An MPG file is a common video file that uses a digital video format standardized by the Moving Picture Experts Group (MPEG). It stores video, audio, and metadata interleaved together. MPG files are often used for creating movies that are distributed on the Internet.
MPG files typically incorporate MPEG-1 or MPEG-2 audio and video compression. MPEG-1 is one of the most widely used lossy video/audio formats in the world since it is supported by a large number of video and audio applications. MPEG-2 was developed to improve on the shortcomings of MPEG-1, which includes only a two channel audio compression system and insufficient support for the demands of higher resolution video.
MPG files are saved in a program stream container format known as PS or MPEG-PS. The format stores audio, video, and metadata that has been interleaved together in one stream for efficient deliverability.
If you receive an MPG file, there are a large number of applications you can use to open it. Windows Media Player comes bundled with Windows and QuickTime Player comes with macOS. There are also many free and commercial applications, such as VLC media player and Elmedia Player.