Stereo Checker

Is This Real Stereo?

Check whether an audio or video file is mono, dual-mono, or real stereo before you upload it.

Drop audio or video here

or click to choose a file

Files over 1 GB may not work — analysis runs in your browser, so memory is limited.

Your file stays in your browser. Nothing is uploaded.

How to use

Drag a file in, or click the dropzone to choose one.
Click Analyze. We sample the start, middle, and end of the file. Results appear within a few seconds for typical files.
Copy the result if you need to share it.

What this checks

We compare the left and right channels and report two metrics: L/R correlation and the L−R difference ratio. When both channels are nearly identical, the file is flagged as dual-mono suspected — a common symptom of a mono source rendered into a stereo container.

All metrics are estimates. Center-heavy mixes can read narrow, so treat the verdict as a guide.

Privacy

Your file stays in your browser. Decoding and analysis run locally with the Web Audio API and ffmpeg.wasm. Nothing is uploaded to a server.