vst.media_addon
version 0.4.0
VST is a trademark von Steinberg Soft- und Hardware GmbH
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Usage
As the name implies, the VST add-on is not an application itself (well, it does include
the preferences application, but that's another story). To make real use of VST
plugins you'll still need a Media Kit savvy application that is able to instantiate and
stream data through media add-ons. At the time of this writing, the only application
to support this was Cortex. But you
can expect more applications featuring this kind of functionality in the near future,
and even with Cortex alone you can already accomplish a whole slew of different
things. The following is a basic description of how to use VST plugins within Cortex.
Dormant Nodes
After launching Cortex, you should see the VST plugins you've installed listed in
Cortex' Media-AddOns window. Effect plugins (which are the only ones
supported currently) will show up with a yellow "stomp-box" icon.
This list tells you what nodes are available on your system, they are referred
to as dormant (inactive) nodes.
- You can get a short description of a dormant node by resting the mouse
over it to bring up a tool-tip. For more detailled information, right-click on
the item and select Get Info.
Instantiating a Node
To instantiate (activate) such a node, just drag its entry out of the Media Add-Ons
windows and drop it onto a free spot in Cortex' main window.
In the main window, a corresponding node panel should show up, displaying the
name and icon of the node.
- This will not make the dormant node disappear from the Media Add-Ons
window. Effectively, you can have many different instances of a particular
dormant node in the main window by repeating the operation above.
As with dormant nodes, you can right-click on the panel and select Get Info from
the context menu to see some information about the node. This is not the same info as for
the dormant node, rather it will include things like latency and run mode.
- The latency displayed in Cortex' info windows is always the total
latency, ie the time in ms it will take from the input of the node to your speakers,
effectively including the latency of all nodes down the stream. In addition, the VST
add-on will calculate latency dynamically based on buffer size and complexity of
the plugins algorithm.
Getting Connected
The node panel of an instantiated plugin will display the nodes input and outputs, where
inputs are on the left side and outputs on the right side of the panel (or if you're using
Cortex in "Mini Icon View", inputs are at the top and outputs at the bottom),
showing an abbreviation of their names as label. To view the full name of an input or
output, rest the mouse over it and a tool-tip will appear displaying its name and the
type of media it supports (raw audio in this case).
- Again you can select Get Info from the inputs/outputs context
menu for detailled information, including the preferred data format of that "jack".
VST plugins can currently have one the following input/output configurations:
- Single mono input, single mono output
- Single mono input, single stereo output
- Single stereo input, single stereo output
- Single stereo input, single mono output
- Both stereo and mono inputs, single stereo
output, where the two inputs are alternatives and can not be connected at
the same time. These are provided for plugins that do stereo processing
by default but can also accept the same signal on both channels.
- Both stereo and mono inputs, single mono output.
- The VST specification does actually allow for more inputs and outputs,
but generally very few host applications can make use of such plugins.
Nevertheless, support for any number of inputs and outputs will be added to
the VST add-on very soon.
To actually connect two nodes, they will have to negotiate a common media format.
Steinberg has chosen 32 bit floating point format for the VST specification, so this
is the format preferred by VST plugins. However, the VST add-on has been designed
to handle the conversion from and to many common audio formats, most prominently
16 bit Integer as used by most consumer-level soundcards and the vast majority of
sound file formats. What this means is that you're able to directly connect VST plugins
to most audio nodes, and if conversion is necessary it will be done automatically.
In Cortex, connecting two nodes works by dragging a virtual wire from one jack to the
other. If format negotiation succeeds the wire will remain in place, otherwise you'll
get an error message.
- Currently, you should always connect the input of a VST plugin
first, because this usually determines the buffer-size that will be used for format
negotiation on the output.
Note that you'll always have to connect a stereo output to the stereo input of a VST
plugin, and a mono output to the mono input of a VST plugin. Sometimes this will not be
possible.
- To find out whether an input of a VST plugin is stereo or mono, just wait
for the tool-tip to display, as the name of the input includes this information (it
will be something like "[plugin-name] Stereo/Mono Input"). Other nodes will not
necessarily do this, so you might have to request an info window on the jack
(by invoking Get Info from the context menu).
Tweaking a Plugins Parameters
One of the first things you'll want to do with a plugin is to look at the parameters it
offers to configure its "behaviour". The VST add-on offers three different kind of
interfaces for this:
- Parameter View:
VST plugins export their set of parameters to the Media Kit via standard
Parameter Webs. These simply define the name, type and range
of every parameter and can be displayed using different themes.
This is what you get when you double click a node or select Tweak
Parameters from the node panels' context menu.
- Custom Control Panel:
Some plugins include their own spiffy user interface. You can bring that
up by selecting Start Control Panel from the Advanced
sub menu in the node panels' context menu.
- Default Control Panel:
If you invoke Start Control Panel on a plugin without a custom
editor, a default control panel will be displayed.
Often this interface will be better readable than the parameter view,
because it displays the current value for every parameter as text.
To change a parameter, select its entry in the list so it gets
highlighted, and either:
- drag the vertical slider on the right side of the window
- drag horizontally inside the list itself (use the left mouse
button for normal precision and the right button for fine grained
control)
- or use the left/right arrow keys on your keyboard
Pressing the Mute button will instantly cause the plugin to stop
passing incoming data further downstream, while Bypass will
just bypass the effect, which means you'll be hearing the original audio
data.
If supported by the plugin, you'll also get a peak display at the bottom
of the window. It is neither really precise nor beautiful, but at least
the latter might change in future.
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