The crashed previously because:
A VCA is-a Automatable is-a Evoral::ControlSet
After VCA's d'tor completes ~Automatable runs and emits signal to
DropReferences of all master-controls.
This in turn calls SlavableAutomationControl::master_going_away()
for slaved parameters for the given master-control
In ::master_going_away() the weak-pointer reference to the master's
AutomationControl (owned by the destroyed VCA) is still valid.
Execution is in the d'tor of Automatable which is-a ControlSet and
the ContolSet keeps a reference to the Control and hence also to the
AutomationControl which is-a Evoral::Control.
So master_going_away() locks a boost::shared_ptr<ARDOUR::AutomationControl>
which is actually the MuteControl owned by the VCA.
It calls SlavableAutomationControl::remove_master() which
in turn calls MuteControl::pre_remove_master() which uses the
MuteMaster API to retrieve the value. The MuteMaster however is the
VCA that has just been destroyed.
The solution is twofold:
1) emit "drop_references" from the VCA d'tor itself,
before the VCA is destroyed.
2) disconnect a slaved control from the master's drop_references signal
when un-assigning a master-control.
Keep Pannable::value_as_string() for now. That is another inconsistency
which needs cleaning up. GUI StereoPanner and MonoPanner print
the value as they see fit, the panner-plugin provided formatting
is not used.
Probably due to historical reasons, there are two APIs to format a
control's value. In all both variants end up calling either
ARDOUR::value_as_string() or the Controllable's formatting function
(except for panners).
TempoMap::get_grid() supplies a list of beat positions, leaving the lines
to work out any subdivision positions.
This is fine, unless a tempo section falls in between beats.
Use a BeatsFramesConverter along with a quarter note position
(in the BBTPointsList) to make this easier.
Since 478f26b2ad, transport_rolling() is only true when actually rolling.
Count-in is a no-roll process (don't move playhead, no playhead UI
position interpolation 55b8b448).
But transport isn't exactly stopped either (preparing to roll), so
during count-in transport_stopped() == transport_rolling() == false.
Previously there were large spurious spikes in the signal when
the bandwidth parameter was adjusted on a pure sine tone
for the peaking circuits. This has been *greatly* reduced if not
eliminated by fixing a typo in two of the equations.
If the parameters change too slowly the filter may never get updated. Indeed,
in spite of v_f0, v_g or v_bw being updated, set_params may never be called,
thus v_filter never updated.
Useful as temporary buffer: This allows a controllable to
get a master's automation-curve and combine it with its own
(gain, trim, send) automation buffer.
The property names with underscores are "normalized" to replace the underscores
with hyphens in the XMLProperty constructor from within Meterbridge::get_state
and so have always been written with hyphens.
