CVS to SOU Converter

Change CVS audio to SOU format right in your browser

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No Expertise Needed

Upload your CVS recording, select SOU, and download the result — three steps, no technical skills required.

Confidential Handling

Uploaded CVS recordings are erased right after conversion. SOU outputs are automatically removed from servers within 24 hours.

Format Transition

CVS is a niche legacy format with minimal support. Converting to SOU brings your audio into a format recognized by SoX and many other tools.

How to convert CVS 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

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 Though modern wideband codecs have superseded CVS, it retains historical importance and niche utility in legacy telephony and embedded communication devices.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
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 CVS to SOU?

CVS is a obsolete encoding that limits playback options. Converting to SOU gives you raw 8-bit unsigned PCM.

How do I open a SOU audio?

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

Does CVS to SOU conversion affect quality?

SOU preserves audio data faithfully. Since CVS already has limited fidelity, the SOU output matches the original quality exactly.

Can I convert CVS 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 CVS recordings at once?

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

Does CVS to SOU conversion cost anything?

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