The menu syntax is similar to mpv.net, with some enhancements:

• define menu title after #menu:
  • define separator with -
  • split title with > to define submenus
  • use #@keyword to display selection menu for:
    • #@tracks: track list (video/audio/subtitle)
      • #@tracks/video: video track list
      • #@tracks/audio: audio track list
      • #@tracks/sub: subtitle list
      • #@tracks/sub-secondary: subtitle list (secondary)
    • #@chapters: chapter list
    • #@editions: edition list
    • #@audio-devices: audio device list
    • #@playlist: playlist
    • #@profiles: profile list
  • use #@state=<expr> to update menu state:
    • <expr> is like the profile-cond option in Conditional auto profiles
    • the result of <expr> should be comma seprated state string
    • supported states: checked / disabled / hidden
• use _ if no keybinding
• use ignore if no command

Ctrl+a  show-text foobar    #menu: Foo > Bar
_       ignore              #menu: -
_       ignore              #menu: Tracks #@tracks
_       ignore              #menu: Chapters #@chapters
_       ignore              #menu: Editions #@editions
_       ignore              #menu: -
_       cycle mute          #menu: Audio > Mute #@state=(mute and 'checked')
_       ignore              #menu: Audio > Devices #@audio-devices

NOTE: You don't need to add a keybinding in input.conf to trigger menu since 2.4.0 version, see also FAQ.

• use_mpv_impl=no: do not use mpv's menu implementation.
• uosc_syntax=yes: enable uosc menu syntax support.
• escape_title=no: disable escaping of & to && in title (this will enable Keyboard Accelerators).
• max_title_length=80: Limits the title length in dynamic submenu, set to 0 to disable.
• max_playlist_items=20: Limit the playlist items in submenu, set to 0 to disable.