The latest DDS formats support BC# compression, and DOpus as well as most image viewers fail to open them. It would be nice to have this support built into DOpus. Photoshop, with the Intel DDS plugin, is currently the only way I can open these to view effectively.
https://software.intel.com/en-us/articles/intel-texture-works-plugin (for code samples if you want to peak at how it is implemented)
https://software.intel.com/en-us/articles/fast-ispc-texture-compressor-update (same as above)
http://www.reedbeta.com/blog/understanding-bcn-texture-compression-formats/ (Detailed info on the compression)