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Severe artifacts in footage

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Ed Giles
Severe artifacts in footage
on Sep 14, 2009 at 8:22:46 pm

Greetings,
I'm having a problem with artifacts on a video i'm currently grading and colouring in AECS4 using Magic Bullet Colorista and Looks.

It seems that the video I started with has these artifacts embedded, even though it's uncompressed PAL footage exported from FCP.

Having realised the extent of it after grading, the director is kicking off at me to get it fixed!

Here's a frame of ungraded video

And a frame of graded video

I've given a more intense grade than the one I'm actually using, just to show what I'm talking about. The artifacting appears on the wall on the right the most:

I have tried MB Deartifactor to no avail, as well as masking out background and blurring etc - but this leaves me with a huge amount of roto to do. Grrr....

Can anyone shed light on why this might be happening in the first place, or perhaps how to do something about it?

Thanks,
Ed Giles


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Dave LaRonde
Re: Severe artifacts in footage
on Sep 14, 2009 at 9:12:39 pm

[Ed Giles] "It seems that the video I started with has these artifacts embedded, even though it's uncompressed PAL footage exported from FCP. "

Uncompressed, schmuncompressed.

There are quite a few places this footage could have been screwed up before it even got to you.
  • The "before" frame grab looks underexposed, which would be a mistake made either by the director or the DP.
  • If the camera that made the images was something like HDV -- and I wouldn't be surprised to learn that this epic was shot on HDV to save money -- it was false economy. HDV has lousy color resolution, which manifests itself as crappy-looking B&W, especially if underexposed.
  • If the editor captured HDV in its native codec and cut in an HDV timeline, any rendering done in FCP would have deteriorated the footage. HDV is semi-okay for capture, but that's about it.
  • If it was shot on a RED camera at 4K, then the editor screwed up either at ingest into FCP or at the export.


If this footage is the ONLY thing available, you're right about the roto work. And it also sounds like this director of yours is grasping at straws to save his or her Petite Pink Posterior.


Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Ed Giles
Re: Severe artifacts in footage
on Sep 14, 2009 at 9:40:15 pm

Dave,

Your response confirms my fears! I believe it was shot on HDV, and it's interesting to learn of the 'false economy' this provides.

I have also been told that this particular scene was not lit very well on the shoot, which might explain a little the under-exposure.

The editor is, sadly, 'uncontactable' at this stage apparently - so I can't enquire of the process he went through.

I've asked about any raw footage or other exports made, but this is the only one.

So... I'd better get my Mocha hat on... :(

Thanks for the quick, concise and accurate response!
Ed


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Dave LaRonde
Re: Severe artifacts in footage
on Sep 14, 2009 at 11:18:20 pm

[Ed Giles] "...it's interesting to learn of the 'false economy' this provides. "

Yup. It's not uncommon to see ads for this or that HDV camera where a professional cinematographer takes it out for a spin. And the cinematographer dutifully -- and very honestly -- returns with a glowing report.

Then take a good, close look at what got shot.

Was it a period piece demanding a lot of color grading? Nope.
A special effects tour-de-force with green screen work? Certainly not.
A daredevil glimpse into the Dead Man's Caves of Tierra Del Fuego, where you're so cramped you can only use a camera-mounted Frezzi light? Are you joking?

Or was it a series of grand, sweeping images of jaw-dropping scenery that took every advantage of natural light? You can take that one to the bank!

So what conclusions can you draw from such ads? Don't use HDV for intense color-grading, special effects work or in bad lighting conditions.

...and your particular project involves two of the no-nos: lots of color grading and bad lighting.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Paul Conigliaro
Re: Severe artifacts in footage
on Sep 14, 2009 at 9:15:41 pm

It looks like this is a combination of banding and compression artifacting. What was the original footage format? Looks like something with 4:1:1 or 4:1:0 color sampling. This is then further exaggerated when converting to B&W, as you're going from Millions of colors to only 256 levels (or 1024 in 10-bit).

As for an easy fix, I'm not sure there is one.

You could try to isolate that cool-gray and apply some noise and then a small amount of blur.



Adobe CS3, Apple FCS2
[Disclaimer: Sometimes I am an idiot and misinterpret people's posts. I'm sorry.]


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Ed Giles
Re: Severe artifacts in footage
on Sep 14, 2009 at 9:43:13 pm

Thanks Paul, the original footage was HDV, and I have no access to any more footage/edits than the one I have. Dave LaRonde seems to have nailed it really; I've got quite a bit of masking to do to get rid of this!
Cheers for your response,
Ed


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scott novasic
Re: Severe artifacts in footage
on Sep 14, 2009 at 9:17:26 pm

It sounds like this is present from the original shooting. Its a tough one to deal with without seeing in person. Re vision has a plugin set called "smooth kit" and "noise" that may or may not help you on this.

http://www.revisionfx.com/products/smoothkit/

http://www.revisionfx.com/products/denoise/

SuperNova
Animation & Visual Effects
Scott Novasic
Los Angeles Ca
web:http://web.mac.com/finaleffects


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Ed Giles
Re: Severe artifacts in footage
on Sep 14, 2009 at 9:44:52 pm

Scott, thanks for the suggestion - they look like interesting tools, and may well help me out with this or other things in future.
Cheers,
Ed


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