CVSD to SOU Converter

Upload CVSD, download SOU — no installs required

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Remote Processing

Server-based processing keeps your device fast. CVSD to SOU conversion is handled by our infrastructure, not local hardware.

Format Transition

CVSD recordings become far more usable as SOU. The conversion unlocks minimal format overhead that CVSD cannot provide.

No Expertise Needed

The entire CVSD to SOU process is designed for simplicity. Drag your audio in, pick the format, and grab the output.

How to convert CVSD to SOU

1

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

2

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

3

Let the file convert and you can download your sou 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
SOU is a raw audio format designation that functions as an alias for unsigned 8-bit PCM data (u8) in the SoX audio processing framework. Files with the .sou extension contain headerless, uncompressed audio samples stored as unsigned 8-bit integers — each byte represents a single amplitude value from 0 to 255, with 128 as the silence midpoint. Because there is no header, playback parameters such as sample rate and channel count must be specified externally. The default assumption is typically mono at 8000 Hz, though the data can represent any rate the recording hardware supported. The u8 encoding that SOU aliases is one of the simplest possible digital audio representations, predating structured audio containers like WAV and AIFF. Raw unsigned PCM was commonly produced by early sound cards and digitizers in the late 1980s and early 1990s, when storage constraints and limited processing power made headerless formats a practical choice. One advantage is absolute simplicity: SOU files can be read by any program capable of basic file I/O, with no parsing of container structures or metadata decoding required — useful for embedded systems, hardware diagnostics, and educational contexts where audio fundamentals are being explored. The format's minimal overhead also means that conversion to any modern container is lossless and instantaneous, since the raw PCM samples can be wrapped in a WAV or AIFF header without any transcoding.
Developer: SoX Contributors
Initial release: 1991

Frequently Asked Questions

Why convert CVSD to SOU?

CVSD suffers from legacy format that most audio players cannot handle. SOU offers basic audio data.

How do I open a SOU audio?

You can open SOU with SoX, Audacity with raw import, and low-level audio tools.

Is there quality loss from CVSD to SOU?

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

Can I convert CVSD to SOU on any device?

Yes — the converter runs entirely in your browser, so it works on Windows, macOS, Linux, and mobile devices alike.

Can I convert multiple CVSD recordings at once?

Yes — upload several CVSD recordings simultaneously and they will all be converted to SOU in parallel, saving you time.

Does CVSD to SOU conversion cost anything?

Standard conversions are available at no cost. Paid plans unlock higher limits and faster processing for heavy usage.