Video Thumbnails in blocks

so I got the Video module installed an running.

it works great execpt 2 things

thing 1

i got some blocks like random video, Top Videos and that stuff.

but only shows text not the thumbnail.

thing 2

my idea was to let all of the people to upload funny videos and it goes into the podcast feed.

but podcasts only work with videos that quicktime can play.
is there a way i can set that you only can upload .mov, .mpeg and so on

thx!