WebM to VOX Converter

Extract WebM audio as Dialogic VOX ADPCM format online

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Web Video to Telephony

Extract voice content from WebM and compress it as VOX ADPCM — ready for Dialogic IVR systems and telephony voice prompts.

Ultra-Compact Output

VOX ADPCM keeps telephony files tiny at 4 bits per sample. Convert WebM audio into space-efficient phone system prompts.

Private Processing

WebM uploads are removed after conversion. VOX output is deleted within 24 hours — your audio content stays confidential.

How to convert WEBM to VOX

1

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

2

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

3

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

About formats

WebM is an open, royalty-free multimedia container format developed by Google and launched at the Google I/O conference in May 2010. The format pairs the Matroska container (a subset of MKV) with VP8 or VP9 video codecs and Vorbis or Opus audio codecs, creating a fully open media stack designed specifically for web use. Google released WebM alongside the VP8 codec under permissive BSD-style licensing, removing patent and royalty barriers that hindered the adoption of H.264 for open web video. The WebM container inherits the efficient binary structure of Matroska while restricting it to web-optimized profiles, ensuring fast parsing and lightweight implementation in browsers. WebM with VP9 achieves compression efficiency competitive with H.264 High Profile and approaching HEVC, making it practical for delivering high-quality video at reduced bandwidth. Major web browsers including Chrome, Firefox, Edge, and Opera support WebM playback natively, and YouTube uses VP9 in WebM as a primary delivery format for much of its content. The format supports features such as alpha channel transparency in video, making it valuable for compositing web graphics and overlays. More recently, WebM has been extended to support AV1 video, continuing its evolution as a vehicle for open codec adoption. The combination of competitive compression, zero licensing costs, and universal browser support makes WebM a cornerstone of royalty-free web multimedia delivery.
Developer: Google
Initial release: May 19, 2010
VOX is a headerless audio format built around Dialogic ADPCM encoding, widely adopted in telephony, interactive voice response (IVR) systems, and voice mail platforms since the 1980s. Each audio sample is compressed into 4 bits using an algorithm developed by Oki Electric and implemented in hardware on Dialogic Corporation's telephony interface cards. VOX files typically use a sampling rate of 6000 or 8000 Hz, producing extremely compact recordings optimized for speech intelligibility rather than musical fidelity. Because the format carries no header, playback software must know the sample rate and encoding parameters in advance — a trade-off that reduces overhead but demands careful file management. The primary advantage of VOX is storage efficiency: a one-minute voice recording at 8 kHz occupies roughly 240 KB, making it practical for systems storing thousands of prompts. Dialogic ADPCM conforms to the ITU-T G.726 standard, ensuring interoperability across telephony equipment from different vendors. Even as modern call centers migrate to IP-based systems with codecs like Opus), vast libraries of VOX recordings persist in legacy IVR deployments and compliance archives worldwide.
Initial release: 1983

Frequently Asked Questions

Why convert WebM to VOX?

VOX is the Dialogic standard for IVR and telephony. WebM video audio can be compressed into compact phone prompts and voice messages.

How much compression does VOX offer?

VOX stores audio at 4 bits per sample — roughly 4:1 compression versus raw PCM. Highly efficient for telephony voice storage.

Does WebM Opus audio work?

Yes — WebM carries Opus or Vorbis audio, both decoded during conversion. The output is VOX ADPCM regardless of the WebM source codec.

Is VOX headerless?

Yes — VOX has no file header. Your telephony system must know the sample rate (typically 8kHz) when loading and playing VOX files.

Can I batch-convert WebM files?

Upload multiple WebM videos and convert them to VOX at once. Build telephony prompt libraries from web video audio content.