Add Music to Video — Multi-Track Audio Mixer

A browser-based tool for adding background music, sound effects, or voiceover to any video. Supports MP4, WebM, MOV, and other formats with volume control and timeline positioning.

How to Add Music to a Video

Upload your video — drag and drop or click to browse

Click "Add Audio Track" to load music, SFX, or voiceover

Adjust volume, position, trim, and fade for each track

Preview the mix, then click "Export Video" to download

Layer background music, sound effects, and voiceover on your video

Process

Upload video file

MP4, WEBM, MOV, MKV, AVI, WMV, FLV, 3GP ·

File:

Duration:

Size:

Resolution:

Video:

Audio:

0:00 / 0:00

Export Settings

Format:

Audio bitrate:

Channels:

Processing canceled. You can start again when ready.

Done!

Process

Features

Up to 4 audio tracks with per-track volume and mute

Layer the original video sound plus three more tracks for music, sound effects, and voiceover, each with its own volume slider and mute.

Live preview via Web Audio API — hear changes instantly

The Web Audio API plays your mix back in real time, so you can balance music against speech before committing to an export.

Trim, offset, fade in/out, and loop each track

Set an exact start offset in seconds, trim each clip, add fade in/out, and loop a short track to fill the full video length.

Runs in your browser via WebAssembly — no installation needed

FFmpeg WebAssembly stream-copies the video and re-encodes only the audio, mixing MP3, WAV, AAC, OGG, FLAC, M4A, or WMA into the file.

Why Use Tembrica to Add Music to Video

Most online tools limit you to a single audio track, add watermarks, or process on their servers. Tembrica gives you a full multi-track timeline with up to 4 audio layers, real-time preview, and browser-based processing. No watermarks, no sign-up, no file size tricks — just a professional audio mixer that runs entirely on your device.

Frequently Asked Questions

How many audio tracks can I add?

You can have up to 4 audio tracks total: the original video audio plus 3 additional tracks for music, sound effects, or voiceover.

Does adding music reduce video quality?

No. By default we use stream copy for the video track — it stays byte-for-byte identical. Only the audio is re-encoded. You can optionally re-encode the video to a different format or quality.

Can I adjust when the music starts playing?

Yes. Drag the audio clip on the timeline or enter an exact offset in seconds. You can also trim the start and end of each audio track independently.

What if my music is shorter than the video?

Enable the "Loop" option in Advanced Settings. The audio will repeat seamlessly until it matches the video duration.

Does adding music re-encode my video?

Only the sound. The picture is stream-copied straight through, so the resolution, bitrate and quality you started with are exactly what comes back — and the export takes seconds rather than minutes, however long the clip is. What gets rebuilt is the soundtrack: up to four tracks mixed down with your per-track volume, offsets, fades and loops.

💡 Want us to improve this tool just for you?

We can! Just send us a quick message with your idea. If you'd like to discuss it in detail, leave your email and we'll get back to you. You can stay anonymous.

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Who is this tool for?

Published 01 Mar 2026 Updated 04 Jun 2026 Author: The Supreme