Does this replace the original audio?

Yes. The new audio replaces the video's existing sound. To keep both, mix them in an editor first, then add the combined track here.

Are my files uploaded to a server?

Never. Everything runs locally in your browser. Your files never leave your device.

Will the video quality change?

No. The picture is copied as is, so the video quality stays identical to the original. Only the audio is changed.

What if the audio and video are different lengths?

The result is trimmed to whichever is shorter, so the video and audio end together.

Which formats can I use?

Video: MP4, MOV, MKV, WEBM and AVI. Audio: MP3, WAV, AAC, FLAC, M4A and OGG. The result is saved as MP4.

Yes. Adding audio to a video on Sondra is free, with no signup and no watermark.

Can I do this on my phone?

Yes. Sondra works in mobile browsers, with files up to 100MB on mobile and 500MB on desktop.

Can I add audio to a video with no sound?

Yes. If the video has no audio track, your audio is simply added to it.

Does it work without internet?

After the page has loaded once, the work runs offline in your browser. You only need a connection to open the page the first time.

Add Audio to Video - Put Music on a Clip

Add a song or a new soundtrack to your video, or replace the existing audio. Free, private, and right in your browser.

Video file

Audio file

The new audio replaces the video's original sound. The result is trimmed to the shorter of the two.

Add both a video and an audio file to continue.

Fast 100% private Free

How to add audio to a video

Add your video

Drop in or pick the clip you want to add sound to.

Add your audio

Choose the song or soundtrack to put on it.

Download

Save your video with the new audio.

Why add audio to a video?

Sometimes a clip has the wrong sound, no sound, or audio you cannot use. Adding your own music or a new soundtrack lets you set the mood, replace copyrighted audio, or simply give a silent clip a voice.

Sondra keeps the video exactly as it is and swaps in your audio, so the picture quality never changes and it stays fast. The result is trimmed to whichever is shorter, the video or the audio, so they line up.

It works with MP4, MOV, MKV, WEBM and AVI video and MP3, WAV, AAC, FLAC, M4A and OGG audio, adds no watermark, and runs entirely in your browser.

What you can do by adding audio

Putting new sound on a video solves a lot of problems. Here are the most common ones.

Add background music

Drop a song under a clip to set the mood.

Replace copyrighted audio

Swap out music that would get your post muted or taken down.

Give a silent clip sound

Add a voiceover or track to a video that recorded no audio.

Sync a song to footage

Put a full song over a montage or slideshow.

Add audio for any platform

A video with your own audio plays everywhere. A few notes for the most popular places.

Instagram and TikTok

Add a sound the platform allows so your clip is not muted.

YouTube

Replace a track that could trigger a Content ID claim before you upload.

iPhone and Android

The new file plays in any gallery or messaging app.

Presentations

Put a soundtrack on a demo or slideshow clip.

Private by design

Most online tools upload both your video and audio to a server. Sondra does not. All the work happens inside your browser on your own device, so your files are never sent anywhere and nobody else can see them.

That also means there is no waiting for long uploads, no account to create, and no limit on how many videos you make. Close the tab and nothing is left behind.