There are many ways by which videos from youtube can be downloaded to PC but we have noticed that its quality is very poor. Now Its been a long time since Youtube supporting video to be watched in HD quality and now not only this those video can also be downloaded in HD and MP4 format (for mozilla firefox user only, so get it from here) ..
There are two firefox add-ons which u have to install in the first add-ons everytime you watch a video you will get a direct download link of that video in HD and MP4 format ..
In the second one you will be able to view the video in HD quality everytime by default from youtube..
Download the two add-ons from here :
- YouTube-Download-HQ-Videos - Official Addon Page - (create a new mozillaa account or Use these login details to download if you do not have a Mozilla account - Username : firstname.lastname@example.org Password : bugmenot)