AudioLens

AudioLens analyses audio while it plays and gives you numbers you can drive gameplay with.

Feed it a frame of samples each tick and read back an FFT spectrum, onset detection functions, classified drum hits, and a full set of loudness and timbre descriptors - RMS, peak energy, zero-crossing rate, spectral centroid, flatness, crest, rolloff and kurtosis. Five window functions are provided so you can trade frequency resolution against spectral leakage.

That is everything you need for music-reactive visuals, rhythm games, procedural animation, adaptive mixing, or any system that should move in time with what the player is hearing.

AudioLens is part of the Alpha XP audio collection for Unreal Engine 4.27 and 5.8. Every feature is exposed to both Blueprints and C++, it ships with styled HTML documentation, and it follows one consistent API style across the collection. It is compiled and verified warning-free against clean UE 4.27 and UE 5.8 projects.

AudioLens reads audio through AudioForge, which must be installed alongside it.

Key Features:

- FFT spectrum with real, imaginary, magnitude and subband output

- Five window functions: rectangular, Hanning, Hamming, Blackman and Tukey

- Onset detection: energy envelope, energy difference, spectral difference, half-wave rectified difference, complex spectral difference and high-frequency content

- Beat detection with kick, snare and hi-hat classification

- Time-domain features: RMS, peak energy, zero-crossing rate

- Frequency-domain features: spectral centroid, flatness, crest, rolloff and kurtosis

- Pull audio frames by current playback time, time range or frame range

- Configurable frame size, subband count and energy history

Full documentation: https://demo.alphaxp.net/FabStore/Audio/AudioLens/

Support: https://alphaxp.net/