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Video Schmutz Issue – WHY????
Hey all,
I have a quick question regarding something that happens very, very rarely but is a MASSIVE annoyance.
I am working on a comp with some keyed footage and a back plate and I am getting this kind of “schmutzing” effect. It’s not artifacting as the edges are ok but there is this “blockiness” around the my subject’s face. So much so that the face is not as clear, it looks chunky (especially above the eyebrows or with any movement in the face in general).
I have seen this once before when it wasn’t a chromakey shot and it was a matter of deinterlacing. However, this is shot in 24pA on an SDX-900, captured in FCP, converted to 23.976fps in Cinema Tools and then brought into AE. My project specs are as follows:
Footage info – 23.976fps, 10-bit uncompressed RGB->YUV colorspace then YUV->RGB
Composition Info – 720×486 widescreen format, 16bit colorspace
Output – Quicktime, Animation Codec, Premultplied Alpha (for chromakey work with soft edges).
Again, this has happened once before but there is no deinterlacing issues here since it is progressive footage. I did the same exact workflow in Shake and the output was gorgeous! What is causing this in AE. Any explanation would be greatly appreciated.
Seth
Opportunity is missed by most people because it is dressed in overalls and looks like work.
Thomas A. Edison -
9 Replies
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Thanks for the smug answer. However, I failed to see a response or posting to this issue. Are you referring to the aspect ratio for widescreen/pixelation post or the is this a job for masking or the ghosting issues or the chroma key issues posts? Frankly, none of those are specific to what I am talking about.
I didn’t just get my AE Boy Scout Badge an thought I would try something for goofs. I have been doing this quite some time and am perplexed at this very rare occurrence that has happened only twice in the last year and a half. This is a very rare instance and thought perhaps someone has experienced this before and might shed some light here.
Thanks, I guess.
Seth
Opportunity is missed by most people because it is dressed in overalls and looks like work.
Thomas A. Edison -
I think he was referring to pulling the key, at least the link he provided pulled up that thread. Often, clipping black or whites too much to eliminate the greenscreen can cause keylight to add noise to the foreground. The thread suggested using a duplicate layer technique for avoiding this.
If you problems is occurring in the source footage prior to keying…this isn’t a solution for you.
A before/after screenshot my jog some people’s memory to describe what you are seeing…”schmutz” being a rather relative term.Erik
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like dave, when i first read this it sounded like a bad key, where some of the skin tones were starting to get keyed out… that kind of slight keying of compressed footage will can look like a strange blockiness.
do yo work in 24p often? i’m asking because this still could be an interlacing problem. 24pa is shot as progressive frames, but interlaced with an advanced pulldown. that pulldown still need to be removed prior to effecting (or editing). you mentioned ‘converted to 23.976 in cinma tools,’ i’m not familiar with cinema tools… are you using cinema tools to remove the pulldown? i would think that fcp would be able to capture the 24pa, removing the advanced pulldown at capture.
i know you mentioned that you used the same workflow with shake with good results, but i can’t think of any reason why ae would crapify to your footage, so i’m looking at things that may have happened prior to importing into ae.
the only time i’ve seen anything like you describe is with highly compressed footage… footage that has probably been compressed by a few different codecs along the way, most of which used temporal compression and gave areas of slight movement (like facial expressions) a very strange blocky-morphing effect.
Kevin Camp
Designer – KCPQ, KMYQ & KRCW -
Hmm. Just a thought — is there a 480 vs. 486 issue here? In other words, does the camera shoot to 480 and you’re in a 486 comp, with footage scaled up?
(grasping at straws …)
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Guys,
I am starting to think this is an interlacing issue myself. The only reason I say this is because what I get in Shake is what it’s supposed to look like. What I am getting in AE is schmutz.
The only other time this happened was when it was footage shot for another TV spot with no green screen work whatsoever. I think that there is something I am not adjusting in AE to create this anomaly. This is the first time I have been given a project shot on 24pA. Since it came from the SDX-900 (which has no firewire) it had to be captured via SDI then ran through the pulldown conversion in Cinema Tools to get it to play back correctly. So, everything was done correctly and when it is in Shake the key the mattes and light wrap look great. I am just trying to understand what is happening in AE.
I fixed the previous issue through deinterlacing and re-working the footage. That was shot on an analog Beta D35 camera at 29.97 so I knew that could be the culprit. However, I am starting to think that perhaps there is an interlace issue even with 24pA stuff not captured through firewire. All the footage was captured via SDI 10-bit so I know the footage is good it’s just a matter of possibly going down a road that I didn’t think I needed to travel with progressive SD footage. I will give that a try and let you know what I find out here.
I GREATLY appreciate the input and thoughts and suggestions here. This makes me feel better knowing that you at least tried to answer this dilemma.
Peace,
SethOpportunity is missed by most people because it is dressed in overalls and looks like work.
Thomas A. Edison -
Is AE interpreting it as interlaced? Sometimes that can goof up progressive footage.
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It is not. I was thinking about going into AE and telling it that it is interlaced footage and seeing what happens then. I am outputting some TV spots to Beta for delivery by tomorrow now and will be able to get to AE in about an hour or so. Hopefully, I can return with some good news.
Seth
Opportunity is missed by most people because it is dressed in overalls and looks like work.
Thomas A. Edison -
Here’s another random thought to check… Is AE deinterlacing the footage? Because if the advanced pulldown has been correctly removed then AE definitely shouldn’t be. I have experienced AE getting a little ahead of itself in its assumptions on occasion, just something to check.
Darby Edelen
DVD Menu Artist
Left Coast Digital
Aptos, CA -
if it is interlaced and it is 23.976fps then you have more problems… even if you remove the pulldown at this point your footage will now be 20% slower than 23.976… so the new frame rate would be around 19fps.
do you have the original capture, prior to removing the pulldown in cinema tools? i assume that is at 29.97 with the advanced pulldown. ae should be able to remove the advanced pulldown. check the interpret footage settings. make sure it is set to separate fields and then try the guess advanced pulldown.
if ‘guess’ doesn’t work, set it to not separate fields, then go through frame by frame and note the cadence (‘s’ is interlaced, ‘w’ is whole) then choose that cadence from the advanced pulldown. if there are still problems, make sure the field dominance is correct.
Kevin Camp
Designer – KCPQ, KMYQ & KRCW
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