Microsoft has released its latest DirectStorage 1.4 update, focusing on the technicalities behind game asset streaming. Today, the company introduced new compression and decompression technology called Zstandard (Zstd), which should improve game loading times and bring much faster game asset streaming than what was previously used. Microsoft originally developed its DirectStorage in DirectX 12 to take advantage of the quick NVMe SSDs. Powerful consumer GPUs need game assets to load incredibly fast, and DirectStorage devleopment has cut out the middle-man, the CPU, in the process of streaming these assets from storage to the GPU. Traditionally, this has been done over CPU, causing delays and latencies across teh stack.

To push Zstd even further, Microsoft has developed the Game Asset Conditioning Library (GACL), a companion tool that developers run on their assets before a game ships. The idea is that instead of simply compressing textures, GACL first conditions them to be more compressible, allowing Zstd to squeeze files down by up to 50% more than it otherwise could. It does this through a few different techniques. Shuffling rearranges data inside texture files so repeating patterns cluster together, giving Zstd more to latch onto. Block-Level Entropy Reduction (BLER) and Component-Level Entropy Reduction (CLER) then reduce texture complexity at the block and color-channel level, using perceptual quality as a guide so any changes remain invisible to the player. CLER takes this a step further by incorporating machine learning to identify exactly where that reduction can be applied without anyone noticing.