You enabled NPAPI plugins as the guide below?
http://www.tp-link.com/en/faq-884.html

If it doesn't solve the problem, provide a creenshot. Besides, what's the version of your chrome browser?

I had enabled NPAPI but the first day, after many tries i wasn't enabled to see video. Tomorrow, without any other change, it works !
thanks

ps. why web interface hasn't the ability to set the level of brightness/contrast/saturation, as it happens through local interface ?

It can be fulfilled with Camera Control. Why does the web interface need the ability?
http://www.tp-link.com/res/down/doc/NC200_Camera_Control_V1_UG.pdf

The camera control has access through local IP. If i want to change the video brightness when i'm far away from home i need to have a No-IP domain name to access the camera control page.
So, it would be more easy if the web interface was able to do this.

Unfortunately, we cannot set the level of brightness/contrast/saturation remotely...
Locally, we can also do it on the web interface.