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.
How to add audio to MP4:
1
Upload
Drag your audio and your MP4 files over to the Library or click the Import button to bring them over from your device or cloud storage services. You can also use the Record option to record a voiceover using your computer’s microphone.
2
Add audio track to MP4
Drag your video and your audio down to the Timeline. Use the Cut button to cut out any parts you don’t like, drag on the edges of your audio or video clips to trim their duration, and use our precise Timeline to synchronize everything.
You can also use the Object Inspector menu on the right side of the screen to apply a custom Equalizer, add Fade Ins, and other effects for better sound.
3
Export
When you’re done adding music to your MP4, click the Export button in the top right corner and then click on Export and Download. Flixier processes everything in the cloud within minutes, and you’ll be able to save it to your computer or publish it straight on YouTube or other social media platforms.
Why use Flixier to add music to MP4 online?
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.
More "add audio to MP4" tools?
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.
You`re ingood hands
Over 1 million creators use Flixier every month including brands like:
Frequently
Asked
Questions
Can I add MP3 to MP4 video?
You can add MP3 audio files to your MP4 videos easily and quickly with Flixier.
Can I add any audio format to MP4 video?
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.
Can I add multiple audio tracks to an MP4 with Flixier?
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.
What video and audio file formats are supported?
Flixier supports audio and video file formats, from MP4 to MOV, AVI, MKV, and audio like MP3, WAV, AAC, and more.
Can I adjust audio volume in Flixier?
Yes, Flixier allows you to raise, lower, or mute audio directly in the Object Inspector.
