Zamzar - Free conversion online of many type of documents (images, text, video, audio...
Online Convert PPTX to MP4 - Online Convert allows you to convert any Microsoft PowerPoint 2007 PPTX file to MP4 easily.
Vertopal - Vertopal is an online platform for converting computer files to a variety of file formats.
Converter365 Convert PPT to MP4 - Converter365 is an online freeware converter tool that enables you to convert PPT to MP4 with great ease.
FreeConvert Audio Converter - FreeConvert offers a highly efficient Audio Converter to help you convert them from one format to another.
iSpring Convert - Convert PowerPoint to HTML5 and MP4 video