Every 5th frame is interlaced. How do I address this in avisynth?

[LaserBones]

Every 5th frame is interlaced. How do I address this in avisynth? I've attached a sample of the video you can download below.

https://www.dropbox.com/s/cvrrmuayf7wr6xa/every%205th.mkv?dl=0

[jagabo]

You should provide a panning shot. I suspect you'll find more interlaced frames.

You're probably going to want to field match followed by decimation

[lordsmurf]

That would be interesting if it was really every 5th.

I'd be curious to see such a script, just because.

I have a video where interlace reverses itself (not TFF then BFF, but TFF where the field invert; bottom is over top, but still TFF without judder). It comes and goes, so needs a specified frames start/end.

This would need some sort of auto to specify 5th. The issues are related, weird interlace damage.

[jagabo]

That would be interesting if it was really every 5th.

In the OP's case it may simply be because his sample clip is all 12p character animation. That naturally leads to 1 interlaced frame out of every 5 frames when telecined to 29.97i.

Regarding your video which switches between scan lines in the correct order (0,1,2,3,4,5...) and scanlines in the wrong order (1,0,3,2,5,4...) you can probably create two videos, one with just TFM(), the other with SwapFields().TFM(), then use a runtime filter to select the frame with the least aliasing. If you provide a sample I'll take a stab at it...

[LaserBones]

You should provide a panning shot. I suspect you'll find more interlaced frames.

You're probably going to want to field match followed by decimation

There aren't any panning shots but below is a zoom shot. What would be the best way to go about field matching and decimation?

https://www.dropbox.com/s/48j9e6p1dideld4/every%205th%20-%202.mkv?dl=0

[jagabo]

It's standard 3:2 pulldown. A Simple TFM().TDecimate() will restore the original 23.976 film frames.

LWLibavVideoSource("every 5th - 2.mkv", cache=false, prefer_hw=2) 
TFM()
TDecimate(mode=1) # mode 1 might be a little smoother than the default (0)