FAS: Fragment Audio Server

The Fragment Audio Server is a program written with the C language for very fast real-time audio synthesis.

It is recommended to use Fragment with the Fragment Audio Server enabled.

The advantage of using the audio server is that it provide the best audio performances along with audio devices choice, multiple audio outputs, sample rate choice, granular synthesis & sampler method, distributed sound synthesis over multiple machines or cores, realtime scheduling under Linux and more...

Fragment communicate with FAS by sending data through the network when the Fragment FAS option (waveform icon) is enabled, FAS can run on any machines independently of the Fragment application, it gather the pixels data from Fragment in real-time, compute things and deliver the audio through the selected audio device.

FAS is bundled with the graphical launcher which can be downloaded on the Fragment homepage, it can also be compiled from sources on GitHub.

On the Raspberry PI ~700 additive synthesis oscillators can play at the same time with an optimized system

FGL: Fragment Graphical Launcher

The graphical launcher is an application available for Linux and Windows which provide an easy interface to start Fragment with the Fragment Audio Server, the launcher also provide a convenient way to configure the audio server for individual sessions and provide a list of all the sessions you joined in.

The graphical launcher is available on the homepage.

Fragment Independent GLSL editor

The integrated GLSL editor can be too cumbersome to use sometimes with complex sessions and can make the sound choppy when you type.

A solution is to use the independent editor which is only the Fragment GLSL editor portion in a webpage, the independent editor can connect to any sessions and has about the same features as the integrated code editor.

The independent GLSL editor can be found here, the development server is needed in order to execute it, some instructions can be found on the GitHub page

OSC relay

Fragment support OSC input and output with WebSockets, some tools does not support OSC through WebSockets and an OSC relay which translate WebSockets data to UDP packets should then be used.

The OSC relay need NodeJS and NPM and can be found here

To use the OSC relay once NodeJS and NPM is installed, type cd osc_relay & npm install & node osc_relay in a terminal at the OSC relay root level directory

FAS relay

Fragment support distributed sound synthesis on any machines or cores over the network

The FAS relay is a program which listen to port 3003 and wait a client connection, when a client is connected, it relay the data from the client to all audio server instances specified at launch, audio server instances can be remote or local (same computer = multi-core)

Moreover, three type of distribution system can be chosen (the constant must be changed in the source-code at the moment), DSMART is recommended as it provide the best performances/distribution


  • Will split the data in equal blocks and distribute them over each audio server instances


  • Interleaved, this will distribute data over each servers in a linear & cyclical fashion


  • Distribute the data equally by default over all the audio servers
  • Provide the best performances/distribution quality out of the three methods available
  • Will also distribute different channels data to different instances
  • Weight can be defined per servers, this may be of interest to run the servers on machines that has different capabilities, you could have double amount of processing for machine X while normal amount for machine Y and low amount of processing for machine Z etc.

Commands line argument (example for 3 localhost servers)


  • Shortcut when servers are on the same machine, this will connect to 3 localhost servers from port 3004 to 3006
  • Equivalent to -s=""

-s="list of servers address+port separated by whitespace"

  • Example : -s=""

-w="list of servers weight as a float value for each servers"

  • the distribution "weight" is a float which indicate "server performance", 1 is the default weight, a high weight value (say 2 while all others are 1) mean that the server is slower and will take half load, a low value for a server (say 0.5) mean that the server is fast and will take double load
  • Example : -s="1 0.5 1"


A limited portion of the additive synthesis engine has been ported to SuperCollider, it can be used by using the OSC relay and enabling OSC output.

The SuperCollider script is available here

This synthesis engine only support one stereo output channel.