Additional outputs for synths - downward compatibility

[Markus Krause]

The situation:

I created a synth. v1.x has stereo output. VST 2.4.
v2.x comes with an additional drum sequencer. In some cases it would make sense to have more than the stereo output. Plugin ID of both versions are the same to maintain downward compatibility.

What i think could happen:

Some/many/all hosts could freak out when an old project is loaded and the number of outputs setNumOutputs(2) for the synth has changed to setNumOutputs(4);.

Does it break compatibility with old projects?
Have you made experiences with this?
Do you have ideas how it could be solved in an elegant way?

Thanks in advance,
Markus

[mystran]

Does it break compatibility with old projects?
Have you made experiences with this?
Do you have ideas how it could be solved in an elegant way?

I've done this plenty of times with unreleased prototypes (often to add/remove debug outputs for internal signals while developing) and I don't think it ever broke any project in FL, but honestly no idea what it would do in any other host.

This is probably not a terribly useful answer to your question, except as far as "it might work in some hosts just fine."

If you have a bunch of hosts installed for testing, I'd probably just throw together some quick AGain type plugin, setup some projects and then add another output, see what happens?

[Richard_Synapse]

Some/many/all hosts could freak out when an old project is loaded and the number of outputs setNumOutputs(2) for the synth has changed to setNumOutputs(4);.
Markus

It is certainly possible that some hosts may crash or produce unexpected results because extra data per channel is saved that is not present after the change. I would expect most hosts to handle the change gracefully, however.

Richard