What causes this large interlacing pattern?

[LaserBones]

The credit footage of a film I'm encoding has larger interlacing? The rest of the film is interlaced but I can't figure out what's happening with this weird combing. What causes this?

[Sharc]

Vertical resizing without deinterlacing before resizing destroyed the original interlaced structure.

[LaserBones]

Vertical resizing without deinterlacing before resizing destroyed the original interlaced structure.

That makes sense. This is irrepairable correct?

[Sharc]

Vertical resizing without deinterlacing before resizing destroyed the original interlaced structure.

That makes sense. This is irrepairable correct?

The damage is there. Often irreparable yes, unless one knows how it has been resized and no other processing has been applied on top.
Some mitigation is possible (typically a trial and error process). There are posts in this forum and at doom9. Maybe someone with more experience will chime in.

[Selur]

basic idea to undo this is to:
a. downscale to original resolution
b. deinterlace
c. try to lessen ghosting caused by the whole process (using exblend, spotless, FixBlendIVTC, cdblend,..)
so i would say one can lessen this somewhat, but it is irrepairable on natural content. (on simple anime/cartoon content lessing of this is easier)
lessen: yes
get near the original quality, before the messup: not really

Cu Selur

[Samson_stages]

1. If the credits were added later during the telecine transfer process, they might have been interlaced differently than the original film.
2. If the credits are burned into separate title cards filmed at a different frame rate or resolution, their interlacing could differ.
3. If stock footage was used for the credits, it might have a different interlacing pattern.

[Alwyn]

Cut that bit off, fix it, add it back on. Mind you, I don't know how to fix it but I'm sure others do.