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https://ffmpeg.org

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
98
GRADE
A+
FIX
1
REVIEW
2
PASS
12
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
92
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
73
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
83
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

2.12 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

2.72 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

38 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

4.22 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

2.72 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
17
12 PASS 2 REVIEW 1 FIX
D
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

B
Image Optimization
2 images, 0 KB saveable
REVIEW
2 images, 0 KB saveable
Warning::
https://ffmpeg.org/img/ffmpeg3d_white_20.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://ffmpeg.org/img/coverity-lifetime-2024-08.P... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
2 images 63 KB
0 oversized -0 KB
2 legacy format
2 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
254 KB transferred, 11 requests
PASS
254 KB transferred, 11 requests
Info::
Page weighs 505 KB (254 KB transferred)
Info::
11 HTTP requests
Info::
Estimated 0.05 g CO2 per page load
254 KB / 2.4 MB budget
254 KB transferred
11 requests
0.05 g CO2 per page load
Fonts 64.3 KiB 25%
Images 63.0 KiB 25%
JavaScript 38.9 KiB 15%
Other 31.7 KiB 12%
HTML 29.1 KiB 11%
CSS 27.4 KiB 11%
0 2.4 MB 4.9 MB
Under budget
A+
Third-Party Impact
No third-party resources
PASS
No third-party resources
Info::
No third-party resources detected
No third-party resources detected — all resources are first-party.
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
JS Execution Cost
361ms total JS execution
PASS
361ms total JS execution
Warning::
https://ffmpeg.org/: 268ms CPU time
Info::
Unattributable: 93ms CPU time
Info::
Third-party scripts: 93ms (26% of total)

Main Thread Breakdown

Style & Layout 45% Other 28% Script Evaluation 11% Rendering 7% Parse HTML & CSS 6%
ScriptTotalScriptingParse/CompileParty
https://ffmpeg.org/268ms4ms1ms1st
Unattributable93ms5ms0ms3rd
A+
Font Loading
1 fonts (64 KB)
PASS
1 fonts (64 KB)
Info::
1 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

1

64 KB total

Render-blocking

0

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s 1.5 s 2.0 s 2.5 s FCP 2.1 s LCP 2.7 shttps://ffmpeg.org/fonts/fontawesome-webfont.woff?v=4.2.0fontawesome-webfont.woff https://ffmpeg.org/fonts/fontawesome-webfont.woff?v=4.2.0 — 64.3 KiB — 99 ms — font-display: swap
fontawesome-webfont.woff woff swap
Size 64 KB
Load time 99 ms
Start 413 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)

Fixing the unchecked items could save ~19 KB and ~38 ms

A+
JS Bundles
2 scripts, 0 KB unused
PASS
2 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://ffmpeg.org/js/jquery.min.js29 KB—✓1st
https://ffmpeg.org/js/bootstrap.min.js10 KB—✓1st
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A+
Page Weight Inventory
11 resources · 254 KB · 0 KB savings available
PASS
11 resources · 254 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 254 KB
11 resources · 254.3 KiB · 0 third-party Within 1MB page-weight target
Image 37% · 94.6 KiB
Font 25% · 64.3 KiB
JavaScript 15% · 38.9 KiB
Document 11% · 29.1 KiB
CSS 11% · 27.4 KiB
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
Network Waterfall
11 requests over 609ms
INFO
0 ms 500 ms 1.0 s 1.5 s 2.0 s 2.5 s FCP 2.1 s LCP 2.7 shttps://ffmpeg.org// https://ffmpeg.org/ — 200 — 29.1 KiB — 221 ms — http/1.1https://ffmpeg.org/css/font-awesome.min.css/css/font-awesome.min.css https://ffmpeg.org/css/font-awesome.min.css — 200 — 5.3 KiB — 56 ms — http/1.1https://ffmpeg.org/css/bootstrap.min.css/css/bootstrap.min.css https://ffmpeg.org/css/bootstrap.min.css — 200 — 18.7 KiB — 96 ms — http/1.1https://ffmpeg.org/css/simple-sidebar.css/css/simple-sidebar.css https://ffmpeg.org/css/simple-sidebar.css — 200 — 932 B — 108 ms — http/1.1https://ffmpeg.org/css/style.min.css/css/style.min.css https://ffmpeg.org/css/style.min.css — 200 — 2.5 KiB — 147 ms — http/1.1https://ffmpeg.org/img/ffmpeg3d_white_20.png/img/ffmpeg3d_white_20.png https://ffmpeg.org/img/ffmpeg3d_white_20.png — 200 — 995 B — 151 ms — http/1.1https://ffmpeg.org/img/coverity-lifetime-2024-08.PNG/img/coverity-lifetime-2024-08.PNG https://ffmpeg.org/img/coverity-lifetime-2024-08.PNG — 200 — 62.0 KiB — 256 ms — http/1.1https://ffmpeg.org/js/jquery.min.js/js/jquery.min.js https://ffmpeg.org/js/jquery.min.js — 200 — 29.2 KiB — 166 ms — http/1.1https://ffmpeg.org/js/bootstrap.min.js/js/bootstrap.min.js https://ffmpeg.org/js/bootstrap.min.js — 200 — 9.6 KiB — 69 ms — http/1.1https://ffmpeg.org/fonts/fontawesome-webfont.woff?v=4.2.0/fonts/fontawesome-webfont.woff?v=4... https://ffmpeg.org/fonts/fontawesome-webfont.woff?v=4.2.0 — 200 — 64.3 KiB — 99 ms — http/1.1https://ffmpeg.org/favicon.ico/favicon.ico https://ffmpeg.org/favicon.ico — 200 — 31.7 KiB — 51 ms — http/1.1
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
26% of JavaScript execution is third-party
First-party Third-party 93ms · 0KB · лв2/mo
Unattributable
Other
Optional
Execution 93ms
Transfer 0 KB
Monthly Cost лв2/mo

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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