType amf_type;

  211.     char str_val[256];

  212.     double num_val;

  213. 

  214.     num_val = 0;

  215.     ioc = s->pb;

  216. 

  217.     amf_type = avio_r8(ioc);

  218. 

  219.     switch(amf_type) {

  220.         case AMF_DATA_TYPE_NUMBER:

  221.             num_val = av_int2dbl(avio_rb64(ioc)); break;

  222.         case AMF_DATA_TYPE_BOOL:

  223.             num_val = avio_r8(ioc); break;

  224.         case AMF_DATA_TYPE_STRING:

  225.             if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)

  226.                 return -1;

  227.             break;

  228.         case AMF_DATA_TYPE_OBJECT: {

  229.             unsigned int keylen;

  230. 

  231.             if (ioc->seekable && key && !strcmp(KEYFRAMES_TAG, key) && depth == 1)

  232.                 if (parse_keyframes_index(s, ioc, vstream, max_pos) < 0)

  233.                     av_log(s, AV_LOG_ERROR, "Keyframe index parsing failed\n");

  234. 

  235.             while(avio_tell(ioc) < max_pos - 2 && (keylen = avio_rb16(ioc))) {

  236.                 avio_skip(ioc, keylen); //skip key string

  237.                 if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)

  238.                     return -1; //if we couldn't skip, bomb out.

  239.             }

  240.             if(avio_r8(ioc) != AMF_END_OF_OBJECT)

  241.                 return -1;

  242.         }

  243.             break;

  244.         case AMF_DATA_TYPE_NULL:

  245.         case AMF_DATA_TYPE_UNDEFINED:

  246.         case AMF_DATA_TYPE_UNSUPPORTED:

  247.             break; //these take up no additional space

  248.         case AMF_DATA_TYPE_MIXEDARRAY:

  249.             avio_skip(ioc, 4); //skip 32-bit max array index

  250.             while(avio_tell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {

  251.                 //this is the only case in which we would want a nested parse to not skip over the object

  252.                 if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)

  253.                     return -1;

  254.             }

  255.             if(avio_r8(ioc) != AMF_END_OF_OBJECT)

  256.                 return -1;

  257.             break;

  258.         case AMF_DATA_TYPE_ARRAY: {

  259.             unsigned int arraylen, i;

  260. 

  261.             arraylen = avio_rb32(ioc);

  262.             for(i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {

  263.                 if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)

  264.                     return -1; //if we couldn't skip, bomb out.

  265.             }

  266.         }

  267.             break;

  268.         case AMF_DATA_TYPE_DATE:

  269.             avio_skip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)

  270.             break;

  271.         default: //unsupported type, we couldn't skip

  272.             return -1;

  273.     }

  274. 

  275.     if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL

  276.         acodec = astream ? astream->codec : NULL;

  277.         vcodec = vstream ? vstream->codec : NULL;

  278. 

  279.         if(amf_type == AMF_DATA_TYPE_BOOL) {

  280.             av_strlcpy(str_val, num_val > 0 ? "true" : "false", sizeof(str_val));

  281.             av_dict_set(&s->metadata, key, str_val, 0);

  282.         } else if(amf_type == AMF_DATA_TYPE_NUMBER) {

  283.             snprintf(str_val, sizeof(str_val), "%.f", num_val);

  284.             av_dict_set(&s->metadata, key, str_val, 0);

  285.             if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;

  286.             else if(!strcmp(key, "videodatarate") && vcodec && 0 <= (int)(num_val * 1024.0))

  287.                 vcodec->bit_rate = num_val * 1024.0;

  288.             else if(!strcmp(key, "audiodatarate") && acodec && 0 <= (int)(num_val * 1024.0))

  289.                 acodec->bit_rate = num_val * 1024.0;

  290.         } else if(amf_type == AMF_DATA_TYPE_OBJECT){

  291.             if(s->nb_streams==1 && ((!acodec && !strcmp(key, "audiocodecid")) || (!vcodec && !strcmp(key, "videocodecid")))){

  292.                 s->ctx_flags &= ~AVFMTCTX_NOHEADER; //If there is either audio/video missing, codecid will be an empty object

  293.             }

  294.         } else if (amf_type == AMF_DATA_TYPE_STRING)

  295.             av_dict_set(&s->metadata, key, str_val, 0);

  296.     }

  297. 

  298.     return 0;

  299. }

  300. 

  301. static int flv_read_metabody(AVFormatContext *s, int64_t next_pos) {

  302.     AMFDataType type;

  303.     AVStream *stream, *astream, *vstream, *dstream;

  304.     AVIOContext *ioc;

  305.     int i;

  306.     char buffer[11]; //only needs to hold the string "onMetaData". Anything longer is something we don't want.

  307. 

  308.     vstream = astream = dstream = NULL;

  309.     ioc = s->pb;

  310. 

  311.     //first object needs to be "onMetaData" string

  312.     type = avio_r8(ioc);

  313.     if(type != AMF_DATA_TYPE_STRING || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))

  314.         return -1;

  315. 

  316.     //find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.

  317.     for(i = 0; i < s->nb_streams; i++) {

  318.         stream = s->streams[i];

  319.         if(stream->codec->codec_type == AVMEDIA_TYPE_VIDEO) vstream = stream;

  320.         else if(stream->codec->codec_type == AVMEDIA_TYPE_AUDIO) astream = stream;

  321.         else if(stream->codec->codec_type == AVMEDIA_TYPE_VIDEO) dstream = stream;

  322.     }

  323. 

  324.     //parse the second object (we want a mixed array)

  325.     if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)

  326.         return -1;

  327. 

  328.     return 0;

  329. }

  330. 

  331. static AVStream *create_stream(AVFormatContext *s, int stream_type){

  332.     AVStream *st = av_new_stream(s, stream_type);

  333.     if (!st)

  334.         return NULL;

  335.     switch(stream_type) {

  336.         case FLV_STREAM_TYPE_VIDEO:    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;    break;

  337.         case FLV_STREAM_TYPE_AUDIO:    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;    break;

  338.         case FLV_STREAM_TYPE_DATA:

  339.             st->codec->codec_type = AVMEDIA_TYPE_DATA;

  340.             st->codec->codec_id = CODEC_ID_NONE; // Going to rely on copy for now

  341.             av_log(s, AV_LOG_DEBUG, "Data stream created\n");

  342.     }

  343.     av_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */

  344.     return st;

  345. }

  346. 

  347. static int flv_read_header(AVFormatContext *s,

  348.                            AVFormatParameters *ap)

  349. {

  350.     int offset, flags;

  351. 

  352.     avio_skip(s->pb, 4);

  353.     flags = avio_r8(s->pb);

  354.     /* old flvtool cleared this field */

  355.     /* FIXME: better fix needed */

  356.     if (!flags) {

  357.         flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;

  358.         av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");

  359.     }

  360. 

  361.     if((flags & (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))

  362.              != (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))

  363.         s->ctx_flags |= AVFMTCTX_NOHEADER;

  364. 

  365.     if(flags & FLV_HEADER_FLAG_HASVIDEO){

  366.         if(!create_stream(s, FLV_STREAM_TYPE_VIDEO))

  367.             return AVERROR(ENOMEM);

  368.     }

  369.     if(flags & FLV_HEADER_FLAG_HASAUDIO){

  370.         if(!create_stream(s, FLV_STREAM_TYPE_AUDIO))

  371.             return AVERROR(ENOMEM);

  372.     }

  373.     // Flag doesn't indicate whether or not there is script-data present. Must

  374.     // create that stream if it's encountered.

  375. 

  376.     offset = avio_rb32(s->pb);

  377.     avio_seek(s->pb, offset, SEEK_SET);

  378.     avio_skip(s->pb, 4);

  379. 

  380.     s->start_time = 0;

  381. 

  382.     return 0;

  383. }

  384. 

  385. static int flv_get_extradata(AVFormatContext *s, AVStream *st, int size)

  386. {

  387.     av_free(st->codec->extradata);

  388.     st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);

  389.     if (!st->codec->extradata)

  390.         return AVERROR(ENOMEM);

  391.     st->codec->extradata_size = size;

  392.     avio_read(s->pb, st->codec->extradata, st->codec->extradata_size);

  393.     return 0;

  394. }

  395. 

  396. static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)

  397. {

  398.     FLVContext *flv = s->priv_data;

  399.     int ret, i, type, size, flags;

  400.     int stream_type=-1;

  401.     int64_t next, pos;

  402.     int64_t dts, pts = AV_NOPTS_VALUE;

  403.     AVStream *st = NULL;

  404. 

  405.  for(;;avio_skip(s->pb, 4)){ /* pkt size is repeated at end. skip it */

  406.     pos = avio_tell(s->pb);

  407.     type = avio_r8(s->pb);

  408.     size = avio_rb24(s->pb);

  409.     dts = avio_rb24(s->pb);

  410.     dts |= avio_r8(s->pb) << 24;

  411.     av_dlog(s, "type:%d, size:%d, dts:%"PRId64"\n", type, size, dts);

  412.     if (url_feof(s->pb))

  413.         return AVERROR_EOF;

  414.     avio_skip(s->pb, 3); /* stream id, always 0 */

  415.     flags = 0;

  416. 

  417.     if(size == 0)

  418.         continue;

  419. 

  420.     next= size + avio_tell(s->pb);

  421. 

  422.     if (type == FLV_TAG_TYPE_AUDIO) {

  423.         stream_type=FLV_STREAM_TYPE_AUDIO;

  424.         flags = avio_r8(s->pb);

  425.         size--;

  426.     } else if (type == FLV_TAG_TYPE_VIDEO) {

  427.         stream_type=FLV_STREAM_TYPE_VIDEO;

  428.         flags = avio_r8(s->pb);

  429.         size--;

  430.         if ((flags & 0xf0) == 0x50) /* video info / command frame */

  431.             goto skip;

  432.     } else if (type == FLV_TAG_TYPE_META) {

  433.         if (size > 13+1+4 && dts == 0) { // Header-type metadata stuff

  434.             flv_read_metabody(s, next);

  435.             goto skip;

  436.         } else if (dts != 0) { // Script-data "special" metadata frames - don't skip

  437.             stream_type=FLV_STREAM_TYPE_DATA;

  438.         } else {

  439.             goto skip;

  440.         }

  441.     } else {

  442.         av_log(s, AV_LOG_DEBUG, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);

  443.     skip:

  444.         avio_seek(s->pb, next, SEEK_SET);

  445.         continue;

  446.     }

  447. 

  448.     /* skip empty data packets */

  449.     if (!size)

  450.         continue;

  451. 

  452.     /* now find stream */

  453.     for(i=0;i<s->nb_streams;i++) {

  454.         st = s->streams[i];

  455.         if (st->id == stream_type)

  456.             break;

  457.     }

  458.     if(i == s->nb_streams){

  459.         av_log(s, AV_LOG_WARNING, "Stream discovered after head already parsed\n");

  460.         st= create_stream(s, stream_type);

  461.         s->ctx_flags &= ~AVFMTCTX_NOHEADER;

  462.     }

  463.     av_dlog(s, "%d %X %d \n", stream_type, flags, st->discard);

  464.     if(  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY || (stream_type == FLV_STREAM_TYPE_AUDIO)))

  465.        ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && (stream_type == FLV_STREAM_TYPE_VIDEO)))

  466.        || st->discard >= AVDISCARD_ALL

  467.        ){

  468.         avio_seek(s->pb, next, SEEK_SET);

  469.         continue;

  470.     }

  471.     if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)

  472.         av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);

  473.     break;

  474.  }

  475. 

  476.     // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps

  477.     if(s->pb->seekable && (!s->duration || s->duration==AV_NOPTS_VALUE)){

  478.         int size;

  479.         const int64_t pos= avio_tell(s->pb);

  480.         const int64_t fsize= avio_size(s->pb);

  481.         avio_seek(s->pb, fsize-4, SEEK_SET);

  482.         size= avio_rb32(s->pb);

  483.         avio_seek(s->pb, fsize-3-size, SEEK_SET);

  484.         if(size == avio_rb24(s->pb) + 11){

  485.             uint32_t ts = avio_rb24(s->pb);

  486.             ts |= avio_r8(s->pb) << 24;

  487.             s->duration = ts * (int64_t)AV_TIME_BASE / 1000;

  488.         }

  489.         avio_seek(s->pb, pos, SEEK_SET);

  490.     }

  491. 

  492.     if(stream_type == FLV_STREAM_TYPE_AUDIO){

  493.         if(!st->codec->channels || !st->codec->sample_rate || !st->codec->bits_per_coded_sample) {

  494.             st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;

  495.             st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);

  496.             st->codec->bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;

  497.         }

  498.         if(!st->codec->codec_id){

  499.             flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);

  500.         }

  501.     } else if(stream_type == FLV_STREAM_TYPE_VIDEO) {

  502.         size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);

  503.     }

  504. 

  505.     if (st->codec->codec_id == CODEC_ID_AAC ||

  506.         st->codec->codec_id == CODEC_ID_H264 ||

  507.         st->codec->codec_id == CODEC_ID_MPEG4) {

  508.         int type = avio_r8(s->pb);

  509.         size--;

  510.         if (st->codec->codec_id == CODEC_ID_H264 || st->codec->codec_id == CODEC_ID_MPEG4) {

  511.             int32_t cts = (avio_rb24(s->pb)+0xff800000)^0xff800000; // sign extension

  512.             pts = dts + cts;

  513.             if (cts < 0) { // dts are wrong

  514.                 flv->wrong_dts = 1;

  515.                 av_log(s, AV_LOG_WARNING, "negative cts, previous timestamps might be wrong\n");

  516.             }

  517.             if (flv->wrong_dts)

  518.                 dts = AV_NOPTS_VALUE;

  519.         }

  520. 

  521.         if (type == 0 && !st->codec->extradata) {

  522.             if ((ret = flv_get_extradata(s, st, size)) < 0)

  523.                 return ret;

  524.             if (st->codec->codec_id == CODEC_ID_AAC) {

  525.                 MPEG4AudioConfig cfg;

  526.                 ff_mpeg4audio_get_config(&cfg, st->codec->extradata,

  527.                                          st->codec->extradata_size);

  528.                 st->codec->channels = cfg.channels;

  529.                 if (cfg.ext_sample_rate)

  530.                     st->codec->sample_rate = cfg.ext_sample_rate;

  531.                 else

  532.                     st->codec->sample_rate = cfg.sample_rate;

  533.                 av_dlog(s, "mp4a config channels %d sample rate %d\n",

  534.                         st->codec->channels, st->codec->sample_rate);

  535.             }

  536. 

  537.             ret = AVERROR(EAGAIN);

  538.             goto leave;

  539.         }

  540.     }

  541. 

  542.     /* skip empty data packets */

  543.     if (!size) {

  544.         ret = AVERROR(EAGAIN);

  545.         goto leave;

  546.     }

  547. 

  548.     ret= av_get_packet(s->pb, pkt, size);

  549.     if (ret < 0) {

  550.         return AVERROR(EIO);

  551.     }

  552.     /* note: we need to modify the packet size here to handle the last

  553.        packet */

  554.     pkt->size = ret;

  555.     pkt->dts = dts;

  556.     pkt->pts = pts == AV_NOPTS_VALUE ? dts : pts;

  557.     pkt->stream_index = st->index;

  558. 

  559.     if (    stream_type == FLV_STREAM_TYPE_AUDIO ||

  560.             ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY) ||

  561.             stream_type == FLV_STREAM_TYPE_DATA)

  562.         pkt->flags |= AV_PKT_FLAG_KEY;

  563. 

  564. leave:

  565.     avio_skip(s->pb, 4);

  566.     return ret;

  567. }

  568. 

  569. static int flv_read_seek(AVFormatContext *s, int stream_index,

  570.     int64_t ts, int flags)

  571. {

  572.     return avio_seek_time(s->pb, stream_index, ts, flags);

  573. }

  574. 

  575. #if 0 /* don't know enough to implement this */

  576. static int flv_read_seek2(AVFormatContext *s, int stream_index,

  577.     int64_t min_ts, int64_t ts, int64_t max_ts, int flags)

  578. {

  579.     int ret = AVERROR(ENOSYS);

  580. 

  581.     if (ts - min_ts > (uint64_t)(max_ts - ts)) flags |= AVSEEK_FLAG_BACKWARD;

  582. 

  583.     if (!s->pb->seekable) {

  584.         if (stream_index < 0) {

  585.             stream_index = av_find_default_stream_index(s);

  586.             if (stream_index < 0)

  587.                 return -1;

  588. 

  589.             /* timestamp for default must be expressed in AV_TIME_BASE units */

  590.             ts = av_rescale_rnd(ts, 1000, AV_TIME_BASE,

  591.                 flags & AVSEEK_FLAG_BACKWARD ? AV_ROUND_DOWN : AV_ROUND_UP);

  592.         }

  593.         ret = avio_seek_time(s->pb, stream_index, ts, flags);

  594.     }

  595. 

  596.     if (ret == AVERROR(ENOSYS))

  597.         ret = av_seek_frame(s, stream_index, ts, flags);

  598.     return ret;

  599. }

  600. #endif

  601. 

  602. AVInputFormat ff_flv_demuxer = {

  603.     .name           = "flv",

  604.     .long_name      = NULL_IF_CONFIG_SMALL("FLV format"),

  605.     .priv_data_size = sizeof(FLVContext),

  606.     .read_probe     = flv_probe,

  607.     .read_header    = flv_read_header,

  608.     .read_packet    = flv_read_packet,

  609.     .read_seek = flv_read_seek,

  610. #if 0

  611.     .read_seek2 = flv_read_seek2,

  612. #endif

  613.     .extensions = "flv",

  614.     .value = CODEC_ID_FLV1,

  615. };