converting -v5 files to -v7 and -v7.3

hello,

I receive a .mat file -v5 file constructed of many structures within it. The file is originated from some c code and facilitates some signal measurements. The file weighs roughly 5 Mbt. The problem is when I try to covert it to another format with the command save(fileName,'A','-v7') where A is my superstructure contained in the mat file, for example, it doesn't change the type. meaning, when I type in cmd: type('fileName.mat') I receive the following : MATLAB 5.0 MAT-file. Although the new file now weighs 1.7 Mbts. Stranger is, when I type save(fileName,'A','-v7.3') new file is indeed formatted in -v7.3 but now weights 300 Mbt.

can anybody help in figure out what is going on?

Elad

Answer 1

[Walter Roberson]

-v7 files use "MATLAB 5.0" in their internal header. -v7.3 files use "MATLAB 7.3" in their internal header.

[Stephen23]

Elad's "Answer" moved here:

Thanks you for replying,

Can you please explain the significant difference regarding the size of the -v7 -v7.3 files as a result of saving them in a different format?

Elad

[Titus Edelhofer]

Hi Elad,

v7 is a compressed format while v7.3 is an uncompressed format. Depending on the type of data this makes a huge difference...

Titus

[Walter Roberson]

-v7.3 is not necessarily uncompressed, but it can be tricky to get compression turned on correctly.