PVF to CVU Converter

Re-encode telephony PVF audio as CVU online

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Cross-Format Audio

Transform PVF recordings into CVU — bringing voice-optimized audio into a format with real-world usability.

File Privacy

Uploaded PVF files are deleted after conversion. All CVU outputs are automatically erased within 24 hours from servers.

Universal Access

Access the converter from Windows, macOS, Linux, iOS, or Android. All you need is a web browser.

How to convert PVF to CVU

1

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

2

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

3

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

About formats

PVF (Portable Voice Format) is a simple audio file format designed for voice message storage in Linux-based telephony systems, most notably ISDN4Linux and its vbox voicemail application. The format emerged from the European ISDN ecosystem of the late 1990s, when Linux servers increasingly handled PBX and answering machine duties over digital phone lines. PVF files store raw signed 16-bit PCM samples at 8000 Hz mono, preceded by a minimal plain-text header specifying data format and byte ordering. This deliberate simplicity is one of the format's primary strengths — with no compression and a human-readable header, PVF files are trivially easy to parse, pipe, and manipulate using standard Unix tools. The 8 kHz rate matches the Nyquist requirement for telephone-bandwidth speech (300-3400 Hz), making PVF a natural intermediate format for voice processing pipelines. Another advantage is cross-architecture portability: the explicit byte-order declaration means PVF files move between big-endian and little-endian systems without ambiguity. The SoX audio toolkit provides native PVF read/write support, enabling straightforward conversion to modern formats.
Developer: ISDN4Linux Project
Initial release: 1997
CVU is an unsigned variant of the CVS telephony audio format, differing in how delta-encoded values are represented in the binary stream. While CVS stores slope delta values as signed quantities, CVU treats them as unsigned, shifting the numerical interpretation of each sample. Both share the underlying CVSD modulation technique — 1-bit adaptive delta coding where step size varies according to recent output bit patterns — operating at comparable rates, typically 16 kbps for narrowband voice at 8 kHz. The signed-versus-unsigned distinction matters at the decoder, where correct interpretation determines proper waveform reconstruction. CVU files appear in telephony and embedded communication contexts where hardware adopted the unsigned convention. A practical advantage is straightforward interfacing with systems using unsigned arithmetic natively, avoiding sign extension in decoders. Like its signed counterpart, CVU achieves extreme bandwidth efficiency, compressing voice into compact bitstreams for constrained links. SoX supports CVU, providing a reliable path for converting these niche telephony recordings into modern formats for analysis or archival.
Developer: CCITT / ITU-T
Initial release: 1970

Frequently Asked Questions

Why convert PVF to CVU?

PVF is a niche telephony voice format. CVU gives your voice recordings broader compatibility with standard players and tools.

What applications open CVU files?

SOX and voice processing systems can handle CVU files. Most are available as free downloads for major operating systems.

Is CVU suitable for music?

No. CVU is optimized for speech and voice. Music loses significant quality — use AAC or MP3 for music content instead.

How fast is the conversion?

Processing is fast — PVF files are lightweight and CVU encoding completes in seconds on our server hardware.

Are my files kept private?

PVF uploads are removed right after processing. All CVU output files are cleaned from servers within 24 hours.

Can I convert multiple PVF files?

Yes. Upload several PVF files and convert them all to CVU in one session. Batch processing is supported.