About Add audio

Overlay or replace audio on a video in your browser—free, no upload. Adjust volume and timing, export locally with NanoPix.

Tool facts

Processing
Runs locally in your browser. Source files are not uploaded to NanoPix for editing.
Available controls
Video & external audio file import · Keep original audio or mute with gain control · Timeline offset alignment & trimming
Output
Export video with mixed audio track

Frequently asked questions

What can Add audio do?
Overlay or replace audio on a video in your browser—free, no upload. Adjust volume and timing, export locally with NanoPix.
Are my files uploaded to your servers?
No. NanoPix runs in your browser with WebAssembly. Your video, audio, or image files stay on your device—we never receive them.
Is browser-based editing private?
Yes. Processing happens locally on your machine. Nothing is sent to NanoPix servers for encoding or storage.
Is this tool free?
Yes. NanoPix tools are free to use in a modern browser. No account is required for basic editing and export.