AU to CVSD Converter

Easily convert AU audio into CVSD format online

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Intuitive Process

The AU to CVSD converter is designed for simplicity. Upload, convert, download — done in under a minute.

Bulk Conversion

Convert an entire folder of AU recordings to CVSD at once. Just upload all files and let the batch converter handle the rest.

No Installation

The AU to CVSD converter runs entirely in your web browser. No plugins, no downloads, no setup — just open and go.

How to convert AU to CVSD

1

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

2

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

3

Let the file convert and you can download your cvsd 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
CVSD (Continuously Variable Slope Delta modulation) is a voice digitization method standardized for military and telephony use by NATO and the CCITT during the 1970s. It encodes differences between consecutive samples as a single bit — 1 if the current sample exceeds the prediction, 0 otherwise — while a syllabic companding filter adjusts step size by monitoring runs of identical bits. Operating at 16 to 64 kbps, CVSD balances voice intelligibility against bandwidth, making it the encoding of choice for secure military links and tactical radio systems. The bitstream can be decoded with straightforward hardware, originally built into dedicated integrated circuits. One advantage is implementation simplicity — encoders and decoders need minimal resources, enabling real-time processing on low-power embedded hardware. Robustness under noisy conditions is another strength, as single-bit errors affect only local samples rather than corrupting entire frames. SoX provides software encoding and decoding support, letting modern systems work with legacy CVSD recordings from military archives and vintage telecommunications infrastructure.
Developer: CCITT / NATO
Initial release: 1970

Frequently Asked Questions

Why convert AU to CVSD?

The AU format lacks modern audio features. Switching to CVSD gives you better codec support and wider device compatibility.

Which software plays CVSD?

Use SoX, military/telecom audio tools to play or edit CVSD recordings. These tools offer reliable compatibility with the format.

Will I lose audio quality in the conversion?

Quality depends on the codec. If CVSD uses lossy encoding, minor data loss occurs. Lossless targets preserve the original AU audio faithfully.

How many AU files can I convert in one go?

Upload as many AU files as you need and convert them to CVSD simultaneously. The batch feature handles multiple files efficiently.

Is the AU to CVSD conversion secure?

Completely. Your AU files are erased immediately after processing, and converted CVSD results are purged from our servers within 24 hours.