Realization of srt protocol ffmpeg for streaming media analysis

srt audio and video data is based on mpegts package, ffmpeg data flow

1. The mpegts encapsulation format will be described in the following series of articles. The encapsulation implementation interface in ffmpeg is as follows: mpegtsenc.c

AVOutputFormat ff_mpegts_muxer = {
    .name           = "mpegts",
    .long_name      = NULL_IF_CONFIG_SMALL("MPEG-TS (MPEG-2 Transport Stream)"),
    .mime_type      = "video/MP2T",
    .extensions     = "ts,m2t,m2ts,mts",
    .priv_data_size = sizeof(MpegTSWrite),
    .audio_codec    = AV_CODEC_ID_MP2,
    .video_codec    = AV_CODEC_ID_MPEG2VIDEO,
    .init           = mpegts_init,
    .write_packet   = mpegts_write_packet,
    .write_trailer  = mpegts_write_end,
    .deinit         = mpegts_deinit,
    .check_bitstream = mpegts_check_bitstream,
    .flags          = AVFMT_ALLOW_FLUSH | AVFMT_VARIABLE_FPS | AVFMT_NODIMENSIONS,
    .priv_class     = &mpegts_muxer_class,
};

Decapsulation package: FFmpeg-n4.3.3/libavformat/mpegts.c

AVInputFormat ff_mpegts_demuxer = {
    .name           = "mpegts",
    .long_name      = NULL_IF_CONFIG_SMALL("MPEG-TS (MPEG-2 Transport Stream)"),
    .priv_data_size = sizeof(MpegTSContext),
    .read_probe     = mpegts_probe,
    .read_header    = mpegts_read_header,
    .read_packet    = mpegts_read_packet,
    .read_close     = mpegts_read_close,
    .read_timestamp = mpegts_get_dts,
    .flags          = AVFMT_SHOW_IDS | AVFMT_TS_DISCONT,
    .priv_class     = &mpegts_class,
};

 

Implementation of the srt protocol: ffmpeg mainly calls libsrt to realize the interaction between srt and the server and realize audio and video sealing and network transmission:

The following series of articles analyze srt:

const URLProtocol ff_libsrt_protocol = {
    .name                = "srt",
    .url_open            = libsrt_open,
    .url_read            = libsrt_read,
    .url_write           = libsrt_write,
    .url_close           = libsrt_close,
    .url_get_file_handle = libsrt_get_file_handle,
    .priv_data_size      = sizeof(SRTContext),
    .flags               = URL_PROTOCOL_FLAG_NETWORK,
    .priv_data_class     = &libsrt_class,
};