- 100% free, no signup
- No upload — files never leave your device
- No watermark on free exports
- Built by an award-winning NZ creator
How to add audio to a video
Drop a video, drop an audio file, choose replace or mix, and download — all in your browser.
- 1
Drop in your video
Drag in or browse for an MP4, WebM or MOV. It stays on your device — nothing is uploaded.
- 2
Add your audio
Drop in the soundtrack you want to use — an MP3, WAV or M4A music track or voiceover.
- 3
Replace or mix
Pick Replace original audio to swap the sound entirely, or Keep both to blend your track over the clip’s existing sound.
- 4
Add the audio
Hit Add audio to video. The first run loads a one-time ~32MB engine, then a progress bar shows the work happening right in your browser.
- 5
Download your MP4
Preview the result and download a finished MP4 — ready to upload, email or post, with no watermark.
Add Audio to Video — FAQ
Is adding audio to a video free?
Yes — add music or a voiceover for free, with no signup and no watermark. Replacing the audio is always free; an optional Paji Pro membership (NZ$9/mo) unlocks the keep-both mix and batch jobs.
Is my video or audio uploaded anywhere?
No. The video and audio are combined entirely in your browser using a local video engine. Your files never leave your device — there is no server and nothing is stored online.
What is the difference between replace and mix?
“Replace original audio” drops the clip’s existing sound and uses only your new track. “Keep both (mix)” blends your track over the original audio, which is handy for music behind a talking clip — and is a Paji Pro feature.
Which audio formats can I use?
MP3, WAV and M4A all work well for the soundtrack. The video can be MP4, WebM or MOV, and the result is always an MP4 (H.264) that plays just about everywhere.
What if the music is longer or shorter than the video?
The finished clip is trimmed to whichever is shorter — the video or the audio — so it never ends on a black screen or a silent tail. Trim your clip or track first if you want them to line up exactly.
Can I put music behind a property walkthrough?
Absolutely — it is perfect for adding a music bed to an Auckland listing walkthrough or a voiceover to a product demo, all without installing an app or uploading a thing.
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