MusicUnderstanding · IOS API REFERENCE

LoudnessResult

struct · iOS 27.0+ · SDK 27.1

struct LoudnessResult

A structure that contains perceptual loudness measurements for a song, including integrated, momentary, short-term, and peak values. ## Discussion The `LoudnessResult` delivers perceptual loudness measurements that align with human hearing perception, using the Loudness K-weighted Full Scale (LUFS) standard defined in ITU-R BS.1770. The results contain time-based measurements including integrated loudness, short-term loudness, momentary loudness, and peak amplitude. When used in `SessionResult`, a single `LoudnessResult` contains all analysis values for the entire song, with `momentary` and `shortTerm` arrays containing the complete set of measurements across the song's duration. When used in the streaming `loudnessResults` context, the framework delivers multiple results progressively during analysis. Each result's ``LoudnessResult/momentary`` and ``LoudnessResult/shortTerm`` arrays contain only one value representing the measurement at that point in time.

Members (4)

get · iOS 27.0+

integrated

TypeScript

get integrated(): MusicUnderstandingSession_TimedValue<number>

Swift declaration

let integrated: MusicUnderstandingSession.TimedValue<Float>

The integrated loudness of the song, measured in LUFS over its full duration.

get · iOS 27.0+

peak

TypeScript

get peak(): MusicUnderstandingSession_TimedValue<number>

Swift declaration

let peak: MusicUnderstandingSession.TimedValue<Float>

The peak amplitude of the song in decibels (dB).

get · iOS 27.0+

momentary

TypeScript

get momentary(): Array<MusicUnderstandingSession_TimedValue<number>>

Swift declaration

let momentary: [MusicUnderstandingSession.TimedValue<Float>]

An array of momentary loudness measurements sampled across the song in LUFS. The measurement happens in 400 millisecond (ms) increments that advance 100ms at a time.

get · iOS 27.0+

shortTerm

TypeScript

get shortTerm(): Array<MusicUnderstandingSession_TimedValue<number>>

Swift declaration

let shortTerm: [MusicUnderstandingSession.TimedValue<Float>]

An array of short-term loudness measurements sampled across the song in LUFS. Short-term loudness is a 3 second window that advances 100 milliseconds (ms) per result.

Skipped declarations

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