How long does conversion take?

Audio extraction is usually faster than real-time. ffmpeg.wasm is downloaded once (~25 MB) and cached by the browser.

Is my video uploaded?

No — ffmpeg.wasm runs inside your browser. The MP4 is processed locally and discarded as soon as you close the tab.

192 kbps is transparent for speech and most music. 128 kbps is fine for podcasts. 320 kbps for archival quality.

MP4ビデオからMP3オーディオを抽出。ffmpeg.wasmを使用、ブラウザ内で完結。

100% in your browser. Your file never leaves your device.

MP4 video file

MP3 bitrate

Pick an MP4 file to begin.

Podcasting: isolate the audio track from a video interview for hosting on Spotify/Apple Podcasts.
Voice memos: iPhone screen recordings produce MP4 — pull out the audio for transcription.
Lectures & talks: turn recorded video lectures into MP3 audiobooks for offline listening.

How long does conversion take?: Audio extraction is usually faster than real-time. ffmpeg.wasm is downloaded once (~25 MB) and cached by the browser.
Is my video uploaded?: No — ffmpeg.wasm runs inside your browser. The MP4 is processed locally and discarded as soon as you close the tab.
Which bitrate should I choose?: 192 kbps is transparent for speech and most music. 128 kbps is fine for podcasts. 320 kbps for archival quality.

Last updated: 2026-05-20 By jarvisbox