Easy method for adding automatable master bypass to LV2 plugins?

I’m grateful for the vast array of LV2 plugin options out there, but frustrated that so many of them don’t have an automatable master enable/bypass. This usually makes them useless to me. (I’ve been getting by via L/R crossfading between two plugin chains but that’s a CPU hog and I don’t have the luxury on a raspberry pi for that.)

Is there a quick way to add such a bypass to plugins or is such a thing going to be different from plugin to plugin? (I can code, but have literally zero LV2 or plugin programming experience.)

I see that the .ttl file has to have a block (note I think BYPASS should be opposite, something like ENABLED, but this is what gxAxisFace has):

a lv2:InputPort ,
lv2:ControlPort ;
lv2:index 2 ;
lv2:symbol “BYPASS” ;
lv2:name “BYPASS” ;
lv2:default 1.0 ;
lv2:minimum 0.0 ;
lv2:maximum 1.0 ;
lv2:designation lv2:enabled;
lv2:portProperty lv2:toggled;

Which I assume points to port handling in the cpp file

// connect the Ports used by the plug-in class
void Gx_AxisFace_::connect_(uint32_t port,void* data)
switch ((PortIndex)port)
output = static_cast<float*>(data);
input = static_cast<float*>(data);
case BYPASS:
bypass = static_cast<float*>(data); // , 0.0, 0.0, 1.0, 1.0

but then that bypass variable gets involved with some ramp up/down logic in the code… and now my eyes have glazed over.

I’d kill for a core-ardour ability to automate enable/bypass on any plugin. That way it would be done well and all the plugins wouldn’t need it anymore.

Anyway, what are my options here?

Ardour does not know how to click-free bypass a given plugin. Only the plugin (DSP) itself does know.

e.g. for an EQ the correct way is that the plugin internally ramps all EQ-band gain to zero. A distortion plugin would internally ramp gain to 1.0, a reverb cross-fade (wet -> dry) etc.

So to answer your question: It is different for every plugin.

“Bypass enabled” is confusing. Also LEDs showing “bypass” can be tricky to interpret. Most guitar FX pedals for example show a light when active…

LV2 uses “enabled” and not “bypassed” because it can potentially allow for click-free insertion/removal of latent plugins: insert-plugin (true-bypass), add latency (soft-bypass, ready), activate (process). That also follows C/C++ false = 0; true =1; – http://lv2plug.in/ns/lv2core/lv2core.html#enabled

Ugh. Well that can come later anyway. (read: I won’t be doing it). But thanks for the answer.