These individual streams can be in several different compression formats. The MXF file is essentially a 'container' file that contains multiple different streams that make up the video. MXF files can also be easily converted to the AVI or MOV file types if needed. The Society of Motion Picture and Television Engineers created the MXF file format to make it easier to work on the video files on different components, including servers, editing equipment that can handle digital files, cameras, etc. The MXF file contains the audio and digital data components that combine to create the overall complete video.
The best description of the MXF file extension (Material Exchange Format File) is similar to an actual videotape, but it is in a newer digital format.