Delivery & Performance
Balance media discovery and playback with preload, lazy loading, stable CDN URLs, responsive images, and efficient players.
Discovery and playback both suffer when a page downloads too much too early or hides its media behind unstable infrastructure.
- Use
preload="metadata"orpreload="none"for most native media elements. - Size images correctly and serve modern formats with an appropriate fallback.
- Reserve image and player dimensions to reduce layout shift.
- Lazy-load below-the-fold iframes and media, but not the page's primary LCP image.
- Consider a lightweight poster facade for expensive third-party players while retaining crawlable page content.
- Use a CDN and sensible cache headers for stable media URLs. Version URLs when content changes rather than relying on clients to refresh stale assets.
- Avoid short-lived signed URLs in structured data, posters, sitemaps, and other discovery metadata.
- Provide an adaptive streaming experience for viewers and, when video discovery features require it, an authorized crawlable media-file URL in a supported format.
Measure real page performance after adding players. An iframe can load an entire second application, so the number and placement of embeds matters.
HTML + metadata
120 KB
Poster
40 KB
Player JavaScript
0 KB
Media bytes
40 KB