Andrew Somers
Forum Replies Created
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Hi Kk,
1) Personally for real looking grain I have elements that are 24 fps footage of a gray neutral card that I can use to add grain – the grain footage is 24 fps, and the underlying footage is 24 fps.
If you are using the GRAIN plug in in after effects, you would simply have your 24 fps footage inside a 24 fps comp, so that the grain plug in would only update on a whole frame. Using After Effects, the pull down and interlacing can be done automatically in the output module.
2) Depends on the effect you are looking for. What I did in the past was digitize 75% white raster. Though I’ve also done blue or green shooting the actual screen, or digitizing. I developed a synthetic LCD monitor pixel matrix for the screens in “Dark Skies”. I just mentioned the white screen as a fast down and dirty way to get something with real artifacts and subtle scan lines with some noise and motion.
Andrew Somers
VFX & Title Supervisor
https://www.GeneralTitles.com -
Hi Kk,
As it happens I’ve done a LOT of degrading, two films where I did substantial degrading in were “The Fourth Kind” and “Evidence”. I’m also a former broadcast engineer, so I know the inner workings of both 1″ machines and the telecine methods used back in the 80s & 90s (ugh, dating myself, LOL).
I don’t know the Red Giant plug in — I create my own plug -ins/scripts/expressions/FX chains. It’s really a matter of the look you’re going for, and how much time and effort you want to put into it. As such, I can’t help you with the RedGiant plug in, but I can give you some general advice and things to look for or consider:
How Things Worked (most of the time) specific to the era and quality you mentioned:
1) CRT DISPLAYS: Back in those days before the wide spread of LCD, TVs and monitors were CRT type, wherein an electron beam was directed to a glass screen covered in phosphor, and the electrons would excite the phosphor toe cause light to be emitted. And it was all analog, so there was a lot of “trickery” to make images work.One important trick is the nature of interlace. While people refer to NTSC video as “30 frames a second”, in fact if you were using an analog video camera, you would see 60 “frames” per second, each at half the vertical resolution but all 60 at full horizontal resolution. These “half res frames” are called fields. As the electron beam would scan across the CRT display, it would SKIP every other line on the first field, then fill in those missing lines on the second field. The reason this was done was to keep the perceptual image refresh rate high (60 per second) in order to reduce flicker, much the same way the shutter in a film projector has three blades so each film frame is flashed on screen three times before the projector pulls down the next frame.
2) NTSC COLOR: (aka Never The Same Color) This much maligned color encoding system was developed in the 1950s, and was hampered somewhat by the FCC’s insistence that any color system be backwards compatible with existing black and white televisions. So basically it’s a black and white luminance signal with color frosting smeared on top. The RGB colors were encoded onto the Luminance signal using QAM*, with each of R, G, and B being 120 degrees apart from each other (as you can see on a vector scope). But all three colors were not transmitted, only two color channels called Y and C were, and the third was “derived” from those two and the Luminance signal.*QAM essentially allows you to combine two amplitude modulated signals, and and phase shifts relative to a subcarrier to separate them again. The subcarrier used for the color signal was 3.58 MHz, which ended up being 227.5 sine-wave cycles per line — but that’s not the same as “pixels”, as it was a continuously modulating analog signal.
Since the color was combined with the luminance to form a single signal, it was called “composite video”.
3) TELECINE: The high end telecine transfer method was the “Flying Spot” RankCintel machine. The system worked by using a small green CRT like you’d see on an oscilloscope, and it scanned just like a CRT monitor wold, but there was no image on it, just the flying dot, which was focused onto the frame of film. A light sensor on the other side of the piece of film would then sample the light as the dot scanned over the frame.
An important aspect of the system was that there was no pull down claw – the film moved continuously, and each frame was scanned as it moved past the gate. The scanning raster on the CRT would adjust for the film’s motion.
4) 1″ VIDEO TAPE: This was the pinnacle of composite video technology. Composite because the color signal was recorded encoded with the QAM 3.58 method, recorded known as “color under”, where the video was FM modulated from 5 to 10 MHz (highband), and the color was at its 3.58 MHz “under” the frequency of the Luminance signal (but all recorded together at an angle on the tape by heads on a spinning drum).
5) FILM: When shooting on film most TV shows shot at 24 frames per second** for a number of reasons. First, it looks more “filmic”, and second it uses less film which saves $$$. In fact many TV shows shot in “3 perf” where they used 35mm cameras with a modified movement that would only pull down 3 instead of the usual 4 perfs of film. Because the RanCintel had no pull down claw and scanned the film electronically, this was easily accommodated. On many shows the 3 perf film negative was conformed in a traditional negative cut, and the resulting single strip was what was telecined — the film negative then was the international master, as the PAL and SECAM versions could just be telecined from the O neg.
Now to get 24 fps film to fit into 30 fps video, remember that it’s really 60 fields per second. So to this leads to the telecine pulldown: 4 film frames fit into 5 video frames (or ten video fields), such that films frame 1 goes to video fields A1 and A2, film frame 2 goes to video B1, B2, C1, film 3 goes to Vid C2, D1, film 4 goes to D2, E1, D2.
** Commercials were sometimes shot at 30 fps, but TV shows were/are more typically 24 (really 23.976) in the US.
………..SO…………..
The point of this little trip down memory lane, is knowing a bit about how the images were created can lead us to some of the common artifacts and characteristics.
1) To match the “motion feel” you want to shoot at 24 FPS, then use After Effects to do a 3:2 pulldown to create a 30 fps interlaced (60 fields per second) video. Also it is important if you are adding “grain” that the grain pattern match the frame rate of the film and be static with all the fields that a particular film frame is pulled down to.
2) The CRT Scanlines and/or phosphor dot pattern are commonly emulated to give a “video feel”, but too often feels “synthetic” or put on. Aa more natural method is to take WHITE NTSC VIDEO and multiply transfer mode it onto the target image.
2) The NTSC chroma signal created a number of artifacts. One was the “dot crawl”. As the subcarrier is an odd number relative to the number of lines (2/455), the cycle of the subcarrier would move horizontally slightly every frame. On highly saturated sharp edges you could see the “dots crawl”. You can emulate this my multiplying a 45 degree crosshatch. But don’t go too far with this one.
3) The nature of QAM encoding resulted in less than great color reproduction. Saturated reds in particular would bleed, bloom, and smear. (Even today when casting directors are casting cars, they ask for no red).
4) There was a lot image dynamic range compression done particularly for broadcast. Highlights were pushed into clipping, and “soft clipped” so that they rolled into clip. This was partly to keep the image “viewable” even when reception was less than ideal (which was always unless you had cable).
5) But also I think you;d find that colors and luminance did not have “equal” nor well behaved transfer curves, and the gamma for each color primary was in effect a bit different (at lest perceptually) in more complex images.
6) The colorspace is defined by the SMPTE-C icc profile. It should be noted that SMPTE-C is a little different than the original NTSC spec from 1953 (which was never achievable given the technology). The phosphors that are defined in SMPTE C became the de-facto standard in the late 60s, and and were adopted officially by SMPTE circa 1987.
Notice that SMPTE C is very close to Rec709.7) 1″ C Video tape machines usually had time base correctors to clean up the signal, but without there is dihedral error where each line of the scanned video does not exactly line up with the previous or next line.
Andrew Somers
VFX & Title Supervisor
https://www.GeneralTitles.com -
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Because you’re shooting a computer screen closeup, I think this is similar to a Moiré artifact. What I think is happening is the detail of the LCD pixels is interfering with whatever debayering algorithm you are using, resulting in the rainbow red artifacts.
Normally the way to get rid of Moiré in an RGB image is to use a notch filter, but I don’t know how you’d do that with a RAW image that has not be debayered yet — I don’t see such a setting in Redcine…
MAYBE: If you export separate Red, Green, and Blue (mono channels, turning down the other two color completely) and then combine them as separate layers…
If you can upload a single frame, I could experiment with it…
Andrew Somers
VFX & Title Supervisor
https://www.GeneralTitles.com -
Hi Liz,
Yes dealing with matte lines is the never ending task for compositors.
I see you’re in 8 bit mode – 32 bit float might help here, but also are your bag and BG footage masks the exact same size? It might be better to overlap them by expanding one of them, and then feathering them both.
Although that effect you’re using might only be 8 or 16 bit, working in 32 bit with color space set to linear makes these kinds of composites easier (usually). Use the dynamic range compounding preset around the effect if the effect is 8 bit.
Andrew Somers
VFX & Title Supervisor
https://www.GeneralTitles.com -
Hi Jacob,
First of all, check “Ignore Sidecar XMP files”. If you are making changes to a frame somewhere in the sequence and it creates a sidecar of that change, and it WILL affect the frame it is related to! No, AE does NOT just take the grade from the first frame in the sequence – it will take the the grade form every XMP file in finds, and every time you make adjustments in camera RAW, you create another XMP file for that frame.
Remove all the XMP files from the frame sequence folder except the one for the first frame of the sequence.
Second, you might also try unchecking “Use Graphics Processor” to eliminate that as a possible issue.
Also, never set anything like white balance to “as shot” and nothing to “auto” in ACR when working with a sequence. If you are using a preset, make sure the preset does not have “auto” checked. (presets are the second from the right button in ACR).
Finally, what is your project color space and bit depth? Ideally you’ll want to be working in scene linear (linearized gamma 1.0) and 32 bit. Pick a working profile with the same chromacities (white point and primaries) of your destination, i.e. Rec709 or DCI/P3 etc.
I don’t know anything about the Odyssey recorder, and there could easily be issues in settings there. I’d suggest the cinematography forum for your question.
Have you profiled the camera using an XRITE color checker chart? Using a camera profile that was made with your actual camera in RAW, and in the lighting conditions of the scene, is the best way to ensure consistency. Far better than using the build in generic Adobe camera profiles.
NEVERTHELESS, based on how you described your workflow, I am going to guess that you have extra XMP files affecting your color.
Andrew Somers
VFX & Title Supervisor
https://www.GeneralTitles.com -
Hi Nick,
“Assign profile” relates to the profile used to interpret the footage, and is not related to the working space.
It works like this:
Let’s say you’re working space is DCI/P3. And then you import footage that you know is Rec709. You assign the Rec709 profile to the footage, then the CMM in AE maps those colors and whitepoint to the colors/WP in the DCI/P3 working space. The idea behind color management is that everything gets converted to a “same space” environment.
If the footage has an embedded profile (EXR, PNG, JPG often do), you should choose embedded. For footage that is Y’CrCb (422), AE forces it’s interpretation based on what it reads in the header metadata (which is shockingly wrong a good percentage of the time). If you don’t know what the profile is then make a guess (Rec709 works for most video for instance) and choose one that seems to interpret the footage close to how you want it to look.
In your case, since your CGI artist is rendering using Rec709/sRGB chromacities, you should choose those.
Example: Earlier this year I was working on a project and delivering EXRs with AlexaV3 chromacities. This is a wider gamut than sRGB. For the example image I just created below, I setup an sRGB linear working space, then interpreted the EXR of the test pattern in my slate as AlexaV3 (correct) or as the working sRGB space (wrong).
Notice the massive shift in saturation and hue. Everything is set to linear, so the visible change here is just due to the different x,y positions of the RGB primaries. Clearly using the correct profile that matches the imported footage is what’s important.
AE Setup Best Practices:
1) Choose a “well behaved” RGB profile for the working space.
2) It is usually best when that working space profile has primaries that are the same (or very close to) the final output colorspace,
3) Work in linearized space as it is ideal for most compositing and other operations (except when you are generating graphics with an alpha channel that are going to be used in a gamma encoded space, such as a typical editing timeline, in this case it may be better to use a gamma encoded workspace).
4) Always use 32 bit float when working in linear. Use 16 or 32 bit for working in gamma encoded spaces.
5) Assign a a profile to the imported footage that matches the footage’s primaries, whitepoint, and TRC (gamma).
6) All footage needs to be converted to the workspace gamma, meaning that gamma encoded footage needs to be converted to linear for linear workspaces.
7) When working in linear, DisplayColor Management is a necessity, as such the monitor must be properly profiled.Andrew Somers
VFX & Title Supervisor
https://www.GeneralTitles.com -
Hi Nick
Nick said: As far as I understand the CG artist is working to sRGB. By this I mean he is using a calibrated monitor and his 3ds Max viewport is set to 2.2. Renders are displayed as 2.2 in the frame buffer (V-ray) but this can be switched to show the true 1.0 gamma by toggling the sRGB icon on the buffer. Does this make sense?
Okay, so we’ll assume he’s using Rec709/sRGB chromacities (this is common).
Nick said: I actually switched my AE settings ‘Interpret footage’ to ‘Preserve RGB – do not colour manage’ for the image sequence and I can now observe what appears to be gamma 1.0 in the viewport and gamma 2.2 when I toggle ‘linearize working space’ in my project settings. This appears to produce the same results as when toggling sRGB in the frame buffer of the render.
This was just for an experiment, yes? Based on this it sounds like things are in order. Just remember that you don’t want to use “Preserve RGB”, when working in linear you want color management on (and correctly interpreted) for all image items. Preserve RGB is really only for non-image items, such as motion vector maps.
The reason that you see gamma 2.2 when you switch to linear is because this tells Display Color Management to add the appropriate gamma curve to the feed to the display. This is why it’s critical to profile the display.
(Note that you can work linear with color management completely off, but this involves setting up a LUT chain — using the CMM makes working with linear easier.)
Nick said: Is it preferable to have my AE as 32bit? I only ask this because the EXR’s are only 16bit and I noticed that some effects do not function in a 32bit comp.
This is an apples/oranges thing. 16 bit in After Effects is actually 15 bit integer. 16 bit EXR is also known as “half float”. It is a floating point encoding of image data. The difference between integer and floating point numbers is critical.
A problem with integer is that delta E errors increase as you increase the range of values – i.e. if you were to encode an HDR image of 30 stops in an integer format, the math “distance” between each color level would be both large, and fixed in spacing (relative to the gamma curve). the main noticeable artifact is that of “banding”. In fact, a reason we use gamma curves in integer image formats is to compress the perceptual detail relative to vision, encoding more code values (i.e. color levels) in darker image areas. Even so the effective perceptual dynamic range in an 8 bit container is 6-8 stops, and in a 10 bit container really no more than 10-11 stops (a 10 bit DPX with LOG encoding uses about 90 code values per stop).
With a float however, these limitations vanish. Having a moveable decimal point means you can set a color level an arbitrary distance from it’s nearest neighbor, eliminating problems like banding. Because Scene Linear means there is no gamma curve to compress darker image data, we need to be able to set each code value precisely.
16 bit half float in EXR gives us 1024 code values PER STOP, over a 30 stop range (plus an additional 10 stops at lower precision). You can even have negative (blacker than black) in addition to the very high overbrights. As such, when working in linear light, you *must* be in floating point. The key advantage of working in linear is that linear is how light works in the real world, so the math for linear operations like ADD work just like in real life.
In AE, the floating point working space is 32 bit. And it is advantageous to use a working space of a higher bit depth than your output space, as you will be then doing all the math of composition and adjustments at a higher precision, the same way it is best to edit a photo at 16 bit before creating an 8 bit jpeg.
Nick said: I have actually already calibrated my displays with an i1 Display Pro as you recommended.
To answer your question with regards to sRGB vs Rec709, I’m working to sRGB as final output will be for web only.
Good that you profiled your monitor — that’s one thing that trips up a lot of people when they start working in linear.
As for sRGB, that is still the standard for color on the web. Rec709 is the same except for the transfer curve (gamma).
To simplify your workflow, I suggest using a single profile for working space and output (so that you can export using working space in the output module – AE will automatically apply the gamma curve when you render to a non-floating point format.)
The specific sRGB profile I recommend is sRGB-elle-V4-srgbtrc.icc This is a V4 profile, it’s using the correct transfer curve, and it uses parametric curves and not a table, which is preferable as a working space profile. There are many sRGB profiles floating around, and they are NOT all the same!!
Andrew Somers
VFX & Title Supervisor
https://www.GeneralTitles.com -
Hi Nick, in short, I would suggest other settings.
1) Just FYI: the term “linear light” or “scene linear” means the same thing as “Gamma 1.0”.
2) EXRs are specified to be linear by default, with premultiplied alphas. You should see no difference if “interpret as linear light” is checked or not in the interpretation dialog — If you do, then there’s a problem.
3) You *can* use the sRGB primaries as they are the same as Rec709 (sRGB was developed to copy the Rec709 primaries and white point), but it is actually more important to select the same primaries that your CG artist is using. If he is working with Rec709 primaries then fine but if he’s using other primaries you should use those.
4) Linear space is unbounded, and as such you should remain in 32 bit floating point, not 16. Your working space color primaries can again be sRGB/Rec709, but really you should choose a “well behaved” profile with the primaries and white point that your artist used OR that you are going to export to. This may indeed be Rec709/sRGB.
5) It actually has no effect to have “blend using 1.0 gamma” checked or not. When you check “Linearize Workspace” you are setting the gamma to 1.0, and all math/blend operations will work in linear. The “blend using 1.0 gamma” option is for when you are NOT in linear space, but want to match the blend/opacity operations that were done in linear.
6) Most important: When you are working in linearized space you are essentially forced to use Adobe Color Management. This means you need to calibrate and PROPERLY PROFILE your viewing monitor. THEN when you select “display color management” AND set an output simulation for Rec709, you will be seeing what you will be outputting.
I recommend the XRITE i1 DISPLAY PRO for profiling your monitor.
7) The ProEXR plugins are helpful, especially if your animator is putting multiple layers into the EXR file. I believe they now come with After Effects, but if not you can download them free, and see the documentation at Fnord. https://www.fnordware.com/ProEXR/
Question: Is there a reason you are outputting to sRGB instead of Rec709? The only difference is the gamma curve, but it is an important difference…
Andrew Somers
VFX & Title Supervisor
https://www.GeneralTitles.com -
Hi Alex,
Well this works out to be 6.6 seconds a frame, which for a green screen key doesn’t sound too out of the ordinary if you are rendering one frame at a time and you have a lot of things going on in the comp.
But you haven’;t told us *anything* about your project. Resolution? Bit depth? Colorspace? Output codec? Your system setup (number of cores, RAM, AE version, drive type, source file type).
All of these things have a huge affect on the render time.
THAT SAID, in a thread last week I was talking about how the newest versions of AE have a render speed issue due to the fact that they don’t render multiple frames at the same time, If you have a big multi-core computer, you might notice that when rendering using the most recent versions of AE that your total CPU load is low.
Two ways around this: 1) get rendergarden which enables rendering multiple frames at a time. OR 2) download an easier version of AE such as 2014 which allows for multi frame render.
To handle rendering multiple frames at once, your system needs many cores and tons of RAM.
Output file: What do you mean by “enormous” ??? Without knowing your resolution, frame rate, bit depth, output codec, AND the size of the file you are seeing, I can’t tell you if the size is reasonable or not.
How about you tell us some specifics??
Andrew Somers
VFX & Title Supervisor
https://www.GeneralTitles.com
