Unclear .flv files

[meridius10]

Yesterday I downloaded some youtube files and converted them into .flv files using voobys by just replacing youtube with voobys in the url.

I then tried a freeware app but moved to vlc.

The problem I am having is that some of the .flv files are unclear after they have been downloaded, but clear when viewed in youtube. I am looking at videos relating to databases and the authors are showing their laptop screens and it's difficult to read the code they are working with.

Any ideas if there is a fix to this? Is VLC the best freeware for this or is this something to do with the way voobys is converting the file to .flv?