⚡ Core Web Vitals 2026 Diagnostic
Hero Background Video LCP Impact & Waste Calculator
Unoptimized MP4 background loops on mobile are the #1 killer of Google PageSpeed scores. See exactly how much cellular data is wasted and how much LCP freeze you eliminate with silent VP9 WebM + WebP poster.
1. Your Video Parameters
Video Duration (seconds):
8s
Current MP4 File Size:
14.0 MB
Monthly Mobile Visitors:
25,000 visits
💡 Why does PageSpeed penalize raw MP4? Mobile Safari and Chrome pause initial paint while buffering unoptimized MP4 containers with audio tracks, causing Largest Contentful Paint (LCP) to spike to 4.5+ seconds (Red zone).
2. Performance & Conversion Diagnostic
4.2s
Mobile LCP Delay (Raw MP4)
< 0.5s
LCP With WebP Poster
350 GB
Monthly Bandwidth Wasted
1.4 MB
Optimized VP9 Size (-90%)
Production-Ready HTML5 Code:
<video autoplay muted loop playsinline poster="hero-poster.webp">
<source src="hero.webm" type="video/webm">
<source src="hero.mp4" type="video/mp4">
</video>