keijiro/Lasp

LASP

LASP is a Unity plugin that provides low-latency audio input features, making it useful for creating audio-reactive visuals.

Demos

Sphere is the simplest example demonstrating LASP. It features an animated sphere whose scale responds to the audio level. This example utilizes the Audio Level Tracker component to measure the audio level and a Property Binder to animate the sphere's scale property.

LevelMeter is a slightly more advanced example of the Audio Level Tracker in action. It visualizes the audio levels of low, mid, and high frequency bands. Additionally, it makes use of the raw waveform function to render a waveform graph.

DeviceSelector demonstrates how to instantiate the Audio Level Tracker and configure Property Binders programmatically at runtime.

Lissajous showcases how to draw a Lissajous curve using the Input Stream class and its interleaved waveform function.

Spectrum illustrates how to utilize the Spectrum Analyzer component to extract and visualize the frequency spectrum of an audio input stream.

System Requirements

• Unity 2022.3 LTS or later

Currently, LASP supports only desktop platforms (Windows, macOS, and Linux).

Installation

You can install the LASP package (jp.keijiro.lasp) via the "Keijiro" scoped registry using the Unity Package Manager. To add the registry to your project, follow these instructions.

Audio Level Tracker Component

The Audio Level Tracker component receives an audio stream and calculates the current audio level. It supports Property Binders, which modify the properties of external objects based on the normalized audio level.

This component tracks the most recent peak level and calculates the normalized level based on the difference between the current level and the peak level. It only outputs an effective value when the current level falls within its dynamic range, indicated by the gray band in the level meter.

Default Device / Device ID

As an audio source, you can use either the Default Device or a specific audio device by specifying its Device ID.

Device IDs are system-generated random strings, such as {4786-742f-9e42}. In the Editor, you can use the Select button to find a device and retrieve its ID. Note that these ID strings are system-dependent, so you will need to reconfigure them when running the project on a different platform.

At runtime, you can use AudioSystem.InputDevices to enumerate available devices and obtain their IDs. Refer to the DeviceSelector example for more details.

Channel

Select a channel to use as input, or leave it at 0 for monaural devices.

Filter Type

Four filter types are available: Bypass, Low Pass, Band Pass, and High Pass. These filters are useful for detecting specific rhythmic accents. For example, a Low Pass filter can be used to create a response to kick drums or basslines.

Dynamic Range (dB)

The Dynamic Range defines the range of audio level normalization. The output value becomes zero when the input level is equal to or lower than
Peak Level - Dynamic Range.

Auto Gain

When enabled, this feature automatically tracks the peak level as explained above. When disabled, the peak level is fixed at 0 dB, allowing you to manually control the effective range using the Gain property.

Smooth Fall

When enabled, the output value gradually decreases toward the current actual audio level, making choppy animations appear smoother.

Spectrum Analyzer Component

The Spectrum Analyzer component processes an audio stream using FFT (Fast Fourier Transform) to extract spectrum data.

It normalizes the spectrum values using the same algorithm as the Audio Level Tracker. Refer to the section above for details.

You can access the spectrum data via the scripting API. For detailed usage, see the SpectrumAnalyzer example.

Spectrum To Texture Component

The Spectrum To Texture component is a utility that converts spectrum data into a texture, making it useful for creating visual effects with shaders.

There are two ways to utilize the spectrum texture:

Via Render Texture

You can bake the spectrum data into a Render Texture by specifying it in the Render Texture property. The render texture must meet the following requirements:

• Width: Must match the spectrum resolution.
• Height: Must be 1.
• Format: R32_SFloat

Via Material Override

You can override a material's texture property using the Material Override property. This method is convenient when applying the spectrum texture to a Mesh Renderer.

Scripting Interface

LASP provides several public methods and properties in its core classes, such as AudioLevelTracker, AudioSystem, and InputStream.

For detailed usage, refer to the example scripts.