Learning Perceptually Relevant Temporal Envelope Morphing

TL;DR

This paper introduces a perceptually guided machine learning approach to temporal envelope morphing in audio, enabling more natural sound blending by learning from human listening studies and outperforming existing methods.

Contribution

It presents a novel workflow combining perceptual principles, large-scale datasets, and machine learning to improve audio envelope morphing quality.

Findings

Outperforms existing methods in producing natural intermediate morphs

Derived perceptual principles from human listening studies

Developed benchmarks for evaluating envelope morphing

Abstract

Temporal envelope morphing, the process of interpolating between the amplitude dynamics of two audio signals, is an emerging problem in generative audio systems that lacks sufficient perceptual grounding. Morphing of temporal envelopes in a perceptually intuitive manner should enable new methods for sound blending in creative media and for probing perceptual organization in psychoacoustics. However, existing audio morphing techniques often fail to produce intermediate temporal envelopes when input sounds have distinct temporal structures; many morphers effectively overlay both temporal structures, leading to perceptually unnatural results. In this paper, we introduce a novel workflow for learning envelope morphing with perceptual guidance: we first derive perceptually grounded morphing principles through human listening studies, then synthesize large-scale datasets encoding these principles, and finally train machine learning models to create perceptually intermediate morphs. Specifically, we present: (1) perceptual principles that guide envelope morphing, derived from our listening studies, (2) a supervised framework to learn these principles, (3) an autoencoder that learns to compress temporal envelope structures into latent representations, and (4) benchmarks for evaluating audio envelope morphs, using both synthetic and naturalistic data, and show that our approach outperforms existing methods in producing temporally intermediate morphs. All code, models, and checkpoints are available at https://github.com/TemporalMorphing/EnvelopeMorphing.