Long music overflows runtime?

We trim overlays to video durations maintaining sync.

Why is there a recommended file size around 500 MB?

Keeping each file within roughly 500 MB helps decoding and export stay stable on mainstream devices and browser limits; larger files are more likely to run into memory pressure.

Does anything upload mid-merge?

No — merges stay confined to sandboxed heaps consistent with SOC expectations.

Export explosions — next steps?

Retry smaller assets or convert codecs via compressor stack linked below.

Supported yet thermal throttled — desktops faster.

No login walls — ephemeral sessions.

FFmpeg aficionados noticing parity?

We approximate linear mixing philosophies sans shell overhead — bridging accessibility.

Browser-powered · Zero upload

Add Music to Video Online

Add music to video in your browser — upload footage, attach MP3 or WAV, tune levels between dialogue and background music, mute scratch tracks, and export MP4 without uploading to a server.

Up to 500 MBRuns locally in-browserMP4 · H.264 + AACstandard download

Drop your video here or click to browse

Adds music to MP4 timelines (and MOV/WebM/MKV/AVI when decoders cooperate) purely on-device. Perfect when you googled mute video and add music but refuse sketchy uploads.

Supports MP4 · MOV · WebM · MKV · AVI and more

Recommended next steps based on what you're working on — pick up where this tool leaves off.

Browse all free tools

How to Add Background Music to a Video in 3 Steps

Step 1 — Upload footage

Drag and drop MP4, MOV, WebM, or MKV, or browse to select a file. Preview loads locally in your browser — nothing is uploaded for processing.

Step 2 — Upload music and adjust levels

Pick an MP3, WAV, M4A, or AAC track, mute the original audio if needed, and set volume levels. Choose loop or play-once for the background music.

Step 3 — Merge and download MP4

Click merge, watch the progress bar, and download your finished MP4. Keep the tab open while your browser encodes the final file.

Everything You Need to Add Background Music to a Video

Merge audio and video in one export

Combine footage and music tracks in a single click. The tool muxes AAC audio with H.264 video into a standard MP4 ready to share.

Dual sliders for precise balance

Control original audio and background music independently. Duck dialogue under music beds or boost a track for social-ready mixes.

Loop short cues or play once

Loop background music to fill longer clips, or play a single pass when you want silence after an intro or outro.

Private in-browser processing

Your files never leave your device for mixing. Local processing keeps sensitive drafts off cloud servers.

Common questions

Is it free to add music to a video?+

Absolutely — premium merges with anonymous usage — ideal for teams scanning add sound to video free opportunities.

Which codecs feel safest day-to-day?+

MP4 + MP3/WAV paths decode widest; exotic Dolby tracks may require FFmpeg desktop eventually.

Can mute remove entire camera microphones?+

Yes — disables original waveform contribution downstream mixing entirely.

Short music tails vs looping?+

Choose loop for indefinite repeats versus play-once with trailing silence aligning dramatic beats.