原盘的制作质量相当不错:暗场多,以CG绘制的纹理细节丰富,噪点重而细腻,从而构成了本片独特的画风;此外ED更是以全24fps绘制。 本作最大问题在于锐利的线条普遍带有很强的锯齿,尤其影响到颜色线条部分(如琉紫和昂克儿的能力发动型态)。 为维持颜色线条的精确度,我们先拉伸UV平面,再通过混合使用传统与非常规方法,在YUV444下修复色度锯齿。 我们也针对噪点进行处理,在控制成品体积的前提下尽可能地维持了其画风和质感。 基于先前Lolihouse发布的版本,我们调整了亮度平面的反锯齿力度以更好地保留FHD细节,并优化了x265的编码参数。
The original source has fair quality, with sharp pictures and many textural details. We can see Xebec spent effort in creating the CG drawings, dark scenes and a 24fps ED. Unfortunately, the sharp edges have significant aliasing in both luma and chroma planes, making non-destructive anti-aliasing challenging. The strong and fine film grain has also made it difficult for x265 to encode the anime at an acceptable bitrate. To tackle the problems, we adopted a hybrid anti-aliasing approach combining traditional and non-conventional techniques, and operated under the YUV444 color space. The approach repaired most chroma aliasing and without damaging the sharp colored edges. Meanwhile, a tailored grain processing procedure was formulated, which achieved a good balance between picture style preservation and bitrate saving. Based on a previous encode released by Lolihouse, we adjusted anti-aliasing strength of the luma plane to better preserve FHD details, and optimized x265's parameters alongside.