Why are my videos pixelated after uploaded to youtube?

After uploading a video to youtube it gets very pixelated, but the file that is rendered on my computer is perfectly in good quality. I have took the time to look at youtube guidlines and what their recommended video settings are and have tried different formats. Still looks the same, in this case i render using the wmv format. I will link the video and render setting below. I also have a gtx 680 incase that matters at all. Anyways, i'm open to all answers!
P.S The pixelation only occurs in my videos that have lots of motion, specifially a sped up one of minecraft.

Youtube video:

Render Settings:
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image
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Please allow YouTube depending on length of video 1-xx hours to finish uploading and setting quality.