VMS to AIFF Converter

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 Although VMS has been superseded by modern codecs in current voice messaging platforms, it remains relevant for recovering legacy voice mail archives.

AIFF (Audio Interchange File Format) was developed by Apple in 1988, drawing its structural design from Electronic Arts' IFF standard. As an uncompressed audio container, AIFF stores linear PCM data at full CD quality — typically 16-bit at 44.1 kHz — preserving every detail of the original recording without lossy encoding. The format organizes content into chunks that can also carry metadata such as markers, instrument definitions, and comments. Professional audio engineers on macOS frequently rely on AIFF because it guarantees bit-perfect fidelity through every stage of editing and mastering. One significant advantage is zero generational loss: unlike MP3 or AAC, repeated saves never degrade the signal. Another strength is seamless integration with Apple's professional tools, including Logic Pro and GarageBand, where AIFF serves as a native working format. The container supports multiple sample rates and bit depths up to 32-bit, accommodating high-resolution workflows that exceed CD-quality specifications. For anyone prioritizing lossless integrity over storage efficiency, AIFF remains a dependable choice across the recording industry.