Audio problem with Thunderbolt connection

I have a 13" MacBook Pro with Lion 10.7.5 system. I used to connect my laptop to TV with a HDMI cable and a HDMI/Thuderbolt connector. It works fine for a for a long time.

Recently I connected my laptop to TV, but I realized there is a audio problem. When I played a video on Youtube, there was no sound coming out from the TV, even though I went to system preference and change the output to TV. However, when I played music on iTune, it works!

It looks like there is only audio problem when I use online media player. I use Chrome as the broswer.

Anyone has this problem before?

And any solution that you can provide to help me to fix this problem?

Thank you so much!