An MP3 file contains audio but no video frames. This converter keeps the soundtrack and renders a new visual track, so the exported MP4 can be played as a video. It does not create filmed scenes or preserve frames from an uploaded source video.
See real examples
Explore the examples ↗Supported formats
MP3, WAV, M4A, AAC, FLAC and OGG audio; MP4, MOV, WebM and MKV with sound. Export H.264/AAC MP4 in 9:16, 16:9 or 1:1 at 720p or 1080p.
How it works
1. Choose a short recording
Upload an MP3 or another supported audio file. For a podcast, trim to a self-contained excerpt before uploading; this tool does not automatically select highlights.
2. Choose the visual treatment
Select a background, title and aspect ratio. Keep captions enabled for speech or disable them for instrumental audio. The soundtrack is retained in the result.
3. Check captions and export
Generate, listen to the result and correct names or timing where needed. Regenerate after editing, then download the MP4 before it expires.
Limits and privacy
Up to 100 MB and 10 minutes per audio or video upload. Free without sign-up or payment; shared queue and hourly usage limits apply. Private results expire after 24 hours.
What to check before sharing
Speech recognition can make mistakes. The tool does not automatically remove background noise, identify speakers, translate speech or choose podcast highlights. A vertical MP4 is not automatically published to any social platform.
Common questions
Does changing MP3 to MP4 improve audio quality?
No. The MP4 adds a visual track and encodes the soundtrack as AAC; it does not restore detail missing from the source.
Can I use this for a podcast clip?
Yes. Upload a short excerpt and choose a caption layout. Review the transcript before sharing, especially names and overlapping speech.
Can I upload a video instead?
Yes, if it has an audio track. The converter uses that soundtrack to generate new visuals; it does not keep the original video frames.