AU to CVS Converter

Online tool to convert AU audio into CVS

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Clean Transcoding

The engine ensures accurate AU to CVS transcoding — sample rate, channels, and audio data are handled precisely.

Secure Processing

Every AU upload is deleted as soon as the conversion to CVS completes. No files linger on our servers beyond 24 hours.

Rapid Conversion

Our servers convert AU to CVS quickly, even for longer recordings. Download your result as soon as processing finishes.

How to convert AU to CVS

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose cvs or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your cvs file right afterwards

About formats

AU is an audio file format introduced by Sun Microsystems for its Unix workstations and the NeXT platform. It features a minimal 24-byte header specifying data offset, size, encoding type, sample rate, and channel count, followed by the audio payload. AU supports numerous encodings, including uncompressed linear PCM at various bit depths, mu-law and A-law companding (logarithmic compression used in telephone systems), and several ADPCM variants. This versatility made AU a workhorse across early Unix environments, web audio (Java applets defaulted to AU), and telephony applications. One advantage is simplicity: the compact header and straightforward structure make it trivial to parse, generate, and stream programmatically. The built-in mu-law option provides another benefit, delivering reasonable voice quality at just 8 KB per second — half the rate of 16-bit uncompressed audio — invaluable when storage and bandwidth were scarce. Although modern formats have largely supplanted AU in consumer applications, it retains a foothold in scientific computing and audio processing pipelines where minimal overhead and reliable cross-platform behavior are valued.
Developer: Sun Microsystems
Initial release: 1992
CVS is a telephony audio encoding based on Continuously Variable Slope Delta modulation, representing voice through a 1-bit delta scheme where step size adapts to track input amplitude. Developed within CCITT (now ITU-T) standards during the 1970s, CVS encodes by comparing each sample to the previous one and outputting a single bit — up or down — with slope magnitude adjusting based on recent bit patterns. This yields extremely low bit rates, typically 16 kbps at 8 kHz sampling, efficient for narrowband voice over constrained channels. CVS files store signed delta-encoded data and are commonly processed using tools like SoX. A significant advantage is bandwidth economy: the 1-bit-per-sample approach demands minimal transmission capacity, essential for military radio links and early digital telephone infrastructure. The adaptive slope mechanism also prevents overload distortion on rapidly changing signals while keeping granular noise acceptable during quiet passages. Though modern wideband codecs have superseded CVS, it retains historical importance and niche utility in legacy telephony and embedded communication devices.
Developer: CCITT / ITU-T
Initial release: 1970

Frequently Asked Questions

Why convert AU to CVS?

Since AU is a dated Sun Microsystems format, moving to CVS brings your audio into a modern, widely recognized container.

How do I open a CVS recording?

Open CVS with SoX, telephony software, specialized decoders. These applications provide full playback and editing support for the format.

Does converting AU to CVS affect quality?

Lossless-to-lossless conversions preserve all audio data. When the target uses lossy compression, some quality reduction is inherent in the codec.

Can I convert several AU recordings at once?

Yes — upload multiple AU files simultaneously and convert them all to CVS in a single batch. No need to process one at a time.

What happens to my files after conversion?

Your original AU is deleted as soon as conversion ends. The resulting CVS is available for download and automatically removed within 24 hours.