Portfolio
Open the file “templates/grid.php” and on line 181 change 'autoplay' => 'true',
to be 'autoplay' => 'false',
Open the file “single-portfolio.php” and on line 74 change 'autoplay' => 'true',
to be 'autoplay' => 'false',
Blog
To do the same for blog gallery posts you would open the file “templates/post-gallery.php” and on line 36 change 'autoplay' => 'true',
to be 'autoplay' => 'false',
(updated April 2nd 2014)
Keep in mind that if you modify core theme files then each time you update the theme you will need to make all of those modifications again to the updated theme files. If you are going to customise PHP templates it’s best to do that in a child theme because that will make it easier for you to update the parent theme. There are more details about how to create a child theme for Vellum here → http://para.llel.us/support/tutorials/making-a-vellum-child-theme/