@Frankie: For me I use bandicam video capture program and then I use Arcsofts Media Converter 8 to reduce the size of the file for uploading. both these programs cost real money.
If you are looking for free then there are a number of programs out there that will get the job done...but there will be limitations as to what these programs offer in the way of features.
There is
1. A tube catcher...http://www.atube.me/video/
2. X-Split free version .. https://www.xsplit.com/?lang=en
I have tried just about every free program out there and those two give the best result considering the limitions of free...but hey you get what you pay for.
But I have to ask...what are you playing that is taking up 4GB of space for video?...I am also curious as to what settings you are using to record with? I know video takes up alot of space but there are settings that you use other than Full Uncompressed Frames.