Accoring to a long-time and reliable inside source of ours, deep inside the DC/WB system, this was CGI test footage for a proposed Dc Universe Animated Feature from years ago, but was shelved after the Wonder Woman Dc Animated Movie didn't do as well as they'd have liked. The Brave and the Bold crew grabbed it for fun and thats why we get to see it! Its quite a treat, really.
This is in NO way a reflection of the 2012 CGI Batman show. None. The style for that show will also NOT be in the same Timm style as the Green Lantern CGI animated show. The 2012 show is headed up by Teen Titans alum Glen Murakami. More on that soon!
...and thats the scoop. Case closed bat-fans!