Weird Telecine cadence in Wizard of Speed and TIme

[Doc Sane]

Okay, I'm just about at my wit's end. Most of the laserdisc of the cult classic "The Wizard of Speed and Time" can be IVTC'ed using SmartDecimate or Decomb, but there's a musical sequence near the beginning of the film that has a bizarre telecine cadence. I've posted two clips from it:

http://neil.anime-translator.com/Weird01.avi
http://neil.anime-translator.com/Weird02.avi


The cadence in clip 1 runs like this:

IIPPPPPIIPPPPPIIPPPIPIIPPPIPIIPPPII

and the one in clip 2 is:

PPPIIIIPPPIIIIPPPIIIIPPPIIPIPP


Can anyone tell me what in Mike Jittlov's name is going on here? I've tried every IVTC method and they all drop frames they shouldn't on this sequence.

[scharfis_brain]

hehe, one of the weird methods converting PAL-Film to NTSC.

http://forum.doom9.org/showthread.php?s=&threadid=70035&highlight=batman

http://neuron2.net/ipw-web/bulletin/bb/viewtopic.php?p=3507#3507

x=kernelbob()
smartdecimate(1250,2997,bob=x)

is the way to get a smooth 25fps video

[Doc Sane]

Originally posted by scharfis_brain
hehe, one of the weird methods converting PAL-Film to NTSC.

http://forum.doom9.org/showthread.php?s=&threadid=70035&highlight=batman

http://neuron2.net/ipw-web/bulletin/bb/viewtopic.php?p=3507#3507

x=kernelbob()
smartdecimate(1250,2997,bob=x)

is the way to get a smooth 25fps video

Except this film was shot in the US for the theater. 95% of the film is in the proper 3:2 pulldown cadence...except for this one section. How do I get it to smooth 24 fps?

[scharfis_brain]

bob the video, and count its unique frames to identify the real framerate of the video.

then set up smartdecimate using the proper decimation ratio

to get all frames without dupes and skips

to finally get back to 23.976 fps, you have to slowdown/ speedup the scene...

[Doc Sane]

Originally posted by scharfis_brain
bob the video, and count its unique frames to identify the real framerate of the video.

then set up smartdecimate using the proper decimation ratio to get all frames without dupes and skips to finally get back to 23.976 fps, you have to slowdown/ speedup the scene...


Okay, I've read the documentation for Smartdecimate and I have absolutely no idea how to set up the proper decimation ratio. Can you give me an example? I'm sorry if I'm being especially thick here, but I also couldn't figure this weird telecine problem out when I asked you about the Daicon animations a few months back. Am I going to have to go through every cut of this 88 second sequence to figure out exactly which frames are good and which frames aren't?

[scharfis_brain]

do not try to think about your clip in frames.
try to think field-wise.

this means:

avisource("weird01.avi")
bob()

is the script to analyse your video.

open this script in VDub and count how much unique frames
you get within 240 fields in VDub. (Dupes are not counted!)
for your sample this should be about 100 frames.
this leads to the following equation:

total fields / unique frames = 59.94 / true framerate

equation rearranged:

true framerate = 59.94 * unique frames / total fields

inserting our numbers here:

true framerate = 59.94 * 100 / 240 = 24.975

but 24.975 isn't a valid framerate in worlds television
standards, set lets round up this to 25 fps (PAL framerate for FILM)
this means our framerate ratio is 59.94 fps (fields per second = NTSC) : 25fps (fullframes per second = PAL)
now, setting up smartdecimate with this ratio:

avisource("weird01.avi")
smartdecimate(59.94,25.00)

will jield in an error, cause the numbers have to be integer.
hm.. you'll think, okay then lets move the dot in those numbers, so we get integer:

avisource("weird01.avi")
smartdecimate(5994,2500)

but this won't work, too unfortunately, cause now, the numbers are out of range (they are far to large)
now lets cancel down that fraction (German: Bruch kuerzen ?!?) :
5994 / 2500 = 2997 / 1250
this one cannot be simplified more, so lets insert those numbers to smartdecimate:

avisource("weird01.avi")
smartdecimate(2997,1250)

et viola! we have a perfect smooth 25 fps video.
thats, why smartdecimate is that mighty, every wished
decimation ratio can be achieved, with some little schoolboy's mathematics.

now, have much fun counting the unique frames of your video.