toolkitta.
Local file processing

Add Music to Video

Put a song or voice-over on your video: mix it under the original sound or replace it, pick where the song starts and how loud it is. Nothing is uploaded.

Your videos and music are never uploaded
  • Music, fades & original sound
  • No uploads · Preview before downloading

Use this focused tool, then choose Edit in editor to carry originals and settings onto the timeline.

About Batch and Interactive Editor

How to use Interactive Editor

  1. Open Batch originals as a sequence, or choose Edit in editor to also carry your current settings.
  2. Select a clip to trim, split, slip, set speed, frame the picture or mix its sound. Add tracks, titles, images and music; Undo keeps changes reversible.
  3. Export MP4/WebM or explicitly save a project to keep originals and tracks editable. A recipe repeats the arrangement in either workflow mode.

Mode switching resumes independent sessions. Editor output uses one frame size up to a 1,920 px longest side / 30 fps, and re-encodes frames. Batch retains its existing fast operations and limits. Trim/Crop Batch still edit one video at a time.

Editor limits: 20 sources / 1 GB total, videos up to 500 MB and 15 minutes each, audio up to 50 MB / 15 minutes, 30-minute output. Saved projects include originals and their metadata. Recipes contain only settings and generic source slots; nothing is saved automatically.

How it works

How to add music to a video in Batch

  1. Add up to 20 MP4, MOV, MKV or WebM videos, 500 MB each.
  2. Click Choose music and pick an MP3, M4A, WAV, FLAC, OGG or Opus file. Choose Mix to keep voices with the music underneath, or Replace to use only the music.
  3. Set the volume, skip an intro with Start song here or Song starts at, and play a video preview to hear the mix. Then click Add music. Play each result and download one video or a ZIP.

Hear speech with background music

Compare the spoken video with the mixed result. The English speech is a public-domain LibriVox reading by Kara Shallenberg of Arthur Conan Doyle’s The Red-Headed League; the short melody was composed for this example.

Speech source and public-domain dedication

Before: speech only
Before: speech only · MP4
After: speech + music at 35%
Download the mixed example

The example loads a 12-second, 640 × 360 video and a separate music file. Keep Mix and 35% music volume, play the preview, then click Add music and download. Replace removes the spoken voice; use it when you want music only.

Download the music input · WAV

Measured in Toolkitta on 29 October 2026. Both clips keep the 12-second picture at 640 × 360; the result re-encodes the audio. These sample sizes do not predict the size of your own recording.

Measured sizes: 238.5 KB → 230.2 KB

Frequently asked questions

Useful details

5 answers
Can I arrange clips on a timeline?

Yes. Interactive Editor offers tracks, trim/split/slip, per-clip speed, framing, titles and audio mixing. Edit in editor carries Batch originals and settings. Each mode retains its own session.

Can I keep the original sound?

Yes. Mix keeps the video's own sound and plays the music under it at 35% by default; raise or lower it with the volume slider. Replace drops the original sound. A video without sound always gets the music as its only sound.

Can I start the song from the chorus?

Yes. Play the song, pause at the chorus and press Start song here, or drag Song starts at. Then play a video preview: the song plays along from that moment, at the chosen level, so you can check the mix before saving.

Which music can I use?

Any audio file your browser can decode, up to 15 minutes. Make sure you have the rights to use the song where you post the video; platforms may mute or block copyrighted music.

Is my video uploaded?

No. The video and the music are read and mixed in your browser on this device, and there is no watermark.

More help

Guides, common conversions and useful next steps.

Edit the video

Arrange clips, music and titles together on a local timeline.

Continue with your result

Use the action beside a finished result to send it directly, or open another tool: