10.6 PHD file type exclusion
If you never intend on .avi or .mkv files to be synced you may want to try the following.


Mobile Pane
Skip items that match any of the following
Choose Name Contains and type ".avi" (without quotes). 

Do the same for ".mkv" (without quotes).



If you do intend on syncing both file types and would like only to stop them from syncing when they are found within the Desktop folder you may want to try the following.


Mobile Pane
Skip items that match any of the following
Choose Full Path and type "~/Desktop/*.avi" (without quotes)

Do the same for "~/Desktop/*.mkv" (without quotes)