Free MP3 to MP4 Converter
Add a cover image to your audio and get an MP4 for YouTube, Shorts, Reels or TikTok — free, no watermark, nothing uploaded.
Want motion instead of a still image? Turn a 5-second clip into a new character or scene with Genjutsu-style AI video, or make your cover sharper first with the free image upscaler.
Keepframe's MP3 to MP4 converter combines an audio file (MP3, WAV, M4A, OGG or FLAC) with a cover image into an MP4 video in 16:9, 1:1 or 9:16. It encodes H.264 video and 192 kbps AAC audio in your browser with WebCodecs, so it is free with no sign-up, no watermark and no upload. Audio up to 30 minutes; needs Chrome, Edge or a recent Firefox.
Facts checked October 10, 2026.
What you get
| Price | Free. No credits, no sign-up, no watermark. |
|---|---|
| Output | MP4 (H.264 video + AAC audio, 192 kbps) in 1920×1080, 1080×1080 or 1080×1920. |
| Privacy | Encoded in your browser with WebCodecs; the audio and image are never uploaded. |
| Limits | Audio up to 30 minutes. Needs a browser with WebCodecs AAC encoding (Chrome, Edge, recent Firefox); older Safari versions may not support it. |
| Best for | Uploading songs, podcasts, voice notes or beats to YouTube, TikTok, Instagram or X, which need a video file. |
| Not the right tool for | Animated visualizers or lyric videos — this makes a still-image video. |
How it works
1. Add audio and a cover
MP3 or any common audio format, plus an optional image. No image? We make a clean title card from the file name.
2. Pick the size
16:9 for YouTube, 1:1 for feeds, 9:16 for Shorts, Reels and TikTok. The cover is centered on a blurred backdrop.
3. Create and download
Your browser encodes the MP4 locally — usually a few seconds per minute of audio.
FAQ
How do I convert MP3 to MP4 with an image?
Choose your MP3, choose a cover image (optional), pick 16:9, 1:1 or 9:16 and click Create MP4. Download the video when it's done.
Is it free and without watermark?
Yes. The MP4 is created in your browser: no credits, no sign-up and no watermark.
Are my files uploaded?
No. Decoding and encoding happen on your device with the browser's WebCodecs API; nothing is sent to a server.
Which sizes are supported?
1920×1080 (YouTube), 1080×1080 (square feeds) and 1080×1920 (Shorts, Reels, TikTok). Your image is centered on a blurred version of itself.
Is there a length limit?
Audio up to 30 minutes. A 3-minute song usually converts in a few seconds.
Which browsers work?
Chrome, Edge and recent Firefox. Some Safari versions can't encode AAC audio locally yet; the page tells you if your browser isn't supported.
What quality is the audio?
AAC at 192 kbps, which YouTube and social platforms accept without re-encoding issues.