An open source project by FPL.
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Pindrop is an audio engine designed with the needs of games in mind. It's not just an audio mixer, it also manages the prioritization, adjusts gain based distance, manages buses, and more. It is largely data-driven. The library user needs only to load a handful of configuration files and Pindrop handles the rest.


Sound Bank Management

To save memory, only load the sounds you need by grouping them into sound banks. Load as many banks as you need. Samples are reference counted, so you'll never load the same sample multiple times.

Channel Prioritization

In a busy scene a game might have thousands of samples playing at the same time. Sometimes that is more than the game can handle. Pindrop will manage the priority of each audio channel and only drop the least important channels when too many simultaneous streams play at once.

Distance Attenuation

Pindrop supports positional and non-positional sounds. Positional sounds can be set to attenuate based on their distance from the listener. The attenuation curve can be customized so that the audio rolls off with the curve that sounds right.


A series of hierarchical buses may be specified that can automatically adjust channel gain on the fly. If there is an important sound or voice over that needs to be heard, audio playing on less important buses can be ducked to ensure the player hears what they need.

Easy to Use

Pindrop only requires a few JSON based configuration files, and the code required to hook it into your own game engine is minimal. File loading is made fast by FlatBuffers. All you need to do is initialize the library and run AdvanceFrame once each frame in your main loop.


FlatBuffers, a fast serialization system, is used to store the game's data. The game configuration data is stored in JSON files which are converted to FlatBuffer binary files using the flatc compiler.

MathFu, a geometry math library optimized for [ARM][] and x86 processors. Pindrop uses MathFu three dimensional vectors for distance attenuation calculations.

[SDL Mixer][], an audio mixing library that sits on top of SDL. SDL Mixer handles mixing the playing audio samples and streams that Pindrop manages. SDL Mixer in turn depends on [libogg][] and [libvorbis][] as well.

In addition, fplutil is used to build, deploy, and run the game; build and archive the game; and profile the game's CPU performance.

Supported Platforms

Pindrop has been tested on the following platforms:

We use SDL as our cross platform layer.

Pindrop is written entirely in C++. The library can be compiled using Linux, OS X or Windows.


Pindrop can be downloaded from:

Important: Pindrop uses submodules to reference other components it depends upon, so download the source from GitHub using:

git clone --recursive

Feedback and Reporting Bugs