Convert Audio to Video (MP3 → MP4)

How to Turn an Audio File into an MP4 Video

Many platforms will not accept an audio file on its own; they want a video, even if the content is only sound. This tool solves that: upload an MP3, WAV or M4A file, choose a background color, and you get an MP4 that shows a solid color for the full length of the audio. It suits podcasters, people who record audio lessons, and anyone who wants to share a voice message on a video platform.

The conversion runs in your browser using ffmpeg.wasm, which is downloaded from the internet on first use. Your audio file stays on your device and is not uploaded to any server.

How to use it

1. Drag the audio file into the drop area, or click it and choose the file.
2. In Background color, open the color picker and pick a color that matches your brand. The default is an indigo blue.
3. Click Convert to video (MP4).
4. Wait for the processing library to load the first time, then watch the progress bar while the video is created.
5. The video downloads automatically with the same name as your audio file and an .mp4 extension.

Output specifications

• 1280x720 (HD) resolution in 16:9, the shape most video platforms expect.
• H.264 video with AAC audio at 192 kbps, a combination that plays on nearly every device.
• A very low frame rate (2 frames per second), since the picture never changes, which keeps the file close to the size of the audio.
• The video lasts exactly as long as the audio.
• A single-color background of your choice.

When you need it

• Publishing a podcast episode on a video platform that does not take audio uploads.
• Adding a recorded lesson or talk to an educational video playlist.
• Preparing a base clip to drop into an editor and layer text or images on top.
• Sharing a voice message or song in an app that only shows videos.

Tips and notes

• Use a color that fits your channel and keep it the same across episodes so viewers recognise you.
• The tool does not add a cover image, text or waveform; the background is a plain color. Add other elements in an editor afterwards.
• The audio is re-encoded to AAC, so a low-quality original will not improve.
• Very long recordings take longer and need more memory because everything runs in the browser.
• Keep the page open until the success message appears.

To do the reverse and pull audio out of a video, use video to MP3. To put your logo on the result, try video watermark, or shorten it with the video trimmer.