Help needed to determine what type of vid I'm working with.

[pooksahib]

Hi. I'm having trouble making my mind up if this is a true case of 'motion every two fields'. I've applied assumetff and assumebff but some of the frames seem very 'wavy'. I'd be obliged to anyone willing to have a look and tell me what needs to be in my avisynth script. Thanks!

[LigH.de]

Quite clearly telecine (3:2 pulldown from film to NTSC). Use an IVTC plugin, e.g. TIVTC.

[pooksahib]

Vielen Dank.
Would you include .tdecimate() after tfm(order=-1)?

[Skiller]

Since TFM only matches the fields (does not delete the duplicates), TDecimate afterwards is vital for 23.976 fps output.

[pooksahib]

Danke, Skiller. But the VOB's are 29.970 fps - does that matter?

[Sharc]

Danke, Skiller. But the VOB's are 29.970 fps - does that matter?

That's exactly what it should be for telecined film. After inverse Telecining (TFM() + TDecimate()) you will end up with 23.976 fps progressive frames.

[Selur]

telecine = 3:2 pull down -> https://en.wikipedia.org/wiki/Three-two_pull_down

[pooksahib]

OK, I think I'm getting it... Many thanks, guys.

[pooksahib]

Hello again. I've re-scripted this DVD to include "tfm(order=-1).tdecimate()". The trouble is, I can't edit the movie because the script seems to be ignoring my instructions regarding frame numbers. For example, my request for "trim(87888,90000)" gave me a clip beginning with frame 109860(!)

Does anyone recognise this problem and can tell me how to fix it? I'm using MeGUI. Thank you.

[LigH.de]

That's correct. IVTC removes every 5th frame in the average, the resulting clip will contain only 4/5 of the original frames. After restoring the originally progressive movie, the former frame 109860 will appear at frame 109860*4/5 = 87888 because 21976 frames have been discarded before already.

To cut in respect of IVTC, you will have to count frames as they appear after TDecimate(), and you should apply the Trim() after it because cutting multiple times may confuse the field pattern and disturb the IVTC process when applied before TFM().


PS: It may even work to enable IVTC in DGDecode / MPEG2Source by selecting the matching option in DGIndex.exe so you may even omit TIVTC when it works this way. But never forget to set this option back for the next project...

[pooksahib]

OK, thanks for that. Problem solved, though. I was editing by looking at the frame numbers indicated by 'showframenumber()' but now I see that MeGUI's preview shows the true frame number. And by calling showframenumber AFTER tfm, everything's back to normal.