bc7enc_rdo is now a library that's utilized by the command line tool, which is far simpler now. This makes it trivial to call multiple times to generate large .CSV files.
If you can only choose one set of settings for bc7enc_rdo, choose "-zn -U -u6". (I've set the default BC7 encoding level to 6, not sure that's checked in yet.) I'll be making bc7e.ispc the new default on my next checkin - it's clearly better.
All other settings were the tool's defaults (linear metrics, window size=128 bytes).
The command line tool now detects extremely smooth blocks and encodes them with a significantly higher MSE scale factor. It computes a per-block mask image, filters it, then supplies an array of per-block MSE scale factors to the ERT. -zu disables this.
The end result is much less significant artifacts on regions containing very smooth blocks (think gradients). This does hurt rate-distortion performance.