Check Video Caption Contrast Ratios Against Accessibility Guidelines
Low-contrast captions make video content inaccessible. Check text and background relative luminance values against WCAG accessibility contrast targets.
1 · video segment | text luminance value | background luminance value
FIRST-LOAD
Input is processed locally and a draft is saved automatically in this browser profile when storage is available. Reset to sample clears that draft; Pro history has its own clear button. A state link encodes your inputs in its URL: share only non-sensitive rows. Browser history, clipboard and anyone receiving the link may retain it. Optional AI use below leaves this device; it is not required.
Data note: Everything runs in this browser tab on the subtitle contrast matrix: your video segment | text luminance value | background luminance value stays on this device, nothing is uploaded, and the reading is rebuilt only when you press run.
Perspective: Before: White text over light or moving video backgrounds loses contrast. After: the subtitle contrast matrix shows the working beside each named row so the reader can change the assumption and inspect the consequence.
2 · Read the subtitle contrast matrix
Contrast ratio calculation based on relative luminance inputs. Not legal WCAG compliance certification; verify with automated accessibility tools.
Paid layer: subtitle contrast matrix print and history
one-time step · the free reading above stays complete
Free tier
- one complete subtitle contrast matrix run in the app
- three samples plus unlimited article-demo runs
- unwatermarked result text and an explicit, user-triggered state link
What $4 one-time adds
- print the subtitle contrast matrix with its row workings
- CSV of contrast ratio margin and row explanations
- last five reading summaries saved in this browser profile
$4 once for repeated filing of the subtitle contrast matrix, not for a better answer. Illustrative time basis: avoiding one five-minute manual reformat per saved reading; no market-price or guaranteed-savings claim.
Local history (this device)
- No saved runs yet — your first run files here.
Checkout is unavailable until a payment link is configured. The optional unlock is browser-local, profile-scoped and best-effort, not server-verified access. Clearing browser data can remove it; there is no account or cross-device recovery.
Boundary and sources
Contrast ratio calculation based on relative luminance inputs. Not legal WCAG compliance certification; verify with automated accessibility tools.
- Method: Enter required target ratio (e.g. 4.5:1 for standard text).
- All sample records are invented examples. The app does not fetch measurements, policies, files or personal records.
- Google’s official pricing page, fetched 2026-09-28, lists free-tier access including AI Studio. Optional formatting only; limits and availability can change. Free-tier content may be used to improve products. Never paste private records there.
Mechanism: competence-autonomy-loop
Optional AI formatting, not calculation
For this subtitle contrast matrix, use the free AI Studio interface only if available to you, with no paid API key. Manual entry completes the same workflow for free. Supply only fictional or non-sensitive notes. Review its output against the source; never paste unresolved questions into the numeric rows.
Format my non-sensitive notes for a subtitle contrast matrix. Return plain rows only: video segment | text luminance value | background luminance value. Preserve supplied quantities exactly. Do not guess missing values; list questions separately. Do not calculate or add advice. I will check every row before pasting into the local tool.
Accepted schema: video segment | text luminance value | background luminance value. No AI response is executed as code.