In many cases optional sidechain inputs are not used.
Previously sidechain ports were created, but remained
unconnected and silence was passed to the plugin's key input.
Plugins can detected if a pin is connected. Some plugins
(e.g. VST3 Waves SSL Comp) activate the sidechain processing
automatically when depending in connection.
It is more common that a user does not want to use an external
sidechain, and if they want they should use the pin-dialog
to connect it. So leaving it off by default is sensible.
see also #9223
* in the past, the default behavior was: hiding a group would disable it,
and then showing the group would re-enable it
* problem occurs when user has disabled a group; hiding and showing it
unexpectedly re-enable the group
* there was a config variable to disable this behavior, but it was never
shown on the GUI and therefore not discoverable
Despite the longstanding policy, there's really no reason for
group visibility and enablement to be intertwined.
If this chnage causes a big problem for someone, they can revert to
the prior behavior by setting the new config variable in the text file
So far group-override "inverts" group behavior. Disabled groups
(or group settings) are enabled and vice-versa.
When the setting is disabled, groups can only ever be disabled
(Controllable::NoGroup) and group-override will not enable them
(Controllable::InverseGroup).
This also allows to disable the resampler, effectively disabling
varispeed support, for the benefit of adding no additional latency.
By default 2 * 16 samples latency are added, due to port-resampler,
this is not desirable if Ardour is used as mixer only.
Since Ardour 6, a transport speed of 200% will also double
DSP load. Under the hood Ardour rolls twice the distance and
the output is downsampled.
Vari-speed > +/-200% will likely cause dropouts with many
sessions on most systems, users should explicitly select it.
This works around JACK not allowing to directly access physical
input buffers by creating an explicit connection.
Ardour access input-buffers directly without connection
for input meters and AFL. This work in general since data
on those ports are always read unconditionally at the start of
each process cycle.
jack_port_get_buffer (jack_port_by_name (c, "system:capture_1"), n);
However with jack this fails if the given port is not connected.
Due to an internal jack optimization collecting input data is
skipped for ports that have no connections.
Ben Loftis
Robin Gareus
Paul Davis