Why turn audio into a video
Many places that host or share media accept video files but not audio files. Video platforms, some social networks, and certain messaging and presentation tools fall into this group. Wrapping the sound in an MP4 with a still picture is the simplest way to get a song, a podcast episode, a lecture or a voice recording accepted there.
Typical uses include:
- publishing a song or a mix with its cover art;
- sharing a podcast episode or radio segment with the show's logo;
- posting a recorded talk with a title slide;
- sending a voice recording through an app that only handles photos and videos.
How the video is built
The converter takes your audio file, whether MP3, WAV or M4A, and combines it with one still picture that stays on screen for the whole duration. You can supply the picture yourself, or use a plain dark background if the sound is all that matters. The video is 1280 × 720 pixels by default, a standard HD frame in the 16:9 shape most players expect.
For the most predictable result, use an image with the same 16:9 proportions, such as a 1280 × 720 or 1920 × 1080 graphic. Album covers and logos are often square, so if you want to control exactly how they sit in the frame, place them on a 16:9 canvas in an image editor first.
Everything is encoded on your device with the browser's built-in video encoder. Nothing is uploaded, and files of up to 1 GB are accepted, one at a time.
Browser requirements
Creating video needs a video encoder, and this tool uses the one built into your browser. It works in current versions of Chrome, Edge and Safari. Firefox can do it where the operating system provides H.264 encoding. If your browser cannot encode video, you see a clear message rather than a broken file, and switching to one of the browsers above solves it.
The opposite direction does not need video encoding: MP4 to MP3 extracts the audio from a video and saves it as an MP3.
MP3 and MP4 compared
| MP3 | MP4 made here | |
|---|---|---|
| Contents | Audio only | Your audio plus a video track showing one still picture |
| Picture | None (some players show embedded cover art) | Your image, or a plain dark background |
| Frame size | Not applicable | 1280 × 720 by default |
| Accepted where only video is allowed | No | Yes |
| Plays on | Audio players, phones, browsers | Video players, phones, browsers |
| Best for | Listening | Uploading where video is required |
Tips for a good result
- Start from your best audio. The video carries the sound of the file you choose, and converting cannot improve it. If you have both a WAV and an MP3 of the same recording, use the WAV.
- Keep text large. If the picture contains a title, use big lettering. Small text can look soft once the picture has been compressed as video.
- Allow time for long recordings. The whole duration has to be encoded as video, so an hour-long recording takes longer than a three-minute song.
- Keep the original audio. The MP4 is for uploading; your MP3, WAV or M4A remains the better file for listening and editing.