[CM] processing multi-channel Ladspa effects in SND

e deleflie edeleflie@gmail.com
Mon, 14 May 2007 16:14:22 +1000

Hi all,

Please excuse my extreme green newbie status and subsequent question ...

I'm looking for a scripting environement to run LADSPA plugins, on
multi-channel files. I first looked at ecasound but came across some
impasses. ... so now I'm looking at SND as a scripting environment,
and the learning curve is steep!

I'm pumping a 4 channel Ambisonic file (surround sound format) into a
LADSPA plugin and wanting to save the subsequent 4 outputs into mono
wave files.

(note *.amb files are just wavex files)
#!/usr/bin/snd -l
(open-sound "myAmbisonicFile.amb")

(apply-ladspa (list (make-sample-reader 0 0 0)  ;chan 0
             (make-sample-reader 0 0 1) ;chan 1
             (make-sample-reader 0 0 2) ;chan 2
             (make-sample-reader 0 0 3) ;chan 3)
              (list "ambis1" "Ambisonics-square-decoder" 0 1 1.44 2
500 2) duration? origin?)
(save-sound-as "4_channel_output.wav")
I want 'duration' to be the whole file ... how do I do that?
I also dont understand what 'origin' should be since some examples put
a sound file there ...

(there's an example on how to write mono files from a multi-channel
file, so I should be right with that).

Can anyone help me get that code working?