mirror of https://github.com/ZDoom/fluidsynth.git
65 lines
2.2 KiB
Markdown
65 lines
2.2 KiB
Markdown
|
# FluidSynth LADSPA Interface
|
||
|
|
|
||
|
|
The [LADSPA](http://ladspa.org/) (Linux Audio Developer's Simple Plugin API)
|
||
|
|
binding can be used to route the FluidSynth audio output through any number
|
||
|
|
of LADSPA plugins. As the name implies, it is only available on Linux.
|
||
|
|
|
||
|
|
## Configuration
|
||
|
|
|
||
|
|
To configure and compile FluidSynth with LADSPA support, make sure you have
|
||
|
|
the LADSPA SDK (basically the ladspa.h header file) installed. Then enable
|
||
|
|
LADSPA when calling cmake:
|
||
|
|
|
||
|
|
cmake path/to/source/ -Denable-ladspa=1
|
||
|
|
|
||
|
|
You should see `LADSPA support: yes` in the cmake output.
|
||
|
|
|
||
|
|
To enable the LADSPA engine, use the `synth.ladspa.active` setting when
|
||
|
|
starting FluidSynth:
|
||
|
|
|
||
|
|
fluidsynth -o synth.ladspa.active=1 ...
|
||
|
|
|
||
|
|
|
||
|
|
# Signal Flow
|
||
|
|
|
||
|
|
The LADSPA effects unit runs immediately after the internal reverb and chorus
|
||
|
|
effects have been processed. When no plugins have been configured, the
|
||
|
|
effects unit is dormant and uses no additional system resources.
|
||
|
|
|
||
|
|
When at least one plugin is configured and the engine is activated, the
|
||
|
|
rendered audio is passed into the LADSPA effects unit, each plugin is
|
||
|
|
run in the order that they were created and the resulting audio is
|
||
|
|
passed back into FluidSynth (and from there to the sound card or other
|
||
|
|
output).
|
||
|
|
|
||
|
|
|
||
|
|
# Loading and Connecting Plugins
|
||
|
|
|
||
|
|
Currently the only way to configure the effects unit is via the FluidSynth
|
||
|
|
shell or via a config file.
|
||
|
|
|
||
|
|
## Example Setups
|
||
|
|
|
||
|
|
All examples assume that your `LADSPA_PATH` environment variable points
|
||
|
|
to the directory containing the plugin libraries (e.g. /usr/lib/ladspa).
|
||
|
|
|
||
|
|
### Single Plugin
|
||
|
|
|
||
|
|
The following loads the delay.so plugin library from the LADSPA SDK and
|
||
|
|
instantiates the `delay_5s` plugin from that library. It connects the
|
||
|
|
main left channel output from FluidSynth with the plugin input, the
|
||
|
|
main left channel input to FluidSynth with the plugin output. It also
|
||
|
|
sets the two control ports of the plugin to example values and starts
|
||
|
|
the engine.
|
||
|
|
|
||
|
|
ladspa_plugin delay.so delay_5s
|
||
|
|
ladspa_port Input < in1_L
|
||
|
|
ladspa_port Output > out1_L
|
||
|
|
ladspa_port Delay = 1.0
|
||
|
|
ladspa_port Dry/Wet = 0.5
|
||
|
|
|
||
|
|
ladspa_start
|
||
|
|
|
||
|
|
The audible effect should be an untouch right channel and a slightly
|
||
|
|
lower volume on the left with a delay effect of 1 second on top.
|