Sources & Content Library · Add Sources
Supported file types and size limits
Full table of what you can upload to Ritsu, plus per-file size caps for Free and Pro plans.
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Ritsu accepts most common study materials. Here's the full list, what gets extracted, and the per-file limits.
Supported types
| Type | Extension | What we extract | OCR? |
|---|---|---|---|
.pdf |
Text, headings, tables, figure captions | Yes (for scanned) | |
| Word | .docx |
Text, headings, comments | — |
| PowerPoint | .pptx |
Slide text, speaker notes | — |
| Plain text | .txt, .md |
Verbatim | — |
| HTML | .html, web URL |
Article body (boilerplate stripped) | — |
| YouTube | URL | Transcript (auto-captions or Whisper fallback) | — |
| Audio | .mp3, .m4a, .wav |
Whisper transcription | — |
| Video | .mp4, .webm |
Audio extracted + transcribed | — |
| EPUB | .epub |
Text + chapter structure | — |
| Pasted text | (none) | Verbatim | — |
Size + length limits
| Limit | Free | Pro |
|---|---|---|
| File size | 50 MB | 200 MB |
| PDF pages | 500 | 2000 |
| Audio / video duration | 60 min | 8 hours |
| YouTube duration | 60 min | 8 hours |
| Pasted text length | 100 KB | 500 KB |
| Total storage | 1 GB | 50 GB |
| Sources in library | 50 | Unlimited |
| Imports per day | 10 | Unlimited |
Free plan limits reset at midnight UTC. Hit a daily limit and the next upload is queued until tomorrow — no work lost, just waiting.
What we DON'T support yet
- Live streams (use the recording after the stream ends)
- Encrypted / DRM-protected files (Audible audiobooks, ePubs from Apple Books, etc.)
- Protected video platforms (Coursera, Udemy DRM streams) — paste the transcript text directly instead
- Spreadsheet-style content (.xlsx, .csv) — paste as text or convert to PDF first
- Image-only content (
.png,.jpg) — for OCR-only flows, use the OCR utility in your OS first then paste text
File quality matters
A clean, well-structured source produces better PoKs than a messy one. Specifically:
- Searchable PDFs beat scanned PDFs (no OCR errors)
- Original transcripts beat auto-captions (creator-uploaded subtitles are usually 95%+ accurate)
- Single-language sources beat mixed-language (Ritsu handles mixed but auto-detection sometimes flips mid-source)
- Headings + chapter structure in the source produces sharper PoK extraction
Tips
- Convert obscure formats to PDF first (most apps export to PDF) — that's our most-tested path.
- For lecture audio, the speaker quality matters more than the file format. Clean mic audio = clean transcript.
- For long sources, consider breaking them up. A 1500-page textbook works on Pro, but you'll get better PoKs uploading two chapters at a time.
Trouble
- "Unsupported format" — verify your file extension matches the table. Some platforms add hidden extensions (
.pdf.gz,.docx.zip). - Upload starts then fails — usually a size issue. See Upload failed.
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