A file with a .trp filename extension is an HD (High Definition) video file that uses MPEG-2 compression. TRP files are typically used to synchronize audio and video codecs in DVB (Digital Video Broadcasting). The video codec is usually H.264, whereas audio data comes in AC3 format. This makes the TRP format to be supported by most media player programs.
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.