What is WebM?

In the early days of online video, internet video was heavily reliant on proprietary plugins like Flash. Today, video is a native citizen of the web, thanks in large part to open standards designed specifically for streaming. One of the most significant contributors to this shift is the WebM format.

Developed by Google, WebM was created to provide a royalty-free, high-quality alternative for serving video to virtually any device with a browser. According to Web Media Files, the format was designed to solve the "fragmentation issues" of early web video and offer a "free and unencumbered video standard" for developers.

What is WebM?

At its core, WebM is a multimedia container format. Unlike the ubiquitous MP4 container, which is often associated with proprietary codecs (like H.264), WebM is completely open-source.

As explained in the reference article Web Media Files, the format functions as a container that encapsulates video and audio streams into a single file. It is based on the Matroska (MKV) container format but restricts the allowed streams to a specific set of open codecs to ensure consistent performance across the web.

History and Purpose

The WebM Project launched in 2010 during a pivotal time for the internet. Flash was still the dominant method for playing video, but it suffered from high CPU usage and poor performance on mobile devices. Google sought to create a format that would work natively in HTML5 <video> tags without requiring users to install external plugins.

The project initially launched with the VP8 video codec (acquired from On2 Technologies) and Vorbis for audio. Over time, it has evolved to support newer, more efficient technologies.

Technical Specifications

A standard WebM file is strictly defined to ensure compatibility. Based on the technical details provided by Web Media Files and current web standards, the file structure typically includes:

• Container: A subset of the Matroska (MKV) format, optimized for streaming.

• Video Codecs:

  • VP8: The original codec used at launch.

  • VP9: A successor that offers significantly better compression, allowing for high-definition video at lower bandwidths.

  • AV1: Though described as "experimental" in older documentation, AV1 has largely become the gold standard for next-generation, royalty-free streaming in WebM containers today.

• Audio Codecs:

  • Vorbis: The original audio standard for WebM.

  • Opus: A newer, highly versatile audio codec often used in modern WebM implementations for its superior quality-to-bitrate ratio.

Key Advantages

The zoft.link article highlights several specific advantages that drove WebM's adoption:

1. Open Source & Royalty-Free: Unlike H.264, which requires licensing fees for certain commercial uses, WebM is free for anyone to use, implement, or improve. This encourages innovation and lowers the barrier to entry for developers.

2. High Quality, Low Bitrate: Modern codecs like VP9 and AV1 are highly efficient. They can deliver crisp HD or 4K video using less data than older formats, which translates to faster page loads and reduced data usage for users.

3. Cross-Platform Performance: While support was initially fragmented, WebM is now supported by all major browsers, including Chrome, Firefox, Edge, and Opera. Notably, Apple added support for WebM in Safari (macOS and iOS) in recent years, closing the final major gap in compatibility.

Source:

• Web Media Files – zoft.link. Available at: https://zoft.link/article/10/web-media-files.html