How to Replace Audio in a Video: Change BGM, Voiceover, Or Any Audio Track

Last Updated: 2026. 07. 03

Replacing audio in a video is a quick way to dramatically improve your content—whether you're fixing unclear sound, removing background noise, changing background music, or swapping in a professional voiceover. With the right tool, the process is simple and doesn't require advanced editing skills.

In this guide, we'll walk you through how to use FlexClip to replace audio in a video in 2 easy methods, depending on your specific use case. Let's get started.

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How to Replace Audio in a Video Online in 2 Ways for Different Cases

We have just a great online tool to help you remove and replace the audio track in a video. It works completely online, so you don't have to download and install any software on your device.

As a powerful online video editor, available both on Mac and Windows, FlexClip can work as a video audio replacer helping you replace audio in a video for free. Here are different options for you to replace the audio in a video: add a new music track from FlexClip's music library or upload your own one, record your own voice-over with its easy voice recorder, and even generate a cool ai voice using its advanced ai text to speech tool.

Here, we'll introduce the 2 audio-replace options separately below, you can choose any method your need or try all of them to find your desired one:

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Method 1 Replace the Audio in a Video with a New Music Track

Not satisfied with the bgm of your video? You can easily change the music to a new one at FlexClip in clicks. You can upload your desired song to replace the music or simply search one from FlexClip's music library.

Step 1
Access FlexClip and upload the video you want to replace the audio from your PC, phone, Google Drive, One Drive or Dropbox, etc., then click the plus icon to add it to the timeline and you may trim or split it when needed.
Replace the Audio in a Video with a New Music Track - Upload

Replace the Audio in a Video with a New Music Track - Upload

Step 2
Go to the timeline, and right-click on the video > select Detach Audio > then FlexClip will automatically extract the audio from the video, and you should see a separate audio track below the video track on the timeline. Meanwhile, an extra extracted audio in WAV format will also be saved to your PC for backup.
Replace the Audio in a Video with a New Music Track - Detach Audio

Replace the Audio in a Video with a New Music Track - Detach Audio

Step 3
Now, you can select the audio track on the timeline and delete it for adding a new one. Here you can upload your own song or pick one from FlexClip's audio library.
Replace the Audio in a Video with a New Music Track - Change Music to a New One

Replace the Audio in a Video with a New Music Track - Change Music to a New One

Step 4
Once you changed the music to your desired one, you can trim it, adjust its volume, add apply fade in/out effect, add change even change the speed to make it perfect your video.
Replace the Audio in a Video with a New Music Track - Edit Music

Replace the Audio in a Video with a New Music Track - Edit Music

Method 2 Replace the Audio in a Video with New Voice-over

Besides change the background music of your video to a new one, you can also record your own voice-over use FlexClip's easy voice recorder for your video narration and replace the original sound.

Shy to use your own voice to replace the audio in the video? Then, you can turn to FlexClip's smart AI text to speech tool to generate an AI voiceover for your video. Voice cloning feature is also available for you to narrate your video with any desired voice. Check the steps below to learn how to use an AI voice to replace the audio track in a video.

Step 1
Also, upload your video, detach and delete the original audio in the video first.
Step 2
Then find the AI Speech tab on the side panel. Here you can pick a perset voice from FlexClip's extensive voice library or try its voice cloning feature to duplicate any voice and use it to replace the audio in your video.
Replace the Audio in a Video with AI Voice - AI Speech

Replace the Audio in a Video with AI Voice - AI Speech

Step 3
Once you selected or cloned the voice you want, just go to the text box, paste or enter the script and click the Generate button to create AI voiceover narration. When it finished, click the the Save to Media button to save the voice track to Media.
Replace the Audio in a Video with AI Voice - Generate Voiceover

Replace the Audio in a Video with AI Voice - Generate Voiceover

Step 4
No, go to the Media and find realistic AI voices track and click the plus icon to add it to the video, drag and drop the audio track to sync with the visuals, and you can adjust the audio narration's volume or trim or split the audio or even apply a fade in/out effect.
Replace the Audio in a Video with AI Voice - Edit AI Voice

Replace the Audio in a Video with AI Voice - Edit AI Voice

Final Words

That's all for the best online free video audio replacers to help you replace the audio in a video. Hopefully, with the method we introduced above, everyone can change the audio in a video and take the video next level with great ease.

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