Class TruePeakDetector

Streaming 4× polyphase true-peak detector for ONE channel (ITU-R BS.1770-5 Annex 2). Maintains a 12-sample input history so successive blocks join seamlessly, runs every phase of the polyphase FIR per input sample (giving the 4× oversampled stream), rectifies, and tracks the running max.

The verbatim coefficients are quoted at 48 kHz. At higher input rates fewer oversampling phases are needed for the same accuracy (Annex 2: 96 kHz → 2× suffices); this 4× design is the conservative default at any rate.

Constructors

constructor

Properties

fir history oversample peak writeIndex

Methods

process reset truePeak truePeakDb

Constructors

constructor

  • new TruePeakDetector(sampleRate?): TruePeakDetector

  • Parameters

    • sampleRate: number = 48_000

      Input sample rate in Hz. Selects the oversampling factor so the oversampled rate reaches BS.1770-5's ≥192 kHz requirement (Annex 2, p.18). Defaults to 48 kHz (the rate the verbatim FIR is quoted at → 4×).

    Returns TruePeakDetector

Properties

Readonly fir

fir: readonly (readonly number[])[]

The polyphase FIR actually used (verbatim at 4×, generated for >4×).

Private Readonly history

history: Float32Array

Readonly oversample

oversample: number

Oversampling factor chosen for the input sample rate (≥4; ≥192 kHz).

Private peak

peak: number = 0

Private writeIndex

writeIndex: number = 0

Methods

process

  • process(samples): void

  • Pushes a block of input samples through the polyphase interpolator and updates the running true peak (max absolute oversampled value).

    Parameters

    • samples: Float32Array

    Returns void

reset

truePeak

truePeakDb

  • truePeakDb(): number

  • True-peak level in dBTP (ITU-R BS.1770-5 Annex 2 stage 5: 20·log10 of the rectified oversampled peak, relative to 100% full scale). Returns -Infinity for pure silence.

    Returns number

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