What is WebM?

WebM is an open, royalty-free media file format designed specifically for the web. Developed by Google and released in 2010, WebM is based on the Matroska container and uses VP8, VP9, or AV1 video codecs along with Vorbis or Opus audio codecs.

WebM was created as an alternative to proprietary formats, providing high-quality video compression optimized for HTML5 video streaming without licensing costs.

Key Features

  • Open Source: Completely free and royalty-free
  • Efficient Compression: VP9 and AV1 offer excellent quality-to-size ratio
  • Web Optimized: Designed for HTML5 streaming
  • Browser Support: Native support in Chrome, Firefox, Opera, Edge
  • Transparency Support: Alpha channel with VP8/VP9
  • Adaptive Streaming: Works with DASH and HLS
  • Low Latency: Good for real-time communications

Common Uses

  • YouTube video streaming (alongside MP4)
  • HTML5 video on websites
  • Video conferencing and WebRTC
  • Animated stickers and GIFs alternative
  • Open-source video projects
  • Screen recordings with transparency

Advantages

  • Completely free with no licensing fees
  • Excellent compression efficiency
  • Native browser support for web video
  • Open source and transparent development
  • Supports transparency (alpha channel)
  • Smaller file sizes than H.264 at same quality

Limitations

  • Limited support on Apple devices (Safari, iOS)
  • Not all video players support WebM
  • Encoding can be slower than H.264
  • Less hardware acceleration than MP4
  • Smaller ecosystem than MP4/H.264

Technical Information

  • File Extension: .webm
  • MIME Type: video/webm, audio/webm
  • Developer: Google (sponsored)
  • First Release: May 2010
  • Container: Based on Matroska
  • Video Codecs: VP8, VP9, AV1
  • Audio Codecs: Vorbis, Opus
  • License: BSD-style (royalty-free)