Sonefiler

Sonefiler is a proposed digital media container specification designed to store audio data together with perceptual loudness metadata. It aims to bundle multiple tracks, accompanying time-aligned measurements, and descriptive metadata in a single portable file format. The core idea is to preserve not only the raw audio but also perceptual information that helps reproduce or analyze how the material would be heard in different contexts.

Etymology and origins are straightforward: the term combines sone, a unit of perceived loudness, with file, signaling a self-contained data container. The concept emerged in discussions among researchers and practitioners in digital audio archiving and broadcast engineering, with early drafts circulating in the late 2010s and early 2020s as a way to couple audio with perceptual descriptors for long-term preservation and interoperability.

Technical characteristics are defined around a structured layout that typically includes a header, per-track entries, and a metadata section. A sonefiler may reference embedded audio samples or point to external assets, while recording a sequence of time-stamped sone values that describe loudness over time. In addition to loudness data, tracks may carry optional descriptors such as pitch, timbre indicators, peak levels, and processing history. Metadata fields commonly cover creator information, licensing, sampling rate, loudness norms used, and any steps in the production chain.

Usage and status are largely experimental. Sonefiler is discussed as a tool for post-production archiving, broadcast compliance workflows, and research that requires integrated perceptual data. Adoption remains limited, and interoperability depends on agreed specifications and tooling. Critics note potential redundancy with established loudness standards like LUFS and the need for widespread support, while proponents emphasize clearer preservation of perceptual intent and easier future retrieval.