fn normalize_filter_entry(enabled: bool, level: VolumeLevel) -> Option<String>Expand description
The loudness-normalization filter entry (unwrapped), or None when
normalization is disabled. Uses ffmpeg’s dynaudnorm, a gentle real-time
dynamic normalizer that avoids the gain “pumping” loudnorm’s single-pass
mode can produce on very dynamic material.
dynaudnorm targets a peak amplitude (p, linear 0–1), not a LUFS value,
so the Loud/Normal/Quiet presets become approximate: each preset’s LUFS
offset from the Normal reference is applied as a dB offset to the reference
peak, preserving the Loud > Normal > Quiet ordering. g=15 (gaussian window
size) further smooths gain changes; the peak is clamped to a safe (0, 0.99]
so loud presets never request full-scale.
TRACES: UR-033 | DR-036