Simple experiment for using the transcoder from https://github.com/BinomialLLC/basis_universal together with Qt's upcoming graphics abstraction layer, see f.ex. https://www.qt.io/blog/qt-quick-on-vulkan-metal-direct3d
The example loads a .basis file (generated with basisu -mipmap stuff.png) and transcodes either to ETC2 or BC1, depending on what is supported at run time. Falls back to transcoding to plain RGBA8 otherwise. It then draws a textured quad.
Should work on all QRhi backends, switch with command line args: -d (D3D11) -v (Vulkan) -m (Metal) -g (OpenGL).