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.
APE (Monkey’s Audio) is a lossless audio file format released in 2000 by Matthew T. Ashland. Because it’s a lossless sound format, it doesn’t lose data during compression, unlike other standard formats like AAC, MP3, and Vorbis. However, Monkey’s Audio is available on PC only. To play APE on Mac OS X and Linux, you’ll need a third-party plugin like JRiver Media Center.