Is my audio uploaded anywhere?

No. A full copy of ffmpeg runs inside the browser tab as WebAssembly. The file never leaves the device, and there is no server, no account and no advertising.

Does converting MP3 to FLAC restore quality?

No. Whatever an MP3 encoder threw away is gone for good. A FLAC made from an MP3 is simply a much larger file holding exactly the same sound.

What does evening out the loudness do?

It measures the perceived loudness of the whole track to the EBU R128 standard and adjusts it to a target, so quiet passages come up and peaks come down. Around -16 LUFS suits podcasts and streaming; -23 LUFS is the broadcast standard.

Can it join several files into one?

Yes. Drop them in, put them in the order you want by dragging, and switch on joining. They are decoded and written as one continuous track, with an optional gap between them.

Why is the first conversion slow to start?

The ffmpeg engine is a 30 MB download the first time. It is then kept in the browser's own storage, so every later visit starts immediately and works offline.

Audio Converter — MP3, FLAC, WAV, Opus, M4A, AIFF

Files

Drop audio or click to choose

MP3, WAV, FLAC, M4A, AAC, OGG, Opus, AIFF, WMA, AMR, video files — anything ffmpeg reads. Nothing is uploaded.

What to make of them

Selected file

Output format

Rate control

Bitrate

192 kbps

Stream

Sample rate

Channels

Level

Gain

0.0 dB

Even out the loudness

Measures the whole track to EBU R128 and lands it on a target

Clean-up

Low cut

off

Rolls off rumble, wind and handling noise below the chosen point. 80 Hz is gentle on speech; leave it off for music with real bass.

Trim silence at both ends

Cuts anything under -50 dB before the first and after the last sound

Shape

Fade in

0.0 s

Fade out

0.0 s

Tempo

1.00×

Speeds the track up or slows it down without moving the pitch. Past about half or double speed it starts to sound processed.

See the sound, cut where you mean to.

Field recordings, voice notes, whole albums, the audio out of a video — drop them in, drag across the waveform to keep just the part you want, and take it out as MP3, FLAC, WAV or anything else. Nothing leaves this device.

10 formats · waveform trimming · join tracks · nothing uploaded

BIASAAUDIO CONVERTER

Audio Converter — ffmpeg and a waveform, inside a browser tab

What it writes

Questions

See the sound, cut where you mean to.