computer vision- ''from multimedia file'' in simulink

when trying to read my avi video in ''from multimedia file'' i get error ''in an assignment a(i) = b the number of elements in b and i must be the same''

i checked in the section properties and details of sample avi videos of matlab itself, and i realized that the data rate and total bit rate are the same but in my avi they are just a little bit different.

is this problem because of that? how can i fix? thanks in advance