/*

  * FLV muxer

  * Copyright (c) 2003 The FFmpeg Project

  *

  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either

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

  *

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

  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

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

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

  */

 
 #include "libavutil/intreadwrite.h"

 #include "libavutil/dict.h"

 #include "libavutil/intfloat.h"

 #include "libavutil/avassert.h"

 #include "avc.h"

 #include "avformat.h"

 #include "flv.h"

 #include "internal.h"

 #include "metadata.h"

 static const AVCodecTag flv_video_codec_ids[] = {

     { AV_CODEC_ID_FLV1,     FLV_CODECID_H263 },

     { AV_CODEC_ID_H263,     FLV_CODECID_REALH263 },
     { AV_CODEC_ID_MPEG4,    FLV_CODECID_MPEG4 },

     { AV_CODEC_ID_FLASHSV,  FLV_CODECID_SCREEN },
     { AV_CODEC_ID_FLASHSV2, FLV_CODECID_SCREEN2 },
     { AV_CODEC_ID_VP6F,     FLV_CODECID_VP6 },

     { AV_CODEC_ID_VP6,      FLV_CODECID_VP6 },

     { AV_CODEC_ID_VP6A,     FLV_CODECID_VP6A },

     { AV_CODEC_ID_H264,     FLV_CODECID_H264 },
     { AV_CODEC_ID_NONE,     0 }

 };
 

 static const AVCodecTag flv_audio_codec_ids[] = {

     { AV_CODEC_ID_MP3,        FLV_CODECID_MP3        >> FLV_AUDIO_CODECID_OFFSET },
     { AV_CODEC_ID_PCM_U8,     FLV_CODECID_PCM        >> FLV_AUDIO_CODECID_OFFSET },
     { AV_CODEC_ID_PCM_S16BE,  FLV_CODECID_PCM        >> FLV_AUDIO_CODECID_OFFSET },
     { AV_CODEC_ID_PCM_S16LE,  FLV_CODECID_PCM_LE     >> FLV_AUDIO_CODECID_OFFSET },
     { AV_CODEC_ID_ADPCM_SWF,  FLV_CODECID_ADPCM      >> FLV_AUDIO_CODECID_OFFSET },
     { AV_CODEC_ID_AAC,        FLV_CODECID_AAC        >> FLV_AUDIO_CODECID_OFFSET },
     { AV_CODEC_ID_NELLYMOSER, FLV_CODECID_NELLYMOSER >> FLV_AUDIO_CODECID_OFFSET },
     { AV_CODEC_ID_PCM_MULAW,  FLV_CODECID_PCM_MULAW  >> FLV_AUDIO_CODECID_OFFSET },
     { AV_CODEC_ID_PCM_ALAW,   FLV_CODECID_PCM_ALAW   >> FLV_AUDIO_CODECID_OFFSET },
     { AV_CODEC_ID_SPEEX,      FLV_CODECID_SPEEX      >> FLV_AUDIO_CODECID_OFFSET },
     { AV_CODEC_ID_NONE,       0 }

 };
 

 typedef struct FLVContext {

     int     reserved;

     int64_t duration_offset;
     int64_t filesize_offset;

     int64_t duration;

     int64_t delay;      ///< first dts delay (needed for AVC & Speex)

 } FLVContext;
 

 typedef struct FLVStreamContext {
     int64_t last_ts;    ///< last timestamp for each stream
 } FLVStreamContext;
 

 static int get_audio_flags(AVFormatContext *s, AVCodecContext *enc)
 {

     int flags = (enc->bits_per_coded_sample == 16) ? FLV_SAMPLESSIZE_16BIT
                                                    : FLV_SAMPLESSIZE_8BIT;

     if (enc->codec_id == AV_CODEC_ID_AAC) // specs force these parameters

         return FLV_CODECID_AAC | FLV_SAMPLERATE_44100HZ |
                FLV_SAMPLESSIZE_16BIT | FLV_STEREO;

     else if (enc->codec_id == AV_CODEC_ID_SPEEX) {

         if (enc->sample_rate != 16000) {

             av_log(s, AV_LOG_ERROR,

                    "FLV only supports wideband (16kHz) Speex audio\n");

             return AVERROR(EINVAL);

         }
         if (enc->channels != 1) {

             av_log(s, AV_LOG_ERROR, "FLV only supports mono Speex audio\n");

             return AVERROR(EINVAL);

         }
         return FLV_CODECID_SPEEX | FLV_SAMPLERATE_11025HZ | FLV_SAMPLESSIZE_16BIT;
     } else {

         switch (enc->sample_rate) {
         case 44100:

             flags |= FLV_SAMPLERATE_44100HZ;

             break;

         case 22050:

             flags |= FLV_SAMPLERATE_22050HZ;

             break;

         case 11025:

             flags |= FLV_SAMPLERATE_11025HZ;

             break;

         case 16000: // nellymoser only
         case  8000: // nellymoser only
         case  5512: // not MP3

             if (enc->codec_id != AV_CODEC_ID_MP3) {

                 flags |= FLV_SAMPLERATE_SPECIAL;
                 break;

             }

         default:

             av_log(s, AV_LOG_ERROR,

                    "FLV does not support sample rate %d, "
                    "choose from (44100, 22050, 11025)\n", enc->sample_rate);

             return AVERROR(EINVAL);

         }

     }

     if (enc->channels > 1)

         flags |= FLV_STEREO;

     switch (enc->codec_id) {

     case AV_CODEC_ID_MP3:

         flags |= FLV_CODECID_MP3    | FLV_SAMPLESSIZE_16BIT;

         break;

     case AV_CODEC_ID_PCM_U8:

         flags |= FLV_CODECID_PCM    | FLV_SAMPLESSIZE_8BIT;

         break;

     case AV_CODEC_ID_PCM_S16BE:

         flags |= FLV_CODECID_PCM    | FLV_SAMPLESSIZE_16BIT;

         break;

     case AV_CODEC_ID_PCM_S16LE:

         flags |= FLV_CODECID_PCM_LE | FLV_SAMPLESSIZE_16BIT;

         break;

     case AV_CODEC_ID_ADPCM_SWF:

         flags |= FLV_CODECID_ADPCM  | FLV_SAMPLESSIZE_16BIT;

         break;

     case AV_CODEC_ID_NELLYMOSER:

         if (enc->sample_rate == 8000)
             flags |= FLV_CODECID_NELLYMOSER_8KHZ_MONO  | FLV_SAMPLESSIZE_16BIT;
         else if (enc->sample_rate == 16000)

             flags |= FLV_CODECID_NELLYMOSER_16KHZ_MONO | FLV_SAMPLESSIZE_16BIT;

         else
             flags |= FLV_CODECID_NELLYMOSER            | FLV_SAMPLESSIZE_16BIT;

         break;

     case AV_CODEC_ID_PCM_MULAW:

         flags = FLV_CODECID_PCM_MULAW | FLV_SAMPLERATE_SPECIAL | FLV_SAMPLESSIZE_16BIT;
         break;

     case AV_CODEC_ID_PCM_ALAW:

         flags = FLV_CODECID_PCM_ALAW  | FLV_SAMPLERATE_SPECIAL | FLV_SAMPLESSIZE_16BIT;

         break;

     case 0:

         flags |= enc->codec_tag << 4;

         break;
     default:

         av_log(s, AV_LOG_ERROR, "Audio codec '%s' not compatible with FLV\n",
                avcodec_get_name(enc->codec_id));

         return AVERROR(EINVAL);

     }

     return flags;
 }
 

 static void put_amf_string(AVIOContext *pb, const char *str)

 {
     size_t len = strlen(str);

     avio_wb16(pb, len);
     avio_write(pb, str, len);

 }
 

 static void put_avc_eos_tag(AVIOContext *pb, unsigned ts)
 {

     avio_w8(pb, FLV_TAG_TYPE_VIDEO);

     avio_wb24(pb, 5);               /* Tag Data Size */
     avio_wb24(pb, ts);              /* lower 24 bits of timestamp in ms */
     avio_w8(pb, (ts >> 24) & 0x7F); /* MSB of ts in ms */
     avio_wb24(pb, 0);               /* StreamId = 0 */
     avio_w8(pb, 23);                /* ub[4] FrameType = 1, ub[4] CodecId = 7 */
     avio_w8(pb, 2);                 /* AVC end of sequence */
     avio_wb24(pb, 0);               /* Always 0 for AVC EOS. */
     avio_wb32(pb, 16);              /* Size of FLV tag */

 }
 

 static void put_amf_double(AVIOContext *pb, double d)

 {

     avio_w8(pb, AMF_DATA_TYPE_NUMBER);

     avio_wb64(pb, av_double2int(d));

 }
 

 static void put_amf_bool(AVIOContext *pb, int b)
 {

     avio_w8(pb, AMF_DATA_TYPE_BOOL);
     avio_w8(pb, !!b);

 }
 

 static int flv_write_header(AVFormatContext *s)
 {

     AVIOContext *pb = s->pb;

     FLVContext *flv = s->priv_data;

     AVCodecContext *audio_enc = NULL, *video_enc = NULL, *data_enc = NULL;

     int i, metadata_count = 0;

     double framerate = 0.0;

     int64_t metadata_size_pos, data_size, metadata_count_pos;

     AVDictionaryEntry *tag = NULL;

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

         AVCodecContext *enc = s->streams[i]->codec;

         FLVStreamContext *sc;

         switch (enc->codec_type) {
         case AVMEDIA_TYPE_VIDEO:

             if (s->streams[i]->avg_frame_rate.den &&
                 s->streams[i]->avg_frame_rate.num) {
                 framerate = av_q2d(s->streams[i]->avg_frame_rate);

             }

             if (video_enc) {
                 av_log(s, AV_LOG_ERROR,
                        "at most one video stream is supported in flv\n");
                 return AVERROR(EINVAL);
             }

             video_enc = enc;

             if (enc->codec_tag == 0) {

                 av_log(s, AV_LOG_ERROR, "Video codec '%s' for stream %d is not compatible with FLV\n",
                        avcodec_get_name(enc->codec_id), i);

                 return AVERROR(EINVAL);

             }

             if (enc->codec_id == AV_CODEC_ID_MPEG4 ||
                 enc->codec_id == AV_CODEC_ID_H263) {
                 int error = enc->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL;
                 av_log(s, error ? AV_LOG_ERROR : AV_LOG_WARNING,
                        "Codec %s is not supported in the official FLV specification,\n", avcodec_get_name(enc->codec_id));
 
                 if (error) {
                     av_log(s, AV_LOG_ERROR,
                            "use vstrict=-1 / -strict -1 to use it anyway.\n");
                     return AVERROR(EINVAL);
                 }
             }

             break;
         case AVMEDIA_TYPE_AUDIO:

             if (audio_enc) {
                 av_log(s, AV_LOG_ERROR,
                        "at most one audio stream is supported in flv\n");
                 return AVERROR(EINVAL);
             }

             audio_enc = enc;

             if (get_audio_flags(s, enc) < 0)

                 return AVERROR_INVALIDDATA;

             if (enc->codec_id == AV_CODEC_ID_PCM_S16BE)
                 av_log(s, AV_LOG_WARNING,
                        "16-bit big-endian audio in flv is valid but most likely unplayable (hardware dependent); use s16le\n");

             break;
         case AVMEDIA_TYPE_DATA:

             if (enc->codec_id != AV_CODEC_ID_TEXT) {

                 av_log(s, AV_LOG_ERROR, "Data codec '%s' for stream %d is not compatible with FLV\n",
                        avcodec_get_name(enc->codec_id), i);

                 return AVERROR_INVALIDDATA;
             }
             data_enc = enc;
             break;
         default:

             av_log(s, AV_LOG_ERROR, "Codec type '%s' for stream %d is not compatible with FLV\n",
                    av_get_media_type_string(enc->codec_type), i);

             return AVERROR(EINVAL);

         }

         avpriv_set_pts_info(s->streams[i], 32, 1, 1000); /* 32 bit pts in ms */

 
         sc = av_mallocz(sizeof(FLVStreamContext));
         if (!sc)
             return AVERROR(ENOMEM);
         s->streams[i]->priv_data = sc;
         sc->last_ts = -1;

     }

     flv->delay = AV_NOPTS_VALUE;
 

     avio_write(pb, "FLV", 3);

     avio_w8(pb, 1);
     avio_w8(pb, FLV_HEADER_FLAG_HASAUDIO * !!audio_enc +
                 FLV_HEADER_FLAG_HASVIDEO * !!video_enc);
     avio_wb32(pb, 9);
     avio_wb32(pb, 0);
 
     for (i = 0; i < s->nb_streams; i++)
         if (s->streams[i]->codec->codec_tag == 5) {
             avio_w8(pb, 8);     // message type
             avio_wb24(pb, 0);   // include flags
             avio_wb24(pb, 0);   // time stamp
             avio_wb32(pb, 0);   // reserved
             avio_wb32(pb, 11);  // size
             flv->reserved = 5;

         }

     /* write meta_tag */

     avio_w8(pb, 18);            // tag type META
     metadata_size_pos = avio_tell(pb);
     avio_wb24(pb, 0);           // size of data part (sum of all parts below)
     avio_wb24(pb, 0);           // timestamp
     avio_wb32(pb, 0);           // reserved

 
     /* now data of data_size size */
 
     /* first event name as a string */

     avio_w8(pb, AMF_DATA_TYPE_STRING);

     put_amf_string(pb, "onMetaData"); // 12 bytes
 
     /* mixed array (hash) with size and string/type/data tuples */

     avio_w8(pb, AMF_DATA_TYPE_MIXEDARRAY);

     metadata_count_pos = avio_tell(pb);

     metadata_count = 4 * !!video_enc +

                      5 * !!audio_enc +

                      1 * !!data_enc  +

                      2; // +2 for duration and file size
 

     avio_wb32(pb, metadata_count);

     put_amf_string(pb, "duration");

     flv->duration_offset= avio_tell(pb);

     // fill in the guessed duration, it'll be corrected later if incorrect
     put_amf_double(pb, s->duration / AV_TIME_BASE);
 
     if (video_enc) {

         put_amf_string(pb, "width");

         put_amf_double(pb, video_enc->width);

 
         put_amf_string(pb, "height");

         put_amf_double(pb, video_enc->height);

 
         put_amf_string(pb, "videodatarate");

         put_amf_double(pb, video_enc->bit_rate / 1024.0);

         if (framerate != 0.0) {
             put_amf_string(pb, "framerate");
             put_amf_double(pb, framerate);

             metadata_count++;

         }

 
         put_amf_string(pb, "videocodecid");

         put_amf_double(pb, video_enc->codec_tag);

     }
 

     if (audio_enc) {

         put_amf_string(pb, "audiodatarate");
         put_amf_double(pb, audio_enc->bit_rate / 1024.0);
 

         put_amf_string(pb, "audiosamplerate");

         put_amf_double(pb, audio_enc->sample_rate);

 
         put_amf_string(pb, "audiosamplesize");

         put_amf_double(pb, audio_enc->codec_id == AV_CODEC_ID_PCM_U8 ? 8 : 16);

 
         put_amf_string(pb, "stereo");

         put_amf_bool(pb, audio_enc->channels == 2);

 
         put_amf_string(pb, "audiocodecid");

         put_amf_double(pb, audio_enc->codec_tag);

     }
 

     if (data_enc) {
         put_amf_string(pb, "datastream");
         put_amf_double(pb, 0.0);
     }
 

     while ((tag = av_dict_get(s->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {

         if(   !strcmp(tag->key, "width")
             ||!strcmp(tag->key, "height")
             ||!strcmp(tag->key, "videodatarate")
             ||!strcmp(tag->key, "framerate")
             ||!strcmp(tag->key, "videocodecid")
             ||!strcmp(tag->key, "audiodatarate")
             ||!strcmp(tag->key, "audiosamplerate")
             ||!strcmp(tag->key, "audiosamplesize")
             ||!strcmp(tag->key, "stereo")
             ||!strcmp(tag->key, "audiocodecid")
             ||!strcmp(tag->key, "duration")
             ||!strcmp(tag->key, "onMetaData")
         ){

             av_log(s, AV_LOG_DEBUG, "Ignoring metadata for %s\n", tag->key);

             continue;
         }

         put_amf_string(pb, tag->key);

         avio_w8(pb, AMF_DATA_TYPE_STRING);

         put_amf_string(pb, tag->value);

         metadata_count++;

     }
 

     put_amf_string(pb, "filesize");

     flv->filesize_offset = avio_tell(pb);

     put_amf_double(pb, 0); // delayed write

 
     put_amf_string(pb, "");

     avio_w8(pb, AMF_END_OF_OBJECT);

 
     /* write total size of tag */

     data_size = avio_tell(pb) - metadata_size_pos - 10;

 
     avio_seek(pb, metadata_count_pos, SEEK_SET);
     avio_wb32(pb, metadata_count);
 

     avio_seek(pb, metadata_size_pos, SEEK_SET);

     avio_wb24(pb, data_size);

     avio_skip(pb, data_size + 10 - 3);

     avio_wb32(pb, data_size + 11);

     for (i = 0; i < s->nb_streams; i++) {
         AVCodecContext *enc = s->streams[i]->codec;

         if (enc->codec_id == AV_CODEC_ID_AAC || enc->codec_id == AV_CODEC_ID_H264 || enc->codec_id == AV_CODEC_ID_MPEG4) {

             int64_t pos;

             avio_w8(pb, enc->codec_type == AVMEDIA_TYPE_VIDEO ?

                     FLV_TAG_TYPE_VIDEO : FLV_TAG_TYPE_AUDIO);

             avio_wb24(pb, 0); // size patched later
             avio_wb24(pb, 0); // ts

             avio_w8(pb, 0);   // ts ext

             avio_wb24(pb, 0); // streamid

             pos = avio_tell(pb);

             if (enc->codec_id == AV_CODEC_ID_AAC) {

                 avio_w8(pb, get_audio_flags(s, enc));

                 avio_w8(pb, 0); // AAC sequence header
                 avio_write(pb, enc->extradata, enc->extradata_size);

             } else {

                 avio_w8(pb, enc->codec_tag | FLV_FRAME_KEY); // flags
                 avio_w8(pb, 0); // AVC sequence header
                 avio_wb24(pb, 0); // composition time

                 ff_isom_write_avcc(pb, enc->extradata, enc->extradata_size);
             }

             data_size = avio_tell(pb) - pos;

             avio_seek(pb, -data_size - 10, SEEK_CUR);

             avio_wb24(pb, data_size);

             avio_skip(pb, data_size + 10 - 3);

             avio_wb32(pb, data_size + 11); // previous tag size

         }
     }
 

     return 0;
 }
 
 static int flv_write_trailer(AVFormatContext *s)
 {

     int64_t file_size;
 

     AVIOContext *pb = s->pb;

     FLVContext *flv = s->priv_data;

     int i;
 
     /* Add EOS tag */
     for (i = 0; i < s->nb_streams; i++) {
         AVCodecContext *enc = s->streams[i]->codec;

         FLVStreamContext *sc = s->streams[i]->priv_data;

         if (enc->codec_type == AVMEDIA_TYPE_VIDEO &&

                 (enc->codec_id == AV_CODEC_ID_H264 || enc->codec_id == AV_CODEC_ID_MPEG4))

             put_avc_eos_tag(pb, sc->last_ts);

     }

     file_size = avio_tell(pb);

     /* update information */

     if (avio_seek(pb, flv->duration_offset, SEEK_SET) < 0)

         av_log(s, AV_LOG_WARNING, "Failed to update header with correct duration.\n");
     else
         put_amf_double(pb, flv->duration / (double)1000);

     if (avio_seek(pb, flv->filesize_offset, SEEK_SET) < 0)

         av_log(s, AV_LOG_WARNING, "Failed to update header with correct filesize.\n");
     else
         put_amf_double(pb, file_size);

     avio_seek(pb, file_size, SEEK_SET);

     return 0;
 }
 

 static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)

 {

     AVIOContext *pb      = s->pb;
     AVCodecContext *enc  = s->streams[pkt->stream_index]->codec;
     FLVContext *flv      = s->priv_data;

     FLVStreamContext *sc = s->streams[pkt->stream_index]->priv_data;

     unsigned ts;

     int size = pkt->size;
     uint8_t *data = NULL;

     int flags = -1, flags_size, ret;

     if (enc->codec_id == AV_CODEC_ID_VP6F || enc->codec_id == AV_CODEC_ID_VP6A ||

         enc->codec_id == AV_CODEC_ID_VP6  || enc->codec_id == AV_CODEC_ID_AAC)

         flags_size = 2;

     else if (enc->codec_id == AV_CODEC_ID_H264 || enc->codec_id == AV_CODEC_ID_MPEG4)

         flags_size = 5;

     else

         flags_size = 1;

     switch (enc->codec_type) {
     case AVMEDIA_TYPE_VIDEO:

         avio_w8(pb, FLV_TAG_TYPE_VIDEO);

         flags = enc->codec_tag;

         if (flags <= 0 || flags > 15) {

             av_log(s, AV_LOG_ERROR,

                    "Video codec '%s' is not compatible with FLV\n",

                    avcodec_get_name(enc->codec_id));

             return AVERROR(EINVAL);

         }
 

         flags |= pkt->flags & AV_PKT_FLAG_KEY ? FLV_FRAME_KEY : FLV_FRAME_INTER;

         break;
     case AVMEDIA_TYPE_AUDIO:

         flags = get_audio_flags(s, enc);

         av_assert0(size);

         avio_w8(pb, FLV_TAG_TYPE_AUDIO);

         break;
     case AVMEDIA_TYPE_DATA:

         avio_w8(pb, FLV_TAG_TYPE_META);

         break;
     default:
         return AVERROR(EINVAL);

     }

     if (enc->codec_id == AV_CODEC_ID_H264 || enc->codec_id == AV_CODEC_ID_MPEG4) {

         /* check if extradata looks like mp4 formated */

         if (enc->extradata_size > 0 && *(uint8_t*)enc->extradata != 1)

             if ((ret = ff_avc_parse_nal_units_buf(pkt->data, &data, &size)) < 0)
                 return ret;

     } else if (enc->codec_id == AV_CODEC_ID_AAC && pkt->size > 2 &&

                (AV_RB16(pkt->data) & 0xfff0) == 0xfff0) {

         if (!s->streams[pkt->stream_index]->nb_frames) {

         av_log(s, AV_LOG_ERROR, "Malformed AAC bitstream detected: "

                "use the audio bitstream filter 'aac_adtstoasc' to fix it "

                "('-bsf:a aac_adtstoasc' option with ffmpeg)\n");

         return AVERROR_INVALIDDATA;

         }
         av_log(s, AV_LOG_WARNING, "aac bitstream error\n");

     }

     if (flv->delay == AV_NOPTS_VALUE)
         flv->delay = -pkt->dts;

     if (pkt->dts < -flv->delay) {

         av_log(s, AV_LOG_WARNING,
                "Packets are not in the proper order with respect to DTS\n");

         return AVERROR(EINVAL);
     }

     ts = pkt->dts + flv->delay; // add delay to force positive dts

 
     /* check Speex packet duration */

     if (enc->codec_id == AV_CODEC_ID_SPEEX && ts - sc->last_ts > 160)

         av_log(s, AV_LOG_WARNING, "Warning: Speex stream has more than "
                                   "8 frames per packet. Adobe Flash "
                                   "Player cannot handle this!\n");
 

     if (sc->last_ts < ts)
         sc->last_ts = ts;

     avio_wb24(pb, size + flags_size);

     avio_wb24(pb, ts & 0xFFFFFF);

     avio_w8(pb, (ts >> 24) & 0x7F); // timestamps are 32 bits _signed_
     avio_wb24(pb, flv->reserved);

     if (enc->codec_type == AVMEDIA_TYPE_DATA) {
         int data_size;

         int64_t metadata_size_pos = avio_tell(pb);

         avio_w8(pb, AMF_DATA_TYPE_STRING);
         put_amf_string(pb, "onTextData");
         avio_w8(pb, AMF_DATA_TYPE_MIXEDARRAY);
         avio_wb32(pb, 2);
         put_amf_string(pb, "type");
         avio_w8(pb, AMF_DATA_TYPE_STRING);
         put_amf_string(pb, "Text");
         put_amf_string(pb, "text");
         avio_w8(pb, AMF_DATA_TYPE_STRING);
         put_amf_string(pb, pkt->data);
         put_amf_string(pb, "");
         avio_w8(pb, AMF_END_OF_OBJECT);
         /* write total size of tag */
         data_size = avio_tell(pb) - metadata_size_pos;
         avio_seek(pb, metadata_size_pos - 10, SEEK_SET);
         avio_wb24(pb, data_size);
         avio_seek(pb, data_size + 10 - 3, SEEK_CUR);
         avio_wb32(pb, data_size + 11);
     } else {

         av_assert1(flags>=0);

         avio_w8(pb,flags);

         if (enc->codec_id == AV_CODEC_ID_VP6)
             avio_w8(pb,0);

         if (enc->codec_id == AV_CODEC_ID_VP6F || enc->codec_id == AV_CODEC_ID_VP6A) {
             if (enc->extradata_size)
                 avio_w8(pb, enc->extradata[0]);
             else
                 avio_w8(pb, ((FFALIGN(enc->width,  16) - enc->width) << 4) |
                              (FFALIGN(enc->height, 16) - enc->height));
         } else if (enc->codec_id == AV_CODEC_ID_AAC)

             avio_w8(pb, 1); // AAC raw

         else if (enc->codec_id == AV_CODEC_ID_H264 || enc->codec_id == AV_CODEC_ID_MPEG4) {

             avio_w8(pb, 1); // AVC NALU
             avio_wb24(pb, pkt->pts - pkt->dts);
         }

         avio_write(pb, data ? data : pkt->data, size);

         avio_wb32(pb, size + flags_size + 11); // previous tag size
         flv->duration = FFMAX(flv->duration,
                               pkt->pts + flv->delay + pkt->duration);

     }

 
     av_free(data);
 

     return pb->error;

 }
 

 AVOutputFormat ff_flv_muxer = {

     .name           = "flv",

     .long_name      = NULL_IF_CONFIG_SMALL("FLV (Flash Video)"),

     .mime_type      = "video/x-flv",
     .extensions     = "flv",
     .priv_data_size = sizeof(FLVContext),

     .audio_codec    = CONFIG_LIBMP3LAME ? AV_CODEC_ID_MP3 : AV_CODEC_ID_ADPCM_SWF,
     .video_codec    = AV_CODEC_ID_FLV1,

     .write_header   = flv_write_header,
     .write_packet   = flv_write_packet,
     .write_trailer  = flv_write_trailer,

     .codec_tag      = (const AVCodecTag* const []) {
                           flv_video_codec_ids, flv_audio_codec_ids, 0
                       },

     .flags          = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS |
                       AVFMT_TS_NONSTRICT,

 };