MP3 to MP4 Converter

YouTube only takes video files, so an MP3 can't go up on its own. The usual answer for a song, a mix or an hour of rain is one picture with the audio underneath, saved as an MP4. That is what this converter makes.

The picture is turned into one 10-second piece at one frame a second, and that piece is repeated for the length of the track. So the picture side of the export takes seconds, whatever the length. When the video matches the track's length, MP3 and AAC audio are copied in untouched. Other formats, and tracks repeated to a longer length, are converted.

1080p is 1920 x 1080 and 4K is 3840 x 2160, both in YouTube's 16:9 shape. Pick 4K when your image is at least 3840 pixels wide. A smaller image gets stretched to fill the frame, so it won't look any sharper than at 1080p.

Fill crops your image to 16:9. Fit with blurred edges shows the whole picture over a soft, darker copy of itself, which suits square cover art. Before you start, the line above the button shows the length, the size and the most the file can weigh.

Add more than one photo and it becomes a photo to video maker. Change image sets the pace: evenly across the audio, every 1 minute or every 5 minutes, with a 1-second crossfade each time. On a long track your photos go round in order until the audio ends.

Gentle zoom pushes slowly in and out over 20 seconds, so the picture never sits still. With one photo it stays quick to export. With several photos and zoom, every frame is drawn, so a long video can take as long as it plays.

Length can match the audio or repeat it to 1, 2 or 3 hours, which is how sleep and study videos get their length from a shorter track. The repeats join with no gap, and the last 3 seconds fade out.

The video is made in your browser and saved straight to your device. Your audio and images are never uploaded. Videos up to 10 minutes are free, and longer ones, up to 3 hours, need a free Chillframe account. Keep the tab open until it's done.