batch relay sound to video

Replace the audio on your video files — fast. Drag in video and audio, Laybacker auto-matches the pairs, normalises loudness to broadcast spec, and exports. Built for sound post-production.

latest release · all versions & release notes

What it does

Drag, drop, done

Drop video and audio together — Laybacker matches them by duration and name, and lets you fix any pairing by hand.

Broadcast-spec loudness

Normalise to LUFS targets (EBU R128 −23, streaming −16, ATSC A/85) or full-scale peak, measured to ITU-R BS.1770-4.

6-frame silence check

Verify and fix head/tail silence for UK broadcast delivery, with clean fades to avoid clicks.

Smart export

Keep the original streams or re-encode to H.264 / AAC. Smart filenames with optional date stamps.

FFmpeg included

No separate install — a pinned, bundled FFmpeg ships inside the app. Nothing else to set up.

Fully local & private

Every file is processed on your own machine. Nothing is ever uploaded.

First launch

First launch? Laybacker is free and open-source but not paid-signed (just like Shutter Encoder), so your computer asks once:
Mac: right-click the app → OpenOpen.
Windows: on the blue SmartScreen box click More infoRun anyway.
Independently verified safe
Every release is scanned, signed, and checksummed — not just trusted.

Verify it's genuine

Don't just take our word for it — Laybacker is built to be independently checkable. Four ways to confirm it's safe and untampered:

Open source

The full source is public and every installer is built automatically by GitHub from a tagged commit, with public build logs. Read the code.

VirusTotal scanned

Each release is scanned by 70+ antivirus engines, with the report links in the release notes. Or scan it yourself at virustotal.com.

Checksums

Every release publishes SHA256SUMS files so you can confirm your download matches our build exactly, byte for byte.

Signed provenance

Each binary carries a cryptographic attestation tying it to the exact public source. Verify with gh attestation verify <file> --repo soundrich-bot/laybacker.