This video demonstrates how to use Amazon OpenSearch Service as a vector database for chatting with PDF documents. The presenter, Praveen Mohan, showcases a web application that allows users to upload PDFs and ask questions based on their content. The demo uses two PDF documents about Amazon OpenSearch Service best practices and FAQs as a knowledge base. The application processes the PDFs, converts them into vectors, and indexes them in OpenSearch. Users can then ask questions, and the system provides relevant answers using the indexed content. The video also explains the architecture behind this solution, including components like Lambda functions, embedding models, and large language models. It highlights how OpenSearch Service powers conversational search for unstructured data, enabling users to extract insights from their documents efficiently.