Everyone knows MP3, but at the same file size it sounds worse today than everything that came after it. Which audio format is right for music, speech, archiving and the web, and why "the best quality" and "runs everywhere" rarely mean the same format.
The basics: lossy vs. lossless
A CD recording has a data rate of around 1,411 kbit/s (44.1 kHz, 16 bit, stereo). Nobody streams it like that, so instead you compress.
There are two worlds here:
- Lossy: MP3, AAC, Opus. Using psychoacoustic models, these codecs deliberately throw away information the human ear barely perceives anyway. The result is far smaller, but no longer identical to the original.
- Lossless: FLAC, WAV. Here every bit is preserved. Perfect for archiving and editing, but correspondingly large.
The crucial point: codecs are not equally good. That's exactly why Opus at 96 kbit/s often sounds as good as MP3 at 128 kbit/s. Bitrate alone says nothing about quality, since the codec decides how cleverly those bits are used.
The five formats in detail
MP3: the universal veteran
MP3 is the format that made digital music popular. Its biggest advantage today is simply ubiquity: every device, every operating system, every car radio, every ancient player plays MP3. On top of that the patents have now expired, making MP3 completely royalty-free.
Technically, though, it's inferior to its successors. Below 128 kbit/s artifacts quickly become audible. For music you should stay at 192–320 kbit/s. MP3 is the right choice when you don't know what your file will be played on.
AAC: the better standard
AAC (Advanced Audio Coding) was designed as the official MP3 successor and is part of the MPEG-2 / MPEG-4 standards. At the same bitrate AAC sounds audibly better: 128 kbit/s AAC roughly equals 192 kbit/s MP3. That saves about 20 % bandwidth at the same perceived quality.
AAC is Apple's default format and is natively supported by iOS, macOS, Windows, Android and practically all streaming services. Small catch: the best AAC encoder comes from Apple and runs only on macOS/iOS, so other encoders are good, but not quite at that level.
Opus: technically the best lossy codec
Opus (IETF, RFC 6716, standardized in 2012) is considered the best lossy audio codec currently available. It combines the speech engine SILK (originally from Skype) with the music codec CELT and thereby covers everything, from speech to music and from 6 to 510 kbit/s.
Its strengths:
- Better quality at any bitrate. At 96 kbit/s Opus is roughly on par with AAC at 128.
- Extremely low latency (around 5 ms algorithmic delay), which is why Opus is the standard for WebRTC, video calls and VoIP.
- Top class for speech: an intelligible voice from as little as 16–24 kbit/s.
- Completely open and royalty-free.
The drawback is compatibility: on iOS, Opus isn't natively supported as a music format (it works on the web via WebM), and some older hardware players or car radios don't know it.
FLAC: lossless and compact
FLAC (Free Lossless Audio Codec) compresses without any quality loss, typically shrinking a WAV file to 50–60 % of its size. The original can be reconstructed bit-for-bit. FLAC is the right choice for the music archive, for audiophile listening and anywhere the original must be preserved, just 3–5× larger than a good lossy file.
WAV: uncompressed raw format
WAV stores pure, uncompressed PCM audio. It's huge, but has no processing overhead. That makes it ideal as a working and mastering format in audio editing, but unsuitable for storing larger collections or for streaming.
Direct comparison
| Format | Type | Quality/bitrate | Compatibility | License | Best use case |
|---|---|---|---|---|---|
| MP3 | lossy | solid | universal | royalty-free | maximum compatibility |
| AAC | lossy | very good | very broad | licensed | streaming, Apple world |
| Opus | lossy | best | good (web/mobile) | royalty-free | speech, web, real-time |
| FLAC | lossless | perfect | good | royalty-free | archive, audiophile |
| WAV | uncompressed | perfect | universal | royalty-free | editing, mastering |
Decision guide
- Stream music / broad audience → AAC at 128–256 kbit/s
- Speech, podcast, real-time, full control over the clients → Opus at 48–96 kbit/s
- Guaranteed to run everywhere → MP3 at 192–256 kbit/s
- Archive, lose nothing → FLAC
- Cut, master, process further → WAV
- Self-hosted podcast feed → AAC (
.m4a) or MP3 for maximum reach; Opus only if you know all the end devices
Common case: WAV from MP3 for editing
A typical scenario: you have an MP3 but want to work with it in an audio editor and need an uncompressed WAV for that. Important to know: the MP3 → WAV conversion does not restore any quality, because the information discarded during MP3 encoding is gone. But you get a lossless working format that every editor handles cleanly and that isn't compressed again during further editing.
Convert audio with wandlio
If you want to convert audio formats quickly and without uploading:
- MP3 → WAV: uncompressed working format for editing
Your file is always deleted after conversion, with no account and no permanent upload.