At LUGRadio Live we agreed an initial feature-set for Jokosher 0.2, and a release schedule. For more details on this, read this this thread.

One of the key features I am keen to see in 0.2 is full LADSPA support. For those of you who have been living under a rock, LADSPA is a plug-in standard for audio effects. There are stacks of plug-ins out there, and we want them to work inside Jokosher. So, how does this work?

Well, there is a GStreamer bridge that worked with 0.8 and was ported to 0.10 and has problems. I have reported this as a bug and hopefully some of the GStreamer guys will fix this up soon. In the meantime, I figured I would write some code to get the plug-in UI up and running.

LADSPA does not actually provide a user interface for plug-ins. I was under the impression that some kind of XML UI description schema (similar to Glade) was available to describe the UI, but it seems not. Instead, you need to probe the LADSPA ports (the virtual knobs on the plug-in) and generate the interface yourself. I figured I would see if the GStreamer LADSPA bridge worked with regard to exposing these ports via GObject properties.

So, I wrote a test script today that queries the GStreamer plug-in registry for LADSPA plug-ins, and provides a list of them. When you select a plug-in, the script generates a settings window with a bunch of sliders and their appropriate minimum and maximum values. As such, the LADSPA querying and UI side of things is written and I can drop it into Jokosher. I plan on merging it in over the next few days. I hope to get LADSPA support finished for entire instruments over the following week, and when the bridge is fixed, we will have working effects support in Jokosher!! :)

Share This
%d bloggers like this: