[ecasound] 1.6.x development info

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Subject: [ecasound] 1.6.x development info
From: Kai Vehmanen (kaiv@wakkanet.fi)
Date: Sat Oct 23 1999 - 15:21:30 EEST

Here's some info about current development:

1. interactive-mode/library interface change

I've spent a lot of time on this, and it's slowly getting
ready. It's been really hard to keep the interface intuitive.
I'd like to hear some comments on this design. For instance,
here's a few i-active mode commands:

c_select some_chain_name // - select some chain (from currently
                                // selected chainsetup)
co_add -efb:1000,500 // - add a chain operator: bandpass filter
                                // added chainop is now selected
co_add_controller -kos:1,50,500,0.5,0.0
                                // - add a sine oscillator to control
                                 // the 1st chainop parameter
                                // (center freq); parameter value
                                // oscillates between 50 and 500,
                                // with freq 0.5Hz
cop_select 2 // - select chainop's 2nd parameter
                                // (filter width, in Hz)
cop_set 500 // - change parameter value to 500

... and so on. I've tried to use the command-line syntax whenever
possible. This should make iactive-mode easier to use.

I've can. There's a few logical problems involved, but otherwise everything
has gone as planned.

2. variable channel count

Until now ecasound has handled all signals as stereo-signals (mono
inputs were automatically converted to stereo). Although somewhat
limiting, this makes effect configuration a lot easier to handle. You
just add a surround-reverb to a chain and that's all. Another way to do
this would be to treat all signals as mono. In many ways, this is
extremely flexible, but there are problems. If you want to add a surround
reverb, you first route your stereo input to two mono channels, then
you route these channels to a two-input stereo-effect and route its
outputs to a stereo output. As you can imagine, user-interface to this
can get really complicated (= patch cords!).

I've tried to combine these approaches in 1.6.x. Number of channels
will no longer be constant. If you connect a 2-channel input to a
chain, this chain will be stereo too, but you can also connect
a 16-channel input, and you'll have a 16-channel chain. I've also
tried to avoid changes in the user interface. You can still connect
surround reverbs and other multichannel effects to chains as usual.
If you connect these effects to mono channels, they won't work of
course, but this shouldn't be a problem. If you connect a mono-effect
(amplify, filter) to a multichannel chain, all channels will be

3. ecawave - ?

I'm currently on a Linux programming course. If my proposal is
approved, my course project will be a disk-based wavefile editor.
I don't want integrate this to ecasound, but I will use libecasound
library extensively. Project deadline is 1.2.2000 so if I get to do
this, I can guarantee to have a working version before that. :)

Kai Vehmanen <kaiv@wakkanet.fi> -------- CS, University of Turku, Finland
 . http://www.wakkanet.fi/ecasound/ - linux audio processing
 . http://www.wakkanet.fi/sculpscape/ - ambient-idm-rock-... mp3/ra/wav
 . http://www.wakkanet.fi/kerttulin_listat/ - music&movies (in Finnish)

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