<audio-level-analyzer>

The level analyzer is a live dynamics tool beside an <audio-player>. Its recent-sample display, peak hold and adjustable threshold help inspect the signal while it sounds. For offline loudness estimates over a decoded clip, use measureLoudness. Neither this tool nor the current API establishes inter-sample true peak.

@webmusic/audio/analyze/element<audio-level-analyzer>

Parameters

playerUnique audio-player selector in the current root. The tool borrows its analyser only while playing.threshold-dbfsSample-peak comparison threshold; the control and threshold line update together.

<audio-player>

srcURL of an audio file. Loading it replaces the selected clip; removing it clears a clip that came from src.formatForces the decode format. Changing it can only land through a reload of src.controlsVisibility only: the transport stays mounted and subscribed, so hiding it keeps the playhead.loopBare (or "true"/"loop") loops the whole clip; "a,b" — also "a-b"/"a:b" — loops those seconds. Applied live.enginebuffer decodes into memory, media streams through an <audio> element; auto prefers media above ten minutes.preserves-pitchHolds pitch while rate ≠ 1 on the media engine; a documented no-op on the buffer engine.volumeLinear master volume, clamped to 0–4 and applied live.ratePlayback speed, clamped to 0.25–4 and applied live.panStereo position, clamped to -1–1 and applied live.preloadWarms context, graph and decoded buffer on mount. `preload="none"` opts out, as on <audio>.

<audio-level-analyzer></audio-level-analyzer>

Import

<script type="module">
  import {defineAudioPlayerElement} from '@webmusic/audio/play/element';
  import {defineAudioLevelAnalyzerElement} from '@webmusic/audio/analyze/element';
  defineAudioPlayerElement();
  defineAudioLevelAnalyzerElement();
</script>

<audio-player id="session" src="/mp3/Arabesque%20No.1.mp3" controls></audio-player>
<audio-level-analyzer player="#session" threshold-dbfs="-12"></audio-level-analyzer>

The demo pairs one player with this tool. Start playback for live samples; the tool’s Freeze, Reset hold and Peak threshold controls operate on its own display. Copy includes both elements, and Reset restores their demo settings.

Signal and lifetime

The element borrows the bound player’s AnalyserNode while that player is playing. Assign .analyser to inspect a caller-owned graph instead; an explicit analyser takes precedence and is sampled while the element remains connected. The element does not create an AudioContext, decode a clip, seek, or own the borrowed node. It samples about every 50 ms, so the RMS and peak describe sampled windows, not continuous loudness or inter-sample true peak. The crest value is sample peak minus RMS in dB.

Freeze holds the current display while sampling continues. Reset hold starts the held peak again from the current sample. A pause, seek, source change or missing live input clears stale samples; a frame stall marks the signal unavailable. The element stops its own polling and subscriptions on rebind or disconnect without stopping the player. player must resolve uniquely in the current Document or ShadowRoot; invalid or ambiguous selectors remain unbound, and later target changes are observed.

API

Member	Kind	Behavior
`player`	attribute	Unique selector for the playback owner whose analyser is borrowed while playing.
`threshold-dbfs`	attribute	Sample-peak comparison threshold in dBFS, clamped to `-60..0`; default `-12`. Invalid values use `-12`.
`.analyser`	property	Caller-owned `AnalyserNode`; takes precedence over the player’s analyser.
`.thresholdDbfs`	property	Reflected peak threshold in dBFS.
`.sample`	read-only property	Latest `{rmsDbfs, peakDbfs}` sample, or `undefined` without a live sample.
`.heldPeakDbfs`	read-only property	Greatest sampled peak since the latest reset, or `undefined` before a sample.
`.frozen`	read-only property	Whether the display is frozen; the tool’s Freeze control changes it.
`webaudio:levelchange`	event	`{rmsDbfs, peakDbfs, crestDb, heldPeakDbfs, thresholdDbfs}` for an accepted sample; bubbles and is composed.
`webaudio:error`	event	`{error: Error}` for a live-input or frame failure; bubbles and is composed.

The threshold is visual feedback against the sampled peak; crossing it does not mute, compress or otherwise change the signal.

Styling

The full-width host honors native hidden. Its outer surface uses --wm-component-background, --wm-component-border, --wm-component-padding and --wm-component-radius; the --wm-audio-level-analyzer-surface-* tokens override this tag. The level presenter exposes --wm-level-analyzer-rms, --wm-level-analyzer-peak and --wm-level-analyzer-threshold for its graph.