<audio-transient-analyzer>

The transient analyzer makes recent attacks visible while a signal sounds. It compares successive frequency and RMS snapshots, shows strength against a sensitivity threshold, and marks accepted cues in a short history. Freeze holds the display; Clear starts a fresh inspection. For a decoded clip’s stable onset times or a DJ beat grid, use the Analyze API and compose positions with <audio-view>.regions. This live tool does not estimate BPM or align a beat grid.

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

Live canvasLive

Parameters

playerUnique audio-player selector in the current root. The tool borrows its analyser only while playing.sensitivityHigher sensitivity lowers the attack threshold; the tool control updates this attribute.min-interval-msMinimum spacing between emitted live attack cues in milliseconds.

<audio-player>

srcURL of an audio file. Loading it replaces the selected clip; removing it clears a clip that came from src.loopBare (or "true"/"loop") loops the whole clip; "a,b" — also "a-b"/"a:b" — loops those seconds. Applied live.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.

<audio-transient-analyzer></audio-transient-analyzer>

CopyReset

Import

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

<audio-player id="session" src="/mp3/Arabesque%20No.1.mp3" controls></audio-player>
<audio-transient-analyzer player="#session" sensitivity="0.55" min-interval-ms="160"></audio-transient-analyzer>

The demo pairs one player with this tool. Start playback, then adjust the Sensitivity control or use Freeze and Clear on the real component. Copy includes both Elements, and Reset restores their demo settings.

Signal and lifetime

The tool borrows the bound player’s analyser while playing, or a caller-owned .analyser in preference to it. The player selector must resolve uniquely in the current Document or ShadowRoot; late targets and source replacement are observed. Neither the element nor its presenter starts playback, opens a microphone, creates an AudioContext, or changes borrowed analyser settings.

Sampling is approximately every 50 ms. Positive FFT-bin change and rising RMS contribute to a normalized 0..1 strength; sensitivity changes its acceptance threshold, and min-interval-ms suppresses hits too close to a previous hit. Silence is shown separately from an unavailable analyser. The recent plot keeps at most 64 sampled observations, not a clip-wide event timeline. Freeze stops sampling but keeps the current history; unfreezing resets the detector’s comparison frame before new cues. When following a player, pause, seek and source change invalidate old readings. Replacing an explicit analyser, graph loss, hiding the document or disconnect also releases old evidence and polling/subscriptions. A stalled source is reported and retried without disposing the borrowed graph.

API

Member	Kind	Behavior
player	attribute	Unique selector for a playback owner whose analyser is borrowed while playing; default absent.
sensitivity	attribute	Detection sensitivity in 0..1, default 0.55; invalid values use the default. Higher sensitivity lowers the cue threshold.
min-interval-ms	attribute	Minimum spacing between accepted cues in milliseconds, clamped to 50..1000; default 160. Invalid values use the default.
.analyser	property	Explicit caller-owned AnalyserNode, preferred over player binding; getter returns the explicitly assigned node.
.sensitivity, .minIntervalMs	properties	Reflected detection settings with the bounds above.
.sample	read-only property	Latest {strength, hit} observation, or undefined before a frame. Strength is normalized 0..1.
.hitCount	read-only property	Accepted cues since the last reset or source/transport invalidation.
.frozen	read-only property	Whether the tool’s Freeze control holds its current history.
.reset()	method	Clear current detector evidence, history and hit count without changing playback or the audio graph.
webaudio:transient	event	{timeMs, strength, threshold, intervalMs?} for each accepted cue. timeMs is an approximate performance.now()-style capture timestamp, not clip seconds; intervalMs is the time since the prior accepted cue when available. Bubbles and is composed.
webaudio:error	event	{error: Error} for input, sampling or stalled-frame failures; bubbles and is composed.

The detector reports onset cues, not exact onset positions. Its timing and strength depend on the borrowed analyser’s FFT size, smoothing and this tool’s polling cadence. The threshold is an internal visual/detection quantity, not a gain or playback control.

Accessibility. Freeze and Clear are native buttons; Freeze exposes aria-pressed. Sensitivity is a labelled native range input. The plot has a text alternative reporting current strength, threshold and hit count; status and numeric readouts remain outside the visual bars.

Styling

The host’s neutral outer surface honors shared --wm-component-* tokens and --wm-audio-transient-analyzer-surface-* overrides. The transient presenter exposes --wm-transient-analyzer-foreground, --wm-transient-analyzer-background, --wm-transient-analyzer-border, --wm-transient-analyzer-padding, --wm-transient-analyzer-strength, --wm-transient-analyzer-hit and --wm-transient-analyzer-threshold tokens. Public parts are root surface, plot, freeze, clear and sensitivity; structural wui-* child classes are not additional styling contracts.