This is for at least two reasons: transport will effectively
move with 32 samples * 6.25% = 2 samples per cycle and the
resampler cannot up/downsample a factor of > 16 with
reasonable quality.
* localize speed changes into varispeed dialog
* make speed-changes idempotent
* remember window position (do not overlap with button)
ideally the window would show up below the "Vari" button
This happens with e.g. the IEM suite when a user has both
/usr/lib/vst and /usr/lib/lxvst in the search path.
The same plugin was found twice due to symlinks:
```
/usr/lib/lxvst/iem.at -> ../x86_64-linux-gnu/iem-plugin-suite/vst
/usr/lib/vst/iem.at -> ../x86_64-linux-gnu/iem-plugin-suite/vst
```
And then blacklisted itself:
> "Ignoring plugin 'MultiBandCompressor'.
> VST-ID conflicts with other plugin 'MultiBandCompressor' files:
> '/usr/lib/x86_64-linux-gnu/iem-plugin-suite/vst/MultiBandCompressor.so' vs
> '/usr/lib/x86_64-linux-gnu/iem-plugin-suite/vst/MultiBandCompressor.so'
Since 80c11a763a the GUI is notified when the xrun counter
is reset (previously the rec-ui xrun counter never returned
to zero).
However when create-xrun-marker is enabled ARDOUR_UI::xrun_handler
tried to create a marker at -1 which causes various issues.
* use dummy-backend (don't expect engine to be running)
* add required TestUI / Receiver
Lots of regions: add scope to prevent SessionHandleRef
existing across session deletion
RunPC: take process-lock before processing, prevents various
assert() and concurrency issues.
Print a less cryptic error message in case the wrapper app
cannot be found. Also address a future race condition (once
we start parallel plugin scans and will exec-wrapper from a
helper thread).
If there are multiple connections, one might fail due to missing hardware,
but the rest could still be valid.
An easy way to reproduce this was to route "mackie control out" to a device
and to the Midi tracer port. When you opened the session again, connection
from the "mackie control out" to the device would not get restored because
the Midi tracer port does not exist at session start.
This most likely caused other issues with connections when changing backends.
Ardour MIDI tracks unconditionally remember any
MIDI CC/Patch changes that are received.
Patch changes are re-played after the session is loaded,
so that they can reach external synths after ports are
re-connected.
This can lead to issues with synth plugins. Their state
is set first. Receiving a patch-change may alter the synth's
state.
