Google Chrome 148 Introduces 'Lazy' Loading for Video and Audio: What It Means

With the release of version 148, Google Chrome fills a functional gap that has existed since 2019, finally extending native support for lazy loading for and elements. Until now, the ability to defer the loading of content not immediately visible in the viewport was limited exclusively to images and

The introduction of the attribute loading="lazy" for native media is, in fact, a fundamental innovation for performance optimization. As highlighted in the official documentation on Chrome Platform Status, the implementation integrates deeply with the browser's resource management logic. The rendering engine is now able to intelligently manage the hierarchy of attributes: when loading="lazy" is detected, it takes precedence over the preload attribute. In practical terms, even if a video element is set to preload, the browser will block its fetch until the user starts scrolling the page closer to the content.

Chrome 148: Lazy Loading Becomes Universal for Multimedia Content

A noteworthy technical aspect concerns interaction with the autoplay attribute. In Chrome 148, if a video is set to play automatically but has the deferred loading tag, playback will not start in the background. The browser will queue the startup operation, launching it only when the element actually enters the viewport. This behavior not only preserves bandwidth but also reduces the CPU computational load during the critical page loading phase.

Unlike methods based on external scripts, Chromium's native lazy loading is designed not to block the window.onload event. This means that the completion of loading the main structure of the page and critical assets will not be delayed by the presence of multimedia elements placed at the bottom of the page. The management of activation thresholds is directly entrusted to the browser's built-in Intersection Observer infrastructure, optimized to be asynchronous and not interfere with the main execution thread.

Although the novelty is branded by Google, its impact will quickly extend to the entire ecosystem of Chromium-based browsers, including Microsoft Edge and Vivaldi. Interestingly, as for third-party platforms like YouTube, the benefit of lazy loading was already partially accessible since their players are usually embedded via iframes, a category that has been supported since 2019. However, for all sites that directly host MP4 files or proprietary audio, the savings in data traffic will be tangible, especially on mobile or metered connections. In addition to Chrome for desktop, the feature will arrive simultaneously on Android, iOS, and Webview instances.