Audio sequencer development - newbie resources?

Hi,

I'm starting up my first audio project, adding realtime audio support
to a MIDI program I've developed. I'm looking for resources on the
principles of audio sequencer development, so I don't have to reinvent
the wheel. All I have to do at first is take in realtime input and do
some basic DSP on it. I can find lots of books and resources on DSP
topics, but not audio-sequencer specific.

I have lots of MIDI programming experience, and with realtime, multi-
threaded development. Any kind of training resources would be greatly
appreciated!

Cheers,
Michael

michael@circular-logic.com wrote:
> Hi,
> 
> I'm starting up my first audio project, adding realtime audio support
> to a MIDI program I've developed. I'm looking for resources on the
> principles of audio sequencer development, so I don't have to reinvent
> the wheel. All I have to do at first is take in realtime input and do
> some basic DSP on it. I can find lots of books and resources on DSP
> topics, but not audio-sequencer specific.
> 

The principles can be summarized in a sentence: low-latency audio thread 
+ background control thread (e.g. GUI) + some form of message-passing 
connection between them = standard model-view-controller system.

I don't think there are any books as such, but there is lots of source 
code out there. A list of GPL audio hosts for LADSPA plugins (etc) is here:

http://www.ladspa.org

Check out Rosegarden, for example. IIRC, it started as a MIDI app and 
later added audio. Other projects probably did it the other way, adding 
MIDI support to an audio application.

Csound also has a wide variety of GUI front ends these days.

"Audio sequencer" can mean a lot of different things (most wheels are 
round, but come in different sizes and materials, and serve different 
purposes). Single-track? Multi-track? Graph-based? And what platform you 
are on make a difference too. A widely used cross-platform audio 
streaming API supporting full-duplex audio i/o is portaudio 
(www.portaudio.com).

You will find many more kindred spirits on this subject on the musicdsp 
mailing list.


Richard Dobson