Is there a free online epilepsy test for videos and GIFs?

Yes, video-audit.com is a completely free, browser-based photosensitive epilepsy safety scanner for videos and GIFs. You do not need to download or install any native desktop software to check your clips. Simply drag and drop your `MP4`, `WebM`, or `MOV` file into our analyzer to instantly test for photosensitive epilepsy risks directly in your web browser.

Is this tool officially recognized by the W3C?

Yes, this tool is listed on the official W3C WAI Evaluation Tools List for verifying WCAG 2.3.1 compliance. It is designed to test specifically for WCAG Success Criterion 2.3.1 regarding flashing content.

What is the Harding test and how does this tool compare?

The Harding FPA is a paid, broadcast-industry software mandated by Ofcom, whereas our tool is a free, web-based WCAG 2.3.1 checker. It is a highly sophisticated, technical piece of paid software designed primarily for professional TV production. While our tool uses similar underlying mathematical concepts (analyzing luminance/red transitions) to detect flashing, we are a free, simplified, web-based tool focused squarely on WCAG 2.3.1 compliance for digital web creators. We are not officially affiliated with the Harding Test.

How do I test my video or website for seizure-triggering flashes?

To test a website or video, simply upload a screen recording or video file directly to our browser-based analyzer. Simply record the content (e.g. using screen-capture software) and upload that video to our tool. The system will analyze it frame by frame.

How do I interpret the analysis charts and warnings?

The analysis charts display relative luminance shifts and red ratios, with warning flags highlighting any WCAG flash violations. Spikes in the luminance chart (usually a white line) indicate bright flashes or transitions; spikes in the red-ratio chart indicate frames where the scene is very red. Above each spike, the tool flags whether it constitutes a WCAG “general flash” or “red flash”. Flashes that occur more than three times per second are considered WCAG violations and listed in warning boxes below the charts.

What should I do if my video violates the flash guidelines?

If your video violates the guidelines, you must edit the content to lower flash frequency, contrast, or saturated red areas. Common fixes include: Reduce Flash Rate: Edit the video so flashing scenes occur at ≤3 times per second or break them into slower sequences. Lower Brightness/Contrast: Tone down sudden brightness jumps (so luminance changes are less than 10%). Avoid Intense Reds: Recolor saturated reds to less intense hues or desaturate them. Minimize Flash Area: Crop or mask large bright areas, so simultaneous flashes cover less than ~25% of the screen.

What is photosensitive epilepsy and what triggers it?

Photosensitive epilepsy is a neurological condition where seizures are triggered by flashing lights or high-contrast visual patterns. In other words, rapid light/dark changes can induce seizures in susceptible people (epilepsy.org.uk, developer.mozilla.org).

How do flashing lights in videos affect people with this condition?

Flashing lights in videos can induce seizures, migraines, or dizziness in photosensitive viewers by overstimulating the brain's visual cortex. Studies show that flashes in the range of about 5–30 times per second are most likely to provoke seizures (developer.mozilla.org). To protect users, the WCAG guidelines specifically require that video or animated content limit flashes.

What do the WCAG guidelines say about flashing content?

WCAG Success Criterion 2.3.1 requires that web content and videos do not flash more than three times per second. Success Criterion 2.3.1 (Three Flashes or Below Threshold, Level A) states that pages must not flash more than 3 times in any one-second period unless each flash is below defined brightness/size limits (w3.org, silktide.com). In other words, either limit yourself to 3 or fewer flashes per second, or ensure any faster flashes meet safety thresholds.

How do I make my video WCAG 2.2 AA compliant for flashing?

To achieve WCAG 2.2 AA compliance, your video must not flash more than three times per second or exceed luminance thresholds. If a sequence does flash rapidly, the flashes must remain below the General Flash and Red Flash Thresholds. You can use our analyzer to visualize these exact thresholds. If the analyzer detects a violation, you must edit your source video to slow down the frame rate of the flashing effect, lower the contrast of the bright flashes, or reduce the physical surface area of the flashing element on screen.

Can this tool analyze GIFs and animated images?

Yes. The analyzer supports standard animated formats like GIFs and animated WebP, as well as MP4, WebM, MOV, and AVI video files. You can drag and drop any image or video asset to run the compliance scan.

Does the tool support HDR and 10-bit video files?

Yes. Our updated engine natively decodes High Dynamic Range (HDR) and 10-bit color depth video files. It correctly linearizes the electro-optical transfer functions (EOTF) to measure exact relative luminance in cd/m² matching viewing environments, preventing false results caused by standard SDR-only conversions.

How does the tool guarantee privacy for pre-release video content?

Your video never leaves your computer. The entire check runs right inside your browser on your device. Your video files are never uploaded, stored, or sent across the web, making the tool completely safe for unreleased edits, client projects under NDA, and confidential internal videos.

Recognized W3C WAI Evaluation Tool

Ensure safety & accessibility

Video Flash Analysis

Scan video flashes to meet accessibility standards and protect viewers with PSE and other sensitivities.

Note: Processing runs locally in your browser. Video data never leaves your device.

Need full broadcast compliance and pattern hazard checks?

Unlock all 5 global standards (including Japan & ITU-R), stripe pattern detection, cloud queues, and certified PDF reports.

Explore Starter & Pro →

How it works

Upload your video

Select or drag & drop a video into the upload box. Available formats: MP4, MOV, WEBM, AVI, MKV, FLV, WMV, M4V, TS, MPG, MPEG, 3GP, OGV

Start the analysis

Review the video metadata and configure your analysis settings::

Standard Selection: Choose between WCAG 2.2 (Web), Ofcom 2017 (UK Broadcast), Trace24 (Consensus), and NHK/JBA (Japan Broadcast).
Engine Tuning: Enable sensitivity adjustments, Reduce Motion Noise, or a WCAG 66ms qualifying window.

Processing video

Analysis runs in your browser, so please keep this tab open. Processing time is based on your computer’s speed and mode selected.

Interpreting results

Interactive Timeline maps luminance & red-ratio fluctuations. Scrub the timeline to sync with Frame Previews showing exact highlighted Flash Zone Overlays (color-coded spatial clusters) where safety violations occur. A detailed Violations Log pinpoints precise timecodes, failing standards, and hazard sizes.

Read the User Guide & Remediation Tips →

Detailed User Guide

9 min read

How to Use Video Audit and Read Seizure Safety Results

A guide to using the free Video Audit tool. Learn to read relative luminance, locate flash zones, and edit video files to fix accessibility failures.

Transparent Plans

Choose the plan that fits your work

Start free in your browser, or use cloud processing for full standards, GIF support, and client reports.

In-Browser

Free

Quickly check a clip for flash risks directly on your device.

$0Free forever

✓ Unlimited local checks

Up to ~1 GB (browser memory limit)

Runs right in your browser (your video never leaves your computer)

WCAG 2.2 and Trace24 standards, plus partial Ofcom (flash checks)

Interactive flash chart and frame-by-frame timeline

Violations table with timestamps to review every hazard

No account, signup, or credit card needed

Use Free Tool

Cloud Processing

Video + GIF

Starter

For creators and video editors who need full standards and PDF reports without keeping a tab open.

$19/ month

⚡ 40 FHD mins / month (or 20 mins in 4K)+ Top-ups available

Up to 2 GB per file

All standards covered: WCAG 2.2, Ofcom (UK), ITU-R, ISO, Trace24, and NHK/JBA (Japan)

Moving pattern checks (stripes, checkerboards) and scene change cuts

Downloadable PDF compliance report for clients or audits

Animated GIF and video format support

40 minutes of HD video a month (or 20 mins in 4K)

Upload videos up to 2 GB per file

Cloud background queue: upload and close your tab while it processes

Extra minute packs available if you need more time

Join Starter Pilot

Certification & Fast Lane

Certified Pass ID

Pro

For teams and editors who deliver certified videos to broadcasters, festivals, or clients.

$49/ month

🚀 120 FHD mins / month (or 60 mins in 4K)+ Top-ups available

Up to 4 GB per file

All standards covered with spatial heatmaps: WCAG 2.2, Ofcom, ITU-R, ISO, Trace24, and NHK/JBA

Moving pattern checks (stripes, checkerboards) and scene change cuts

Official Compliance Pass Certificate with shareable verification link

Downloadable PDF compliance report for broadcast and clients

Priority fast-lane queue: your videos process first

Animated GIF and high-bitrate video support

120 minutes of HD video a month (or 60 mins in 4K)

Upload videos up to 4 GB per file

Direct email support and early API access

Join Pro Pilot

FAQ

Answers to common questions about photosensitive epilepsy, WCAG 2.3.1 compliance, and using Video Audit.

Video creators, developers, and accessibility specialists should use this tool to test animations and videos for photosensitive epilepsy triggers. This includes video creators, editors, web and game developers, and accessibility specialists. For example, web developers can use it to test animated banners or game scenes, and video producers can check their film or ads for safety. WCAG explicitly notes that all content on a webpage must meet seizure-safety criteria w3.org. Our video analysis tool serves the same audience: if your website or video might have flashing content, it’s wise to check it.

Product Roadmap

Discover upcoming milestones, vote on features you want prioritized, and shape the future of video safety.

Explore Interactive Roadmap & Vote →Propose a Feature

Features roadmap
Feature	Description	Delivery
Global Regulatory Standards Parity In Development	Full compliance validation across WCAG 2.3.1, Trace24, Ofcom 2017, ITU-R BT.1702-4, ISO 9241-171, and Japanese broadcast standards (NHK & NAB-J).	End of 2026
Starter & Pro Cloud Tiers In Development	10x faster cloud analysis, official signed PDF pass certificates, advanced geometric pattern hazard detection, and verification IDs for client handoff.	End of 2026
Headless REST API & Webhooks Planned	Serverless API endpoints to automate video safety audits in media pipelines, with webhooks and API keys.	Q1 2027
Model Context Protocol (MCP) Server Planned	Native MCP server allowing AI video agents (Claude, Cursor, custom agents) to inspect video files and timeline sequences for PSE hazards via natural language.	Q1 2027
Automated Hazard Remediation Assist Under Consideration	Smart frame-level auto-dimming guidance, luminance clamping algorithms, and safe-trim markers to fix violations without reshooting.	Q1 2027
Enterprise Custom Cloud & On-Prem VPC Planned	Dedicated private compute queues, custom SLAs, SAML/SSO integration, and Docker VPC on-premise container deployment.	Q2 2027