Sobre os arquivos AU
Áudio Sun AU
Formato áudio Sun Microsystems (1992). Padrão Unix legacy. Usado em sistemas Solaris e java.applet. Substituído por WAV/MP3 modernos.
Família
Audio Files
Extensão
.au
Tipo MIME
audio/basic
Pode ser usado como
COMO NASCEU O
FORMATO AU.
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.
CURIOSIDADES E
FATOS INTERESSANTES.
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.
VANTAGENS E
LIMITAÇÕES.
Vantagens
- 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.
Limitações
- 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.
Tamanhos típicos de arquivo
10-second clip (8-bit µ-law, 8 kHz)
80 KB
10-second clip (16-bit PCM, 44.1 kHz stereo)
~1.7 MB
Especificações técnicas
- 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
CONVERTER A PARTIR DE
AU
Casos de uso comuns
Unix audio, telephony
Formatos relacionados
Comparativos populares
AU vs FLAC
Diferenças, tamanho de arquivo e quando escolher cada formato.
AU vs AAC
Diferenças, tamanho de arquivo e quando escolher cada formato.
AU vs M4A
Diferenças, tamanho de arquivo e quando escolher cada formato.
AU vs OGG
Diferenças, tamanho de arquivo e quando escolher cada formato.
AU vs OPUS
Diferenças, tamanho de arquivo e quando escolher cada formato.
AU vs WMA
Diferenças, tamanho de arquivo e quando escolher cada formato.
Conversões populares de AU
Os destinos mais procurados ao converter arquivos AU.
Perguntas frequentes sobre AU
Perguntas frequentes
AU (Sun AU Audio) is an audio formatoo de arquivo used to store sound recordings — music, voice, podcasts, sound effects. The formato defines how the audio samples are comprimido (or stored raw), what bitrates are suportado, e how metadata como title, artist, album, e cover art is embedded. It is part of the audio arquivos family.
VLC, foobar2000, e the default media players no Windows e macOS handle AU natively. On mobile, iOS Music e Android media apps vary in their support — popular formatoos funcionar everywhere; niche ones may need a dedicated app. If playback fails em um device, convertendo to MP3 ou AAC Geralmente solves it.
Upload the AU to KaijuConverter e pick MP3, WAV, FLAC, AAC, OGG, ou any other target. Our FFmpeg pipeline decodes the audio e re-encodes para o target formato at sensible default bitrates (VBR ~190 kbps para music, 96 kbps para speech). Metadata e cover art travel com the audio where both formatoos support them.
AU can be com perdas ou sem perdas depending no specific variant. com perdas variants (smaller files) discard some audio detail durante compressão in ways tuned to be inaudible; sem perdas variants preserve every sample exactly mas produce larger files. para distribution, com perdas at alta bitrate is padrão; para archival, sem perdas wins.