Andrew Somers
Forum Replies Created
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Wow that green screen is way over-exposed, and uneven. Ideally green screens should be under exposed, and evenly lit.
That said:
We normally handle each shot as a separate clip, in a separate AE project. But you could certainly have all your green screen shots in one project, but I do suggest a separate comp timeline for each clip.
Greenscreen is almost never a “click it and forget it” operation, always requiring massaging and finesse. And especially when you have a poorly shot screen, you need a lot of shot-by-shot adjustments and trickery.
When compositing, I do recommend working in 32 bit linearized workspace in After Effects.
Keylight is only a so-so keyer. If you can, get Primatte—it’s the best available all-in-one keyer for AE. I suggest you get the Red Giant Keying Suite of tools:
If you are stuck with Keylight, then you might find better results using it only to create the matte (alpha channel), and then use multiple layers to create the comp, instead of doing it all inside the plug in in a single layer.
You can do this by using a layer with the Keylight plugin to generate an alpha and putting that layer above the layer to be keyed, using alpha track matte on the foreground footage to make the key. Use masks on the top layer to get rid of the bulk of the green, so you are only worried about the area around the moving objects. On the lower keyed layer, you handle spill suppression separately.
Separating the compositing operation into multiple separate layers gives your finer control, and also allows for other advanced techniques like gamma-blur hold out layers using hicon mattes, building light wraps, etc.
Andrew Somers
VFX & Title Supervisor
https://GeneralTitles.com -
It is specifically because you cannot embed a color profile into a quicktime mov using the After Effects output module. Note that Quicktime DOES support embedded profiles, just that most versions of AE do not for that specific container type. (not sure about the newest versions if they ever addressed this).
Notice how the word “embed” is greyed out:
THAT SAID:
Quicktime and in fact most forms of video are broadcast with NO color management. Instead, there are sets of standards such as Rec709, (which defines camera/source gamma) and Rec1886 (which defines display gamma). The idea being that content then plays correctly on devices that are compliant to the standard without the need for conversion profiles or LUTs to be applied.
As for defining your imported video as sRGB – if you always want to import video as sRGB if there is no embedded profile, you can alter the After Effects import preferences in the “Interpretation rules.txt” file:
/Volumes/Boot Drive/Users/User Name/Library/Preferences/Adobe/After Effects/VersionNum/Interpretation Rules.txt
It’s a human readable file and editable with a text editor (keep it plain text, never RTML). It has instructions in the file and is fairly self explanatory.
Andrew Somers
VFX & Title Supervisor
https://GeneralTitles.com -
Yea, rendering straight to H264 from AE doesn’t take advantage of two pass encoding like you can in AME.
Personally, for QT files I render out first to ProRes, then crunch that in AME using an appropriate profile and two pass encoding.
Glad you got it going.
Andrew Somers
VFX & Title Supervisor
https://GeneralTitles.com -
It’s really hard to tell since you put such small images here to view, and you didn’t tell us much about your setup.
However, I’m going to echo what Dave said, because what I’m seeing above is not an anti-aliasing issue, it looks like ringing in a codec that is compressing too hard or is dealing with channel clipping, or has too low a color resolution.
Here is the information we need to help you diagnose this:
1) Your project WORKING SPACE. what working colorspace (icc profile) is set, what is your bit depth, and are you linearizing?
2) What version AE are you on?
3) As Steve asked, are these text layers inside AE, or are they illustrator? Photoshop?
4) What filters or adjustments are you adding? Motion?
5) How is your output module set for color management? What codec are you going out to and what are teh codec settings (bit depth, compression amount, etc etc.)
If you tell us THESE things, we can better help you solve your issue.
GENERAL THOUGHTS:1) After Effects does not have a “problem with red”. However some codecs certainly do. NTSC was notorious at mangling red in the image, so much so that even today when they cast cars for a TV show they say “NO RED”!!
2) Sharpening filters can cause the kind of artifact you are seeing. But also so can using a bit-mapped image file (i.e. png, jpg, etc) at too low a resolution. Since you have a “before” image at very low resolution, let me ask: is that the actual image you put into AE for the text?
3) If you are not using the built in text layers, you still want to stay with a vector type file (ai, svg, eps) and NOT a bitmapped image. Then, set the layer to “continuously rasterize” — it’s the little layer button that looks like a gear.
4) Also, while I do normally recommend working in linear light, in every version of AE I have used, linear mode messes up the built-in antialiasing, and you need to do a lot of manual tweaking. So if you aren’t compositing and just doing flat text, sometimes 16 bit gamma encoded is best (ESPECIALLY if you are outputting alpha channels).
5) Some codecs, like Avid’s, really do badly on things like text. But also too heavy compression (too low a profile) can lead to these kinds of artifacts in many codecs, particularly DCT with low resolution color sampling.
On this last point, this *looks* a lot like the kind of artifact you get with aDV codec. Part of the reason is the color is subsampled at a FOURTH of the resolution of the luminance. And remember that the majority of luminance is in the GREEN channel (70% or more). Red typically makes up about 18-22%, and blue less than 12%. So while a pure green hard edged object like text might make it through the codec okay, red or blue might get stepped on.
If you *are* fighting the DV codec, then I suggest either desaturating the colors, or mixing in another color so that you are not just primary red, green, blue. For instance, I would not be surprised if you added in some green to make it more orange, instead of red if the problem suddenly disappeared.
Best of luck
Andy
Andrew Somers
VFX & Title Supervisor
https://GeneralTitles.com -
Without question, slow it from 25 to 24 so there is a 1:1 frame relationship.
I’ve done this several times in the past. On the film PEACEMAKER , many of the scenes shot in Europe were shot at 25 fps because they had a ton of television monitors in them and they needed to shoot the film at 25 to reduce rolling bar problems as they were using PAL monitors. All of that footage shot at 25 was played back at 24.
As for audio pitch problems – as long as it isn’t musical, it is often okay to just slow it down. (and this was often the practice as pitch correcting was a bit time consuming back in the day). On Peacemaker, we did have to use a Lexicon Primetime to alter the pitch of Nicole Kidman for those scenes, as she sounded “wrong” when pitched down 4%.
Today, it’s fairly trivial to slow and pitch correct the audio with good results in ProTools.
I have an article discussing best practices and a tutorial here:
Andrew Somers
VFX & Title Supervisor
https://GeneralTitles.com -
Well there is this plug in, but it is only for Windows unfortunately:
https://www.pixelan.com/dissolvemaster/help-adobe-after-effects.htm
Andrew Somers
VFX & Title Supervisor
https://GeneralTitles.com -
AE is forced to emulate ProRes in 10 or 12 bits, but from a 32 bit universe. And as such, can’t quite get the conversion LUT just right.
I don’t remember if ProRes was 10 and 12 bit linear or Log. The latter would complexify that conversion exponentially.Hi Steve,
Most forms of ProRes are either 8 or 10 bits, typically with a video gamma, or sometimes LOG*, but never linear**. ProRes 4444 is 12 bit.
For instance ProRes as it comes out of an Arri Alexa is typically LOG-C, which is a slightly different curve than Cineon LOG, but still “more log than gamma.” ProRes *can* be encoded with any curve you like***, some flavor of log or some flavor of gamma encoding. The transfer curve is a function of the color profile or LUT used when outputting, not the codec itself.
I almost always work in 32 bit linear (gamma 1.0) space inside after effects. Some of the issues that can come up working in linear in AE are partly due to faulty color profiles at various points in the pipeline, including the monitor. If you are working in linear, it is critical to have your monitor both properly calibrated AND PROFILED, so that AE can use your calibrated monitor profile to correctly display images using “View > Use Display Color Management”.
I’m not sure what you meant by “emulate” ProRes — you mean convert from a linear (no gamma) to a gamma encoded form? AE does not use “LUTs” for color management, it is based around ICC profiles****. For color management to work, everything has to be profiled. The issue has nothing at all to do about bit depths — if we were only converting between 10 or 12 bit integer and 32 bit float, the math is trivial. The issue is converting from a flat transfer curve in linear space, to a non-linear space such as video which has a gamma curve, or a film intermediate which typically has a log transfer curve. And here we rely on the profiles.
If you don’t have an accurate monitor profile, what you see inside After Effects working in linearized mode may end up looking very different on output. When outputting from the linear (no gamma curve) environment to video, which has a gamma curve, the image needs to be transformed. In AE that transformation usually happens with an ICC profile.
But I’ve found that those transformations in the output module may come with issues, some are due to how AE handles the linear environment, and some are due to problems with the ICC profiles themselves. For instance in Adobe’s version of the Rec709 profile, the gamma curve is wrong, and no different than the sRGB profile (a simple 0.45 for 2.2 display curve). See this article on Rec709 profiles.
As I mentioned in the previous post, I now avoid using the color management in the output module, and instead set the output to “Preserve RGB” and use an adjustment layer for color conversions. This is of course the required workflow when using 3D LUTs on output, but I find it useful for all outputs instead of relying on CMM. I discuss the reasons in depth in this article.
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* Footnote 1: the reason “LOG” is around is because a film negative density happens to be logarithmic in nature. When Kodak developed Cineon, they were scanning film negative straight into a digital form, and so that digital representation is log due to the fact that it is a scan of negative film densities, which are log. Gamma curves date back to CRT type television systems, and survive today because perceptually we see greater detail in darker areas of an image, and gamma encoding provides greater luminance resolution (more data) in dark areas.** Footnote 2: “video” such as Rec709 is gamma encoded, so it is not linear. Linear means a gamma of 1.0 which is a straight line (linear is also the nature of light in the real world). Most video is encoded with a gamma curve close to 0.45, which unwinds into linear “light” when displayed with a monitor at a gamma around 2.2 to 2.4. So essentially, there is LOG, LIN, and VID. I discuss the point in more detail here:
https://www.generaltitles.com/helpfiles/13-q-a-blog/colorspaces-and-file-types/14-red-and-after-effectsAnd Stu Maschwitz goes into even greater detail here:
https://prolost.com/blog/2009/9/30/passing-the-linear-torch.html*** Footnote 3: Linear (gamma 1.0) will not fit well into an integer storage format, and needs to be stored in a floating point format such as EXR. Integer formats such as ProRes, JPEG, etc. need the image to be encoded with a curve in order to fit a useful dynamic range into the container.
**** Footnote 4: While you can use 3D LUTs in After Effects with a LUT plugin such as OpencolorIO, that is not part of the “color management” system. The color management uses ICC profiles which are a little different in form and purpose. Some ICC profiles may contain LUTs, such as those intended for output. But the idea behind ICC Color Management is that everything gets converted to a neutral space such as CIE L*a*b*, and then converted to some other working or destination space. 3D LUTs as used in the film industry map directly from one color space to another, frequently to emulate a particular device or output type, e.g. to make a digital projector look like a film release print.
Andrew Somers
VFX & Title Supervisor
https://GeneralTitles.com -
I remember over a decade ago this being a problem with Quicktime and Final Cut Pro, as Apple was using different gammas for output and display.
The problem here sounds like a gamma curve problem – as in not being applied, or being applied incorrectly.
EXRs are linear (gamma 1.0), but a prores video needs to be somewhere around 1.9/2.0 if it’s scene referred Rec709.
Questions:
1) Can you screenshot your project color settings?
2) I am assuming you are working in 32 bit linear? What color primaries (profile)?
3) Have you checked “Compensate for scene referred profiles”?
4) What are your Display Compensation and simulate output settings?
5) What are your color settings on your output module? What profile?
I’ve grown a bit tired of Adobe’s Color Mangelment so for color critical situations I use Preserve RGB in the output module, and then use an adjustment layer on top of the output comp to do the conversion from linear 32bit to whatever colorspace I need to deliver. This affords total control of the output conversion, as well as allowing checking/adjusting through a view LUT, set as a guide layer above the conversion layer.
Andrew Somers
VFX & Title Supervisor
https://GeneralTitles.com -
Personally I never use blend.
More typically I Precomp the two layers, and then do opacity keyframe dissolve.
Or to get tricky, instead of opacity use LEVELS (Individual Controls) on BOTH of the layers. Then keyframe the ALPHA channel. This allow using the gamma control on the alpha to adjust and compensate for density shifts in the alphas of the layers during the dissolve.
There’s a more complicated method that involves separating the alpha channels of the layers, but I don’t consider it practical for frequent use.
Andrew Somers
VFX & Title Supervisor
https://GeneralTitles.com -
The “two bars” at the top are the WORK AREA.
It sounds like in your OUTPUT MODULE you are set to segment files at a certain file size. Turn that off.
