Video to MP3

Why MP3, and when not to bother

MP3 is thirty years old and that is exactly its strength: every car stereo, every cheap Bluetooth speaker, every dictation app, every upload form and every editor accepts it without a word. If the file has to go somewhere you do not control, MP3 is the answer.

If it is going to stay on your own devices, it is worth knowing that MP3 is the one format here that can never be a straight copy. Videos do not carry MP3 — they carry AAC, Opus or AC-3 — so an MP3 always means re-encoding audio that has already been encoded once. M4A avoids that entirely for anything filmed on a phone, and plays on every phone and computer made this century.

What your video probably has inside it

How long it takes

MP3 encoding in the tab runs at roughly twenty times real time, single-threaded: a 5-minute video is about fifteen seconds, an hour-long recording is about three minutes, and the progress bar is fed by FFmpeg's own position rather than a guess. You can cancel at any point and nothing half-written is left behind.

A copy — the same video out as M4A — is seconds instead, because the audio is never decoded. If you are converting a long recording and do not specifically need MP3, that is the option worth taking.

Getting the quality right

Three rules cover almost everything. Never ask for a higher bitrate than the soundtrack already has, because it cannot add detail and only adds bytes. For speech, 64 or 96 kbps in mono halves the file again and sounds the same. And if the file is going into an editor or a transcription service rather than a player, skip MP3 and take WAV — those tools want uncompressed audio and will thank you for it.