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FMOD bindings for Defold
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FMOD extension for Defold

Experimental FMOD sound engine bindings for Defold

Commercial usage of FMOD products may require a separate license directly with Firelight Technologies. For details refer to

According to the FMOD license, you must credit FMOD in your project's documentation, or in an on screen format. The text should include at least the words "FMOD" (OR "FMOD STUDIO" IF APPLICABLE) AND "FIRELIGHT TECHNOLOGIES."


Go to the Releases page, copy a dependency URL, then add it to your dependencies in game.project.

Set the speaker mode

This step is only required if you use Studio banks. To set the speaker mode, create an fmod section in your game.project:

speaker_mode = stereo

Supported values for speaker_mode are: default, raw, mono, stereo, quad, surround, 5.1, 7.1, max.

If ever needed, you can also set sample_rate and num_raw_speakers in the same way.

Running in the editor

The game will bundle fine, but in order for FMOD to be available when running from the editor, an extra step is required.

Copy the fmod/res directory from this repo to a directory in your project and add the path to that directory to your game.project:

lib_path = path/to/fmod/res


Structs and classes are exposed on the fmod and namespaces. All method names are converted from camelCase to snake_case. Methods that returned values through pointer arguments now actually return the values and throw with a Lua error when their result is not FMOD_OK.

Enums are exposed on the fmod table without the leading FMOD_. (eg.: FMOD_STUDIO_PLAYBACK_PLAYING is exposed as fmod.STUDIO_PLAYBACK_PLAYING)

A fully initialised instance of FMOD::Studio::System is exposed to Lua as and the corresponding instance of FMOD::System (the low level system), is exposed as fmod.system.

You can use vmath.vector3 instead of FMOD's FMOD_VECTOR struct. Conversion is being done seamlessly.

See an example script to get an idea.

Refer to the FMOD API Documentation for details about the available APIs.

Here's some sample code:"/banks/Master"), fmod.STUDIO_LOAD_BANK_NORMAL)"/banks/Master"), fmod.STUDIO_LOAD_BANK_NORMAL)"/banks/"), fmod.STUDIO_LOAD_BANK_NORMAL)

local event_description ="event:/Vehicles/Basic Engine")
local event = event_description:create_instance()

Memory management

Instances of FMOD_STUDIO_EVENTINSTANCE are automatically garbage collected by Lua and release() is called automatically for you when you no longer hold references.

Any other class is not memory managed and you still need to call instance:release() manually, where applicable.

Error handling

You can retrieve the error code of an FMOD error and use it for more specific error handling:

local ok, err = pcall(function ()
  return"event:/Inexistent event")
if ok then
  local event_description = err
  print(err) -- The error is a string
  local code = fmod.error_code[err] -- The FMOD error code (a number).
  if code == fmod.ERR_EVENT_NOTFOUND then
    print("Ooops! This event doesn't exist!")

64-bit values

A small amount of FMOD functions and structs work with 64-bit number types. Lua 5.1 doesn't have a 64-bit type. Functions with 64-bit arguments accept regular lua numbers instead if the extra precision is not needed, but if you need more, use fmod.s64() and fmod.u64(),

Functions that return 64-bit numbers will return instances of fmod.s64 or fmod.u64.

x = fmod.s64(num) -- Converts a Lua number (up to 52 bits of integer precision) to a 64-bit value
x = fmod.s64(low, high) -- Creates a 64-bit value from two 32-bit integers
x.value -- Does the best-effort conversion to a Lua number (accurate within 52 bits of precision)
x.low -- Gets the lowest 32-bits as an unsigned int value
x.high -- Gets the lowest 32-bits as an unsigned int value
tostring(x) -- Converts the value to a numeric string

Studio Live Update

Add the following setting to your game.project to enable the live update server used by FMOD Studio.

live_update = 1

Loading banks from the file system

For development it's ok to put your banks in custom_resources and use load_bank_memory to load them, but this is inefficient (costs a lot of memory and you don't benefit from streaming).

When building, you want your banks on the file system. In your bundled_resources directory, add the banks to the following paths:

  • For Windows, Linux and iOS: win32/banks/, linux/banks/, ios/banks/
  • For macOS: osx/Contents/Resources/banks
  • For Android: android/assets/banks

Then, from your game code:

local bundle_path = sys.get_application_path() -- The path to your game's directory
local path_to_banks = bundle_path .. "/banks"
local system_name = sys.get_sys_info().system_name
if system_name == "Darwin" then
  path_to_banks = bundle_path .. "/Contents/Resources/banks"
elseif system_name == "Android" then
  path_to_banks = "file:///android_asset/banks"
end .. "/Master", fmod.STUDIO_LOAD_BANK_NORMAL)

Warning: Don't use relative paths for loading banks. Use sys.get_application_path(). Relying on the current working directory being the same as the game's installation directory is not always correct (especially on platforms like macOS and iOS).


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