Add Audio to MP4 Online
Add sound to MP4 videos easily without leaving your web browser, no installs, no delays, just fast editing with full control.
Over 500,000 creators use Flixier every day including brands like:
Why Use Flixier to Add Audio to MP4
Add music to MP4 from any browser
Upload tracks from your computer, cloud storage, or Soundcloud and add music to your videos online. Everything happens in the browser, so no extra software is needed.
Record voiceovers and add them to your MP4
Flixier’s built-in Record function lets you capture sounds using your computer’s microphone. You can then edit like any other track and add them to your videos easily. Cut out anything you don’t like, enhance audio, and sync it with your MP4 video.
Add copyright-free music to your video
Access our built-in Library of copyright-free music tracks, which you can safely add to your videos. Avoid copyright issues on video-sharing websites like YouTube.
Edit and publish in minutes
Flixier runs in the cloud, so you can run it smoothly on any computer (Mac, Windows, Linux, or ChromeOS). Export in minutes directly to YouTube, with no time wasted and no fragmented workflow.
How to add audio to MP4:
Upload
Add audio track to MP4
Export
Who this is for
Educators
Business Owners
Social Creators
Need More Than Adding Audio to MP4?
Edit easily
With Flixier you can trim videos or add text, music, motion graphics, images and so much more.
Publish in minutes
Flixier is powered by the cloud so you can edit and publish your videos at blazing speed on any device.
Collaborate in real-time
Easily collaborate on your projects with Flixier, we offer real-time feedback and sharing of projects.
Still have questions?
We got you!
You can add MP3 audio files to your MP4 videos easily and quickly with Flixier.
Flixier is compatible with all the popular audio formats, so you can use it to add any type of audio file to your videos, regardless of format. Our tool will automatically convert your audio to MP3 when you upload it.
Flixier allows you to create as many audio tracks as you want on the Timeline, so you can easily mix music with dialogue and other sound effects. However, when exporting your video, all the sounds will be mixed on the same track.
Flixier supports audio and video file formats, from MP4 to MOV, AVI, MKV, and audio like MP3, WAV, AAC, and more.
Yes, Flixier allows you to raise, lower, or mute audio directly in the Object Inspector.
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