Video on Your Website: SEO and Performance Audit Guide

# Video on Your Website: SEO and Performance Audit Guide

Video sells. A 30-second product clip can do more for conversion than three paragraphs of copy. But video is also the heaviest thing most small business sites load, and when it goes wrong it goes wrong loudly: pages crawl, mobile visitors bounce, and Google quietly downgrades you on Core Web Vitals.

This guide walks you through auditing the videos already on your site — not adding more. You'll decide what's earning its weight and fix what isn't. No jargon, no theory you can't act on this afternoon.

Why video is the most expensive content on your page

A typical hero image is 100-300KB. A typical autoplay hero video is 2-15MB before the visitor has scrolled, clicked, or read a word. On a 4G phone connection, that's the difference between a page that feels instant and one that feels broken.

Google measures three things that video tends to wreck:

• Largest Contentful Paint (LCP): how fast your main visible content loads. If your hero is a video, your LCP often is too.
• Cumulative Layout Shift (CLS): how much the page jumps as things load. Videos without a fixed aspect ratio cause big shifts.
• Interaction to Next Paint (INP): how snappy the page feels when tapped. Heavy video decoding on the main thread freezes the page.

These three are Google's Core Web Vitals, and they feed ranking. They also map almost perfectly to "does this page feel good to use." Fix the metrics, you fix the experience.

Step 1: Inventory every video on your site

You probably don't actually know how many videos are on your site. Most owners think "the homepage one." It's almost never just that.

Open a spreadsheet and list, for every page:

• URL
• Type: self-hosted MP4, YouTube embed, Vimeo, Wistia
• Behavior: autoplay, click-to-play, background loop, lightbox
• Position: above the fold, mid-page, footer
• Purpose: hero, product demo, testimonial, decorative

This is the single most useful thing you'll do. You can't audit what you haven't counted. If a video doesn't tie to a clear business outcome, that's already a finding.

Step 2: The performance audit

Open your site in Chrome on a real phone, not a desktop simulator. Throttle to 4G (DevTools → Network → Slow 4G). Load the page and watch what happens.

What you're looking for

1. The page is usable before the video loads. Headline, copy, and call-to-action should be readable within 2 seconds. If your page is a black box waiting for video, you have a problem.

2. The video has a poster image. A poster is the still shown until the video plays. Without one you get a black rectangle and a layout shift. Every tag should have a poster="..." attribute pointing to a compressed image under 100KB (WebP or optimized JPG).

3. The video isn't trying to autoplay with audio. Browsers block it anyway, but the attempt triggers retries and main-thread work that slows everything else.

4. Below-the-fold video is lazy-loaded. A testimonial three screens down should not load until the visitor scrolls near it. For YouTube embeds, use loading="lazy" on the iframe, or better, a facade pattern: show a thumbnail and only load the real player on click.

5. YouTube embeds cost more than you think. A single YouTube iframe pulls roughly 500KB-1MB of JavaScript and tracking before the user clicks play. Three YouTube embeds on a homepage is often the entire reason a site feels slow.

Quick performance checklist

• [ ] Each has a poster attribute
• [ ] No autoplay with audio
• [ ] Below-the-fold videos use loading="lazy" or a facade
• [ ] Self-hosted videos use compressed MP4 (H.264) or WebM
• [ ] No single video file over 5MB on any page
• [ ] Total video weight on first paint under 1MB
• [ ] Container has a fixed aspect ratio (CSS aspect-ratio: 16 / 9)

Fail more than two of these and your performance score is bleeding because of video.

Step 3: The SEO audit

Google can't watch your video. It reads what you tell it about the video. That's the whole game.

Captions and transcripts

This is the highest-leverage change you can make. A transcript turns a 90-second clip into 200-400 words of relevant page content. That content is indexable, searchable, and accessible to screen readers and visitors who can't or won't turn audio on — which is most of them, on mobile.

YouTube auto-generates captions. They're usually 80% right and 20% embarrassing. Spend ten minutes editing the caption file, then paste the cleaned transcript onto the page below the video, ideally inside a collapsed