PRODUCTENGINEERING

Behind the Scenes: How Learnex Turns PDFs into Video Lessons

By Learnex TeamSeptember 1, 2026

1. Document Extraction

When you upload a PDF or lecture slide, the first step is making sense of it. Our vision and text models parse the document, understanding the difference between a header, body text, and an image caption. We extract the raw knowledge while ignoring formatting artifacts.

2. Topic Segmentation

A 50-page PDF is overwhelming. Learnex's engine breaks the document down into distinct "Topics" (like "Cellular Respiration" or "Photosynthesis"). This creates the nodes in your study trail.

3. Grounded Generation

This is the most important part. When we generate a quiz question or a flashcard, we use a technique called RAG (Retrieval-Augmented Generation). The AI is strictly instructed to only use facts found in your uploaded document. This prevents "hallucinations" and ensures you're studying exactly what your professor taught.

4. Video & Audio Synthesis

To create a video lesson, we first generate a concise, engaging script based on the topic. We then use state-of-the-art TTS (Text-to-Speech) models to narrate it, and pair the audio with dynamic visuals and text highlights to create a bite-sized video explainer.

The entire process takes less than a minute, saving you hours of manual work.