Where to buy good and authentic blank media in China?

I’m running out of hard drive space on my laptop and I need to burn some stuff on to some blank DVDs. My mistake was not bringing any blank media with me. Now I need to buy some. Does anyone here know where I can buy good and real blank discs? I’m currently in Luoyang and I won’t arrive in a big major city like Beijing until June 26th. Any advice and information would be greatly appreciated!