Which bitrate should I pick?

192 kbps is transparent for most listening. Use 320 kbps if you want the maximum MP3 quality, or 128 kbps if file size matters more — for speech recordings even 128 kbps is plenty.

Are my files uploaded?

No. The first time you use an audio/video tool, your browser downloads the open-source FFmpeg engine — a 32 MB file, roughly 10 MB once your connection compresses it — as a static file, and that is the only network traffic. Your media files are then processed entirely on your device and never reach a Filesvo server.

Why is processing slower than a desktop app?

The FFmpeg engine runs inside your browser's WebAssembly sandbox on a single thread, which is several times slower than a native install. Short clips finish quickly; re-encoding long videos can take minutes. The progress bar shows the honest state, and you can cancel at any time.

Does this work on phones?

Yes on recent devices, with limits: the engine is a 32 MB file (roughly 10 MB compressed in transit), and phones have less memory available to the browser, so large videos can fail on mobile. If a file fails on your phone, try a smaller file or a desktop browser. The 100 MB per-file limit applies everywhere.

Convert MP4 to MP3 Online

Pull the sound out of a video: this tool decodes your MP4's audio track and re-encodes it as a standard MP3 you can play anywhere. Pick a bitrate, press the button, and download — the video itself never leaves your device.

or drag and drop a .mp4 / .m4v file here — up to 100 MB

This tool runs the open-source FFmpeg engine in your browser. First use downloads it once (a 32 MB file, roughly 10 MB compressed in transit); after that it loads from your browser cache. Your files are never uploaded. The engine is ffmpeg.wasm, distributed unmodified under the GPL-2.0-or-later.

Processed on your device — files are never uploaded to Filesvo.

How to use Filesvo

Select or drop an MP4 video (up to 100 MB).
Choose an MP3 bitrate — 192 kbps is a good default.
Click Extract MP3, watch the progress bar, and download the result.

About extracting MP3 from MP4

An MP4 file is a container holding separate video and audio streams. This tool ignores the video stream entirely and re-encodes the audio stream with the LAME MP3 encoder at the bitrate you choose, so the output plays in every music app, car stereo and browser.

Because the audio is re-encoded rather than copied, the conversion works no matter which audio codec the video uses — AAC, Opus or anything else FFmpeg can decode. Re-encoding is lossy, but at 192 kbps and above the difference from the source is inaudible for most content.

The FFmpeg command this runs

This tool is FFmpeg itself, compiled to WebAssembly and running in your browser. Below is the command it builds with the options set as they arrive — generated from the same code that performs the conversion, not written out by hand, so it cannot drift out of date. Paste it into a terminal with FFmpeg installed and it does the same job there.

ffmpeg -y -i input.mp4 -vn -c:a libmp3lame -b:a 192k output.mp3

What each option on the tool changes in that command:

MP3 bitrate

128 kbps — smaller file — -b:a 128k

192 kbps — recommended — -b:a 192k

320 kbps — highest quality — -b:a 320k

The input and output names are placeholders. Your own filenames are used inside the browser, and neither file leaves your device.

Private by design

Your files are processed directly in your browser using the open-source FFmpeg engine compiled to WebAssembly and are not uploaded to Filesvo. Nothing is stored on our servers, because nothing ever reaches them.

The engine is a static file your browser downloads once and then caches — the only network request this tool makes. It is used exactly as its authors published it; see the engines and their licences.

Frequently asked questions

Which bitrate should I pick?: 192 kbps is transparent for most listening. Use 320 kbps if you want the maximum MP3 quality, or 128 kbps if file size matters more — for speech recordings even 128 kbps is plenty.
Are my files uploaded?: No. The first time you use an audio/video tool, your browser downloads the open-source FFmpeg engine — a 32 MB file, roughly 10 MB once your connection compresses it — as a static file, and that is the only network traffic. Your media files are then processed entirely on your device and never reach a Filesvo server.
Why is processing slower than a desktop app?: The FFmpeg engine runs inside your browser's WebAssembly sandbox on a single thread, which is several times slower than a native install. Short clips finish quickly; re-encoding long videos can take minutes. The progress bar shows the honest state, and you can cancel at any time.
Does this work on phones?: Yes on recent devices, with limits: the engine is a 32 MB file (roughly 10 MB compressed in transit), and phones have less memory available to the browser, so large videos can fail on mobile. If a file fails on your phone, try a smaller file or a desktop browser. The 100 MB per-file limit applies everywhere.

Compress Audio

Shrink MP3, WAV, M4A, OGG and FLAC files to a bitrate you choose, with honest before/after sizes.

WAV to MP3

Convert uncompressed WAV recordings into small, universal MP3 files at the bitrate you choose.

Video Trimmer

Cut a clip out of a video with a live preview — frame-exact re-encode or instant lossless keyframe copy.