These are the same shot from a Canon C100 as shown by Media Player Classic ( CCCP - Combined Community Codec Pack (http://www.cccp-project.net/) ) and VLC ( VideoLAN - Official page for VLC media player, the Open Source video framework! (http://www.videolan.org/vlc/) ).

Why are they so different? What is the "right one"?

Picture:
http://i.imgur.com/FCHqRtS.jpg (http://imgur.com/FCHqRtS)

I have noticed it also but do not know the answer.

there are many reason.
-the way the video is displayed.
The is 2 way to display video on a PC, like a desktop image, or like a directX video.
while the result look the same, it is totally different, with different settings in the video card.

- the way the video is decoded
Some codecs skip quality for performance, other can apply the wrong color cube (rec 601 or 709, or even other like adobe RGB)

-particularly if the video is not displayed at full scale, it could be a problem of scaling, antialiasing.