Decomb IVTC issue

[iamtehsux]

im having an issue with still getting the occasional interlaced frame after normal ivtc in gordian knot with the decomb filter. my source is ntsc and dgindex reports frame type as interlaced but going through one of the vobs frame by frame in vdub it has 3 progressive frames and 2 interlaced frames in every 5 frame sequence. here is an uncompressed vobsample if anyone can help with what to edit in the avs telecie/decimate line.

http://www.sendspace.com/file/gek1za

[manono]

No problem here using:

AssumeTFF()#Set the field order. The sample was TFF
Telecide(Guide=1)
Decimate()

[iamtehsux]

its only in 1-2 places for 1-2 frames in the rip is there a vob cutting program i can use that has a preview window so i can cut a sample from one of those places and post?

[poisondeathray]

You can use DGIndex, use the "[" and "]" to mark in/out

File=>save project and demux video

This will give you .m2v (elementary video) and elementary audio stream

[manono]

its only in 1-2 places for 1-2 frames in the rip.

So why didn't you send a sample showing the problem? What good is a sample where everything works? I did notice in the included sample that after a scene change there was an orphaned field which was deinterlaced by Decomb's post-processor. Is this a TV series, because it looks as if it was shot on film but edited as video? If so, there could be places that Decomb doesn't handle well - other places where the cadence is broken, but broken worse. You might give TIVTC a try if that's the case. Otherwise a better sample would be nice.

Another possible solution would be to use Decomb as you are doing and then add in Vinverse at the end. It'll only deinterlace any left over interlaced frames, and it may be better at picking them up than is Decomb's post-processor at default settings, although Decomb's one can easily be tweaked to make it more sensitive to left over interlacing.

[iamtehsux]

yes it is a tv series. i had deleted the avi files and couldn't remember the exact spot where i had the problem i will do some test encodes on a couple episodes and post screen shots of what im talking about and uncompressed vob samples from those spots.

[iamtehsux]

sample1: http://i42.tinypic.com/15ppe9k.jpg - http://www.sendspace.com/file/fkvnxm

sample2: http://i44.tinypic.com/2mcajie.jpg - http://www.sendspace.com/file/i90n39

sample3: http://i42.tinypic.com/acbf4w.jpg - http://www.sendspace.com/file/k76iqx

sample4: http://i44.tinypic.com/20pokk2.jpg - http://www.sendspace.com/file/4mmlw0

[manono]

Yes, you do have a problem. I checked the first pic and sample. There are 3 orphaned fields in that sample, and all but the first are taken care of without any tweaks. Tweaking the VThresh helps a bit with the frame 46, the one in the pic:

AssumeTFF()
Telecide(Guide=1,VThresh=20)
Decimate()

However, I had better luck using TIVTC at default settings, as it seems to clear it up just fine:

TFM()
TDecimate()

You can get it here:

http://bengal.missouri.edu/~kes25c/TIVTCv105.zip

If you want to try it out, put the TIVTC.dll where the other DLLs are located (probably in the AviSynth plugins folder), replace Decomb with TIVTC in the Plugins portion at the top of the GKnot generated script, and replace the Telecide/Decimate lines further down in the IVTC section with the TFM/TDecimate lines. And thanks for the pic. I missed that frame in my first run-through of the sample. I didn't download the other 3 samples, so I hope they don't have even more serious problems.

[iamtehsux]

ok thanx i will try that tonight and post my result tomorrow. also was doing some reading on tivtc if you are using chroma motion do you have to add chroma=true anywhere? read something in another thread about tivtc with another source with 3 progressive frames and 2 interlaced they had to use something like:
tfm(order=-1).tdecimate(hybrid=0)
FieldDeinterlace(chroma=true)

[manono]

Your source seems to be relatively simple and doesn't need anything fancy. Use the basic TIVTC script I gave you unless and until you find something peculiar in the result. And there's no need to add in FieldDeinterlace afterwards. Ever. If something really does need some further deinterlacing, there are better deinterlacers. In addition, that particular FieldDeinterlace line of yours deinterlaces all frames, which is the last thing you want after an IVTC.