Browser Video Playback Technology

HTML5 Video Element

HTML5 introduced the video element, enabling video playback in browsers without plugins. The video element provides native video playback capabilities, supporting multiple formats including MP4, WebM, OGG. Through JavaScript APIs, developers can fully control playback, pause, seek, volume, etc.

Media Source Extensions

Media Source Extensions (MSE) is a W3C standard allowing JavaScript to dynamically provide media data to video elements. MSE is key to adaptive bitrate playback - libraries like HLS.js and Dash.js are基于 MSE.

MSE works by: creating MediaSource objects, creating SourceBuffers, and appending video data (usually fMP4) to SourceBuffers. Browsers automatically read from SourceBuffers for decoding and playback.

Encrypted Media Extensions

Encrypted Media Extensions (EME) is a W3C标准 for playing encrypted video in browsers. EME provides APIs for interacting with DRM systems like Widevine, FairPlay, PlayReady.

WebCodecs API

WebCodecs API is a new W3C standard providing底层 access to browser built-in codecs. Unlike MSE, WebCodecs allows direct control over video encoding/decoding without依赖 specific container formats.