Waveform Viewer — compare & measure audio

Draw waveforms for any audio on a page. Stack lanes, align onsets, play them together, measure gaps, download clips.

Waveform Viewer turns any audio on a web page into a real waveform you can look at, compare, and measure — without downloading files into a desktop editor first. It was built for language practice, where the whole point is comparing a model recording against your own attempt, but it works anywhere audio plays: podcasts, music tools, transcription apps, QA of your own site’s audio. WHAT IT DOES • Draws a waveform for every audio clip the page loads, stacked as lanes in a floating panel you can drag, resize, and pop out into its own window. • Shares one time scale across all lanes, so two recordings line up vertically and differences in pacing are obvious at a glance. • One-click onset alignment shifts every lane so their first audible moment starts together. You can also drag any lane sideways to align it by hand, with the exact offset shown in milliseconds. • Plays every lane together through a single synced playhead, so you hear the comparison instead of guessing. Mute or solo individual lanes while it plays. • Drag across the waveform to measure any interval to the millisecond — the gap between two phrases, the length of a pause, how long a word takes. HOW IT FINDS AUDIO Many players never create an PRIVACY No accounts, no servers, no analytics, no tracking. Audio is decoded locally in your browser and nothing ever leaves your machine. The extension makes no network requests of its own beyond re-reading the audio files the page already loaded. Open source under the MIT license.