VST 2.x: Additional Effect Categories

[Xaymar]

Heyo, it's that weird guy that made a vst2sdk that happened to end up in here. Not sure if this is the right place, but none of the other ones seemed to fit and I didn't want to make an Issue for it. Recently I've had a bit of free time and used it to automate scanning thousands of VST 1.x and 2.x plugins and I think I figured out the categories.

I didn't fully go through the whole DPF source code, so I don't know if DPF even supports proper categories. If it does, these can probably help a bit.

[falkTX]

Very nice to hear from you! And thanks for the opensource liberal licensed work, it was always weird to use the LMMS based header on DPF until I switched to yours, so thanks again!

For categories, they are very limited in VST2 and not used a lot. It is hard to create mapping with other things...

After you are done with updates on your side please ping me and I will update the version in DPF, alongside any new correct enum values that became usable.

[Xaymar]

I've tagged the latest work as v0.3.0 and made a migration guide from v0.2.0 to v0.3.0. Note that categories in VST 2.x seem to be not optional as they change how the plug-in is treated by some hosts - especially DAWs. Here's a table of the information I was able to gather so far:

	Delay	Tail	MIDI	Notes
VST_EFFECT_CATEGORY_EFFECT	❔	✔	✔	Some hosts ignore delay
VST_EFFECT_CATEGORY_INSTRUMENT	❔	✔	✔	Some hosts ignore delay
VST_EFFECT_CATEGORY_METERING	❌	✔	❔	Latency causes crash, MIDI Events not always supported
VST_EFFECT_CATEGORY_MASTERING	✔	❔	✔	Some hosts ignore tail samples
VST_EFFECT_CATEGORY_SPATIAL	❌	❔	✔	Some hosts ignore tail samples
VST_EFFECT_CATEGORY_DELAY_OR_ECHO	✔	✔	✔
VST_EFFECT_CATEGORY_07	❔	❔	❔	Ends up unlisted in many hosts
VST_EFFECT_CATEGORY_RESTORATION	✔	✔	✔	Has additional processing time in many DAWs
VST_EFFECT_CATEGORY_OFFLINE	❌	❌	❌
VST_EFFECT_CATEGORY_CONTAINER	❌	❌	❌
VST_EFFECT_CATEGORY_WAVEGENERATOR	✔	✔	❌

So it likely is necessary to bother the user to provide the proper category. Also of note is the VST 2.3?+ exclusive effect flag VST_EFFECT_FLAG_INSTRUMENT which must be set otherwise the plug-in is always treated like a generic effect instead. The category should be purely visual but some hosts decided to be weird about it.

[Xaymar]

There's also VST_EFFECT_FLAG_SILENT_TAIL which complements VST_EFFECT_OPCODE_TAIL_SAMPLES in notifying the host that if the input is silent our plug-in has no tail and can be safely suspended. No host I tested appears to actually support it, but it is there if a host wants to implement it.

[Xaymar]

I think v0.3.2 is as good as it gets for now. There's still a bunch of known features left to do, but they require more specific data than I have right now. The best I have is guesses about the functionality.