Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.
iSpring Convert - Convert PowerPoint to HTML5 and MP4 video
Adobe Acrobat DC - Make your job easier with Adobe Acrobat DC, the trusted PDF creator. Use Acrobat to convert, edit and sign PDF files at your desk or on the go.
Online Convert PPTX to MP4 - Online Convert allows you to convert any Microsoft PowerPoint 2007 PPTX file to MP4 easily.
Wondershare PDFelement - All-in-one PDF editor
Converter365 Convert PPT to MP4 - Converter365 is an online freeware converter tool that enables you to convert PPT to MP4 with great ease.