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Sony NXCAM NEX-FS700 CineAlta
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Old August 2nd, 2012, 04:55 PM   #1
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Solution to salvage flickering footage at high fps

I recently learned the hard way that the camera writes slow motion to the card at 60fps and flickering wouldnt be noticeable until played back at 24fps in the visual index. I was attempting to salvage the footage with color stabilization in AE (which was not getting me anywhere) when I realized that if I set my RAM-preview to skip 1 frame, there was no flicker. It was playing back at 11.988fps. So, I used the interpret footage option to change the source footage (23.976fps) to double (47.952). No more flicker. Next time I know now to plan for this in production, but it was nice to save the footage this time.
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Old August 4th, 2012, 05:34 AM   #2
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Re: Solution to salvage flickering footage at high fps

I'm shooting from the hip, thinking out loud (thinking from the hip?) but...

I was given thousands of JPEGs from a locked off camera to do a timelapse recently - shots every half hour over days and weeks. Of course the exposure 'pumped' a little. However, I used 'LRtimelapse' with Adobe LightRoom:

LRTimelapse - advanced Time Lapse Photography made easy!

which analyses every frame and tweaks them a bit to average out the exposure.

So....

One could, theoretically, also take one's master footage, export each frame as a PNG, DNG or JPEG and use the LRtimelapse workflow on that, as if it were a bunch of low resolution DSLR images.
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Old August 4th, 2012, 09:48 AM   #3
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Re: Solution to salvage flickering footage at high fps

That's a good idea Matt! The problem lies in the changing color cast. I was able to get the exposure pretty close with color stabilization, but I was using LEDs to supplement the ugly warehouse lighting. The color really changed when the flicker happened. Does the LRtimelapse match color as well as exposure?
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Old August 4th, 2012, 12:24 PM   #4
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Re: Solution to salvage flickering footage at high fps

Y'know, I think it might.

I get the impression it's leveraging lots of clever stuff in LightRoom - I see lots of impressive graphs as it tracks all sorts of stuff, and I think it's doing a bit of WB manipulation.

It's not the only one-trick-pony in town, though. There's lots of solutions I didn't get around to try, but fluctuations in WB are pretty much guaranteed between daylight, overcast and noon/golden hour.
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Old August 4th, 2012, 12:40 PM   #5
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Re: Solution to salvage flickering footage at high fps

Quote:
Originally Posted by Eric Aumen View Post
It was playing back at 11.988fps. So, I used the interpret footage option to change the source footage (23.976fps) to double (47.952). No more flicker. Next time I know now to plan for this in production, but it was nice to save the footage this time.
If you skip 1 frame, then you have 30p slowed down to 24p which is playing %80 of the original speed rather than %40 of the original speed. Depending on the motion characteristic of your footage and the effect you want, you could keep the %40 slow motion by time averaging. For example,

frame 1 = average of frame 1 + 2
frame 2 = average of frame 2 + 3
frame 3 = average of frame 3 + 4

might remove the objectionable part of the flicker while keeping all the frames. While not perfect, this is simple and it might be closer to the original effect you were looking for.
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