Most of the original audio files ended in the extension .wav. The video files ended in the extension of .avi. Your operating system had to have the appropriate drivers installed to hear and see these files.
Eventually, software developers developed files and viewers to auto-magically stream or download all MPEG formats.
MPEG-1 is a standard for lossy compression of video and audio. MPEG-1 makes digital cable/satellite TV and digital audio broadcasting possible. MPEG-1 is the most compatible audio/video format in the world. The MP3 audio format is the most widely recognized part of the MPEG-1 standard.
The MPEG-4 method of defining compression for moving pictures and sound has become the most compatible and widely used HD video format.
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