AV1 to VMS Converter

Extract VMS voice message audio from AV1 video

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Voice Messaging

VMS is designed for enterprise voicemail — converting from AV1 produces audio compatible with those telephony systems.

Browser-Based

No specialized telephony software required — convert AV1 to VMS from any modern web browser.

Secure Files

Your AV1 uploads are erased right after conversion, and VMS outputs are deleted within 24 hours.

How to convert AV1 to VMS

1

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

2

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

3

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

About formats

AV1 (AOMedia Video 1) is an open, royalty-free video coding format developed by the Alliance for Open Media, a consortium whose founding members include Google, Mozilla, Microsoft, Amazon, Netflix, and Intel, among others. The specification was finalized in June 2018 with the goal of providing a next-generation video codec that surpasses the compression efficiency of H.264 and HEVC while remaining free from licensing fees. AV1 achieves roughly 30-50% better compression than HEVC at equivalent visual quality, making it particularly attractive for streaming platforms seeking to reduce bandwidth costs without sacrificing viewer experience. The codec supports a broad range of features including film grain synthesis, flexible tiling for parallel processing, content-adaptive resolution switching, and a rich set of intra and inter prediction modes. Hardware decoding support has expanded rapidly across mobile processors, GPUs, and smart TVs, addressing early concerns about computational demands during encoding. AV1 has seen wide adoption from major streaming services for delivering 4K and HDR content, and it serves as the video component of the WebM container for web-based playback. The royalty-free status makes AV1 especially important for open web standards and accessible media distribution.
Initial release: June 25, 2018
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

Frequently Asked Questions

Why convert AV1 to VMS?

VMS is a voice message system format used by specific telephony platforms and enterprise voicemail solutions.

What opens VMS files?

SoX and enterprise voicemail systems handle VMS audio. It is a specialized format for voice messaging infrastructure.

Is VMS widely supported?

VMS is niche — it targets specific telephony systems. For general use, WAV or MP3 are much more versatile.

What quality does VMS offer?

VMS is optimized for voice clarity at low bitrates — adequate for speech but not suitable for music.

Are my uploads private?

AV1 uploads are deleted immediately. VMS outputs are purged from our servers within 24 hours.