Distributed audio under Linux

• Student: Daniel Warren (2004), now at Ashland Inc. in Lexington, KY.
• Purpose: Design and implement a daemon that lets clients create multichannel audio streams and add/remove sources and sinks, which can be tied to files, hardware devices (such as microphones, CD players, and speakers), and other instances of the daemon.
• Method: Alsad listens on a well-known port for clients to connect. It spawns a new thread for each client. It dedicates a circular buffer to each stream. It spawns a new thread for each sink. It periodically grants permission to the source to send more data as the sinks consume the data from the buffer. A client program takes command-line parameters to specify commands that it then sends to alsad.
• What the student learned
  1. Tools: Alsa library, threads (including thread synchronization), doxygen
  2. Language: C
  3. Techniques: Client-server protocols, design and documentation of a large-scale project
  Code and documentation can be found at this site.