Twenty for one.
"the ratio for its American Depositary Shares (the "ADSs") representing common shares of VisionChina Media will change from one (1) ADS representing one (1) common share to one (1) ADS representing twenty (20) common shares (the "ratio change") effective as of December 12, 2012. The record holders of VisionChina Media's current ADSs at the close of business on December 11, 2012 will be required to surrender their certificates to the Bank of New York Mellon, as depositary, on a mandatory basis in order to exchange every twenty current ADSs for one new ADS."
Your 100 shares would become 5 shares. The stock price should theoretically multiply by 20. Instead of having 100 shares at $0.20 each ($20 of stock), you will have 5 shares @ $4.00 each (still $20 of stock).