I'm looking to download a free video editing software to crop, rotate, reduce sound of original clip, and add my own sounds/music
to the clip, and also take snapshots from the clip. Now i found 3 sites that offer some of what i want, but I'm not sure how safe it is to download from the sites. Can some 1 please have a look at them and give me some advice and feedback ?
the site links are below
( that last 1 say "open source", what exactly is open source ? )