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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. 

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

  144.         int64_t** current_array;

  145.         unsigned int arraylen;

  146. 

  147.         // Expect array object in context

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

  149.             break;

  150. 

  151.         arraylen = avio_rb32(ioc);

  152.         if(arraylen>>28)

  153.             break;

  154. 

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

  156.             current_array= &times;

  157.             timeslen= arraylen;

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

  159.             current_array= &filepositions;

  160.             fileposlen= arraylen;

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

  162.             break;

  163. 

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

  165.             ret = AVERROR(ENOMEM);

  166.             goto finish;

  167.         }

  168. 

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

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

  171.                 goto finish;

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

  173.         }

  174.         if (times && filepositions) {

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

  176.             // to finish parsing the object

  177.             ret = 0;

  178.             break;

  179.         }

  180.     }

  181. 

  182.     if (timeslen == fileposlen) {

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

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

  185.     } else

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

  187. 

  188. finish:

  189.     av_freep(&times);

  190.     av_freep(&filepositions);

  191.     avio_seek(ioc, initial_pos, SEEK_SET);

  192.     return ret;

  193. }

  194. 

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

  196.     AVCodecContext *acodec, *vcodec;

  197.     AVIOContext *ioc;

  198.     AMFDataType amf_type;

  199.     char str_val[256];

  200.     double num_val;

  201. 

  202.     num_val = 0;

  203.     ioc = s->pb;

  204. 

  205.     amf_type = avio_r8(ioc);

  206. 

  207.     switch(amf_type) {

  208.         case AMF_DATA_TYPE_NUMBER:

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

  210.         case AMF_DATA_TYPE_BOOL:

  211.             num_val = avio_r8(ioc); break;

  212.         case AMF_DATA_TYPE_STRING:

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

  214.                 return -1;

  215.             break;

  216.         case AMF_DATA_TYPE_OBJECT: {

  217.             unsigned int keylen;

  218. 

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

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

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

  222. 

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

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

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

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

  227.             }

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

  229.                 return -1;

  230.         }

  231.             break;

  232.         case AMF_DATA_TYPE_NULL:

  233.         case AMF_DATA_TYPE_UNDEFINED:

  234.         case AMF_DATA_TYPE_UNSUPPORTED:

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

  236.         case AMF_DATA_TYPE_MIXEDARRAY:

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

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

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

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

  241.                     return -1;

  242.             }

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

  244.                 return -1;

  245.             break;

  246.         case AMF_DATA_TYPE_ARRAY: {

  247.             unsigned int arraylen, i;

  248. 

  249.             arraylen = avio_rb32(ioc);

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

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

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

  253.             }

  254.         }

  255.             break;

  256.         case AMF_DATA_TYPE_DATE:

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

  258.             break;

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

  260.             return -1;

  261.     }

  262. 

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

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

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

  266. 

  267.         if(amf_type == AMF_DATA_TYPE_BOOL) {

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

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

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

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

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

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

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

  275.                 vcodec->bit_rate = num_val * 1024.0;

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

  277.                 acodec->bit_rate = num_val * 1024.0;

  278.         } else if (amf_type == AMF_DATA_TYPE_STRING)

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

  280.     }

  281. 

  282.     return 0;

  283. }

  284. 

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

  286.     AMFDataType type;

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

  288.     AVIOContext *ioc;

  289.     int i;

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

  291. 

  292.     vstream = astream = dstream = NULL;

  293.     ioc = s->pb;

  294. 

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

  296.     type = avio_r8(ioc);

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

  298.         return -1;

  299. 

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

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

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

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

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

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

  306.     }

  307. 

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

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

  310.         return -1;

  311. 

  312.     return 0;

  313. }

  314. 

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

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

  317.     if (!st)

  318.         return NULL;

  319.     switch(stream_type) {

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

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

  322.         case FLV_STREAM_TYPE_DATA:

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

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

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

  326.     }

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

  328.     return st;

  329. }

  330. 

  331. static int flv_read_header(AVFormatContext *s,

  332.                            AVFormatParameters *ap)

  333. {

  334.     int offset, flags;

  335. 

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

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

  338.     /* old flvtool cleared this field */

  339.     /* FIXME: better fix needed */

  340.     if (!flags) {

  341.         flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;

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

  343.     }

  344. 

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

  346.              != (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))

  347.         s->ctx_flags |= AVFMTCTX_NOHEADER;

  348. 

  349.     if(flags & FLV_HEADER_FLAG_HASVIDEO){

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

  351.             return AVERROR(ENOMEM);

  352.     }

  353.     if(flags & FLV_HEADER_FLAG_HASAUDIO){

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

  355.             return AVERROR(ENOMEM);

  356.     }

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

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

  359. 

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

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

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

  363. 

  364.     s->start_time = 0;

  365. 

  366.     return 0;

  367. }

  368. 

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

  370. {

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

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

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

  374.         return AVERROR(ENOMEM);

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

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

  377.     return 0;

  378. }

  379. 

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

  381. {

  382.     FLVContext *flv = s->priv_data;

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

  384.     int stream_type=-1;

  385.     int64_t next, pos;

  386.     int64_t dts, pts = AV_NOPTS_VALUE;

  387.     AVStream *st = NULL;

  388. 

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

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

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

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

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

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

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

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

  397.         return AVERROR_EOF;

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

  399.     flags = 0;

  400. 

  401.     if(size == 0)

  402.         continue;

  403. 

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

  405. 

  406.     if (type == FLV_TAG_TYPE_AUDIO) {

  407.         stream_type=FLV_STREAM_TYPE_AUDIO;

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

  409.         size--;

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

  411.         stream_type=FLV_STREAM_TYPE_VIDEO;

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

  413.         size--;

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

  415.             goto skip;

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

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

  418.             flv_read_metabody(s, next);

  419.             goto skip;

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

  421.             stream_type=FLV_STREAM_TYPE_DATA;

  422.         } else {

  423.             goto skip;

  424.         }

  425.     } else {

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

  427.     skip:

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

  429.         continue;

  430.     }

  431. 

  432.     /* skip empty data packets */

  433.     if (!size)

  434.         continue;

  435. 

  436.     /* now find stream */

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

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

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

  440.             break;

  441.     }

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

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

  444.         st= create_stream(s, stream_type);

  445.         s->ctx_flags &= ~AVFMTCTX_NOHEADER;

  446.     }

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

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

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

  450.        || st->discard >= AVDISCARD_ALL

  451.        ){

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

  453.         continue;

  454.     }

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

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

  457.     break;

  458.  }

  459. 

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

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

  462.         int size;

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

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

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

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

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

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

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

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

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

  472.         }

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

  474.     }

  475. 

  476.     if(stream_type == FLV_STREAM_TYPE_AUDIO){

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

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

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

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

  481.         }

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

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

  484.         }

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

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

  487.     }

  488. 

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

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

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

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

  493.         size--;

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

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

  496.             pts = dts + cts;

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

  498.                 flv->wrong_dts = 1;

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

  500.             }

  501.             if (flv->wrong_dts)

  502.                 dts = AV_NOPTS_VALUE;

  503.         }

  504.         if (type == 0) {

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

  506.                 return ret;

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

  508.                 MPEG4AudioConfig cfg;

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

  510.                                          st->codec->extradata_size);

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

  512.                 if (cfg.ext_sample_rate)

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

  514.                 else

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

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

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

  518.             }

  519. 

  520.             ret = AVERROR(EAGAIN);

  521.             goto leave;

  522.         }

  523.     }

  524. 

  525.     /* skip empty data packets */

  526.     if (!size) {

  527.         ret = AVERROR(EAGAIN);

  528.         goto leave;

  529.     }

  530. 

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

  532.     if (ret < 0) {

  533.         return AVERROR(EIO);

  534.     }

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

  536.        packet */

  537.     pkt->size = ret;

  538.     pkt->dts = dts;

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

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

  541. 

  542.     if (    stream_type == FLV_STREAM_TYPE_AUDIO ||

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

  544.             stream_type == FLV_STREAM_TYPE_DATA)

  545.         pkt->flags |= AV_PKT_FLAG_KEY;

  546. 

  547. leave:

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

  549.     return ret;

  550. }

  551. 

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

  553.     int64_t ts, int flags)

  554. {

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

  556. }

  557. 

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

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

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

  561. {

  562.     int ret = AVERROR(ENOSYS);

  563. 

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

  565. 

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

  567.         if (stream_index < 0) {

  568.             stream_index = av_find_default_stream_index(s);

  569.             if (stream_index < 0)

  570.                 return -1;

  571. 

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

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

  574.                 flags & AVSEEK_FLAG_BACKWARD ? AV_ROUND_DOWN : AV_ROUND_UP);

  575.         }

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

  577.     }

  578. 

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

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

  581.     return ret;

  582. }

  583. #endif

  584. 

  585. AVInputFormat ff_flv_demuxer = {

  586.     .name           = "flv",

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

  588.     .priv_data_size = sizeof(FLVContext),

  589.     .read_probe     = flv_probe,

  590.     .read_header    = flv_read_header,

  591.     .read_packet    = flv_read_packet,

  592.     .read_seek = flv_read_seek,

  593. #if 0

  594.     .read_seek2 = flv_read_seek2,

  595. #endif

  596.     .extensions = "flv",

  597.     .value = CODEC_ID_FLV1,

  598. };