GitHub - keijiro/ChromaPack: ChromaPack -- A lossy texture compression plugin for Unity.

ChromaPack is a lossy texture compression plugin for Unity. By using chroma subsampling technique, it reduces the memory requirements of an image to 12-bits per pixel (x2.67 compression for 32bit RGBA image) without introducing noticeable artifacts. The algorithm is quite simple and even previous-generation mobile GPUs can decode it on the fly. The screenshot above shows the compression quality of

[crist18]

unity png import

[motch1cm]

Unity向けのクロマサブサンプリング技術を使った圧縮形式らしい