The reworked TexturedVideo implementation is in the Git master code and now has native support for planar formats and X-Video attributes for brightness, contrast, hue, saturation, gamma, and color-space are implemented within the driver. These X-Video attributes though are not currently supported when using bi-cubic filtering. This reworked video support that affects all supported card generations was done by Alex Deucher and Roland Scheidegger.
Checkout the latest xf86-video-ati Git code for the support. Alex also made an announcement about this new support on his personal blog.