You can enable or disable autoplay in the template fields plugin.

Go to your CMS admin panel and navigate to Plugins >> Template Fields.

Select the location you wish to edit "Members"

Scroll down to "Flash Player Settings" and locate the "flashvarsgalleryautoplay" entry and click "edit".
1 - yes the video will auto-play
0 - no the video will NOT auto-play.

Click "save entry" to save your changes.