You can search for identifiers within the package.
in-package search v0.2.0
type decoder = t
type t
type track = int
type sample = int
val is_mp4 : string -> bool
val openfile : ?write:(string -> int) -> ?seek:(int -> int) -> ?trunc:(unit -> int) -> (int -> string * int * int) -> t
val openfile_fd : Unix.file_descr -> t
val tracks : t -> int
val find_aac_track : t -> track
val init : t -> decoder -> track -> int * int
val seek : t -> track -> int -> int * int
val samples : t -> track -> int
val read_sample : t -> track -> sample -> string
val decode : t -> track -> sample -> decoder -> float array array
val metadata : t -> (string * string) array