Deoldify Vapoursynth filter

[Dan64]

The scene change detection is usually performed by HAVC_ddeoldify. But there are 2 exceptions:

1) When is used "Ref merge". How "Ref merge" works is quite complex but is explained at page 18 of HAVC User Guide. In summary in this case HAVC apply the following strategy:

1.     all the clip frames are colored using DDColor and/or DeOldify (because the parameter SC min freq = 1)
   
2.     using the threshold specified (in this case 0.10) a subset of colored frames is sampled by the scene change detection algorithm and these frames are used as reference images for the selected exemplar-based model (in this case ColorMNet).
   
3.     the frames obtained at step 1 are merged with the weight specified (in this case 0.50) with the frames propagated by the selected exemplar-based model.
   

2) When is used method=5. In this case the reference clip is not generated by HAVC_ddeoldy because is used an external clip already colored and HAVC_deepex must know how to generate the reference frames.

So the scene detection parameters are necessary also to HAVC_deepex. I reduced the number to the minimum necessary to enable HAVC_deepex to perform such task.

Dan