What does MP3 to MP4 Converter do?
MP3 to MP4 builds a video from an audio file. An MP3 has no frames, so the picture is a cover image, a solid color, a vertical gradient, or the default dark background. Choose 16:9, 9:16, 1:1, or 4:5 at 720p or 1080p. Fit a cover with contain or cover, set its position, volume, and optional fades. The export keeps the full audio duration and uses H.264 plus AAC. It does not recover footage that was never in the file.
How to use MP3 to MP4 Converter
- 1Upload an MP3 and wait for its duration.
- 2Add a cover or choose a color, gradient, aspect ratio, and resolution.
- 3Set fit, position, volume, and fades. Fades must be shorter than the audio.
- 4Create the MP4, check the duration and file size, then download. Cancel stops the local encode.
Supported inputs and outputs
Inputs
MP3 audio, Optional JPG, PNG, or WebP cover
Outputs
MP4 with H.264 video and AAC audio
Practical uses
- Making a still-picture video for a podcast clip
- Pairing cover art with a song before uploading
- Choosing a vertical or square frame for a short
Browser and media limitations
- The picture is a still cover or background. This does not create original video footage.
- An animated WebP cover contributes its first frame only.
- Export supports files up to 40 MB and 15 minutes.
- Fades are optional and their combined length must be shorter than the audio.
- The media engine downloads on first use. Your file is not sent to a processing server.
How local processing works
Your media is processed locally in your browser and is not uploaded to Tubelexity for processing. FFmpeg.wasm is downloaded on first use, but your media is not sent to a processing server.
What a sample MP3 becomes
This example uses a generated sample, not a user file. An MP3 has no video frames. A 16:9 720p export is 1280 by 720 pixels, and a 9:16 1080p export is 1080 by 1920. The same cover or background is held for the whole audio duration. The picture is H.264 and the sound is AAC. Volume and optional fades change the audio filter. They do not trim the file.
A cover that is an animated WebP contributes its first frame only. The preview canvas is the frame that is looped. If you need the picture to react to the music, use the music visualizer, which is a different tool with a 40 second export limit.
Frequently asked questions
Can an MP3 file be converted into MP4?
Yes. The MP4 pairs the MP3 audio with a picture you choose. The sound is re-encoded as AAC and the picture is H.264.
Does MP3 contain video?
No. An MP3 is audio. The video frame is the cover, color, or gradient shown in the preview.
How do I add an image to an MP3?
Upload the MP3, choose a JPG, PNG, or WebP cover, then set contain or cover and the image position. Create the MP4.
How can I make an MP4 from audio for YouTube?
Use 16:9 at 720p or 1080p for a standard frame, or 9:16 for a vertical frame. The duration follows the audio. Tubelexity does not upload the file.