Clips Automations

Both audio and midi clips parameters can be automated.

For example we can make the volume go from a value to another value in a timespan and with a certain curve.

Not all parameters can be automated, and those who can are specific to the clip type.

How to automate

To automate a parameter of a clip, we use the AddAutomationPoint() method, which takes the parameter to automate, the time in seconds at which to place the automation point, the value of the parameter at the point and optionally the curve type to use for going to the next point

// Linearly pan from left to right from 0s to 12s
audioClip.AddAutomationPoint(AutomationParameter.Pan, 0, -50);
audioClip.AddAutomationPoint(AutomationParameter.Pan, 12, 50);

// Smoothly change volume from -12dB to 0dB in the first 4s
audioClip.AddAutomationPoint(AutomationParameter.Volume, 0, -12, InterpolationType.Smooth);
audioClip.AddAutomationPoint(AutomationParameter.Volume, 4, 0);

// Abrubptly change the pitch to -6 semitones at 8s
audioClip.AddAutomationPoint(AutomationParameter.Pitch, 0, 0, InterpolationType.Step);
audioClip.AddAutomationPoint(AutomationParameter.Pitch, 8, -6);

Note

The InterpolationType refers to the curve going to the next point. That’s why we haven’t set it in the second automation point for Volume and Pitch parameters.

To delete an automation for a parameter we use the ClearAutomation() method, passing the parameter we want to remove.

If we want to remove all the automations from a clip we use the ClearAllAutomations() method.

audioClip.ClearAutomation(AutomationParameter.Pan); // Remove the Pan automation from the audio clip
audioClip.ClearAllAutomations(); // Remove all automations from the audio clip

Note

The time at which the point is placed doesn’t account for the clip StartMarker and EndMarker. If you have a clip of 10s with a StartMarker of 6s and make an automation which changes a parameter from 0s to 4s, when the clip starts playing the value will already be at what the 4s point value is.

audioClip.StartMarker = 6; // Make the clip playback start at 6 seconds

// Create an automation which changes the pan from left to right during the first 4 seconds of the clip playback
audioClip.AddAutomationPoint(AutomationParameter.Pan, 0, -50);
audioClip.AddAutomationPoint(AutomationParameter.Pan, 4, 50);

audioClip.Play(); // Here the clip playback starts at 6 seconds, so the pan is already 50, not -50

Also, automation points can be placed outside of the clip time range, so they could even be negative or exceed the clip duration. What must not exceed are the values of the points, else the automation will stop or an exception will be thrown.

Automation parameters

Here is a list of parameters which can be automated for each clip type and some info on their possible values.

Audio Clips

• Volume: ranges from -90 to +6
• Pan: ranges from -50 to +50
• Pitch: unlimited range

Midi clips

All midi clips parameters ranges from 0 to 127.

• Volume: controls the midi velocity
• Pan: 0 = hard left, 64 = center, 127 = hard right
• Balance: 0 = hard left, 64 = center, 127 = hard right
• Sustain pedal: enabled if value >= 64
• Portamento: enabled if value >= 64
• SostenutoPedal: enabled if value >= 64
• SoftPedal: enabled if value >= 64
• LegatoPedal: enabled if value >= 64
• Modulation: controls a vibrato effect

Accessing the clip automations

To access the automations added to a clip and their points, we use the Automations property of the clip, which is a dictionary containing the automated parameter as the key, and the lane for that parameter as the value. The lane contains all the points.

public IReadOnlyDictionary<AutomationParameter, AutomationLane> Automations => _automations;

// Iterate on each automated parameter, print its name, then iterate on all of its points and print their time and value at time
foreach (var automation in audioClip.Automations)
{
    Console.WriteLine($"Parameter: {automation.Key}");

    AutomationLane lane = automation.Value;
    foreach (var point in lane.Points)
    {
        Console.WriteLine($"Time: {point.Time} Value: {point.Value}");
    }
}