This is also true of a version 7 3 file.
Mat file format version 7.
Headers from a file saved as v6 v7 and v7 3 in matlab 2015a are shown below preceded by the version in.
Version 7 3 mat files use an hdf5 based format that requires some overhead storage to describe the contents of the file.
Although the bulk of the file is in binary form the header of a level 5 mat file can be read with a text editor.
For cell arrays structure arrays or other containers that can store heterogeneous data types version 7 3 mat files are sometimes larger than version 7 mat files.
Save to nondefault mat file version.
Note that the headers for v6 and v7 files have the same 5 0 identification.
Atomic combat saved game files is another file format that has a similar file extension of mato but those types of files open with atomic combat.
As a side note i find it highly ironic that the proprietary v6 v7 mat format is more cross platform compatible due to its documentation compared to the v7 3 format that is supposed to rely on the standard hdf5 format and yet is sufficiently different in a non documented manner to make this format unusable on any platform outside matlab.
Save to nondefault mat file version.
Version 7 3 mat files use an hdf5 based format that requires some overhead storage to describe the contents of the file.
For cell arrays structure arrays or other containers that can store heterogeneous data types version 7 3 mat files are sometimes larger than version 7 mat files.