How to use 3d dct using file mirt_dctn(a)?

• I use this
• http://www.mathworks.com/matlabcentral/fileexchange/24050-multidimensional-discrete-cosine-transform-dct/content/mirt_dctn.m to perform a cube 3d-dct (eg. 280 by 280 by 280)
• Also, i can cut them into 8*8*8 block first (i.e. total 42875 blocks) and use the above function mirt_dctn(a) to perform 3D- dct

1. My Question is do they have exactly same output?
2. If i want to use the latter one, i have to handle so many blocks. Actually i don't how to cut them (index them) and reconstruct them to 280 by 280 by 280.

• Please also provide me code. Thank you
• Background information: The values in the 3d matrix of 280 by 280 by 280 is either 255 or 0.