M4P (MPEG-4 Protected) is a digital audio file extension for the AAC (Advanced Audio Codec) container format. It uses lossy compression and is an audio-only file. In most cases, M4P files are purchased on Apple iTunes, which means they are DRM-protected. M4A is the unprotected version of M4P.
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.