处理方面,我们根据实时分析结果自动选择逆向拉伸重构的流程,并调整了逆向拉伸带来的锐化效果,然后附加适当的滤镜清除残留的锯齿和振铃,让各种算法得到的结果相近,以尽量统一画风。最后是常规的自适应去色带、补偿性锐化和自适应降噪。对于特典,我们人工挑选出了带缟的画面,通过拆场逆向拉伸解缟,然后做了时域稳定以改善线条的时域抖动现象,最后使用具有较强抗锯齿效果的倍高滤镜拉升回来,具体可看第 4 组对比图。部分特典出现了带缟锐化的情况,导致缟缟周围有一圈缟状晕轮,这东西实在奇葩,只好硬着头皮拆场去晕轮然后再解缟,具体可看第 1 组对比图。对于带缟缩放导致没法通过逆向拉伸处理的,我们使用了强力 AA 加收线锐化处理,具体可看最后一组对比图。剩下的就是对症下药,进行反交错、IVTC 等操作,就不再赘述了。
The overall quality of the BD source for the entire series is average, with a highly chaotic production. The native resolution is 720p, but the official release used various poor upscaling algorithms, resulting in multiple art styles in the lines: in the first season, there are instances of sharpness with severe aliasing and ringing, while at times, it appears blurry with slight aliasing; the second season, however, is consistently more blurred, sometimes with a lot of fine aliasing and at other times, displaying slight rough aliasing. Both seasons exhibit significant color banding in dark scenes, with the second season being worse. The specifications in the OVAs are incredibly diverse, with various peculiar and mismatched sources—some stretched, some with combings, some repeating, some normal. Furthermore, there are combinations of the aforementioned situations, as well as scaling and editing with combings, which are essentially unsolvable.
In terms of PP, we automatically select the descaling and reconstruction process based on real-time analysis results. We adjust the sharpening effects caused by descaling and then apply appropriate filters to remove residual aliasing and ringing, ensuring that the results from various algorithms are as close as possible for a unified art style. Finally, we conduct standard adaptive de-banding, compensatory sharpening, and adaptive denoising. For OVAs, we manually select frames with combings, use field separation, descaling and reconstruction to eliminate combing effects, improve temporal jitter in lines through temporal stabilization, and upscale using filters with strong anti-aliasing effects, as shown in the 4th comparison set. Some scenes exhibits combing sharpening, causing a combing-like halo around the edges, which is quite bizarre and required disassembly to eliminate the halo and then address the combing, as illustrated in the 1st comparison set. In cases where combing scaling prevented descaling, we employed powerful anti-aliasing, line thinning and sharpening, as depicted in the last comparison set. The remaining steps involve specific treatments such as deinterlacing, IVTC, and others tailored to the issues encountered, which will not be further elaborated.