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Swan-Song -- Math Rules


Chris Davidson
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I created a gif showing the end result of reverse telecining which shows the conversion of the 3/2 pulldown or 5 frames back to its original 4 progressive.

The top part of the gif is the 3/2 pulldown process from the original.

The middle part is the reverse telecine result converting it back to its original four progressive frames.

Added on edit: I would suggest downloading this and playing it at full view so the pulldown frames are quite obvious to see.

https://drive.google.com/file/d/0BwrExtVD005OTjgyVDJSTXlnZUE/view?usp=sharing

Edited by Chris Davidson
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It seemed a stretch to believe that Underwood or an associate would have filmed the SS recreation at 18fps since the camera he normally used was most likely a "Bell and Howell Filmo" standard 16mm/24fps camera.

The pulldown frames conversion answered that question.

Reconstruction shot at 24fps.

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There was a suggestion that the SS recreation video was shot at approx 18/18.3fps.

If that was indeed true, the pulldown conversion ratio would have been different.

29.97/18 = 1.665/1 ratio = 5/3 pulldown ratio.

for those uninitiated, the why's of 29.97fps is explained here... https://documentation.apple.com/en/finalcutpro/usermanual/index.html#chapter=D%26section=6%26tasks=true

Edited by David G. Healy
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There was a suggestion that the SS recreation video was shot at approx 18/18.3fps.

If that was indeed true, the pulldown conversion ratio would have been different.

29.97/18 = 1.665/1 ratio = 5/3 pulldown ratio.

for those uninitiated, the why's of 29.97fps is explained here... https://documentation.apple.com/en/finalcutpro/usermanual/index.html#chapter=D%26section=6%26tasks=true

There was a suggestion that the SS recreation video was shot at approx 18/18.3fps.

If that was indeed true, the pulldown conversion ratio would have been different.

29.97/18 = 1.665/1 ratio = 5/3 pulldown ratio.

for those uninitiated, the why's of 29.97fps is explained here... https://documentation.apple.com/en/finalcutpro/usermanual/index.html#chapter=D%26section=6%26tasks=true

David,

More math, you know how much I hate that subject.

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I then took the liberty of removing all but the progressive frames from the SS reconstruction video so now we're only dealing with whole frames.

You might remember this:

https://drive.google.com/file/d/0BwrExtVD005OUmxsRlJLSGhwNE0/view?usp=sharing

Now, all one has to do is apply a rate x time = distance equation and/or a frame count comparison between the two films using common Dealy Plaza landmarks in relation to the same part of the vehicles.

Here's a hint at this time. That is a 1959 Chevy Impala Sport Coupe. It is 210.9" long = 17.57ft. The difference in length between the two vehicles is 3.77ft

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There was a suggestion that the SS recreation video was shot at approx 18/18.3fps.

If that was indeed true, the pulldown conversion ratio would have been different.

29.97/18 = 1.665/1 ratio = 5/3 pulldown ratio.

for those uninitiated, the why's of 29.97fps is explained here... https://documentation.apple.com/en/finalcutpro/usermanual/index.html#chapter=D%26section=6%26tasks=true

There was a suggestion that the SS recreation video was shot at approx 18/18.3fps.

If that was indeed true, the pulldown conversion ratio would have been different.

29.97/18 = 1.665/1 ratio = 5/3 pulldown ratio.

for those uninitiated, the why's of 29.97fps is explained here... https://documentation.apple.com/en/finalcutpro/usermanual/index.html#chapter=D%26section=6%26tasks=true

David,

More math, you know how much I hate that subject.

lol.... simply b&w to color concerns, Chris. :)

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Since I have the landmark frame comparison completed and ready to post, I'll do the R X T = D formula first.

I chose z173- z232 for a total of 59 frames partly because we can get feedback on the WC specs from CE884 final plat version of May 1964.

Their span from z171-z231= 60 frames @ 63.4ft traveled

A 24fps movie using these numbers will get you this:

60/24 = 2.5seconds 63.4ft/2.5sec = 25.36ft per sec = 17.25mph

59 frames using that average would equal the same 17.25mph

That would be quite a consistent speed with the overlay comparison movie between the lexus and limo.

Added on edit below:

z171-z231.png

Edited by Chris Davidson
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The distance per frame for the 17.25mph average is: 17.25 x 1.47 = 25.35ft per sec / 24 frames = 1.056 ft per frame

The 1959 Impala is 3.77ft shorter than the limo so any comparison between the two in terms of landmarks has to be considered.

3.77ft / 1.056ft per frame = 3.57 frames or 4 whole frames added.

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z173-z232 = 59frames

Reconstruction = frame 181-236 = 55 frames

59 Impala is 3.77ft shorter than the limo.

3.77ft made up in terms of average speed throughout this span = 3.57 frames = 4 whole frames.

55 + 4 =59 fames = Reconstruction total

The cars front and rear ends in relation to the Stemmons sign are the markers.

59frames to cover the same distance in each film.

59/24fps = 2.458sec 62.35ft / 2.458 = 25.36 ft per sec = 17.25mph

The recreation film is shot at 24fps.

The extant zfilm is a stepped down frame version.

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