Thanks for your answer. I agree that chromecat is not perfect : for me it works perfectly with youtube, but is not as good as the wdtv for streaming local videos.
Unfortunately my wdtv is very unstable : it sometimes works perfectly, but also has a lot of problems. Apart from using the local disk (that also works with my wd gen1), the most stable I could find is using with an UPNP server (Universal Media Server). But this does not prevent having the network that sometimes does not work.
eg : last days I could not be able to copy a 1 GB file from my PC onto the local disc through the network : the transfert works OK some minutes, but looses the network.
When I use the network test menu entry, it takes 10 seconds to have the 3 green lights that say the network is OK. Yesterday : it stayed on the 2 red lights with a DNS error. Sometimes I have to reconfigure the wifi network tu be able to use it. I am not a network expert, but I think there probably should be some solution to maintain the wifi network working at the wd tv level…