MUX=ass
Muxer ass [SSA (SubStation Alpha) subtitle]:
    Common extensions: ass,ssa.
    Mime type: text/x-ass.
    Default subtitle codec: ass.
ass muxer AVOptions:
  -ignore_readorder  <boolean>    E........ write events immediately, even if they're out-of-order (default false)

MUX=jacosub
Muxer jacosub [JACOsub subtitle format]:
    Common extensions: jss,js.
    Mime type: text/x-jacosub.
    Default subtitle codec: jacosub.
MUX=microdvd
Muxer microdvd [MicroDVD subtitle format]:
    Common extensions: sub.
    Mime type: text/x-microdvd.
    Default subtitle codec: microdvd.
MUX=srt
Muxer srt [SubRip subtitle]:
    Common extensions: srt.
    Mime type: application/x-subrip.
    Default subtitle codec: subrip.
MUX=sup
Muxer sup [raw HDMV Presentation Graphic Stream subtitles]:
    Common extensions: sup.
    Mime type: application/x-pgs.
    Default subtitle codec: hdmv_pgs_subtitle.
MUX=webvtt
Muxer webvtt [WebVTT subtitle]:
    Common extensions: vtt.
    Mime type: text/vtt.
    Default subtitle codec: webvtt.