The goal of this wiki is to get a roadmap how to get to an low latency PD-System. Therfore everyone please fill in your konowledge links and so on about this.

• What is latency, how to measure, why we need it ?

  Latency is a measure of how long it takes for a system to react. In Pd, we are primarily concerned with the time it takes for audio, MIDI, or other input to cause audio output. This is "audio latency". For reference, the audio latency between your speakers and your ears is approximately 1 ms per foot.

So in pratice you need for an reactive Audiosystem for

• BigHallConcerts: < 30ms
• SmallBarsConcerts: < 20ms
• StudioMixing < 10ms
• ScientificPurposes <= 0ms

(Comment: Isn't Pd's latency just added to the room's latency??? --Frank Barknecht)

Analysis:

Which hardware causes what, which driver causes what, overall performance tests of OS System

• PD structure causing latency causing latency, options !
  • [Meassurements with pd]? patches to use and results
• OS structure causing latency for different OS systems which parts are responsible
  • [Meassurements on system outside pd]? tools to measure and results
• Limits of Hardware cards Which cards have limits to latency and why
  • What is known about this of the OS

Solutions:

• Guidelines for Patch-Programming for low latency patches
  • simple in/out latency versus complex patches
  • which objects can cause dac slips
• Low Latency OS systems
  • linux
  • Windows
  • Mac
• What configuration does what ?

Measurements:

• How to Measure and Datasheet ?
• The low latency top 5

  (here please fill in if you are below the top five of the Archive)

  1. UnkownSystem 500ms
  2. UnkownSystem 500ms
  3. UnkownSystem 500ms
  4. UnkownSystem 500ms
  5. UnkownSystem 500ms
• [Archive of low latency measurements]?

Timeline:

• Projectend: Christmas 2003
• 1. Version am 20.11.

Related Links:

• "JACK Design Documentation": http://jackit.sourceforge.net/docs/design/design.html