VST plugin Program presets not accessible

[petrikaj]

I have tried to access and change iZotope's VST plugins' Program presets but it seems they are not exposed.

Parameters work ok.

Here's what MrsWatson prints out from plugin —display-info

Notice it's not part of the parameters.

Using plugin.show_editor() allows to access those presets and changing them will change the parameters accordingly after quitting the showeditor(/).

MrsWatson allows to change it while loading the plugin:
"mrswatson64 --plugin 'plugin_name,preset_name’ -i input.wav -o output.wav"

[Glenn 'devalias' Grant]

Looking at the MrsWatson source code, this seems to be where the 'Programs' is being printed:

• https://github.com/teragonaudio/MrsWatson/blob/32ec2b4404190d7f2710cdd9beaf4b153e6ff37d/source/plugin/PluginVst2x.cpp#L686-L699

It reads from:

• data->pluginHandle->numPrograms
• data->pluginHandle effGetProgramNameIndexed nameBuffer->data
• data->pluginHandle effGetProgramName nameBuffer->data

Googling for effGetProgramNameIndexed, it seems to be part of the VST2 SDK or similar.

Eg. Here's a go package that implements bindings for it:

• https://github.com/pipelined/vst2

  • Build vst2 plugins and hosts with Go

  • vst2 implements VST2 SDK API. It provides capabilities to build both VST2 hosts and plugins.

  • https://pkg.go.dev/github.com/pipelined/vst2

    • // EffGetProgramNameIndexed passed to get program name by index.
      // Index: program index.
      // Ptr: *[maxProgNameLen]uint8 buffer for program name.
      // Return: true for success.
      EffGetProgramNameIndexed

Pedalboard doesn't seem to support VST2, but not sure if there is an equivalent function in VST3. We can start by looking at the VST3 SDK:

• https://github.com/steinbergmedia/vst3sdk

  • VST 3 Plug-In SDK

Searching for effGetProgramNameIndexed doesn't seem to turn up any results there (neither does GetProgramName / ProgramName)

Clicking through from that repo lead me to:

• https://github.com/steinbergmedia/vst3_pluginterfaces

  • VST 3 API

And searching that repo for GetProgramName lead me to this definition:

• https://github.com/steinbergmedia/vst3_pluginterfaces/blob/f0eeef7ca771f3cac2dfe1922dc5733349766c7b/vst/ivstunits.h#L154-L166

IUnitInfo describes the internal structure of the plug-in.
- The root unit is the component itself, so getUnitCount must return 1 at least.
- The root unit id has to be 0 (kRootUnitId).
- Each unit can reference one program list - this reference must not change.
- Each unit, using a program list, references one program of the list.

    /** Component intern program structure. */
	/** Gets the count of Program List. */
	virtual int32 PLUGIN_API getProgramListCount () = 0;

	/** Gets for a given index the Program List Info. */
	virtual tresult PLUGIN_API getProgramListInfo (int32 listIndex, ProgramListInfo& info /*out*/) = 0;

	/** Gets for a given program list ID and program index its program name. */
	virtual tresult PLUGIN_API getProgramName (ProgramListID listId, int32 programIndex, String128 name /*out*/) = 0;

	/** Gets for a given program list ID, program index and attributeId the associated attribute value. */
	virtual tresult PLUGIN_API getProgramInfo (ProgramListID listId, int32 programIndex,
		CString attributeId /*in*/, String128 attributeValue /*out*/) = 0;

/** Basic Program List Description.
\see IUnitInfo
*/
struct ProgramListInfo
{
	ProgramListID id;				///< program list identifier
	String128 name;					///< name of program list
	int32 programCount;				///< number of programs in this list
};

Then we can find the definition for ProgramListID in the following:

• https://github.com/steinbergmedia/vst3_pluginterfaces/blob/f0eeef7ca771f3cac2dfe1922dc5733349766c7b/vst/vsttypes.h#L83

typedef int32 ProgramListID;	///< program list identifier

So it definitely seems like the concept of 'programs' still exists in the VST3 SDK.

---

Looking at an example CLI app for using the vst-rs Rust bindings for VST2, they don't seem to print the 'programs' details either; but they do have a section called 'presets':

• https://github.com/RustAudio/vst-rs/blob/master/examples/simple_host.rs#L41-L53

    // Get the plugin information
    let info = instance.get_info();

    println!(
        "Loaded '{}':\n\t\
         Vendor: {}\n\t\
         Presets: {}\n\t\
         Parameters: {}\n\t\
         VST ID: {}\n\t\
         Version: {}\n\t\
         Initial Delay: {} samples",
        info.name, info.vendor, info.presets, info.parameters, info.unique_id, info.version, info.initial_delay
    );

Tracing through the code a bit, I found the definition for Info, which again doesn't mention 'program', but does mention 'presets':

• https://github.com/RustAudio/vst-rs/blob/master/src/plugin.rs#L297-L356

Tracing through the code a bit more I found this implementation of PluginInstance, which seems to equate presets with programs:

• https://github.com/RustAudio/vst-rs/blob/master/src/host.rs#L472-L517

plug.info = Info {
  // ..snip..
  presets: effect.numPrograms,
  // ..snip..
  preset_chunks: flags.intersects(PluginFlags::PROGRAM_CHUNKS),
}

---

Looking at the vst3-sys Rust bindings for VST3:

• https://github.com/RustAudio/vst3-sys/blob/f3e8f01c3de6d5df2f503c920c9f2bf8166a771b/src/vst/vsttypes.rs#L11

  •  pub type ProgramListID = i32;

• https://github.com/RustAudio/vst3-sys/blob/f3e8f01c3de6d5df2f503c920c9f2bf8166a771b/src/vst/ivstunits.rs#L23-L27

  • #[repr(C)]
    #[derive(Copy, Clone)]
    pub struct ProgramListInfo {
        pub id: i32,
        pub name: [u16; 128],
        pub program_count: i32,
    }

• https://github.com/RustAudio/vst3-sys/blob/f3e8f01c3de6d5df2f503c920c9f2bf8166a771b/src/vst/ivstunits.rs#L43-L63

  • #[com_interface("3D4BD6B5-913A-4FD2-A886-E768A5EB92C1")]
    pub trait IUnitInfo: IUnknown {
      // ..snip..
      unsafe fn get_program_list_count(&self) -> i32;
      unsafe fn get_program_list_info(&self, list_index: i32, info: *mut ProgramListInfo) -> tresult;
      unsafe fn get_program_name(&self, list_id: i32, program_index: i32, name: *mut u16) -> tresult;
      unsafe fn get_program_info(
          &self,
          list_id: i32,
          program_index: i32,
          attribute_id: *const u8,
          attribute_value: *mut u16,
      ) -> tresult;
      unsafe fn has_program_pitch_names(&self, id: i32, index: i32) -> tresult;
      unsafe fn get_program_pitch_name(
          &self,
          id: i32,
          index: i32,
          pitch: i16,
          name: *mut u16,
      ) -> tresult;
      // ..snip..

• https://github.com/RustAudio/vst3-sys/blob/f3e8f01c3de6d5df2f503c920c9f2bf8166a771b/src/vst/ivstunits.rs#L82-L97

  • #[com_interface("8683B01F-7B35-4F70-A265-1DEC353AF4FF")]
    pub trait IProgramListData: IUnknown {
        unsafe fn program_data_supported(&self, list_id: i32) -> tresult;
        unsafe fn get_program_data(
            &self,
            list_id: i32,
            program_idx: i32,
            stream: SharedVstPtr<dyn IBStream>,
        ) -> tresult;
        unsafe fn set_program_data(
            &self,
            id: i32,
            idx: i32,
            stream: SharedVstPtr<dyn IBStream>,
        ) -> tresult;
    }

[petrikaj]

Here's less technical explanation on the github docs:

https://steinbergmedia.github.io/vst3_dev_portal/pages/Technical+Documentation/Presets+Program+Lists/Index.html