VMS to WMA Converter

Quick VMS to WMA transformation — fully online

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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 constant bitrate for the audio track. Leaving this setting to "Auto" will automatically choose a bitrate to achieve a decent quality based on the source audio.
Set the number of audio channels. This setting is most useful when downmixing channels (e.g., from 5.1 to stereo).

vms

VMS (Voice Messaging System) is a compressed audio format designed for telephony and voice mail applications, originally used in Germany. Files with the .vms extension encode spoken audio using Continuously Variable Slope Delta modulation (CVSD), a method suited to low-bandwidth voice transmission over telephone networks. The format operates at 8 kHz, matching the standard digital telephony sampling frequency, and produces self-describing files that embed encoding parameters within a short header. This header distinguishes VMS from raw CVSD streams, letting playback tools process recordings without external configuration. The SoX audio toolkit provides native read and write support, making it straightforward to convert VMS recordings into WAV or other modern formats. A practical advantage is the format's small file size — CVSD compression keeps voice mail messages compact enough for systems with limited disk capacity, which was critical in early telephony infrastructure. The encoding degrades gracefully under noisy channel conditions, preserving speech intelligibility even when errors occur. Although VMS has been superseded by modern codecs in current voice messaging platforms, it remains relevant for recovering legacy voice mail archives.
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wma

WMA (Windows Media Audio) is a family of proprietary audio codecs developed by Microsoft and first released in 1999 as part of the Windows Media framework. Created to compete with MP3 and AAC, WMA Standard uses perceptual coding to deliver what Microsoft claimed was near-CD quality at bitrates as low as 64 kbps — roughly half the data rate MP3 typically needed for comparable results. The codec family grew to include WMA Professional for surround sound and high-resolution audio, WMA Lossless for bit-perfect archival compression, and WMA Voice optimized for spoken content at very low bitrates. Deep integration with Windows, Windows Media Player, and the Zune ecosystem gave WMA a strong distribution advantage throughout the 2000s, and digital rights management (DRM) support made it attractive to online music stores of that era. Encoding and decoding are handled natively by Windows, requiring no third-party software for playback on any Windows machine. Cross-platform support has improved through libraries like FFmpeg and GStreamer, though WMA remains less universally compatible than MP3 or AAC on non-Microsoft devices. The format still appears in legacy media libraries, though newer codecs have largely taken its place for streaming and portable use.
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Easy to Use

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

Browser-Based

Skip the software installations. This browser-based tool handles VMS to WMA conversion entirely online, from any modern browser.

Better Compatibility

VMS recordings become far more usable as WMA. The conversion unlocks good compression at low bitrates that VMS cannot provide.

How to convert VMS to WMA

1

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

2

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

3

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

About formats

VMS (Voice Messaging System) is a compressed audio format designed for telephony and voice mail applications, originally used in Germany. Files with the .vms extension encode spoken audio using Continuously Variable Slope Delta modulation (CVSD), a method suited to low-bandwidth voice transmission over telephone networks. The format operates at 8 kHz, matching the standard digital telephony sampling frequency, and produces self-describing files that embed encoding parameters within a short header. This header distinguishes VMS from raw CVSD streams, letting playback tools process recordings without external configuration. The SoX audio toolkit provides native read and write support, making it straightforward to convert VMS recordings into WAV or other modern formats. A practical advantage is the format's small file size — CVSD compression keeps voice mail messages compact enough for systems with limited disk capacity, which was critical in early telephony infrastructure. The encoding degrades gracefully under noisy channel conditions, preserving speech intelligibility even when errors occur. Although VMS has been superseded by modern codecs in current voice messaging platforms, it remains relevant for recovering legacy voice mail archives.
Developer: SoX Contributors
Initial release: 1991
WMA (Windows Media Audio) is a family of proprietary audio codecs developed by Microsoft and first released in 1999 as part of the Windows Media framework. Created to compete with MP3 and AAC, WMA Standard uses perceptual coding to deliver what Microsoft claimed was near-CD quality at bitrates as low as 64 kbps — roughly half the data rate MP3 typically needed for comparable results. The codec family grew to include WMA Professional for surround sound and high-resolution audio, WMA Lossless for bit-perfect archival compression, and WMA Voice optimized for spoken content at very low bitrates. Deep integration with Windows, Windows Media Player, and the Zune ecosystem gave WMA a strong distribution advantage throughout the 2000s, and digital rights management (DRM) support made it attractive to online music stores of that era. Encoding and decoding are handled natively by Windows, requiring no third-party software for playback on any Windows machine. Cross-platform support has improved through libraries like FFmpeg and GStreamer, though WMA remains less universally compatible than MP3 or AAC on non-Microsoft devices. The format still appears in legacy media libraries, though newer codecs have largely taken its place for streaming and portable use.
Initial release: 1999

Frequently Asked Questions

Why convert VMS to WMA?

VMS suffers from legacy German telephone format. WMA offers native Windows format.

How do I open a WMA audio?

You can open WMA with Windows Media Player, VLC, Winamp, and most Windows applications.

Is there quality loss from VMS to WMA?

The source VMS audio has inherently low fidelity. WMA conversion preserves what is there while adding broad compatibility.

Can I convert VMS to WMA 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 VMS recordings at once?

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

Does VMS to WMA conversion cost anything?

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