Another VSFilter problem if anyone is interested:
VSFilter: Shadow is not drawn when Border is very thin (#2588)
When the border width is very small but not zero, MPC-HC "forgets" to draw the shadow, both in hardsubbing and softsubbing. Left to right, border=0.25 / 0.125 / 0.0625 / 0.062499 / 0 (@ 100%; if zoomed, the threshold will change):
This results in several realistic problems, such as unintended shadow blinking when the border width is slowly animated from non-zero to 0, or from 0 to non-zero (
Sample clip).
User-side workaround: For example, instead of \bord1\t(0,2000,\bord0), try \bord1\t(0,1750,\bord0.125)\t(1750,2000,\3a&Hff). Instead of \bord0\t(0,2000,\bord1), try \bord0.125\3a&Hff\t(0,250,\3a&H00)\t(250,2000,\bord1).