[S8/8mm film transfer] A setup for fast-capture and frame accurate result

[chmars]

Here is a more complete description of my setup for capturing 8mm/super8 footages.
It needs some work to be build but then, capture is fast and gives good results.

Users on this forum helped me a lot to understand Avisynth and S8/8mm aspects.
EDIT: especially on this thread
My turn to give back...

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One more capture system?
What is new in this system, is the use of an LED to allow synchronisation between video and footage frames.
Please let me know if you know a similar setup as I didn't find any on the net.
This whole thing is a [good working] work in progress and I am probably inaccurate on some points. Please feel free to correct and comment.



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LED for images synchronisation
The idea is to use an LED signal on the side of the filmgate as mark for software post-synchronisation with the projector:
The LED is turned on while the projector changes from one frame to the next one. (the LED is captured on the side of the framegate).
This was inspired from JohnMeyer's system where the software detects the framechange to be able to keep only one video frame for each film frame.
I didn't feel confortable with the idea of relying on software to determine which image to throw away. (And was upmost too lazy, as I feared having to tweak a lot to find the right parameters for every different type of footage).
Intuitively, the LED solution also seems to me faster to calculate, instead of calculating if images are mixed or not. Especially while pans or scenes changes, for example.


Projection phases:

Projector with blades, normal:
|---------------Frame 1------------|change||---------------Frame 2------------|change| ...
|bright| dark |bright| dark |bright| dark ||bright| dark |bright| dark |bright| dark | ...


Projector without blades, LED:
|---------------Frame 1------------|change||---------------Frame 2------------|change| ...
|L. OFF|--------------------------|LED ON-||L. OFF|--------------------------|LED ON-| ...

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