.mp (MPEG Layer Audio) The .mp format is an audio coding format for digital audio which uses a form of lossy data compression. It is a common audio format for consumer audio streaming or storage, as well as a standard de facto codec for the transfer and playback of music on most digital audio players. MP files compress audio data by eliminating sounds that are outside the hearing range of most people, thus reducing the file size without significantly affecting the perceived sound quality.

OGA files are the audio-only element of the OGG multimedia file system. If you were accessing an OGA file before 2007, it would probably have appeared on your PC as a document with .ogg extension. However, since the OGG format creator, Xiph.Org Foundation, created other extensions to cater to specific data types, multimedia files are now stored with data-specific extensions like .ogv, .oga, .ogm, .ogx, all under the OGG file system. In effect, instead of having a media file containing audio, video, text, and metadata all encoded into a chunk, each data type is encoded separately with a specific extension.