>>341477705
>>341477901
>>341478209
There are multiple stages of compression. The first is a lossy, constant bitrate block-based compression method like DXT1, DXT5, or BC7. These methods can be loaded and stored directly in video memory. If you opt for crunch compression, there is a lossy, variable bitrate DCT compression step, which needs to be uncompressed before loading into memory. Finally, there is the Huffman-based archive compression for the whole asset bundle, like .zip or .7z, which uses a tree to eliminate redundancies. Crunch compressed textures are minimally redundant, so this step has little effect on their file size, but it reduces the file size of the more redundant CBR memory formats significantly.

The most important thing to take away is that the memory compression formats do not behave like typical lossy or lossless image formats; they encode blocks at a constant bitrate and the end results contain redundancies. Two DXT1 textures with the same resolution will always be the same size.