Add Music to Video – Mix or Replace the Soundtrack
Add music to video clips in your browser: pick a song, then either mix it under the original sound or replace the soundtrack completely. Set both volumes, let short songs loop to fill the clip, and fade the music in and out. The video stream is copied untouched, so the picture keeps its quality, and neither the video nor the song is uploaded.
- Runs on your device
- WebCodecs · GPU
- Web Audio
- Works offline
Updated
Drop your videos here
How to add music to a video
Step 1: Drop your video on the box above, then choose the song under Music or audio (MP3, M4A, WAV, FLAC, OGG or Opus).
Step 2: Set Original sound to Mix with music to keep voices, or Replace to use only the song.
Step 3: Adjust Music volume and, when mixing, Original volume. Keep Loop music to fit and Fade music in and out on for a polished result.
Step 4: Press Apply and download the video with its new soundtrack.
Good to know
Settings explained
- Music or audio
- The track to add. It stays on your device like everything else.
- Start music at
- Skip the beginning of the music track.
Formats
Batch-friendly: add many files and they are processed one after another — if one fails, the rest still finish.
How it runs
- Hardware video engine
- Video is decoded and encoded by your device’s media hardware through WebCodecs — usually several times faster than real time.
- Web Audio
- Audio is processed with the browser’s built-in Web Audio engine, sample-accurate and fast.
- FFmpeg (when needed)
- Older formats and a few filters use FFmpeg compiled to WebAssembly. It downloads once (about 31 MB) the first time it is needed and is cached for offline use.
Mix or replace: what each setting does
Mix lays the song under the sound that is already in the clip, which suits vlogs and anything with speech. Replace throws the original sound away, which suits silent footage, montages and clips with noise you do not want.
| Setting | What it does | Tip |
|---|---|---|
| Original sound: Mix with music | Both soundtracks play together | Music at 20–40% keeps speech clear |
| Original sound: Replace | Only your song is heard | Music at 100% with no fade, loop or offset copies the song without re-encoding when it is AAC (Opus for WebM) |
| Music volume / Original volume | 0% to 200% each | Values above 100% boost; a limiter stops the mix from clipping |
| Loop music to fit | A short song repeats with a soft crossfade until the video ends | Turn it off to let the song end naturally |
| Fade music in and out | Fades in over 1.5 s; fades out over 2.5 s where the video cuts the song | A song that ends before the video keeps its own ending |
| Start music at (Advanced) | Skips into the song, for example straight to the chorus | It does not delay the music; it always starts with the video |
What if the song and the video have different lengths?
The finished video is always exactly as long as the original clip. A song that is longer is cut at the end of the video and, with fading on, fades out over the last 2.5 seconds instead of stopping mid-note. A song that is shorter repeats when Loop music to fit is on; the seam is blended so the restart is smooth. With looping off, the song just ends and the rest of the clip plays with only the original sound (or silence, in Replace mode).
Add music to a video without losing quality
The picture is never re-encoded: the video stream is copied packet by packet, so resolution and sharpness stay exactly as they were. Only the soundtrack is rebuilt, as AAC at 192 kbps (Opus for WebM files), which is plenty for music and speech. In the simplest case, replacing the sound with an AAC song at 100% volume and no fade, even the song is copied as it is.
The file format stays the same: an MP4 stays MP4, a MOV stays MOV.
Add a song to a video on iPhone, Android or PC
The steps are the same on every device: one video, one audio file, press Apply. The difference is where your music lives.
iPhone
Pick the clip from Photo Library and the song from the Files app in Safari. Songs streamed from music apps are protected and cannot be added; use a file you own.
Android
In Chrome, choose the video from your gallery and an MP3 or M4A from Downloads or your music folder. The finished video is saved to Downloads.
Windows and Mac
Drag the video and choose the song from your music folder. Batches work too: every video in the queue gets the same track and settings.
Tips & troubleshooting
Only want part of the song? Cut it first with the MP3 cutter, or use Start music at to skip the intro.
Several clips, one soundtrack: join them with Merge Videos first, then add the music once so it runs across the cuts.
Turning photos into a music video? The slideshow maker adds the song while it builds the video.
To strip the sound without adding anything, use Remove audio from video.
Add Music to Video FAQ
How do I add music to a video for free?
Drop the video here, choose a song file you have on your device, pick Mix or Replace and press Apply. There is no account, no watermark and no upload; the result downloads straight away.
How do I replace the audio in a video?
Set Original sound to Replace, choose the new audio file and press Apply. The old soundtrack is removed and yours takes its place; the video itself is copied without re-encoding.
How do I fade music in and out on a video?
Leave Fade music in and out on. The song fades in over 1.5 seconds at the start and fades out over 2.5 seconds wherever the end of the video cuts it off.
Can I use any song?
Technically yes, but YouTube, Instagram and TikTok may mute or block videos with copyrighted music. Use music you own or have a licence for, or add the song inside the app when you post.
How do I add background music to a WhatsApp Status video?
Mix the song under the clip here with Music volume around 40%, download the result and post it as your Status. Trim the video first if it is longer than one Status allows.
Are your video and music uploaded anywhere?
No. Your video and music are processed by your own browser on your own device. There is no server that receives files, so nothing is uploaded, stored or shared. You can even switch to airplane mode once the page has loaded.