VOB to VMS Converter

Extract DVD audio and save in VMS voice format

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Voice Messaging Format

VMS serves telephony systems — converting VOB audio to VMS provides content compatible with voice mail infrastructure.

Cloud-Based Conversion

All processing runs on our servers, keeping your machine unloaded during the VOB to VMS extraction.

Secure Processing

Your VOB uploads are deleted after conversion. VMS outputs are automatically purged within 24 hours.

How to convert VOB 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

VOB (Video Object) is the primary container format used on DVD-Video discs, defined as part of the DVD specification developed by the DVD Forum. The format first appeared with the DVD standard finalized in September 1996 and has since been used on billions of DVD discs produced worldwide. VOB files are based on the MPEG-2 program stream format, containing multiplexed MPEG-2 video alongside audio in AC-3 (Dolby Digital), DTS, MPEG-1 Layer II, or LPCM formats. Beyond audio and video, VOB files also carry DVD subtitle streams as bitmap overlays, navigation data for menu interaction, and chapter point information. The files reside in the VIDEO_TS directory on a DVD disc, with naming conventions (VTS_01_1.VOB, etc.) reflecting the title and part structure of the content. Individual VOB files are limited to approximately 1 GB to accommodate the UDF file system requirements, with longer content spanning multiple files seamlessly. The format supports both NTSC (720x480) and PAL (720x576) video resolutions at bit rates up to 9.8 Mbps for combined audio and video. Integration of video, multi-track audio, subtitles, and navigation into a single program stream made VOB a complete solution for consumer movie delivery. While streaming and newer disc formats have supplanted DVD for new content, VOB remains hugely relevant for accessing the vast library of existing DVD content.
Developer: DVD Forum
Initial release: September 1996
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 VOB to VMS?

VMS is used in voice messaging and telephony infrastructure — converting DVD audio to VMS integrates content with these systems.

What processes VMS files?

Sox and voice messaging platforms handle VMS files. The format serves specific telephony and voicemail applications.

Is VMS the same as DVMS?

VMS and DVMS are closely related voice messaging formats with minor differences in header structure and metadata.

What quality does VMS offer?

VMS is optimized for intelligible speech at low bitrates — suitable for voice messages but not for high-fidelity audio.

Can I convert multiple files?

Upload several VOB files and convert each audio track to VMS independently — download them as processing completes.