Events, parameter changes, and the individual queues contained within
the parameter changes all use dynamic memory allocation. Preallocating
some memory for those things inside of the objects may prevent latency
spikes when they those objects are first filled. This is especially
useful for the parameter changes since there's no way to reserve memory
in a vector of vectors.
This prevents reinitializing `std::variant`s when the variant we want to
deserialize is already active. We store audio buffers in variants, so
reinitializing them results in a lot of unnecessary memory frees,
allocations and writes during every processing cycle.
With `vfork()` the child process inherits the parents process image and
prevents copying them, but if it outlives its parent then the file
descriptors will still remain open. Manually closing all file
descriptors is the only solution here.
This was only an issue with Ardour since they don't open all of their
files with `FD_CLOEXEC`. Last update's watchdog timer somewhat mitigated
the issue, but Ardour should now no longer freeze when reopening because
of this. The watchdog timer is still necessary, since hanging Wine
processes will still prevent the Wine server from shutting down.
This makes much more sense, since all plugin instances will be sharing a
single GUI thread. What would happen was that resize calls from one
instance and GUI thread function calls from another instance would
collide. Using a single shared mutual recursion mechanism (just like on
the Wine side) fixes this.
This was causing a timing issue with DMG plugins where the plugins would
try to resize after receiving new state (and not during the call), while
REAPER at the same time would try to set channel context information on
the plugin (which also has to be handled on the GUI thread).
We do this by using this new `MessageReference<T>` type to avoid copying
our `YaAudioProcessor::Process` struct and the contained `YaProcessData`
object. This is only part of the work, but this redesign lets us keep
the these objects alive on both the plugin and the host side. On the
plugin side, we'll simply serialize the data from the referred to object
without copying it. On the Wine side, we'll write the data to a
persistent thread local object, and then reassign the
`MessageReference<T>` to point to that object. This lets us serialize
'references', thus avoiding potentially expensive allocations. With
these last few changes alone VST3 plugins are already at the same
performance level as our optimized VST2 plugin groups.
Bitwig prepends some data when passing an `IBStream*` to the plugin, and
when we do copy it iZotope Rx7 plugins cannot load their state (even if
we also copy over the same seek position). Not copying that preamble
fixes the issue, and it seems like it doesn't break anything.
VST3 plugins could freeze in REAPER when the plugin sends
`IComponentHandler::performEdit()` followed by
`IPlugFrame::resizeView()` when REAPER simultaneously tries to call
`*::getState()`. Here `*::getState()` gets called from the GUI thread,
while `IPlugFrame::resizeView()` has to be handled on REAPER's GUI
thread, resulting in a deadlock unless we use the plugin-side mutual
recursion mechanism.
I've seen this cause issues with PSPaudioware InfiniStrip.
The VST3 version of Voxengo TEOTE would deadlock in Ardour when Ardour
calls `IEditController::setState()`, the plugin calls
`IUnitHandler::notifyProgramListChange()` in response, and then when
Ardour calls `IUnitInfo::getProgramName()` while handling that callback.
All of these functions have to be called from the same thread in Voxengo
plugins.
We would never try to shut the group host down if nothing ever tried to
connect to it. This could happen when the native host gets killed after
initializing the yabridge plugin but before it gets the chance to
request the group host process to host a plugin.
This means we only have to compile everything two times, instead of four
times. We sadly still need to compile lots of files at least three
times. (once for native, once for 64-bit Wine, and once for 32-bit Wine)
Those DAWs would immediately call `IEditController::performEdit()` with
the same parameter change the plugin has just announced, which would
result in a deadlock. Hopefully this helps with #100.
With this we should be able to handle `setState()`s that try to resize
the currently open editor. This could pop up when using the preset
browser in REAPER with plugins that recall their old size when loading a
preset.
This greatly improves compatibility with VST3 plugins in Ardour and
Mixbus. Most notably the FabFilter plugins would previously freeze when
having the GUI open while duplicating or inserting new instances.
Since that makes it much clearer what we're actually doing. With old
`cache_time_info` was actually caching the response, but now we're
querying it before the plugin has even requested the information.
This works around a bug in the VST3 version of W. A. Production
Imperfect as mentioned in #97. Even if it's a synth and numInputs is 0,
the plugin will still try to read the input arrangement.
After a quick round of testing it seems like REAPER doesn't always
enable this on the audio thread, but Bitwig, Ardour, Carla and Renoise
do. So it should be safe to just get rid of the option and to leave this
enabled all the time.
This prevents Kush Audio REDDI from taking down the DAW when the host
passes it denormalized audio to process. I've discovered that the issue
with this plugin had to do with denormals in the issue linked below, but
I didn't realize that we can just enable the FTZ flag for plugins that
don't already do so.
https://github.com/osxmidi/LinVst/issues/174
This can be useful when plugins have (broken) host-specific behaviour
that you want to avoid. I'll later add a list of host/plugin
combinations where this may be useful to the readme.
Robbert van der Helm