CVU to VOC Converter

Browser-based CVU to VOC audio conversion tool

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Settings

The codec to encode the audio track. Codec "Without reencoding" copies the audio stream from the input file into output without re-encoding if possible.
Set the number of audio channels. This setting is most useful when downmixing channels (e.g., from 5.1 to stereo).
Set the sample rate of the audio. Music with a full spectrum (20 Hz — 20 kHz) requires values not lower than 44.1 kHz to achieve transparency. More info can be found on the wiki.

cvu

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.
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voc

VOC (Creative Voice) is a digital audio container developed by Creative Technology and introduced alongside the original Sound Blaster card in 1989. It served as the native audio format for the Sound Blaster family during the DOS era, when Creative's hardware dominated PC audio. VOC files are block-based: each file consists of typed data blocks that can carry 8-bit unsigned PCM, 4-bit and 2.6-bit Creative ADPCM, 16-bit signed PCM, as well as A-law and mu-law encoded audio. This block structure also supports silence intervals, repeat loops, and marker points, giving game developers fine-grained control over sound playback. A notable advantage was hardware-level decoding — Sound Blaster cards could play VOC data directly via DMA transfer, freeing the CPU for other tasks in an era when processor cycles were precious. The format saw extensive use in DOS games from id Software, Sierra, and LucasArts. With the rise of Windows and the WAV format, VOC gradually fell out of mainstream use, yet it remains important for retro gaming preservation and for anyone working with vintage PC audio archives.
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Works Everywhere

Whether on Windows, Mac, Linux, or mobile — the CVU to VOC converter works the same in any modern browser.

Quick Turnaround

Expect fast results — converting CVU to VOC typically takes just a few seconds thanks to optimized server-side processing.

Format Upgrade

Moving from CVU to VOC transitions your audio from an obscure encoding to Sound Blaster heritage — a significant practical improvement.

How to convert CVU to VOC

1

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

2

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

3

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

About formats

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
VOC (Creative Voice) is a digital audio container developed by Creative Technology and introduced alongside the original Sound Blaster card in 1989. It served as the native audio format for the Sound Blaster family during the DOS era, when Creative's hardware dominated PC audio. VOC files are block-based: each file consists of typed data blocks that can carry 8-bit unsigned PCM, 4-bit and 2.6-bit Creative ADPCM, 16-bit signed PCM, as well as A-law and mu-law encoded audio. This block structure also supports silence intervals, repeat loops, and marker points, giving game developers fine-grained control over sound playback. A notable advantage was hardware-level decoding — Sound Blaster cards could play VOC data directly via DMA transfer, freeing the CPU for other tasks in an era when processor cycles were precious. The format saw extensive use in DOS games from id Software, Sierra, and LucasArts. With the rise of Windows and the WAV format, VOC gradually fell out of mainstream use, yet it remains important for retro gaming preservation and for anyone working with vintage PC audio archives.
Initial release: 1989

Frequently Asked Questions

What is the benefit of converting CVU to VOC?

Since CVU has raw delta-modulated audio unreadable by standard software, switching to VOC provides simple structure for basic audio.

What programs can play VOC?

You can open VOC with VLC, Audacity, SoX, and retro audio tools.

Will I lose audio quality converting CVU to VOC?

Converting to VOC is lossless — the audio quality in the VOC output will be identical to the original CVU recording.

Does this converter work on mobile devices?

Absolutely. Since conversion happens in the browser, any device with internet access and a modern browser will work.

How long does CVU to VOC conversion take?

Most conversions finish within seconds. Processing time depends on recording length, but the cloud-based engine handles it quickly.

What if my CVU recording is very long?

The converter handles recordings of various lengths. For very large or numerous files, premium plans provide extended capacity.