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max 1GB

Inspector media/spectrogram

Spectrogram Viewer

Overview

A spectrogram shows time across, frequency up and level as brightness — which makes it the fastest way to see what a file actually contains. This one uses a log frequency axis, so an octave takes the same space everywhere and bass, voice and air are all legible, rather than a linear axis that spends half its height on the region music barely uses. The most useful thing it shows is the shelf: lossy encoders discard everything above a cut-off, leaving a dead-straight horizontal edge somewhere around 16 to 20 kHz. A file claiming to be lossless with that edge in it was made from an MP3, and one glance at the picture tells you.

Check whether a FLAC is genuineSpot the encoder shelf that reveals a transcode from a lossy source.
Diagnose a noise problemHum, whine and hiss have distinctive shapes that are obvious in a spectrogram and invisible in a waveform.
See what a filter didCompare before and after and watch the band disappear.

Set

Media Tools 16

Neighbours

01 Audio Converter 02 BPM Detector 03 Compress Video 04 Extract Audio from Video 05 Audio HLS Stream Generator 06 HLS Stream Generator

Specification

Command: media.spectrogram
Set: Media
Input: MIXED
Output: —
Max file: 1GB
Batch: single file

MPEG WAV FLAC MP4 OGG OPUS AAC WEBM

Runtime

Engine: ffmpeg-wasm 0.12
Threads: — workers
Isolated: —
WebGPU: —
Memory: —

Transport 0 B

The file is opened, worked on and written back inside this tab. No upload step exists in this tool — there is nowhere for the bytes to go.

Keys

Search: ⌘K
Panels: ⌘1 · ⌘2
Full width: F
All keys: ⌘/

How it works

Drop a file

Decoded on your device at 48 kHz, so the whole audible range stays visible.

Watch it build

Columns stream in as they are computed rather than appearing all at once.

Read the top edge

A straight horizontal cut-off near 16–20 kHz is an encoder shelf, not music.

Frequently asked

How do I tell whether a file came from a lossy source?

Look at the top of the picture. Real recordings fade out gradually towards the top of the audible range; a lossy encoder cuts everything above its bandwidth, leaving a hard, dead-straight horizontal line — typically near 16 kHz for a 128 kbps MP3 and near 20 kHz for a high-bitrate one. A FLAC with that line in it was transcoded from a lossy file.

Why a log frequency axis?

Because a linear axis gives half its height to 10–20 kHz, where music has almost nothing, and squeezes every fundamental anyone cares about into the bottom eighth. On a log axis an octave is an octave everywhere.

What does the window size change?

A larger FFT window resolves frequency more finely and time more coarsely — good for seeing pitch and tuning, worse for seeing exactly when a drum hit. A smaller one does the opposite. 2048 is the usual compromise.

Is my audio uploaded?

No. The file is decoded and transformed entirely in your browser.

Keys

Search: ⌘K
Panels: ⌘1 · ⌘2
Full width: F
All keys: ⌘/

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