local sound = require "sound"

  sound:load(file_path [, file_type])                     -- load a audio file
  sound:unload(file_path)                                 -- unload a audio file
  sound:play(file_path, [loop, [pitch, [gain]]])          -- play a effect sound

  local music = require "music"

  music.load(file_path)          -- preload a music sound
  music.play(file_path, loop)    -- play a music sound, will load audio file when not load.
  music.stop()                   -- stop the current playing music sound
  
  music.open()                   -- open background music
  music.close()                  -- close background music

  local audio = require "audio"

  audio:load(file_path)          -- load sound file
  audio.unload(file_path)        -- unload sound file

  audio:listen_position(x, y, z) -- set listener position

  local audio = require "audio"

  local group1 = audio:create_group([count]) -- create a sound group has count source
  local handle = group1:add(file_path, [loop, [pitch, [gain, [max_distanc]]]]) -- add sound file to group

  group1:play(handle)    -- play sound
  group1:stop(handle)    -- stop sound
  group1:rewind(handle)  -- rewind sound
  group1:pause(handle)   -- pause sound
  group1:position(handle, x, y, z) -- set source position
  group1:volume(handle, v)  -- set source volume

  group1:open()          -- open group all sound
  group1:close()         -- stop and close group all sound