Ecasound Support for Sun and NeXT AU Files
Ecasound fully supports audio encapsulation within Sun and NeXT AU
(.au and .snd) files, allowing users to read,
process, and write audio using this format. Through its native design
and its tight integration with the libsndfile library,
Ecasound provides seamless routing, converting, and multi-track
processing capabilities for both modern and legacy AU-encapsulated
streams.
Native and Libsndfile Integration
Ecasound relies on libsndfile as one of its primary
audio file input/output subsystems. Because libsndfile
natively supports the Sun/NeXT audio container format, Ecasound inherits
full read and write compatibility for AU files. When an input or output
target uses the .au or .snd extension,
Ecasound automatically detects the container structure and invokes the
appropriate format drivers.
Supported Audio Encodings in AU Containers
Audio encapsulation inside an AU container requires defining both the container headers and the underlying sample encoding. Ecasound supports the most common encodings stored in AU files, including:
- Uncompressed Linear PCM: 8-bit, 16-bit, 24-bit, and 32-bit signed integer formats.
- Floating-Point PCM: 32-bit and 64-bit IEEE floating-point audio data.
- Logarithmic Formats: Traditional 8-bit \(\mu\)-law (u-law) and A-law encodings, which are historically common in Sun Microsystems and telecommunication architectures.
Usage in Ecasound
Ecasound treats AU files like any other supported format, requiring no special plugins or external converters.
To convert an existing audio file (such as a WAV) into a Sun/NeXT AU
container, define the target with the .au extension:
ecasound -i input.wav -o output.auTo specify explicit sample parameters—such as an 8-bit \(\mu\)-law stream at 8 kHz—you can format the command directly using Ecasound’s format flags:
ecasound -i input.wav -f:u8,1,8000 -o output.auTo use an AU file as an input source for multi-track processing, filtering, or routing to system outputs:
ecasound -i input.au -o alsaEcasound’s support for AU files makes it a versatile tool for legacy hardware integration, telecommunication audio processing, and standard file conversions directly from the Linux and Unix command line.