Status report on Gnome Wave Cleaner, and possibility of plug-ins

[Jeff Welty <welty harbornet com>]

There is a development release (0.17-2) of the Gnome Wave Cleaner at:

http://gwc.sourceforge.net/

This now incorporates libsndfile, and now can handle many more
sound formats.  A bug was fixed in the lorber-hoeldrich denoising
algorithm which greatly improves the denoising results.

Many people have asked for plugins of the declicking and denoising
algorithms.  This is a complicated task -- LADSPA plugins will not
be possible.  The algorithms do not operate on a window at a time,
they must look ahead (or sometime behind) of the current window to
repair the data.

The strategy I am taking (slow, as it is ;-), is to
start creating library functions for declicking and denoising.  The
basic idea is that the algorithms will ask for input data from a
function pointer passed to the algorithm, and once enough data
has been processed, the algorithms will start sending cleaned data "out"
via a different function pointer.

Once library functions exist, then I hope that it will be easier to
determine requirements for a pluggin API that would support these
algorithms.  Probably then also, someone smarter than me could make
the libraries into pluggins.  It would also be possible to code
stand alone programs that would read from stdin, write to stdout...

I will once again caution that proper denoising requires a proper sampling
of the noise -- applications could try to find "noise only" regions and
pass that to the denoising algorithm, but with some chance of really mutilating
the wanted audio portion of the signal.

Jeff Welty