ComfyUI-VST

ComfyUI-VST

ComfyUI custom nodes for audio processing using VST3 and Audio Unit plugins via Spotify's Pedalboard library.

Features

• Load VST3 plugins with auto-detection from system paths
• Auto-detect plugin parameters (booleans, choices, numeric sliders)
• Apply effects to audio with adjustable parameters
• Manual or dynamic parameter configuration
• Compatible with ComfyUI V3 API

Note: Currently only Effect VST plugins are supported. Instrument/Synthesizer plugins are not yet supported.

Installation

1. Clone this repository into your ComfyUI custom nodes folder:

cd ComfyUI/custom_nodes
git clone https://github.com/MuziekMagie/ComfyUI-VST.git

2. Install dependencies:

cd ComfyUI-VST
pip install -r requirements.txt

Requirements

• Python 3.10+
• ComfyUI with V3 API support
• pedalboard>=0.9.0

Nodes

1. Load VST Plugin (VSTLoader)

Loads a VST3 plugin from disk. Auto-scans system VST directories and provides a dropdown of detected plugins.

Inputs:

• vst_selection (COMBO): Dropdown of detected VST plugins (scans standard directories)
• manual_vst_path (STRING, optional): Manual path override for plugins not in scanned directories
• plugin_name (STRING, optional): For multi-plugin bundles
• timeout (FLOAT): Initialization timeout in seconds [1.0-60.0], default 10.0

Outputs:

• plugin (VST_PLUGIN): The loaded plugin object
• parameter_schema (VST_PARAMETER_SCHEMA): Parameter schema/definitions
• is_effect (BOOLEAN): True if plugin is an audio effect
• is_instrument (BOOLEAN): True if plugin is a synthesizer/instrument

Scanned directories:

• Windows: Program Files\Common Files\VST3, Program Files\VSTPlugins, Steinberg\VSTPlugins
• macOS: /Library/Audio/Plug-Ins/VST3, ~/Library/Audio/Plug-Ins/VST3, /Library/Audio/Plug-Ins/VST
• Linux: ~/.vst3, /usr/lib/vst3, /usr/local/lib/vst3

2. Inspect VST Plugin (VSTInspector)

Inspects a loaded plugin to display its parameters and metadata.

Inputs:

• plugin (VST_PLUGIN): Loaded plugin from VSTLoader

Outputs:

• summary (STRING): Human-readable parameter list
• parameter_schema (VST_PARAMETER_SCHEMA): Parameter schema (custom type)
• parameter_schema_dict (DICT): Parameter schema as Python dictionary
• parameter_schema_json (JSON): Parameter schema as JSON string
• parameter_names (STRING): Comma-separated list of parameter names

3. VST Manual Parameters (VSTManualParameters)

Creates a parameter dictionary using autogrowing name-value pairs.

Inputs:

• param_names (AUTOGROW): List of parameter names
  • Each slot: name_0, name_1, etc. (STRING)
• param_values (AUTOGROW): List of parameter values
  • Each slot: value_0, value_1, etc. (accepts any type)

Outputs:

• vst_settings (VST_SETTINGS): Parameter values for Apply VST Effect

Usage:

1. Add parameter name slots and set names (e.g., "mix", "room_size")
2. Connect Float nodes, Int nodes, or other widgets to value slots
3. Names and values are paired by position (name_0 with value_0, etc.)

Note: Any parameters not explicitly defined in this node will use the plugin's default values when processed by Apply VST Effect.

4. VST Parameters (VSTParameters) ⚠️ EXPERIMENTAL

Dynamic parameter configuration with auto-generated widgets.

Warning: This node is experimental and currently does not work inside Subgraphs. Use VST Manual Parameters instead if you need to encapsulate your workflow in a Subgraph.

How it works: This node generates parameter widgets dynamically based on the connected plugin. The workflow must be run twice to fully configure parameters:

1. First run: Connect your plugin and execute the workflow. The audio is processed using the plugin's default parameter values. Meanwhile, the node detects the available parameters and generates the corresponding widgets.
2. Second run: The parameter widgets are now visible and adjustable. Modify the values and run the workflow again to process the audio with your custom settings.

Note: This is required because the node needs to "see" the plugin output once to know what parameters to create.

Inputs:

• parameter_schema (VST_PARAMETER_SCHEMA): Parameter schema from VSTLoader/VSTInspector
• dynamic_values_json (STRING, multiline): JSON string of parameter values from frontend widgets

Outputs:

• vst_settings (VST_SETTINGS): Parameter values dictionary

Note: This node requires the frontend JavaScript extension to generate parameter widgets dynamically based on the connected plugin.

5. Apply VST Effect (VSTApplyEffect)

Applies a VST plugin effect to audio.

Note: This node only works with Effect plugins. Instrument/Synthesizer plugins (VSTi) are not supported - they require MIDI input which is not yet implemented.

Inputs:

• audio (AUDIO): Input audio from ComfyUI
• plugin (VST_PLUGIN): Loaded plugin
• vst_settings (VST_SETTINGS, optional): Parameter settings from VST Manual Parameters or VST Parameters
• buffer_size (INT): Processing buffer size [512-65536], default 8192
• reset (BOOLEAN): Reset plugin state before processing, default True

Outputs:

• AUDIO: Processed audio

Usage Example

Basic VST Effect Chain

Workflow Steps

1. Load a plugin:

   • Use Load VST Plugin and select from the dropdown
   • Or enter a manual path for plugins not auto-detected

2. Inspect parameters:

   • Connect to Inspect VST Plugin to see available parameters
   • Check SUMMARY output for parameter names, types, and ranges

3. Configure parameters:

   • Option A: Use VST Manual Parameters with autogrowing name-value pairs (recommended for Subgraphs)
   • Option B: Use VST Parameters with dynamic widgets (requires JS extension, not for Subgraphs)

4. Apply effect:

   • Connect audio to Apply VST Effect
   • Connect plugin from Load VST Plugin
   • Connect parameters from parameter node

Parameter Types

The nodes automatically detect three types of VST parameters:

1. Boolean (Toggle)

Parameters with two valid values: true/false

2. Choice (Dropdown)

Parameters with a list of valid text values (up to 16 options or text-based values)

3. Numeric (Slider)

Continuous parameters with min/max ranges. Values are automatically normalized.

Platform Support

• Linux: VST3 (.vst3 files and bundles)
• macOS: VST3 (.vst3) and Audio Units (.component)
• Windows: VST3 (.vst3 files and bundles), VST2 (.dll)

Troubleshooting

Plugin not in dropdown

• Check that the plugin is in a scanned directory
• Use manual_vst_path to load plugins from custom locations
• Ensure the plugin file exists and is readable

Plugin fails to load

• Ensure the plugin format matches your OS (VST3 for Linux/Windows, VST3/AU for macOS)
• Increase the timeout value if the plugin takes long to initialize
• Check that the plugin binary exists inside bundle directories (.vst3 folders)

Audio processing fails

• Verify that the plugin is an effect plugin (check IS_EFFECT output)
• Try increasing buffer_size if you encounter glitches
• Set reset=True if audio sounds wrong (clears plugin internal state)

Parameters not working

• Use Inspect VST Plugin to verify parameter names are correct
• Check that parameter names match exactly (case-sensitive)
• Some plugins may reject invalid parameter values

VST Parameters node not working in Subgraphs

• This is a known limitation
• Use VST Manual Parameters instead for Subgraph workflows

License

This project is licensed under the GNU General Public License v3.0 (GPL v3.0).

Credits

Built using Spotify's Pedalboard library.

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VST is a registered trademark of Steinberg Media Technologies GmbH.