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Parameter Automation

Introduction

Blue allows for a few ways to enter in values to automate parameters over time. The parameters that can be automated are those in BlueSynthBuilder Instruments, Mixer Effects, Mixer Sends, and Mixer Volumes. The following sections will describe how to use Parameter Automation and technical details in how this all works within the context of Blue and Csound.

Available Parameters

Besides the Volume sliders in the mixer and level amount on mixer sends, the following GUI Parameters are automatable when found in BlueSynthBuilder instruments and Mixer Effects:

  • Knob

  • HSlider

  • HSliderBank

  • VSlider

  • VSliderBank

  • XYController

  • Dropdown

  • Checkbox

Assigning Parameters

Automations for Parameters are assignable to SoundObject LayerGroup Layers that exist in the root Score by selecting from the popup menu that appears when selecting the "A" button on a SoundLayer's panel (on the left of the timeline). The menu shows what Parameters are available to use from Instruments and the Mixer. Those with normal color text are Parameters which are not currently automated, those in green are ones currently automated in that SoundLayer, and those in orange are ones which are currently automated on a different SoundLayer. Selecting normal color text will enable automation for that parameter on the SoundLayer, while selecting a green colored text one will disable automation for that parameter, and selecting an orange one will move it from the layer it is currently on to the one being worked with.

Score Timeline Modes

The Score timeline has three different modes:

Score
This is the primary mode for adding and editing SoundObjects. Parameter Automations will be drawn but are not editable in this mode.
Single Line
This is the primary mode for editing line points for Parameter Automations. The user is able to edit a single line at a time per SoundLayer, and can enter and remove points, modify points by dragging them, as well as selecting a region and move the the points by dragging the region. While dragging the region, the region will show that data will overwrite the area dragged to. This overwriting will not be committed however until the user releases the mouse button.
Multi Line
This is the mode for selecting and moving line points for all Parameter Automations on a single or multiple SoundLayers. The use can click and drag to create a selection region, then click within the selection region to move all points from all lines within the region. While dragging the region, the region will show that data will overwrite the area dragged to. This overwriting will not be committed however until the user releases the mouse button.

Editing Automations

To edit line values in a Parameter Automation, first switch to Single Line mode. Then, for the desired SoundLayer, select which of the assigned parameters to edit. This can be done either by using the SoundLayer Edit Panel's Parameter selector (found on the second row below the row with mute, solo, etc.; only shown when SoundLayer size is greater than 1), or by right-clicking the SoundLayer in the main area and selecting from the popup menu (the actively editable Parameter Automation will be disabled from the popup menu).

Once a parameter is selected, the user can change the color of the line by using the color box next to the parameter selector panel on the SoundLayer Edit Panel. To add new points, use the mouse and mouse over to where you would like to add a point and press the left mouse button. After pressing, the point will be added, and the user can drag to modify the just entered point. Releasing the button will complete the addition of the line point. To edit an existing point, mouse over a point until it is highlighted in red, then press the left mouse button, drag, and release when finished. To remove an existing point, mouse over a point until it is highlighted and press the right mouse button.

To manipulate data for a single automation, use shift-drag to select a region of the automation data. Once selected you can ctrl-c to copy and ctrl-click to paste that data. You can also drag the selection to move the region or drag at the edges to scale the automation data. ctrl-z may be used to undo the above changes.

For finer control over the line points, right-click on the parameter line panel when not over an existing line point. A popup menu will appear and select "Edit Line Points". A dialog showing a table of line points with time values in one column and parameter values in a second column. The user can then enter in values by text entry.

For changes of automation data for an entire layer or set of layers, use multi-line mode. This will alow you to select, copy/paste, drag, and resize automation data. If shift is used when making a selection, it will also select underlying ScoreObjects. This will allow you to move both automation and ScoreObject data together. If you the selected region completely contains ScoreObjects (i.e., no part of any selected ScoreObjects extend outside of the region) you can also scale the automation and ScoreObject data together.

Technical Details

Blue's parameter automation system is implemented in Csound code in a few different areas. For instruments and effects, when an Automatable Parameter is not set for automation, it will replace its replacement key in its ORC code with a constant value from the UI item. If the parameter is set to allow automation, then the replacement key is replaced with a Blue generated global k-rate signal name. Therefore, when coding instruments and effects, the user should be careful to make sure that if they want the parameter to be automatable that the replacement key is placed in the code where a k-rate signal is legal to use. If the user is not expecting to automate that value, then it would be safe to place that replacement key wherever a constant is allowed. This is also useful to know when migrating older BSB Instruments and Effects to be used with the purpose of Automation.

After setting up the Instrument and Effects, Blue will then handle compiling the automations into a way that works with Csound. Currently, Blue will first calculate init statements from where the render start time is and add that to the CSD to make sure that the global krate signals will be initiated by the time any instrument could use them. Then, Blue creates instruments for each parameter that will be automated. The instruments are driven by score and either an instrument for continuous data or resolution dependent data will be created. Score is then generated for the parameter automation data that together with the instruments generated will create the signals.

Care was taken to optimize the generated score and instruments. Unnecessary score will not be generated if multiple points with the same value are found as well as when there is a discontinous break in the values. Values from the parameter automation will also correctly be generated from render start time until render end time (if used). For parameters with resolution, every value is a discrete jump, so the instrument for resolution based parameters will on it's i-time run will simply set the new value and then turn the instrument instance off to save CPU cycles.