Formato file

Informazioni sui file AU

AU (Sun AU Audio · Formato audio)

Rilasciato 1988 Di Sun Microsystems

Sun AU Audio (.au) è un formato di file standard supportato da KaijuConverter per l’archiviazione, la condivisione e la conversione multipiattaforma.

Famiglia

Audio Files

Estensione

.au

Tipo MIME

audio/basic

Utilizzabile come

Input Output

La storia

COME AU
È NATO.

AU — sometimes called Sun au or NeXT/Sun audio — was the native uncompressed audio format on Sun SPARC workstations and NeXT computers in the late 1980s. The header is 24 bytes, minimalist: magic number, data offset, size, encoding code, sample rate, channels, and an optional text annotation. After that comes raw audio samples, usually 8-bit µ-law or 16-bit PCM.

AU achieved minor immortality in the Java world because the early Applet API used it as the default audio format for java.applet.Applet.play(). Every "Web 1.0" applet that played a sound played a .au file. Outside Java and Sun workstation archives, AU is effectively extinct — supplanted by WAV on Windows, AIFF on Mac, and OGG/MP3 on the web. FFmpeg and sox still read and write it for compatibility.

CURIOSITÀ E
ANEDDOTI.

Java applets used .au as their default audio format via Applet.play() — every Web 1.0 applet chime came from a .au file.

The AU header is just 24 bytes — one of the simplest audio file formats ever designed.

Sun workstations shipped with cowbell.au, crash.au, ding.au, and rooster.au as standard system sounds — now internet nostalgia artifacts.

NeXT computers (including Steve Jobs' post-Apple workstation) used AU as the native audio format.

The format supports µ-law compression — the same logarithmic PCM encoding used in North American telephony.

PUNTI DI FORZA E
LIMITAZIONI.

Punti di forza

Trivially simple format — 24-byte header, then samples.
µ-law 8-bit variant fits hours of speech in kilobytes.
Stable since 1988; every major audio library reads it.
Streaming-friendly: size field is optional.

Limitazioni

Aging — obsolete outside legacy and compatibility scenarios.
No metadata beyond a single annotation string.
No native multi-channel surround support.
Limited to 8 codecs, none modern.

Dimensioni e pesi tipici

10-second clip (8-bit µ-law, 8 kHz)

80 KB

10-second clip (16-bit PCM, 44.1 kHz stereo)

~1.7 MB

Specifiche tecniche

MIME types: audio/basic, audio/au, audio/x-au
Extensions: .au, .snd
Header: 24 bytes (magic, offset, size, encoding, rate, channels, info)
Codecs: PCM 8/16/24/32-bit, µ-law, A-law, IEEE float
Byte order: Big-endian

CONVERTI DA
AU

au mp3 au wav au flac au aac au m4a au ogg au opus au wma au aiff

CONVERTI IN
AU

mp3 au wav au flac au aac au ogg au opus au m4a au

Casi d'uso comuni

Unix audio, telephony