M4B is an audio filename extension for AAC format, which is developed by Apple Inc. It is mainly used on podcast and audiobook files. Typically, M4B files contain audio and other metadata like images, hyperlinks, and chapter markers. M4B files are DRM copy-protected and can be opened on Apple iTunes and QuickTime Player.
SWF (Small Web Format/ShockWave Format) is a digital Adobe flash file format that stores vector-based animations, audios, and videos. Generally, it is used to stream media online, mostly browser-based games. Sadly, Adobe recently announced that they are ending Flash format support by the end of 2020 due to its shortcomings such as performance issues and lack of security.
Adobe Flash Player Adobe Flash Professional CC GOM Player Adobe Dreamweaver 2020