PDFCrowd - Pdfcrowd is a Web/HTML to PDF online service. Convert HTML to PDF online in the browser or in your PHP, Python, Ruby, .NET, Java apps via the REST API.
iSpring Convert - Convert PowerPoint to HTML5 and MP4 video
DocRaptor - As the only API powered by the Prince HTML-to-PDF engine, DocRaptor provides the best support for complex PDFs with powerful support for headers, page breaks, page numbers, flexbox, watermarks, accessible PDFs, and much more
Online Convert PPTX to MP4 - Online Convert allows you to convert any Microsoft PowerPoint 2007 PPTX file to MP4 easily.
PDFShift - Convert any HTML documents to high-fidelity PDF using a single POST request
PPTX to Video - PPTX to Video is a simple but powerful mobile application that lets you convert a PowerPoint file to MP4 and play it on any video player.