Deoldify Vapoursynth filter

[Dan64]

So it seems that the problem is related to the message

Information: Note: NumExpr detected 32 cores but "NUMEXPR_MAX_THREADS" not set, so enforcing safe limit of 8.
Information: NumExpr defaulting to 8 threads.

In effect, after this message, vsPipe display the warning

y4m: failed to parse y4m header.

You should provide an option in Hybrid config to set the value of  NUMEXPR_MAX_THREADS .

Dan