using LADSPA plugins on banks

[arretxe]

Hi all!
I am using fluidpatcher for live performing and I want to add some plugins to my sf2. I have tried setting the SC4 compressor but I cannot seem to make it work. I set the threshold, makeup gain and attack to the minimum and still it seems to sound exactly the same...
When loading the bank i don't see any error so first I thought it was understanding what I was setting, but then i set some fake port names and i don't get any errors, so right now I can't tell if I am setting it properly....

Any help would be really appreciated!

These is the plugin I am using:
analyseplugin /usr/lib/ladspa/sc4_1882.so

Plugin Name: "SC4"
Plugin Label: "sc4"
Plugin Unique ID: 1882
Maker: "Steve Harris steve@plugin.org.uk"
Copyright: "GPL"
Must Run Real-Time: No
Has activate() Function: No
Has deactivate() Function: No
Has run_adding() Function: Yes
Environment: Normal or Hard Real-Time
Ports: "RMS/peak" input, control, 0 to 1, default 0
"Attack time (ms)" input, control, 1.5 to 400, default 101.125
"Release time (ms)" input, control, 2 to 800, default 401
"Threshold level (dB)" input, control, -30 to 0, default 0
"Ratio (1:n)" input, control, 1 to 20, default 1
"Knee radius (dB)" input, control, 1 to 10, default 3.25
"Makeup gain (dB)" input, control, 0 to 24, default 0
"Amplitude (dB)" output, control, -40 to 12
"Gain reduction (dB)" output, control, -24 to 0
"Left input" input, audio
"Right input" input, audio
"Left output" output, audio
"Right output" output, audio

And my files:
fluidpatcherconf.yaml

soundfontdir: /home/st/scripts/config/sf2
bankdir: /home/st/scripts/config/banks
mfilesdir: /home/st/scripts/config/midi
plugindir: /usr/lib/ladspa
currentbank: bank1.yaml
fluidsettings:
audio.driver: alsa
audio.realtime-prio: 99
audio.alsa.device: hw:CODEC
audio.period-size: 64
audio.periods: 2
midi.autoconnect: 1
player.reset-synth: 0
synth.audio-groups: 1
synth.chorus.active: 0
synth.reverb.active: 0
synth.sample-rate: 48000
synth.gain: 0.8
synth.cpu-cores: 4
synth.ladspa.active: 1
synth.min-note-length: 0
synth.polyphony: 32

bank1.yaml

patches:
mysf:
1: my_sf.sf2:000:000
ladspafx:
compressor1:
lib: sc4_1882.so
audio: stereo
group: 1
vals:
Ratio: 20
Threshold: -30
Attack: 1.5
Release: 800
Makeup: 0

Related questions:
Can I set the plugin at the init section of the bank? I have tried it with no success...
Is there some kind of wet/dry setting that I am missing?
Since I am setting synth.audio-groups to 1 I guess the group setting of the plugin should also be set to 1 right?

[arretxe]

I have edited the init.py file to check for the port names and make sure they are correct, by adding these lines in the load_bank function within the for fx in zone.get...

            result = subprocess.run(['analyseplugin', str(fx['lib'])], capture_output=True, text=True)
            valid_ports = []
            for line in result.stdout.splitlines():
                if 'input, control' in line:
                    port_name = line.split('"')[1]  # Extract port name
                    valid_ports.append(port_name)
            user_vals = fx.pars.get('vals', {});
            for port in user_vals.keys():
                if not any(valid_port.startswith(port) for valid_port in valid_ports):
                    raise ValueError(f"Invalid port name: {port}. Must be one of {valid_ports}")

[arretxe]

I tried with jack instead of alsa and still the same behavior.

[albedozero]

Hey, sorry for the delayed response. You need to change the audio: stereo parameter to audio: Left in, Right in, Left out, Right out.

As explained in the Plugins section of the docs, audio: stereo is an alias for audio: Input L, Input R, Output L, Output R, since the majority of LADSPA plugins I surveyed named their outputs this way. Steve Harris didn't, though - if you look at the last four lines of output from analyseplugin you can see they're named differently. If you run fluidpatcher from a command line with the wrong input/output port names you should see some errors like

fluidsynth: error: Port 'Input L' not found on effect 'compressor10'
fluidsynth: error: Port 'Output L' not found on effect 'compressor10'
fluidsynth: error: Port 'Input R' not found on effect 'compressor10'
fluidsynth: error: Port 'Output R' not found on effect 'compressor10'
fluidsynth: error: LADSPA check failed, unable to activate effects

which can hopefully give you a clue when this is happening.

[albedozero]

Here's a version of your bank that should work, with some added router rules so you can tweak the compressor effect.

patches:
  withcomp:
    1: my_sf.sf2:000:000
    ladspafx:
      compressor1:
        lib: sc4_1882.so
        audio: Left in, Right in, Left out, Right out
        group: 1
        vals:
          Ratio: 20
          Threshold: -30
          Attack: 1.5
          Release: 800
          Makeup: 0
    router_rules:
    - {type: cc, par1: 30, par2: 0-127=1-20, ladspafx: compressor1, port: Ratio}
    - {type: cc, par1: 31, par2: 0-127=-30-0, ladspafx: compressor1, port: Threshold}
    - {type: cc, par1: 32, par2: 0-127=1.5-400, ladspafx: compressor1, port: Attack}
    - {type: cc, par1: 33, par2: 0-127=2-800, ladspafx: compressor1, port: Release}
  nocomp:
    1: my_sf.sf2:000:000

[arretxe]

Hey, sorry for the delayed response. You need to change the audio: stereo parameter to audio: Left in, Right in, Left out, Right out.

As explained in the Plugins section of the docs, audio: stereo is an alias for audio: Input L, Input R, Output L, Output R, since the majority of LADSPA plugins I surveyed named their outputs this way. Steve Harris didn't, though - if you look at the last four lines of output from analyseplugin you can see they're named differently. If you run fluidpatcher from a command line with the wrong input/output port names you should see some errors like

fluidsynth: error: Port 'Input L' not found on effect 'compressor10'
fluidsynth: error: Port 'Output L' not found on effect 'compressor10'
fluidsynth: error: Port 'Input R' not found on effect 'compressor10'
fluidsynth: error: Port 'Output R' not found on effect 'compressor10'
fluidsynth: error: LADSPA check failed, unable to activate effects

which can hopefully give you a clue when this is happening.

Thanks for the help! You are absolutely right about the stereo alias not matching the audio ports of the compressor, however, your suggested code does not seem to work either :(

fluidsynth: error: Port ' Left out' not found on effect 'compressor10'
fluidsynth: error: Port ' Right in' not found on effect 'compressor10'
fluidsynth: error: Port ' Right out' not found on effect 'compressor10'
fluidsynth: error: LADSPA check failed, unable to activate effects

What's weird is that with the stereo setting it did not return any error. I have also checked the actual names are "Left input" "Right input" "Right input" and "Right output" but I think it is not necessary to use the whole name as long as it matches a single port right? I have tried with the whole names just in case and got the same error. I also tried wrapping the names between " and ' but it gives a different error:

while parsing a block mapping
  in "<unicode string>", line 54, column 9:
            lib: sc4_1882.so
            ^
expected <block end>, but found ','

[arretxe]

I have just tried with this:
audio: {Left input, Right input, Left output, Right output}
And it does not give any error but it does not seem to change the sound at all...

I have also tried this:

    ladspafx:
      compressor11:
         lib: tap_dynamics_st.so
         audio: stereo
         group: 1
         vals:
           Attack: 4
           Release: 800
           Offset Gain: -20
           Makeup Gain: -20
           Function: 6

Whose ports are named Input Left and so on, so the stereo alias should match, and again, no error but no noticeablea effect.
I don't use any router rule but that should not matter right?
Also might be worth noting that I am using version 0.8.5 (i don't remember why but the newer one did not work with the client script i had...).
Do you know if there is some way to check the status of the ladspa plugin (ideally checking if it is compressing at all ^_^')? or check if the routing is correct?
jack_lsp returns this:

jack_lsp -c
system:playback_1
   fluidsynth:left
system:playback_2
   fluidsynth:right
fluidsynth:left
   system:playback_1
fluidsynth:right
   system:playback_2

EDIT: I just had to remove the spaces within the string, this seems to be accepted:
audio: Left input,Right input,Left output,Right output
However again, no error but I don't notice any difference... Maybe my signal is too week and does not get compressed?

[albedozero]

Right - base YAML syntax says lists should be in brackets, so audio: [Left in, Right in, Left out, Right out] should also work. I added some parsing so that the brackets shouldn't be required, but apparently it's not stripping spaces properly.

Compressor effects can indeed be subtle, especially if your input signal isn't that hot as you suggest. I can hear a slight difference when I switch between the withcomp and nocomp patches, though.

[albedozero]

Related questions:
Can I set the plugin at the init section of the bank? I have tried it with no success...

No, but you could create the plugin at the bank level. You'll hear it on all your patches, for any MIDI channels that are in the same audio group(s) as the plugin

Is there some kind of wet/dry setting that I am missing?

Nope, unless it's built into the plugin. Fluidpatcher sends all the sound through the plugins - it's 100% wet.

Since I am setting synth.audio-groups to 1 I guess the group setting of the plugin should also be set to 1 right?

Yes. Having one audio group means that all MIDI channels will pass through any plugins you have. If you want to be more selective, have multiple audio groups. The way MIDI channels get assigned to audio groups by FluidSynth is a bit odd - channels are assigned to groups in order, with wrapping. So, with 3 audio groups, the midi channels are:

• group 1: channels 1, 4, 7, 10, 13, 16
• group 2: channels 2, 5, 8, 11, 14
• group 3: channels 3, 6, 9, 12, 15

Easiest way is to have 16 audio groups - then the group(s) you assign a plugin to correspond exactly to the MIDI channels you'll hear them on.