Why do my HD videos look bad on youtube but not in WMV?

[ITechFreek]

So I upload my videos in HD, here are some screenshots:

In Windows Media Player:

There is a noticeable difference. I render my videos in Sony Vegas With Very popular HD render settings. What is the problem here?

 

[Simojo]

YouTube automatically compresses videos that are uploaded so you need to work on that basis. If you google it then you will find the right settings