Make plugin truly mono

[mikeoliphant]

Currently the plugin is not really mono - it is "1 > 2". This change makes it truly mono, which makes more sense, as no stereo processing is currently going on.

To verify, when loading in Reaper you can see "(mono)" after it.

Most hosts are pretty good about handling things, but making the plugin explicitly mono may help inform the host. It also should avoid the cheap, but unnecessary copy of output to the second channel.

Btw, I think we should support stereo workflows (perhaps providing both mono and stereo versions of the plugin), but that will require more work (mostly just UI).

[olilarkin]

I'm not sure this is a good idea, and I think it should be tested on a few DAWs in all plug-in formats they support. It will also totally break the standalone at the moment without modifications to that

[mikeoliphant]

Forgot about the standalone. Is there an #ifdef we can check for the standalone build?

Any DAW that doesn't support mono plugins is pretty broken.

[sdatkinson]

Yeah. Kind of like @olilarkin said, I used to have it true mono, but the standalone wasn't pleasant to use, outputting on only 1 channel.

I'd like to get stereo worked in (first L/R/sum into a mono amp, then dual mono later; then stereo IR support).

I can do some grooming on the Issues to sort it out this weekend, but I'm unfortunately a bit busy the rest of this week yet.

[mikeoliphant]

Yeah. Kind of like @olilarkin said, I used to have it true mono, but the standalone wasn't pleasant to use, outputting on only 1 channel.

Ideally that would be fixed in the standalone audio config code, along with other I/O bugs that seem to be causing a lot of people trouble (#209 #196 #157 #117).

[sdatkinson]

@mikeoliphant

Is there an #ifdef we can check for the standalone build?

I'm not confident it's the recommended way to do it, but it seems that #ifdef APP_API has the desired effect.

[mikeoliphant]

@sdatkinson If you are going to look at mono/dual-mono/stereo in a more comprehensive way soon, then this change probably isn't important independent of that - so I'll close this PR.

It is probably worth having a discussion about the best way to handle things, though, to make sure that the more complex workflows are made possible without confusing users with the more standard use cases.

[sdatkinson]

I did some scribbling on it this morning. Basically what to do when (1) Stereo/mono input, (2) single/dual amp, (3) stereo/mono output.

And how to ship pieces in a way that builds up without surprises.