The front-end is written, now all of my effort has been on designing an efficient intermediate file format for ETC1 and a decent enough (but an improvable) encoder to go along with it. The idea is to prioritize the development of a powerful enough intermediate file format itself first, along with a "hopefully good enough" encoder. So I've been quickly trying a bunch of different RDO-driven (mostly back end) optimizations, to find some interesting ones to exploit later down the line. Because once the transcoder ships I can't change it for a long time, if ever.
The next step is to add one more major feature, port it to Linux, and ship it to our first customer.