Accessibility Caption Generator for ADA, WCAG, and Section 508
Upload any video. Musely transcribes it with Seed-ASR 2.0, formats captions to your chosen compliance standard, and exports SRT, VTT, or plain text at 97.3% accuracy.
Musely Accessibility Caption Generator is an AI captioning tool that produces ADA, WCAG 2.1, and Section 508 compliant captions from any video or audio file. Powered by Seed-ASR 2.0, it achieves 97.3% transcription accuracy across 51 languages and processes files up to 120 minutes using a chunked strategy with 2-second overlaps. Choose from 4 compliance presets — WCAG 2.1 AA, WCAG 2.1 AAA, Section 508 Federal, and Educational — each with enforced reading speeds between 130 and 160 words per minute. Configure line length from 32 to 47 characters and export captions as SRT, VTT, or plain text.
Under the Hood
🤖ASR Engine
Compliance Output
Generate Compliant Captions in 3 Steps
Upload Your Video or Audio File
Drag and drop any video or audio file into Musely. Supports MP4, MOV, AVI, MKV, MP3, WAV, M4A, and other major formats up to 120 minutes long. Select your audio language or leave on auto-detect for automatic recognition across 51 supported languages.
Select Compliance Preset and Caption Settings
Choose a Musely preset: WCAG 2.1 AA Compliant for the most common web standard, Section 508 Federal for U.S. government content, WCAG 2.1 AAA for the strictest accessibility level, or Educational for university lectures and course videos. Set characters per line (32 mobile to 47 widescreen), choose your non-speech audio detail level, toggle speaker identification, and pick caption timing style (Pop-on, Roll-up 2-Line, Roll-up 3-Line, or Paint-on).
Download Your Compliant Caption Files
Review the generated captions with enforced reading speeds and accessibility formatting. Download as SRT for video players and LMS platforms, VTT for web embedding with styling support, or plain text for transcripts. Captions are ready to attach to any video player or upload to Canvas, Moodle, Coursera, or your CMS.
Who Uses Musely Accessibility Captions
Caption every course video to meet ADA Title II requirements
We process 80-150 lecture recordings per semester for students with hearing impairments. The Educational preset preserves technical terms like neuropharmacology and biostatistics exactly as the professor says them. Musely cut our captioning vendor costs by about 70% and we no longer have a 5-day turnaround backlog.
Generate VTT files that pass automated accessibility audits
I build WCAG 2.1 AA compliant marketing sites for clients. Musely generates VTT files that pass axe and WAVE automated audits on the first try. The 32-character line length matches FCC mobile recommendations, and the SRT export works with every video player my clients use.
Caption HR training videos for federal contractor compliance
We are a federal contractor and every internal training video must meet Section 508. The Section 508 Federal preset handles verbatim transcription with uppercase sound effect descriptions automatically. Musely replaced a $40,000 annual contract with a vendor that took 24 hours per video.
Caption public service videos to Section 508 standards
State agencies must meet Section 508 for all public-facing video. Musely processes our 90-minute town halls in under 3 minutes and identifies each speaker accurately. The fact that I do not need to go through procurement for an enterprise contract is the biggest time saver.
Add accessible captions to advocacy campaign videos
Our disability advocacy videos must be captioned by definition. We never had budget for Verbit. Musely's free tier let us caption 30+ awareness videos in our first month. The Include All non-speech audio setting captures the music swells and ambient sounds that matter for AAA compliance.
Caption e-learning courses for Canvas and Coursera
I build courses for higher ed clients who require accessibility certification before launch. The Educational preset adds visual reference notes like [referring to slide chart] which my reviewers love. I upload to Canvas and the captions sync perfectly. Saves me about 4 hours per course module.
Musely vs. Other Accessibility Caption Tools
| Feature | Musely | Verbit | AI-Media | Subly |
|---|---|---|---|---|
| Compliance Presets | ✓ 4 presets (WCAG AA / AAA / 508 / Educational) | ⚠ WCAG AA + 508 (manual) | ⚠ WCAG AA + 508 (manual) | ✗ No compliance presets |
| Self-Serve Access | ✓ Yes — no contract required | ✗ Enterprise contract only | ✗ Enterprise contract only | ✓ Yes — self-serve |
| Reading Speed Control | ✓ 130-160 wpm enforced automatically | ⚠ Set per project (manual) | ⚠ Set per project (manual) | ✗ No control — default speed |
| Non-Speech Audio Detail Levels | ✓ 4 levels (All / Essential / Minimal / Omit) | ⚠ Included (manual review) | ⚠ Included (manual review) | ✗ Not included |
| Characters Per Line | ✓ 32 / 37 / 42 / 47 configurable | ⚠ Fixed per project | ⚠ Fixed per project | ✗ No control |
| Languages Supported | ✓ 51 languages | ⚠ 35+ languages | ⚠ 30+ languages | ⚠ 20+ languages |
| Typical Turnaround | ✓ Under 3 minutes (automated) | ⚠ 4-24 hours (human review) | ⚠ 2-24 hours (human review) | ✓ 5-10 minutes (automated) |
What Compliance Teams Say
4.8/5 based on 1,862 reviews
“We process about 120 lecture videos per semester for our disability services office. The WCAG 2.1 AA preset matches what our auditors expect, and the Educational preset preserves anatomical and pharmacological terms exactly. Musely saved us about $28,000 last year compared to our previous vendor.”
“I switched from Verbit because the contract minimums did not work for a 15-person agency. Musely's Section 508 preset produces output that has passed every accessibility audit our federal clients have run. Turnaround dropped from 24 hours to under 3 minutes per video.”
“The 32-character line length and 130 wpm reading speed handle our cognitive accessibility requirements without me configuring anything. Speaker identification occasionally merges two voices in heated panel discussions, but the additional instructions field lets me fix that. Cut my captioning time by about 80%.”
Frequently Asked Questions
Musely accessibility caption generator achieves 97.3% accuracy across 51 languages using Seed-ASR 2.0. It includes 4 compliance presets (WCAG 2.1 AA, WCAG 2.1 AAA, Section 508 Federal, Educational), enforces 130-160 wpm reading speeds, supports configurable line lengths from 32 to 47 characters, and exports SRT, VTT, and plain text without enterprise contracts.
Musely provides self-serve access with automated processing in under 3 minutes per video, while Verbit and AI-Media require enterprise contracts with 4-24 hour human review turnaround. Musely also offers 4 built-in compliance presets that auto-configure reading speed, line length, and non-speech audio rules instead of manual per-project setup.
Yes. The Musely WCAG 2.1 AAA preset enforces a 130 words per minute reading speed, includes verbatim transcription, identifies all speakers explicitly, describes background music with mood and genre, and adds tone of voice indicators like [whispering] or [sarcastically]. Silence markers appear every 30 seconds for extended quiet periods.
Musely outputs accessibility captions as SRT (compatible with virtually every video player and LMS platform), VTT (web-optimized with CSS styling support), and plain text. SRT is the default format for most accessibility use cases, while VTT works best for HTML5 video embeds requiring color or positioning styles.
Musely processes audio and video files up to 120 minutes long. For longer files, Musely uses a chunked strategy with 2-second overlaps between segments to prevent caption gaps at chunk boundaries. A typical 60-minute lecture processes in about 2 minutes end to end.
Musely offers 4 non-speech audio detail levels: Include All (music, sound effects, ambient — required for AAA), Include Essential (music and key effects — recommended for AA), Include Minimal (only sounds referenced in dialogue), and Omit. Each setting matches specific compliance standard requirements automatically.
Musely achieves 97.3% transcription accuracy on clear audio using the Seed-ASR 2.0 engine. Accuracy may decrease with heavy background noise, multiple overlapping speakers, or strong regional accents. For Section 508 federal content, the Section 508 preset enforces verbatim transcription with 99%+ accuracy targets.