It is huge. Put it this way, I have tried numerous times to buy legitimate copies of DVD's, VCD's and computer software and couldn't. They just aren't available. When you ask for them the salespeople look at you like you're mental and when they stop laughing ask you "Why?"
Even the CD's for sale in Wal-Mart are pirated!! When I want a legit copy I have to buy it in HK. And this is true all up and down China. This is MASSIVE. For an instructive example the sales people here when you buy stuff they don't say "its real" they say "its a good copy".
Its so wrong that I download pirated software for my computer because it feels more right to get it for free by stealing online it than to "buy" it hence paying someone else to steal it. Its more morally correct to me. I'd never do this back home but here I am.
Also as of late Amazon will no longer ship to China or Hong Kong because someone finally figured out how the pirates were getting a lot of their originals to burn.