CVSD to AU Converter

Switch from CVSD to AU with a browser-based converter

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Safe Conversion

All uploaded files are handled securely — CVSD inputs are removed after processing, and AU outputs expire within 24 hours.

Modern Format

CVSD recordings become far more usable as AU. The conversion unlocks simple well-documented structure that CVSD cannot provide.

Bulk Conversion

Handle multiple CVSD to AU conversions at once. Upload your batch and let the converter process them in parallel.

How to convert CVSD to AU

1

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

2

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

3

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

About formats

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
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

Frequently Asked Questions

Why should I switch from CVSD to AU?

CVSD suffers from not playable outside specialized telephony software. AU offers cross-platform Unix support.

Which software opens AU recordings?

You can open AU with VLC, Audacity, SoX, and Unix/Linux media players.

Is there quality loss from CVSD to AU?

No quality is lost. AU stores audio without additional compression, so your CVSD recording carries over at full original fidelity.

Is CVSD to AU conversion available on all platforms?

It works on any platform — desktop or mobile. Just open your browser, upload the CVSD recording, and convert to AU.

Is my CVSD audio kept private during conversion?

Your uploaded CVSD recordings are deleted immediately after conversion. The resulting AU outputs are removed within 24 hours.

Do I need to install anything for CVSD to AU?

No installation required. The converter runs entirely in your web browser — just upload, convert, and download.