As part of Microsoft's 2007 suite another open XML document type was introduced. This time in the PowerPoint sphere, PPTX is a Presentation format that stores slides used for slide shows or presentations; like a normal PPT format it may include text, images, and other media; however PPTX is based on the Open XML format and uses ZIP compression for smaller file sizes
A PPTX file is quite unique. The specifications for PPTX are in the ECMA-376 standard for Office Open XML. You can make a PPTX file by zipping up a directory, but the material in the directory has to match an OPC structure, including subfolders that have the content in XML format. Any application that supports XML can access and work with data in the new file format. Just like the DOCX file format, PPTX improves file and data management and data recovery.
PDF is a file format developed by Adobe Systems for representing documents in a manner that is separate from the original operating system, application or hardware from where it was originally created. A PDF file can be any length, contain any number of fonts and images and is designed to enable the creation and transfer of printer-ready output.
Each PDF file encapsulates a complete description of a 2D document (and, with the advent of Acrobat 3D, embedded 3D documents) that includes the text, fonts, images and 2D vector graphics that compose the document. They do not encode information that is specific to the application software, hardware, or operating system used to create or view the document.