More IVTC

[bouis]

I've spent a bit of time playing with decomb.dll 4.01, and I've come to a few conclusions:

1) telecide(post=false,guide=1,gthresh=55)

Pros: Rarely errs up on nearly 100% film, 55 being the lowest "safe" value on my test clips.

Cons: Too cautious with poorly-telecined-but-24fps-progressive material. The default gthresh setting does a little better, but it's still worse.

Locate errors: "overrides" in the output log (only those which aren't decimated; use debug=true).

Correction: Manually decimate combed frames (ovr="overfile.txt") which get through (works ~90%?).

2) telecide(post=false)

Pros: Fixes poorly telecined material.

Cons: Often errs on film, resulting in sequences of combed frames slipping through.

Locate errors: Watch output carefully?

Correction: Manually decimate combed frames?

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I don't really consider postprocessing to cover up errors an option, as misses most slightly combed frames or blurs too many good frames, resulting in a "blinking" effect. The anticomb (http://www.avisynth.org/index.php?page=AntiComb) filter works extremely well, but even on the lowest settings blurs far too many false positives.

Decomb's override function (ovr="file") works well but it isn't suited for long clips (especially since telecide(guide=1) doesn't work virtualdub's seeking).

The best option would appear to be giving different frame ranges on the same clip different decomb settings. This doesn't seem possible with decomb itself, but I think it can be done using avisynth; for example, by breaking the clip up into subclips1/2/3/etc, running the subclips through decomb, and rejoining them. If anyone could suggest a method of accomplishing this, I'd appreciate it.

[bouis]

I wrote my own:


---

# Load Plugins

LoadPlugin("D:\mpeg2dec.dll")
LoadPlugin("D:\decomb41.dll")

# Stream

stream=mpeg2source("E:\VIDEO_IN\heatofthenight\heat.d2v")

# Substreams

clip1=Trim(Stream,0,147143)
clip2=Trim(Stream,147144,147707)
clip3=Trim(Stream,147708,0)

# Functions

function decomb_film(clipper)
{
clipper=Telecide(clipper,post=false,guide=1,gthresh=55)
clipper=Decimate(clipper,cycle=5)
return(clipper)
}

function decomb_ntsc(clipper2)
{
clipper2=Telecide(clipper2,post=false)
clipper2=Decimate(clipper2,cycle=5)
return(clipper2)
}

# Process

clip1=decomb_film(clip1)
clip2=decomb_ntsc(clip2)
clip3=decomb_film(clip3)

# Rejoin

clip1+clip2+clip3

# Extra

ResampleAudio(44100)

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Edit: I've changed the lines appearing in bold. It appears to work.