There are two kinds of audio files: the ones that throw data away to save space (lossy), and the ones that don't (lossless). Most people can't hear the difference. Audiophiles will tell you otherwise, at length. The real question isn't quality — it's what your device, your app, and the person you're sending it to can actually open.
MP3 is universal. AAC is better but less recognisable. FLAC is lossless but bigger. WAV is uncompressed but enormous. OGG is technically superior but nobody's phone plays it. The format landscape for audio is simpler than video — there are fewer containers to worry about — but the lossy-vs-lossless decision matters more because audio enthusiasts have strong opinions and recording engineers have legitimate needs.
For music distribution, MP3 at 320 kbps or AAC at 256 kbps is transparent for most listeners. For archiving, FLAC preserves everything. For recording and editing, WAV is the working format. For voice memos and podcasts, AAC in an M4A container is the modern default.
| Format | Type | Quality | File size | Best for |
|---|---|---|---|---|
| .mp3 | Lossy | Good (320 kbps) | ~1 MB/min | Universal sharing |
| .aac | Lossy | Better than MP3 | ~1 MB/min | Streaming, Apple |
| .ogg | Lossy | Better than MP3 | ~1 MB/min | Open source, games |
| .flac | Lossless | Perfect | ~5 MB/min | Archiving, audiophiles |
| .wav | Uncompressed | Perfect | ~10 MB/min | Recording, editing |
| .m4a | Lossy/Lossless | Varies | ~1-5 MB/min | Apple ecosystem |