Richard Geldreich's Blog: XUASTC's next step: Intra-prediction of weight grids

Rich Geldreich outlines the next development step for XUASTC, Binomial's GPU texture compression format. Currently, XUASTC applies JPEG-style DCT coding to ASTC weight grids, including standard luminance quantization tables with adaptive quantization. The proposed improvement is to port WebP-style intra-prediction into the weight grid domain — predicting weight grids from neighboring blocks and then coding only the residuals with DCT. This approach mirrors how modern image codecs work and is expected to push bitrates lower, especially at very low quality factors where pure DCT struggles. The author emphasizes targeting existing hardware decoders rather than neural compression techniques.