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rendering interlaced footage, to output in 1080/50i: adjusment layer flicker on fields

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miron auslander
rendering interlaced footage, to output in 1080/50i: adjusment layer flicker on fields
on Jun 14, 2016 at 11:38:04 am

original footage is 25 fps 1080i
working with adjustment layer and basic coloring effects
the final output render results in adj layer flicker "on/off" on each field
the problem was tested on 2 different HP workstations and problem persist.
working on PCs windows 7.

i had the exact same problem while using the rotobrush tool.
i solved the render flickering issue, by pre-composing the designated layer to be roto and changing the comp setting to 50FPS
rotobrushing in the 50fps comp but rendering the working comp of 25fps.
problem solved.
but working with adjustment layers on this project remain an issue.


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Tudor "Ted" Jelescu
Re: rendering interlaced footage, to output in 1080/50i: adjusment layer flicker on fields
on Jun 14, 2016 at 1:15:44 pm

De-interlace the 1080 25i footage and render clean frames in lossless format. Apply whatever fx you need to the rendered 1080 25p and then export as 1080 50i.

Tudor "Ted" Jelescu
Senior VFX Artist


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miron auslander
Re: rendering interlaced footage, to output in 1080/50i: adjusment layer flicker on fields
on Jun 14, 2016 at 1:32:46 pm

hi Tudor,

thank you for your replay.

i will try but not sure it with pass with the On-Line editor(which is done on an old avid nitris i believe).
i'm guessing once i will render clean frames in lossless format the fields will be gone resulting in flickring on the online system,
they working for broadcast on 25i, i had problems before with them if i De-interlace= progressive render that i send in the beginning.
BUT WILL TRY!

so far only rendering with pulldown wssww
i was able to get 31.2 FPS but "smooth" interlaced playback
then converting to 25 again.

not really sure what im doing with pulldown (never used it before)

if you think of something else please let me know/
and again thanx
Miron


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Tudor "Ted" Jelescu
Re: rendering interlaced footage, to output in 1080/50i: adjusment layer flicker on fields
on Jun 15, 2016 at 7:04:05 am

You do not need to use pulldown, that's for converting film to video, from 24fps to 29.97 or 25 fps.
Next, let's adress a naming convention: I have seen both 25i and 50i used. In my experience both mean the same thing, that is PAL footage at 25 frames per second interlaced, which in turn means 50 fields per second interlaced. There is also a 50 fps, as in frames per second, but I think in your case we are talking about 50i as in 25 frames per second interlaced.
So, once you interpret your footage and use 25 fps (full frames) to do your fx, you need then to render out a 50i clip (fields interlaced) with the right field order. In your case is Upper Field first ( good field order resource: https://www.motionelements.com/blog/workflow/video-field-order-reference-li... )
You should not have any issues with Avid then.

Interpret footage in AE (once you do that you actually do not need to render out a frames sequence, that was a slip up from my past when I had to do that):
https://helpx.adobe.com/after-effects/using/importing-interpreting-video-au...

Tudor "Ted" Jelescu
Senior VFX Artist


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miron auslander
Re: rendering interlaced footage, to output in 1080/50i: adjusment layer flicker on fields
on Jun 15, 2016 at 9:40:36 am

you are right the footage is 25 fps with 50 fields per second interlaced.
after effects on import recognize (automatically)correctly the footage and interpret it as upper first (and manually i'm adding the checkbox for preserve edges (best quality only) in the interpret footage dialog box. and on render i export 50i
with field render set to "upper fields first" and in most cases all is good.

only in specific shots i had problems with fields flickring.
* when i worked with the rotobrush tool, and DIDNT pre-comps the footage to a 50fps comp i had these problem.
but once i pre-comps the rotobrush layer to 50 fps comp, did the rotobrush process in a 50 fps comp and then returnig to the main 25 fps comp and render the main comp, problem was solved and the render came just fine.

but know i still have these problem in specific shots, recent example:
when working with adjustment layer, applying some color effects (tried different effects append with all effects) while previewing everything seems fine but when rendering the final output, While rendering is in progress i "see" the fields, upper first and on the lower field after effects completely ignores the adjustment layer as if it doesn't exist.
Resulting in a flickering unusable file.

and i can't for the life of me understand the Common ground causing the adjustment layer to react like these.
hope i was clear inaf, and maybe something that i described will ring a bell for you what might cause this issue


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Tudor "Ted" Jelescu
Re: rendering interlaced footage, to output in 1080/50i: adjusment layer flicker on fields
on Jun 15, 2016 at 10:28:53 am

Try rendering out 25fps (full frame) in uncompressed format, bring that in and re -render 50i. This should eliminate the issue.

Tudor "Ted" Jelescu
Senior VFX Artist


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miron auslander
Re: rendering interlaced footage, to output in 1080/50i: adjusment layer flicker on fields
on Jun 15, 2016 at 10:57:04 am

i did tried it, and it did solve the issue.
but the online room rejected the shot - for a general flickering in areas of fast camera movement.
for know this how we handle the situation.
the online editor applies in avid on my render(like your suggestion) -fluidmotion: progressive to interlaced.
but its far from ideal cause in the process of 25fps (full frame) in uncompressed format
i'm loosing the fields resulting in poor image quality.


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Tudor "Ted" Jelescu
Re: rendering interlaced footage, to output in 1080/50i: adjusment layer flicker on fields
on Jun 15, 2016 at 11:03:25 am

If you get flickering in areas of fast camera movement you can try to apply a CC Force Motion Blur or Pixel Motion Blur on the frame footage before interlacing it again.

Tudor "Ted" Jelescu
Senior VFX Artist


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Richard Herd
Re: rendering interlaced footage, to output in 1080/50i: adjusment layer flicker on fields
on Jun 15, 2016 at 9:39:50 pm

Timewarp to 2008: http://lurkertech.com/lg/fields/


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miron auslander
Re: rendering interlaced footage, to output in 1080/50i: adjusment layer flicker on fields
on Jun 16, 2016 at 11:08:42 am

thank you very much.
very interesting and enlightening.
but still didn't found the solution i was hoping for.


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