Basis Update: ETC1 Prototype Completed

We just finished the first ready-to-ship prototype of Basis, with support for the popular ETC1 format. This version of the compressor covers most mobile platforms (with the main exception being iOS devices without Metal support) as well as platforms like Android TV. In addition, we'll be adding support and optimization for texture arrays as a feature.

The graph below plots size (on the x axis) against quality (y axis), and below are some images compressed with the compressor so you can judge quality for yourself. Green is our compressor with different quality settings, red represents a common current method (losslessly compressing ETC1 with LZMA). The test is for "RDO mode"-- in other words, instead of using our intermediate format we use our compressor to make smart quality tradeoffs in a .ktx file that can be losslessly compressed further. Our custom intermediate format should perform even better, and we'll post updates as development progresses.

Rich does a good job of blogging in-progress updates, so for technical details check out some of his recent posts:

Of course we'll continue to refine this, but you can see for not too much quality reduction we can easily half your storage size. These results are looking promising.

Also remember that we've done this feature as a pre-order request. We are still open to supporting other platforms or features earlier-- if you would like to request that your feature be prioritized, just contact us at

If you'd like to try a drop of this, feel free to contact us at, or sign up for our Google Group at!forum/binomialcompressor/ for more frequent updates.