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YT-RAG: A Multimodal Retrieval-Augmented Generation Framework for YouTube Video Understanding

Gangadhari Swapna, C. Yogesh, G. J. S. Hari Teja

International Research Journal on Advanced Science Hub, 2026

Abstract

The vast body of video content on platforms such as YouTube represents one of the richest yet most query-inaccessible knowledge repositories in existence. We present YT-RAG, a multimodal Retrieval-Augmented Generation (RAG) system that enables natural-language conversation with any YouTube video by independently indexing its spoken transcript as 384-dimensional text embeddings and its visual frames as 512-dimensional image embeddings using FastEmbed, with no GPU infrastructure required. Three principal contributions define the system: (i) a parallel dual-modality ingestion pipeline running transcript and frame extraction as concurrent asyncio tasks; (ii) an agentic retrieval loop powered by Google Gemini 2.0 Flash’s native tool-call API, making retrieval conditional on model judgment rather than mandatory; and (iii) a semantic user-notes channel providing a personalised third retrieval layer absent from all prior video RAG literature. Empirical evaluation across six YouTube content categories — Comedy, Podcast, Cooking, News, Tutorials, and Coding — shows aggregate dual-modality retrieval achieves Hit@5 approximately 4× higher than text-only and 8× higher than image-only retrieval. A systematic anti-correlation in per-category modality strengths confirms that the two channels retrieve complementary evidence. Deployed as a Chrome extension operating natively alongside the YouTube player, YT-RAG is training-free, containerised, and built entirely on official APIs without…

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