Pull the audio out of any MP4. Drop in a video from your phone, a screen recording, a concert clip, or a downloaded lecture, and Solmi decodes its audio track and re-encodes it as a standard MP3, right in your browser. The video never leaves your device and there is no upload wait.
1. Choose the MP4 from your computer or phone. 2. Pick the MP3 bitrate: 192 kbps is the default, 320 kbps for music, 128 kbps for speech. 3. Press Convert. Your browser reads the audio track and Solmi encodes it as MP3; the video is not uploaded. 4. Play the MP3 on the page, then download it.
The audio in an MP4 is usually AAC at 128 to 256 kbps, so an MP3 at a much higher bitrate than the source only makes a bigger file.
| MP3 bitrate | Size per minute | Use it for |
|---|---|---|
| 128 kbps | About 1 MB | Lectures, interviews, meeting recordings |
| 192 kbps (default) | About 1.4 MB | Most phone videos and screen recordings |
| 256 kbps | About 1.9 MB | Concert clips and music videos |
| 320 kbps | About 2.4 MB | Music you will edit or master later |
The converter runs in the phone's browser, with no app to install. Choose the video from your files or your gallery, convert it, and download the MP3. The work uses the phone's own processor and memory, so a very long video takes longer than it would on a laptop.
Only the audio track is decoded, in your browser, and the MP3 is encoded on your device. Nothing is sent to a server, which is why there is no upload wait and no file-size paywall, and why a private recording stays private.
Drop the MP4 onto the converter, pick an MP3 quality, and press Convert. Your browser reads the file's audio track, Solmi re-encodes it as MP3, and the download appears on the page. Nothing is uploaded, so a long video converts in about the time it takes to encode.
MP4 audio is usually AAC, which is already compressed, and MP3 compresses again, so there is a small loss on paper. At 192 kbps or higher the difference is inaudible on normal speakers or earbuds. Choose 320 kbps if the source is music you care about.
Yes. There is no server quota, so the limit is your device's memory. A two-hour MP4 decodes to a large audio buffer, which works on a laptop or a recent phone; on an older phone, split the file first.
No. A clip with no audio track has nothing to extract, and the browser will report that it could not decode the file.
MOV works in every browser and WebM in Chrome and Firefox. Use the Video to MP3 page for those. MKV is not decoded by browsers, so remux it to MP4 first.
No. This converter does not download from YouTube or any other site; it converts MP4 files that are already on your device. If the video is yours, download it from your own account first, then drop the file in.
No. The converter runs entirely in your browser: your file is decoded and re-encoded on your own device, and nothing is sent to a server. That is also why it is fast — there is no upload wait and no download wait, just the conversion itself.
Yes, completely free with no signup, no file-size paywall, and no watermark. Once your audio is converted, you can turn the track into a music video with Solmi's AI music video generator — also free to start.