Digital Formats · Audio

Digital Audio
Formats

From raw waveforms to compressed streams — how audio data is captured, encoded, and stored.

01 How digital audio is captured

Sound is a continuous pressure wave. To store it digitally, a recording system takes snapshots — samples — of the wave at regular intervals and assigns each a numeric value. Two settings determine the quality of the result.

Sample

Each measurement of the wave's amplitude at a point in time — assigned a numeric value.

8-bit vs 16-bit

Bit depth

Memory allocated per sample. 8-bit = 256 levels, 16-bit = 65,536 levels. More levels = more dynamic range.

44,100 samples/sec

Sampling rate

How many samples taken per second (Hz). CD quality = 44.1 kHz. Higher rate → better high-frequency reproduction.

02 Bitrate & file size

Bitrate = kilobits of audio data processed per second (Kbps). Higher bitrate → better quality → larger file.

.wav
1,411 Kbps
Uncompressed · best quality
.aiff
1,411 Kbps
Uncompressed · Apple equiv.
.mp3
128–320 Kbps
Lossy · very common
.aac
96–256 Kbps
Lossy · better than MP3
.wma
64–192 Kbps
Lossy · Windows-centric
.midi
~1 Kbps
Protocol — no audio data
Note: MIDI contains no audio waveforms — only instructions (note, pitch, timing). File size is negligible.
03 Format profiles
.wav
Uncompressed
Waveform Audio File — created 1991 by Microsoft & IBM for Windows 3.1. The standard for broadcast, editing, and archiving. Large files make it impractical on mobile.
broadcast editing large files
.aiff
Uncompressed
Audio Interchange File Format — Apple's uncompressed equivalent to WAV, released 1988. Preferred on macOS for editing. Same high quality and large file size trade-off.
macOS editing large files
.mp3
Lossy
MPEG Layer 3 — patented 1996. Uses auditory masking to reduce file size by 75–95% while preserving perceived quality. Sparked the digital music era of the mid-1990s.
universal small files irreversible
.aac
Lossy
Advanced Audio Coding — 1997. More sophisticated compression than MP3, achieving better quality at the same file size. Used by YouTube, iOS, Android, and gaming platforms.
YouTube iOS/Android better than MP3
.wma
Lossy
Windows Media Audio — released 1999 by Microsoft to avoid MP3 licensing fees. Similar quality-to-size ratio as MP3. Primarily Windows-centric and not widely supported elsewhere.
Windows only limited support
.midi
Protocol
Musical Instrument Digital Interface — late 1980s. Contains zero audio data — only instructions: which notes, when, how long, at what velocity. Tiny files, infinitely editable.
tiny size editable no audio data
04 Side-by-side comparison
Format Compression Editable Mobile-friendly Best for
.wav None Yes No Recording, broadcast
.aiff None Yes No Mac editing, archiving
.mp3 Lossy Limited Yes Music, podcasts
.aac Lossy Limited Yes Streaming, apps
.wma Lossy Limited Windows Windows Media Player
.midi N/A Fully Yes Music production
Uncompressed
Lossy compressed
Protocol (no audio data)
Digital Literacy · 2025