MP3, M4A, Opus or WAV — Which Should You Actually Pick?
Four formats, four genuinely different answers. The right pick depends on what you are doing with the file, not on which is "best".
Short answer: MP3 if it needs to play anywhere, M4A on Apple devices, Opus if size matters, WAV if it is going into editing or transcription software. The longer answer explains why.
One thing to understand first
When you extract audio from an online video, the source is already compressed. Converting that to WAV does not restore anything — it stores the same audio in a much bigger file. Quality is capped by the source, always.
What you are really choosing is how much further to compress, and what will play the result.
MP3 — the safe default
Thirty years old and still the correct answer surprisingly often. Every phone, car stereo, games console, smart speaker and cheap MP3 player made this century handles it. Its compression is not the most efficient any more, but at a decent bitrate the difference is inaudible to most people on most equipment.
Pick MP3 when: you want zero compatibility thinking, you are putting files on an older device or in a car, or you are sharing with someone whose setup you do not know.
M4A — better compression, Apple-friendly
M4A wraps AAC audio, which beats MP3 at the same bitrate. It is the native format across the Apple ecosystem and plays fine on modern Android and Windows too.
Pick M4A when: you are on iPhone, iPad or Mac, or you want better quality per megabyte and your devices are recent.
Opus — the technically best, if it plays
Opus is the most efficient of the four by a clear margin, especially at low bitrates where speech stays intelligible in remarkably small files. It is the modern choice on paper.
The catch is compatibility. Modern browsers, VLC and current Android handle it happily. Older car head units and some portable players do not.
Pick Opus when: you are storing a lot of spoken-word audio, you are short on space, and you know what will play it.
WAV — uncompressed, and enormous
WAV applies no compression, so nothing is discarded in the conversion step. A minute is roughly 10MB, against about 1MB for a good MP3.
The genuinely useful case is as an input to something else: transcription tools, editing software and audio analysis all prefer uncompressed input, because they would rather not decode someone else's compression first.
Pick WAV when: the file is going into transcription, an edit, or any further processing. Not for listening — you are spending ten times the disk for no audible gain.
Quick reference
- Podcast on my phone — MP3, or M4A on an iPhone.
- Music for the car — MP3. Car stereos are conservative.
- Lots of lectures, limited space — Opus.
- Feeding it to a transcription tool — WAV.
- Not sure — MP3. Genuinely.
Boo extracts the best available audio stream and converts locally with a bundled converter, so you avoid the double re-encoding that online conversion sites introduce.
Quick answers
Which audio format has the best quality?
WAV, because it is uncompressed — but it can never exceed the source. If the source is a compressed stream, WAV just stores that same audio in a much larger file.
Is Opus better than MP3?
Technically yes — Opus delivers better quality at the same file size. MP3 wins on compatibility, since essentially every device made in the last twenty-five years plays it.