MP3 to MP4

How an audio file becomes a video

An MP3 has no picture, so making a video from it means supplying one. This tool pairs your audio with a still image, your cover art, a photo, or a plain background, and encodes the two into a standard MP4: the image becomes the video track, the audio plays underneath, and the result ends exactly when the track does.

The encode runs on your own device, which matters more here than for most conversions, because the common reason to need this is unreleased music, a podcast episode, or a demo that has no business sitting on a server you do not control before publication.

• Drop the MP3 and pick a cover image
• Both are encoded locally into a standard MP4
• The video ends when the audio ends, nothing padded

Why platforms force this, and why the file stays small

Video platforms and several social feeds simply refuse bare audio; the accepted workaround has always been a static-image video, which is what this produces. The output is ordinary H.264 and AAC, so it uploads anywhere video is accepted.

Because the picture never moves, the video track encodes at a low frame rate, 5 frames per second by default, which keeps both the encode time and the file size a fraction of what real footage would cost. Nothing about the audio is harmed by the low rate; sound and picture are independent tracks.