WebM
An open multimedia container based on a subset of Matroska and designed primarily for video and audio delivered on the web.
General information
- Format name
- WebM Media Container
- Extension
.webm- MIME types
video/webmaudio/webm- Category
- video
- Data type
- Binary
- Developer
- WebM Project
- Introduced
- 2010
Media properties
- Compression
- Varies
- Common codecs
- VP8, VP9, AV1, Vorbis, Opus
File signatures
| Offset | Hexadecimal | ASCII | Description |
|---|---|---|---|
| 0 | 1A 45 DF A3 | — | WebM begins with an EBML header, but this signature is shared with Matroska. The EBML DocType must identify the document as webm for reliable identification. |
Common uses
Web video
HTML video
Streaming media
Browser-based video
Open media distribution
Related formats
Technical resources
| Resource | Publisher | Link |
|---|---|---|
| WebM Container Guidelines | WebM Project | Open resource ↗ |
| About WebM | WebM Project | Open resource ↗ |
Record information
- Verified
- October 3, 2026
- Last updated
- October 3, 2026