[CM] adding an extra channel

[e deleflie]

On 6/12/07, Bill Schottstaedt <bil@ccrma.stanford.edu> wrote:
> > the LADSPA plugin requires 4 channels. So when I read a 3 channel
> > file, I need to create a fourth, empty (no signal) channel.
>
> Doesn't apply-ladspa take a list of readers?

apparently, yes.

(apply-ladspa reader (plugin-library plugin-type [param1 [param2
...]]) samples origin)

> Perhaps an easy fix would
> be to allow #f (as a null-reader) in that list, then apply_ladspa (in C)
> would send a stream of 0's in each channel that had no reader -- this
> is a one line change, if it seems like the right thing.

That would seem to work for my case scenario (I have confirmed with
the plugin author).

Whether that is a correct LADSPA API interpretation, I dont know...

I've looked briefly through the LADSPA developers documentation, but
cant see anything of note:
http://gdam.ffem.org/ladspa-doc/ladspa.html......... need a LADSPA
guru.

Etienne