More about ProRes RAW

A few weeks ago I wrote a two-part post – HDR and RAW Demystified. In the second part, I covered Apple’s new ProRes RAW codec. I still see a lot of misinformation on the web about what exactly this is, so I felt it was worth an additional post. Think of this post as an addendum to Part 2. My apologies up front, if there is some overlap between this and the previous post.

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Camera raw codecs have been around since before RED Digital Camera brought out their REDCODE RAW codec. At NAB, Apple decided to step into the game. RED brought the innovation of recording the raw signal as a compressed movie file, making on-board recording and simplified post-production possible. Apple has now upped the game with a codec that is optimized for multi-stream playback within Final Cut Pro X, thus taking advantage of how FCPX leverages Apple hardware. At present, ProRes RAW is incompatible with all other applications. The exception is Motion, which will read and play the files, but with incorrect default – albeit correctable – video levels.

ProRes RAW is only an acquisition codec and, for now, can only be recorded externally using an Atomos Inferno or Sumo 19 monitor/recorder, or in-camera with DJI’s Inspire 2 or Zenmuse X7. Like all things Apple, the complexity is hidden under the surface. You don’t get the type of specific raw controls made available for image tweaking, as you do with RED. But, ProRes RAW will cover the needs of most camera raw users, making this the raw codec “for the rest of us”. At least that’s what Apple is banking on.

Capturing in ProRes RAW

The current implementation requires a camera that exports a camera raw signal over SDI, which in turn is connected to the Atomos, where the conversion to ProRes RAW occurs. Although no one is very specific about the exact process, I would presume that Atomos’ firmware is taking in the camera’s form of raw signal and rewrapping or transforming the data into ProRes RAW. This means that the Atomos firmware would require a conversion table for each camera, which would explain why only a few Sony, Panasonic, and Canon models qualify right now. Others, like ARRI Alexa or RED cameras, cannot yet be recorded as ProRes RAW. The ProRes RAW codec supports 12-bit color depth, but it depends on the camera. If the SDI output to the Atomos recorder is only 10-bit, then that’s the bit-depth recorded.

Until more users buy or update these specific Atomos products – or more manufacturers become licensed to record ProRes RAW onboard the camera – any real-word comparisons and conclusions come from a handful of ProRes RAW source files floating around the internet. That, along with the Apple and Atomos documentation, provides a pretty solid picture of the quality and performance of this codec group.

Understanding camera raw

All current raw methods depend on single-sensor cameras that capture a Bayer-pattern image. The sensor uses a monochrome mosaic of photosites, which are filtered to register the data for light in the red, green, or blue wavelengths. Nearly all of these sensors have twice as many green receptors as red or blue. At this point, the sensor is capturing linear light at the maximum dynamic range capable for the exposure range of the camera and that sensor. It’s just an electrical signal being turned into data, but without compression (within the sensor). The signal can be recorded as a camera raw file, with or without compression. Alternatively, it can also be converted directly into a full-color video signal and then recorded – again, with or without compression.

If the RGGB photosite data (camera raw) is converted into RGB pixels, then sensor color information is said to be “baked” into the file. However, if the raw conversion is stored in that form and then later converted to RGB in post, sensor data is preserved intact until much later into the post process. Basically, the choice boils down to whether that conversion is best performed within the camera’s electronics or later via post-production software.

The effect of compression may also be less destructive (fewer visible artifacts) with a raw image, because data, rather than video is being compressed. However, converting the file to RGB, does not mean that a wider dynamic range is being lost. That’s because most camera manufacturers have adopted logarithmic encoding schemes, which allow a wide color space and a high dynamic range (big exposure latitude) to be carried through into post. HDR standards are still in development and have been in testing for several years, completely independent of whether or not the source files are raw.

ProRes RAW compression

ProRes RAW and ProRes RAW HQ are both compressed codecs with roughly the same data footprint as ProRes and ProRes HQ. Both raw and standard versions use a variable bitrate form of compression, but in different ways. Apple explains it this way in their white paper: 

“As is the case with existing ProRes codecs, the data rates of ProRes RAW are proportional to frame rate and resolution. ProRes RAW data rates also vary according to image content, but to a greater degree than ProRes data rates. 

With most video codecs, including the existing ProRes family, a technique known as rate control is used to dynamically adjust compression to meet a target data rate. This means that, in practice, the amount of compression – hence quality – varies from frame to frame depending on the image content. In contrast, ProRes RAW is designed to maintain constant quality and pristine image fidelity for all frames. As a result, images with greater detail or sensor noise are encoded at higher data rates and produce larger file sizes.”

ProRes RAW and HDR do not depend on each other

One of my gripes, when watching some of the ProRes RAW demos on the web and related comments on forums, is that ProRes RAW is being conflated with HDR. This is simply inaccurate. Raw applies to both SDR and HDR workflows. HDR workflows do not depend on raw source material. One of the online demos I saw recently immediately started with an HDR FCPX Library. The demo ProRes RAW clips were imported and looked blown out. This made for a dramatic example of recovering highlight information. But, it was wrong!

If you start with an SDR FCPX Library and import these same files, the default image looks great. The hitch here, is that these ProRes RAW files were shot with a Sony camera and a default LUT is applied in post. That’s part of the file’s metadata. To my knowledge, all current, common camera LUTs are based on conversion to the Rec709 color space, not HDR or wide gamut. If you set the inspector’s LUT tab to “none” in either SDR or HDR, you get a relatively flat, log image that’s easily graded in whatever direction you want.

What about raw-specific settings?

Are there any advantages to camera raw in the first place? Most people will point to the ability to change ISO values and color temperature. But these aren’t actually something inherently “baked” into the raw file. Instead, this is metadata, dialed in by the DP on the camera, which optimizes the images for the sensor. ISO is a sensitivity concept based on the older ASA film standard for exposing film. In modern digital cameras, it is actually an exposure index (EI), which is how some refer to it. (RedShark’s Phil Rhodes goes into depth in this linked article.)

The bottom line is that EI is a cross-reference to that camera sensor’s “sweet spot”. 800 on one camera might be ideal, while 320 is best on another. Changing ISO/EI has the same effect as changing gain in audio. Raising or lowering ISO/EI values means that you can either see better into the darker areas (with a trade-off of added noise) – or you see better highlight detail, but with denser dark areas. By changing the ISO/EI value in post, you are simply changing that reference point.

In the case of ProRes RAW and FCPX, there are no specific raw controls for any of this. So it’s anyone’s guess whether changing the master level wheel or the color temp/tint sliders within the color wheels panel is doing anything different for a ProRes RAW file than doing the same adjustment for any other RGB-encoded video file. My guess is that it’s not.

In the case of RED camera files, you have to install a camera raw plug-in module in order to work with the REDCODE raw codec inside of Final Cut Pro X. There is a lot of control of the image, prior to tweaking with FCPX’s controls. However, the amount of image control for the raw file is significantly more for a REDCODE file in Premiere Pro, than inside of FCPX. Again, my suspicion is that most of these controls take effect after the conversion to RGB, regardless of whether or not the slider lives in a specific camera raw module or in the app’s own color correction controls. For instance, changing color temperature within the camera raw module has no correlation to the color temperature control within the app’s color correction tools. It is my belief that few of these actually adjust file data at the raw level, regardless of whether this is REDCODE or ProRes RAW. The conversion from raw to RGB is proprietary with every manufacturer.

What is missing in the ProRes RAW implementation is any control over the color science used to process the image, along with de-Bayering options. Over the years, RED has reworked/improved its color science, which theoretically means that a file recorded a few years ago can look better today (using newer color science math) than it originally did. You can select among several color science models, when you work with the REDCODE format. 

You can also opt to lower the de-Bayering resolution to 1/2, 1/4, 1/8, etc. for a RED file.  When working in a 1080p timeline, this speeds up playback performance with minimal impact on the visible resolution displayed in the viewer. For full-quality conversion, software de-Bayering also yields different results than hardware acceleration, as with the RED Rocket-X card. While this level of control is nice to have, I suspect that’s the sort of professional complication that Apple seeks to avoid.

The main benefit of ProRes RAW may be a somewhat better-quality image carried into post at a lower file size. To get the comparable RGB image quality you’d need to go up to uncompressed, ProRes 4444, or ProRes 4444 XQ – all of which become very taxing in post. Yet, for many standard productions, I doubt you’ll see that great of a difference. Nevertheless, more quality with a lower footprint will definitely be welcomed.

People will want to know whether this is a game-changer or not. On that count, probably not. At least not until there are a number of in-camera options. If you don’t edit – and finish – with FCPX, then it’s a non-starter. If you shoot with a camera that records in a high-quality log format, like an ARRI Alexa, then you won’t see much difference in quality or workflow. If you shoot with any RED camera, you have less control over your image. On the other hand, it’s a definite improvement over all raw workflows that capture in image sequences. And it breathes some life into an older camera, like the Sony FS700. So, on balance, ProRes RAW is an advancement, but just not one that will affect as large a part of the industry as the rest of the ProRes family has.

(Note – click any image for an enlarged view. Images courtesy of Apple, FilmPlusGear, and OffHollywood.)

©2018 Oliver Peters

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HDR and RAW Demystified, Part 2

(Part 1 of this series is linked here.) One of the surprises of NAB 2018 was the announcement of Apple ProRes RAW. This brought camera raw video to the forefront for many who had previously discounted it. To understand the ‘what’ and ‘why’ about raw, we first have to understand camera sensors.

For quite some years now, cameras have been engineering with a single, CMOS sensor. Most of these sensors use a Bayer-pattern array of photosites. Bayer – named for Bryce Bayer, a Kodak color scientist who developed the system. Photosites are the light-receiving elements of a sensor. The Bayer pattern is a checkerboard filter that separates light according to red/blue/green wavelengths. Each photosite captures light as monochrome data that has been separated according to color components. In doing so, the camera captures a wide exposure latitude as linear data. This is greater than what can be squeezed into standard video in this native form. There is a correlation between physical photosite size and resolution. With smaller photosites, more can fit on the sensor, yielding greater native resolution. But, with fewer, larger photosites, the sensor has better low-light capabilities. In short, resolution and exposure latitude are a trade-off in sensor design.

Log encoding

Typically, raw data is converted into RGB video by the internal electronics of the camera. It is then subsequently converted into component digital video and recorded using a compressed or uncompressed codec and one of the various color sampling schemes (4:4:4, 4:2:2, 4:1:1, 4:2:0). These numbers express a ratio that represents YCrCb – where Y = luminance (the first number) and CrCb = two difference signals (the second two numbers) used to derive color information. You may also see this written as YUV, Y/R-Y/B-Y or other forms. In the conversion, sampling, and compression process, some information is lost. For instance, a 4:4:4 codec preserves twice as much color information than a 4:2:2 codec. Two methods are used to preserve wide-color gamuts and extended dynamic range: log encoding and camera raw capture.

Most camera manufacturers offer some form of logarithmic video encoding, but the best-known is ARRI’s Log-C. Log encoding applies a logarithm to linear sensor data in order to compress that data into a “curve”, which will fit into the available video signal “bucket”. Log-C video, when left uncorrected and viewed in Rec. 709, will appear to lack contrast and saturation. To correct the image, a LUT (color look-up table) must be applied, which is the mathematic inverse of the process used to encode the Log-C signal. Once restored, the image can be graded to use and/or discard as much of the data as needed, depending on whether you are working in an SDR or HDR mode.

Remember that the conversion from a flat, log image to full color will only look good when you have bit-depth precision. This means that if you are working with log material in an 8-bit system, you only have 256 steps between black and white. That may not be enough and the grade from log to full color may result in banding. If you work in a 10-bit system, then you have 1024 steps instead of only 256 between the same black and white points. This greater precision yields a smoother transition in gradients and, therefore, no banding. If you work with ProRes recordings, then according to Apple, “Apple ProRes 4444 XQ and Apple ProRes 4444 support image sources up to 12 bits and preserve alpha sample depths up to 16 bits. All Apple ProRes 422 codecs support up to 10-bit image sources, though the best 10-bit quality is obtained with the higher-bit-rate family members – Apple ProRes 422 and Apple ProRes 422 HQ.”

Camera raw

RAW is not an acronym. It’s simply shorthand for camera raw information. Before video, camera raw was first used in photography, typified by Canon raw (.cr2) and Adobe’s Digital Negative (.dng) formats. The latter was released as an open standard and is widely used in video as Cinema DNG.

Camera raw in video cameras made its first practical introduction when RED Digital Cinema introduced their RED ONE cameras equipped with REDCODE RAW. While not the first with raw, RED’s innovation was to record a compressed data stream as a movie file (.r3d), which made post-production significantly easier. The key difference between raw workflows and non-raw workflows, is that with raw, the conversion into video no longer takes place in the camera or an external recorder. This conversion happens in post. Since the final color and dynamic range data is not “baked” into the file, the post-production process used can be improved in future years, making an even better result possible with an updated software version.

Camera raw data is usually proprietary to each manufacturer. In order for any photographic or video application to properly decode a camera raw signal, it must have a plug-in from that particular manufacturer. Some of these are included with a host application and some require that you download and install a camera-specific add-on. Such add-ons or plug-ins are considered to be a software “black box”. The decoding process is hidden from the host application, but the camera supplier will enable certain control points that an editor or colorist can adjust. For example, with RED’s raw module, you have access to exposure, the demosaicing (de-Bayering) resolution, RED’s color science method, and color temperature/tint. Other camera manufacturers will offer less.

Apple ProRes RAW

The release of ProRes RAW gives Apple a raw codec that is optimized for multi-stream playback performance in Final Cut Pro X and on the newest Apple hardware. This is an acquisition codec, so don’t expect to see the ability to export a timeline from your NLE and record it into ProRes RAW. Although I wouldn’t count out a transcode from another raw format into ProRes RAW, or possibly an export from FCPX when your timeline only consists of ProRes RAW content. In any case, that’s not possible today. In fact, you can only play ProRes RAW files in Final Cut Pro X or Apple Motion, but only FCPX displays the correct color information at default settings.

Currently ProRes RAW has only been licensed by Apple to Atomos and DJI. The Atomos Inferno and Sumo 19 units are equipped with ProRes RAW. This is only active with certain Canon, Panasonic, and Sony camera models that can send their raw signal out over an SDI cable. Then the Atomos unit will remap the camera’s raw values to ProRes RAW and encode the file. DJI’s Zenmuse X7 gimbal camera has also been updated to support ProRes RAW. With DJI, the acquisition occurs in-camera, rather than via an external recorder.

Like RED’s RECODE, Apple ProRes RAW is a variable bit-rate, compressed codec with different quality settings. ProRes RAW and ProRes RAW HQ fall in line similar to the data rates of ProRes and ProRes HQ. Unlike RED, no controls are exposed within Final Cut Pro X to access specific raw controls. Therefore, Final Cut Pro X’s color processing controls may or may not take affect prior to the conversion from raw to video. At this point that’s an unknown.

(Read more about ProRes RAW here.)

Conclusion

The main advantage of the shift to using movie file formats for camera raw – instead of image sequence files – is that processing is faster and the formats are conducive to working natively in most editing applications.

It can be argued whether or not there is really much difference in starting with a log-encoded versus a camera raw file. Leading feature films presented at the highest resolutions have originated both ways. Nevertheless, both methods empower you with extensive creative control in post when grading the image. Both accommodate a move into HDR and wider color gamuts. Clearly log and raw workflows future-proof your productions for little or no additional investment.

Originally written for RedShark News.

©2018 Oliver Peters

HDR and RAW Demystified, Part 1

Two buzzwords have been the highlight of many tech shows within this past year – HDR and RAW. In this first part, I will attempt to clarify some of the concepts surrounding video signals, including High Dynamic Range (HDR). In part 2, I’ll cover more about camera raw recordings.

Color space

Four things define the modern video signal: color space (aka color gamut), white point, gamma curve, and dynamic range. The easiest way to explain color space is with the standard triangular plot of the color spectrum, known as a chromaticity diagram. This chart defines the maximum colors visible to most humans when visualized on an x,y grid. Within it are numerous ranges that define a less-than-full range of colors for various standards. These represent the technical color spaces that cameras and display systems can achieve. On most charts, the most restrictive ranges are sRGB and Rec. 709. The former is what many computer displays have used until recently, while Rec. 709 is the color space standard for high definition TV. (These recommendations were developed by the International Telecommunications Union, so Rec. 709 is simply shorthand for ITU-R Recommendation BT.709.)

Next out is P3, a standard adopted for digital cinema projection and more recently, new computer displays, like those on the Apple iMac Pro. While P3 doesn’t display substantially more color than Rec. 709, colors at the extremes of the range do appear different. For example, the P3 color space will render more vibrant reds with a more accurate hue than Rec. 709 or sRGB. With UHD/4K becoming mainstream, there’s also a push for “better pixels”, which has brought about the Rec. 2020 standard for 4K video. This standard covers about 75% of the visible spectrum, although, it’s perfectly acceptable to deliver 4K content that was graded in a Rec. 709 color space. That’s because most current displays that are Rec. 2020 compatible can’t actually display 100% of the colors defined in this standard, yet.

The center point of the chromaticity diagram is white. However, different systems consider a slightly different color temperature to be white. Color temperature is measured in Kelvin degrees. Displays are a direct illumination source and for those, 6500-degrees (more accurately 6504) is considered pure white. This is commonly referred to as D-65. Digital cinema, which is a projected image, uses 6300-degrees as its white point. Therefore, when delivering something intended for P3, it is important to specify whether that is P3 D-65 or P3 DCI (digital cinema).

Dynamic range

Color space doesn’t live on its own, because the brightness of the image also defines what we see. Brightness (and contrast) are expressed as dynamic range. Up until the advent of UHD/4K we have been viewing displays in SDR (standard dynamic range). If you think of the chromaticity diagram as lying flat and dynamic range as a column that extends upward from the chart on the z-axis, you can quickly see that the concept can be thought of as a volumetric combination of color space and dynamic range. With SDR, that “column” goes from 0 IRE up to 100 IRE (also expressed as 0-100 percent).

Gamma is the function that changes linear brightness values into the weighted values that are translated to our screens. It defines numerical pixel value to its actual brightness. By increasing or decreasing gamma values, you are in effect, bending that straight-line between darkest and lightest values into a curve. This changes the midtone of the displayed image, making the image appear darker or lighter. Gamma values are applied to both the original image and to the display system. When they don’t match, then you run into situations where the image will look vastly different when viewed on one system versus another.

With the advent of UHD/4K, users have also been introduced to HDR (high dynamic range), which allows us to display brighter images and recover the overshoot elements in a frame, like bright lights and reflections. It is important to understand that HDR video is not the same as HDR photography. HDR photos are created by capturing several bracketed exposures of the same image and then blending those into a composite – either in-camera or via software, like Photoshop or Lightroom. HDR photos often yield hyper-real results, such as when high-contrast sky and landscape elements are combined.

HDR video is quite different. HDR photography is designed to work with existing technology, whereas HDR video actually takes advantage of the extended brightness range made possible in new displays. It is also only visible with the newest breed of UHD/4K TV sets that are HDR-capable. Display illumination is measured in nits. One nit equals one candela per square meter – in other words, the light of a single candle spread over a square meter. SDR displays have been capable of up to 100 nits. Modern computer displays, monitors, and consumer television sets can now display brightness in the range of 500 to 1,000 nits and even brighter. Anything over 1,000 nits is considered HDR. But that’s not the end of the story, as there are currently four competing standards: Dolby Vision, HDR10, HDR10+, and HLG. I won’t get into the weeds about the specifics of each, but they all apply different peak brightness levels and methods. Their nit levels range from 1,000 up to Dolby Vision’s theoretical limit of 10,000 nits.

Just because you own a high-nits display doesn’t mean you are seeing HDR. It isn’t simply turning up the brightness “to 11”, but rather providing the headroom to extend the parts of the image that exceed the normal range. These peaks can now be displayed with detail, without compressing or clipping them, as we do now. When an HDR master is created, metadata is stored with the file that tells the display device that the signal is an HDR signal and to turn on the necessary circuitry. That metadata is carried over HDMI. Therefore, every device in the playback chain must be HDR-capable.

HDR also means more hardware to work with it accurately. Although you may have grading software that accommodates HDR – and you have a 500 nits display, like those in an iMac Pro – you can’t effectively see HDR in order to properly grade it. That still requires proper capture/playback hardware from Blackmagic Design or AJA, along with a studio-grade, external HDR monitor.

Unfortunately, there’s one dirty little secret with HDR. Monitors and TV sets cannot display a full screen image at maximum brightness. You can’t display a total white background at 1,000 nits on a 1,000 nits display. These displays employ gain circuitry to darken the image in those cases. The responsiveness of any given display model will vary widely depending on how much of the screen is at full brightness and for how long. No two models will be at exactly the same brightness for any given percentage at peak level.

Today HDR is still the “wild west” and standards will evolve as the market settles in on a preference. The good news is that cameras have been delivering content that is “HDR-ready” for several years. This brings us to camera raw and log encoding, which will be covered in Part 2.

(Here is some additional information from SpectraCal and AVForums.)

Originally written for RedShark News.

©2018 Oliver Peters

FCPX Color Wheels Take 2

Prior to version 10.4, the color correction tools within Final Cut Pro X were very basic. You could get a lot of work done with the color board, but it just didn’t offer tools competitive with other NLEs – not to mention color plug-ins or a dedicated grading app like DaVinci Resolve. With the release of 10.4, Apple upped the game by adding color wheels and a very nice curves implementation. However, for those of us who have been doing color correction for some time, it quickly became apparent that something wasn’t quite right in the math or color science behind these new FCPX color wheels. I described those anomalies in this January post.

To summarize that post, the color wheels tool seems to have been designed according to the lift/gamma/gain (LGG) correction model. The standard behavior for LGG is evident with a black-to-white gradient image. On a waveform display, this appears as a diagonal line from 0 to 100. If you adjust the highlight control (gain), the line appears to be pinned at the bottom with the higher end pivoting up or down as you shift the slider. Likewise, the shadow control (lift) leaves the line pinned at the top with the bottom half pivoting. The midrange control (gamma) bends the middle section of the line inward or outward, with no affect on the two ends, which stay pinned at 0 and 100, respectively. In addition to luminance value, when you shift the hue offset to an extreme edge – like moving the midrange puck completely to yellow – you should still see some remaining black and white at the two ends of the gradient.

That’s how LGG is supposed to work. In FCPX version 10.4, each color wheel control also altered the levels of everything else. When you adjusted midrange, it also elevated the shadow and highlight ranges. In the hue offset example, shifting the midrange control to full-on yellow tinted the entire image to yellow, leaving no hint of black or white. As a result, the color wheels correction tool was unpredictable and difficult to use, unless you were doing only very minor adjustments. You ended up chasing your tail, because when one correction was made, you’d have to go back and re-adjust one of the other wheels to compensate for the unwanted changes made by the first adjustment.

With the release of FCPX 10.4.1 this April, Apple engineers have changed the way the color wheels tool behaves. Corrections now correspond to the behavior that everyone accepts as standard LGG functionality. In other words, the controls mostly only affect their part of the image without also adjusting all other levels. This means that the shadows (lift) control adjusts the bottom, highlights (gain) will adjust the top end, and midrange (gamma) will lighten or darken the middle portion of the image. Likewise, hue offsets don’t completely contaminate the entire image.

One important thing to note is that existing FCPX Libraries created or promoted under 10.4 will now be promoted again when opened in 10.4.1. In order that your color wheel corrections don’t change to something unexpected when promoted, Projects in these Libraries will behave according to the previous FCPX 10.4 color model. This means that the look of clips where color wheels were used – and their color wheel values – haven’t changed. More importantly, the behavior of the wheels when inside those Libraries will also be according to the “old” way, should you make any further corrections. The new color wheels behavior will only begin within new Libraries created under 10.4.1.

These images clarify how the 10.4.1 adjustments now work (click to see enlarged and expanded views).

©2018 Oliver Peters

What’s up with Final Cut’s Color Wheels?

NOTE: The information presented here has been superseded by the release of FCPX 10.4.1 in April 2018. With that release the color wheels model has been changed. Please read the linked blog post for updated information.

Apple Final Cut Pro X 10.4 introduced new, advanced color correction tools to this editing application, including color wheels, curves, and hue vs. saturation curves. These are tools that users of other NLEs have enjoyed for some time – and, which were part of Final Cut Studio (FCP 7, Color). Like others, my first reaction was, “Super! They’ve added some nice advanced tools, which will improve the use of FCPX for higher-end users.” But, as I started to primarily use the Color Wheels with real correction work, I quickly realized that something wasn’t quite right in how they operated. Or at least, they didn’t work in a way that we’ve come to understand.

In trying to figure it out, I reached out to other industry pros and developers for their thoughts. Naturally this led to some spirited discussions at forums like those at Creative COW. However, other editors have noticed the same problems, so you can also find threads in the Facebook FCPX group and at FCP.co. It is certainly easy to characterize this as just another internet kerfuffle, surrounding Apple’s “think different” approaches to FCPX. But those arguments fall flat when you actually try to use the tools as intended.

The FCPX Color Wheels panel includes four wheels – Master, Shadows, Midtones, and Highlights. The puck in the center of each wheel is a hue offset control to push hues in the direction that you move the puck. The slider to the right of the wheel controls the brightness of that range. The left slider controls the saturation. One of the main issues is that when you adjust luminance using one of these controls, the affected range is too broad. Specifically, in the case of the Midtones control, as you adjust the luminance slider up or down, you are affecting most of the image and not just the midrange levels. This is not the way this type of control normally works in other tools, and in fact, it’s not how FCPX’s Color Board controls work either.

“What’s the big deal?” you might ask. Fair enough. I see two operational issues. The first is that to properly grade the image using the Color Wheels, you end up having to go back-and-forth a lot between wheels, to counteract the changes made by one control with another. The second is that using the Midtones slider tends to drive highlights above 100 IRE, where they will be clipped if any broadcast limiting is used. This doesn’t happen with other color tools, notably Apple’s own Color Board.

A lot of the discussion focuses on luma levels and specifically the Midtones slider, since it’s easy to see the issue there. However, other controls are also affected, but that’s too much to dissect in a single post. Throughout this post, be sure to click on the images to see the full view. I have presented various samples against each other and you will only get the full understanding if you open the thumbnail (which is small but also cropped) to the full image. I have compared the effect using five different tools – the Color Board, the Color Wheels, a color corrector plug-in that I built as a Motion template using Motion effects, Rubber Monkey Software FilmConvert (the wheels portion only), and finally, the Adobe Lumetri controls in Premiere Pro.

I am using three different test images – a black-to-white ramp, a test pattern, and a demo video image. The ramp without correction will appear as a diagonal line (0-100 IRE) on the scope, which makes it easy to analyze what’s happening. The video image has definite shadow and highlight areas, which lets us see how these controls work in the real world. For example, if you want to brighten the area of the shot where the man is in the shadows, but don’t want to make the highlights any brighter, this would normally be done using a Midtones control. Be aware that these various tools certainly aren’t calibrated the same way and some have a greater range of control than others. The weakest of these is FilmConvert’s wheels, since this plug-in has additional level controls in other parts of its interface.

Color science models

In the various forum threads, the argument is made that Apple is simply using a different color science method or a different weighing of some existing models. That’s certainly possible, since not all color correctors are built the same way. The most common approaches are Lift/Gamma/Gain and Shadows/Mids/Highlights. Be careful with naming. Just because something uses the terminology of Shadows, Midtones, and Highlights, does not mean that it also uses the SMH color science model. Many tools use the Lift/Gamma/Gain model, but in fact, call the controls shadows (Lift), mids (Gamma), and highlights (Gain). Another term you may run across is Set-up in some correction tools. This is typically used for control of shadows (equal to Lift), but can also function is an offset control that raises the level of the entire image. Avid Symphony employs this solution. Finally, both Symphony and Adobe SpeedGrade use what has been dubbed a 12-way color corrector. Each range is further subdivided into its own subset of shadows, mids, and highlights controls.

An LGG model provides broad control of shadows and highlights, with the midtones control working like a curve that covers the whole range, but with the largest effect in the middle. An SMH model normally divides the levels into three distinct, precisely overlapping ranges. This is much like a three-band audio equalizing filter. A number of the color correctors add a luma range control, which gives the user the ability to change how much of the image a specific range will affect. In other words, how broad is the control of the shadows, mids, or highlights control? This is like a Q control in an audio equalizer, where you change the shape of the envelope at a certain frequency.

Red Giant’s Magic Bullet Looks offers both color correction models with two different tools – the 4-way color corrector (SMH) and the Colorista color corrector (LGG). When you adjust the midrange control of their 4-way, the result is a graceful S-shaped curve to the levels on the waveform.

To study the effect of an LGG-based corrector, test the ramp. The shadows control (Lift) will raise or lower the dark areas of the image without changing the absolute highlights. The diagonal line of the ramp on the waveform essentially pivots, hinged at the 100 IRE point. Conversely, change the highlights control (Gain) pivots the line pinned to 0 IRE (at black). When you adjust the midtones control (Gamma), you create a curve to the line, which stays pinned at 0 and 100 IRE at either end. In this way you are effectively “expanding” or “compressing” the levels in the middle portion of your image without changing the position of your black or white points.

How the various color correction tools react

Looking at the luma control for the Midtones, two things are clear. First, all of these tools are using the LGG color science model. It’s not clear what the Color Wheels are using, but it isn’t SMH, as there is no bulge or S-curve visible in the scope. Second, the Color Wheels quickly drive the image levels into clipping, while the other tools generally keep black and while levels in place. In essence, the Midtones control affects the image more like a master or offset control would, than a typical mids or Gamma control. Yet, clearly Apple’s Color Board controls adhere to the standard LGG model. The concern, of course, is clipping. In the test image of the man walking on the village street, the sunlit building walls on the opposite side of the street will become overexposed and risk being clipped when the Color Wheels are used.

What about color? As a simple test, I next shifted the Midtones puck to the yellow. Bear in mind that the range of each of these controls is different, so you will see varying degrees of yellow intensity. Nevertheless, the way the control should work is that some pure black and white should be preserved at the top and bottom of the video levels. All of these tools maintain that, except for the Color Wheels. There, the entire image is yellow, effectively making the hue offset puck function more like a tint control.

One other issue to note, is that the Color Wheels offer an extraordinarily control range. The hue offset control RGB intensity values go from 0 (center of the wheel) to 1023. However, the puck icon can only go to the rim of the wheel, which it hits at about 200. With a mouse (or numerical entry), you can keep going well past the stop of the wheel icon – five times farther, in fact. The image not only becomes very yellow in this case, but you can easily lose the location of your control, since the GUI position in no longer relevant.

The working theory

The big question is why don’t the Color Wheels conform to established principles, when in fact, the Color Board controls do? Until there is some further clarification from Apple, one possible explanation is with HDR. FCPX 10.4 introduced High Dynamic Range (HDR) features. One of the various HDR standards is Rec. 2020 PQ. In that color space, the 0-100 IRE limitations of Rec. 709 are expanded to 0-10,000 nits. 0-100 nits is roughly the same brightness as we are used to with Rec. 709.

Looking at this image of the man walking along the street – where I’ve attempted to get a pleasing look with all of the tools – you’ll see that the Color Wheels in Rec. 709 don’t react correctly and will drive the highlights into a range to be clipped. However, in the bottom pane, which is the same image in Rec. 2020 PQ color space, the grade looks pretty normal. And, in practice, the Color Wheels controls work more or less the way I would have expected them to work. Yes, the same controls work differently in the different color spaces – properly in 2020 PQ and not in 709.

But why is that the case? I have no answer, but I do have a wild guess. Maybe, just maybe, the Color Wheels were designed for – or intended to only be used for – HDR work. Or maybe there’s conversion or recalibration of the controls that hasn’t taken place yet in this version. If the tool is only calibrated for HDR, then its range and weighing will be completely wrong for Rec. 709 video. If you increase the Midtones luma of the ramp in both Rec. 709 and Rec. 2020 PQ, you’ll see a similar curve. In fact, if you overlay a screen shot of each waveform, placing the full Rec. 709 scope image over the bottom portion of the Rec. 2020 PQ scale, you’ll notice that these sort of align up to about 100 IRE and nits. It’s as if one is simply a slice out of the other.

Regardless of why, this is something where I would hope Apple will provide a white paper or other demonstration of what the best practices will be for using this tool effectively. If it isn’t intentional, and actually is a mistake, then I presume a fix will be forthcoming. In either case, put in your feedback comments to Apple.

A word about HDR

Over the course of testing this tool and this theory, I’ve done a bit of testing with the HDR color spaces in FCPX. If you want to know more about HDR, I would encourage you to check out these contrary blog posts by Stu Maschwitz and Alexis Van Hurkman. I tend to side with Stu’s point-of-view and am not a big fan of HDR.

The way Apple has implemented these features in Final Cut Pro X 10.4 is to allow the user to set and override color spaces. If you set up your project to be Rec. 2020 PQ (and set preferences to “show HDR as raw values”), then the viewer and a/v output (direct from the Mac, not through a hardware i/o device) are effectively dimmed through the Mac’s color profile system. When you grade the image based on the 0-10,000 nits scale, you’ll end up seeing an image that looks pleasing and essentially the same as if you were working in Rec. 709. However – and I cannot over-emphasize this – you are not going to be able to produce an image that’s truly compatible with Dolby Vision and actually look correct as HDR, unless you have the correct AJA i/o hardware and a proper display. And by display, I mean a top-end Dolby, Canon, or Sony unit, costing tens of thousands of dollars.

As I understand the PQ specs, the bulk of the higher range is for the highlights that are normally constrained or clipped in our current video systems. However, that 10,000 nits scale is weighed, so that about 50% of the image value is in the first 100 nits, making it of comparable brightness to the current 100 IRE. The rest of that range is for brighter information, like specular highlights. You don’t necessarily get more brightness in the shadow detail. Therefore, if you are grading a shot in FCPX in a 2020 PQ color space and you only have the computer display to go by, you’ll grade by eye as much as by scope. This means that to get a pleasing image, you will end up making the average appearance of the image brighter than it really should be. When this is viewed on a real HDR monitor, it will be painfully bright. Having a higher-nits computer display, like on the iMac Pro (up to 500 nits), won’t make much difference, unless maybe, you crank the display brightness to its maximum (ouch!).  “Mine goes the 11!”

Right now, HDR is the wild, wild west. If you are smart, you’ll realize that you don’t know what you don’t know. While it’s nice to have these new features in FCPX, they can be very dangerous in the wrong hands.

But that’s another matter. Right now, I just hope Apple (or one of the usual suspects, like Ripple Training, LumaForge, or Larry Jordan) will come out with more elaboration on the Color Wheels.

©2018 Oliver Peters

More 4K

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I’ve talked about 4K before (here, here and here), but I’ve recently done some more 4K jobs that have me thinking again. 4K means different things to different people and in terms of dimensions, there’s the issue of cinema 4K (4096 pixels wide) versus the UltraHD/QuadHD/4K 16:9 (whatever you want to call it) version of 4K (3840 pixels wide). That really doesn’t make a lot of difference, because these are close enough to be the same. There’s so much hype around it, though, that you really have to wonder if it’s “the Emperor’s new clothes”. (Click on any of these images for expanded views.)

First of all, 4K used as a marketing term is not a resolution, it’s a frame dimension. As such, 4K is not four times the resolution of HD. That’s a measurement of area and not resolution. True resolution is usually measured in the vertical direction based on the ability to resolve fine detail (regardless of the number of pixels) and, therefore, 4K is only twice the resolution of HD at best. 4K is also not sharpness, which is a human perception affected by many things, such as lens quality, contrast, motion and grading. It’s worth watching Mark Schubin’s excellent webinar on the topic to get a clearer understanding of this. There’s also a very good discussion among top DoPs here about 4K, lighting, high dynamic range and more.

df_4kcompare_1A lot of arguments have been made that 4K cameras using a color-pattern filter method (Bayer-style), single CMOS sensor don’t even deliver the resolution they claim. The reason is that in many designs 50% of the pixels are green versus 25% each for red and blue. Green is used for luminance, which determines detail, so you do not have a 1:1 pixel relationship between green and the stated frame resolution of the sensor. That’s in part why RED developed 5K and 6K sensors and it’s why Sony uses an 8K sensor (F65) to deliver a 4K image.

The perceived image quality is also not all about total pixels. The pixels of the sensor, called photosites, are the light-receiving elements of the sensor. There’s a loose correlation between pixel size and light sensitivity. For any given sensor of a certain physical dimension, you can design it with a lot of small pixels or with fewer, but larger, pixels. This roughly correlates to a sensor that’s of high resolution, but a smaller dynamic range (many small pixels) or one with lower resolution, but a higher dynamic range (large, but fewer pixels). Although the equation isn’t nearly this simplistic, since a lot of color science and “secret sauce” goes into optimizing a sensor’s design, you can certainly see this play out in the marketing battles between the RED and ARRI camps. In the case of the ALEXA, ARRI adds some on-the-sensor filtering, which results in a softer image that gives it a characteristic filmic quality.df_4kcompare_2

Why do you use 4K?

With 4K there are two possible avenues. The first is to shoot 4K for the purpose of reframing and repositioning within HD and 2K timelines. Reframing isn’t a new production idea. When everyone shot on film, some telecine devices, like the Rank Cintel Mark III, sported zoom boards that permitted an optical blow-up of the 35mm negative. You could zoom in for a close-up in transfer that didn’t cost you resolution. Many videographers shoot 1080 for a 720 finish, as this allows a nice margin for reframing in post. The second is to deliver a final 4K product. Obviously, if your intent is the latter, then you can’t count on the techniques of the former in post.

df_4kcompare_3When you shoot 4K for HD post, then workflow is an issue. Do you shoot everything in 4K or just the items you know you’ll want to deal with? How will this cut with HD and 2K content? That’s where it gets dicey, because some NLEs have good 4K workflows and others don’t. But it’s here that I contend you are getting less than meets the eye, so to speak.  I have run into plenty of editors who have dropped a 4K clip into an HD timeline and then blown it up, thinking that they are really cropping into the native 4K frame and maintaining resolution. Depending on the NLE and the settings used, often they are simply blowing up an HD shot. The NLE scaled the 4K to HD first and then expanded the downscaled HD image. It didn’t crop into the actual 4K native resolution. So you have to be careful. And guess what, if the blow up isn’t that extreme, it may not look much different than the crop.

df_4kcompare_4One thing to remember is that a 4K image that is scaled to fit into an HD timeline gains the benefits of oversampling. The result in HD will be very sharp and, in fact, will generally look better perceptually than the exact same image natively shot in an HD size. When you now crop into the native image, you are losing some of that oversampling effect. A 1:1 pixel relationship is the same effective image size as a 200% blow-up. Of course, it’s not the same result. When you compare the oversampled “wide shot” (4K scaled to HD) to the “close-up” (native 4K crop), the close-up will often look softer. You’ll see defects of the image, like chromatic aberration in the lens, missed critical focus and sensor noise. Instead, if you shoot a wide and then an actual close-up, that result will usually look better.

On the other hand, if you blow up the 4K-to-HD or a native HD shot, you’ll typically see a result that looks pretty good. That’s because there’s often a lot more information there than monitors or the eye can detect. In my experience, you can commonly get away with a blow-up in the range of 120% of the original image size and in some cases, as much as 150%.

To scale or not to scale

df_4K_comparison_Instant4KLet me point out that I’m not saying a native 4K shot doesn’t look good. It does, but often the associated workflow hassles aren’t worth it. For example, let’s take a typical 1080p 50” Panasonic plasma that’s often used as a client monitor in edit suites. You or your client may be sitting 7 to 10 feet away from it, which is closer than most people sit in a living room with that size of a screen. If I show a client the native image (4K at 1:1 in an HD timeline) compared with an separate HD image at the same framing, it’s unlikely that they’ll see a difference. Another test is to take two exact images – one native HD and the other 4K. Scale up the HD and crop down the 4K to match. In theory, the 4K should look better and sharper. In fact, sitting back on the client sofa, most won’t see a difference. It’s only when they step to about 5 feet in front of the monitor that a difference is obvious and then only when looking at fine detail within the shot.

df_gh4_instant4k_smNot all scaling is equal. I’ve talked a lot about the comparison of HD scaling, but that really depends on the scaling that you use. For a quick shot, sure, use what your NLE has built in. For more critical operations, then you might want to scale images separately. DaVinci Resolve has excellent built-in scaling and lets you pick from smooth, sharp and bilinear algorithms. If you want a plug-in, then the best I’ve found is the new Red Giant Instant 4K filter. It’s a variation of their Instant HD plug-in and works in After Effects and Premiere Pro. There are a lot of quality tweaks and naturally, the better it does, the longer the render will be. Nevertheless, it offers outstanding results and in one test that I ran, it actually provided a better look within portions of the image than the native 4K shot.

df_4K_comparison-C500_smIn that case, it was a C500 shot of a woman on a park bench with a name badge. I had three identical versions of the shot (not counting the raw files) – the converted 4K ProRes4444 file, a converted 1080 ProRes4444 “proxy” file for editing and the in-camera 1080 Canon XF file. I blew up the two 1080 shots using Instant 4K and cropped the 4K shot so all were of equal framing. When I compared the native 4K shot to the expanded 1080 ProRes4444 shot, the woman’s hair was sharper in the 1080 blow-up, but the letters on the name badge were better on the original. The 1080 Canon XF blow-up was softer in both areas. I think this shows that some of the controls in the plug-in may give you superior results to the original (crisper hair); but, a blow-up suffers when you are using a worse codec, like Canon’s XF (50 Mbps 4:2:2). It’s fine for native HD, but the ProRes4444 codec has twice the chroma resolution and less compression, which makes a difference when scaling an image larger. Remember all of this pertains to viewing the image in HD.

4K deliverables

df_4K_comparison-to-1080_smSo what about working in native 4K for a 4K deliverable? That certainly has validity for high-resolution projects (films, concerts, large corporate presentations), but I’m less of a believer for television and web viewing. I’d rather have “better” pixels and not simply “more” pixels. Most of the content you watch at theaters using digital projection is 2K playback. Sometimes the master for that DCP was HD, 2K or 4K. If you are in a Sony 4K projector-equipped theater, most of the time, it’s simply the projector upscaling the content to 4K as part of the projection. Even though you may see a Sony 4K logo at the head of the trailers, you aren’t watching 4K content – definitely not, if it’s a stereo3D film. Yet, much of this looks pretty good, doesn’t it?

df_AMIRAEverything I talked about, regarding blowing up HD by up to 120% or more, still applies to 4K. Need to blow up a shot a bit in a 4K timeline? Go ahead, it will look fine. I think ARRI has proven this as well, taking films shot with the ALEXA all the way up to Imax. In fact, ARRI just announced that the AMIRA will get in-camera, on-the-fly upscaling of its image with the ability to record 4K (3840 x 2160 at up to 60fps) on the CFast 2.0 cards. They can do this, because the sensor starts with more pixels than HD or 2K. The AMIRA will expose all of the available photosites (about 3.4K sensor pixels) in what they call the “open gate” method. This image is lightly cropped to 3.2K and then scaled by a 1.2 factor, which results in UltraHD 4K recording on the same hardware. Pretty neat trick and judging by ARRI’s image quality, I’ll bet it will look very good. Doubling down on this technique, the ALEXA XT models will also be able to record ProRes media at this 3.2K size. In the case of the ALEXA, the designers have opted to leave the upscaling to post, rather than to do it in-camera.

To conclude, if you are working in 4K today, then by all means continue to do so. It’s a great medium with a lot of creative benefits. If you aren’t working in 4K, then don’t sweat it. You won’t be left behind for awhile and there are plenty of techniques to get you to the same end goal as much of the 4K production that’s going on.

Click these thumbnails for full resolution images.

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©2014 Oliver Peters

Post Production Mastering Tips

The last step in commercial music production is mastering. Typically this involves making a recording sound as good as it possibly can through the application of equalization and multiband compression. In the case of LPs and CDs (remember those?), this also includes setting up the flow from one tune to the next and balancing out levels so the entire product has a consistent sound. Video post has a similar phase, which has historically been in the hands of the finishing or online editor.

That sounds so sweet

The most direct comparison between the last video finishing steps and commercial music mastering is how filters are applied in order to properly compress the audio track and to bring video levels within legal broadcast specs. When I edit projects in Apple Final Cut Pro 7 and do my own mixes, I frequently use Soundtrack Pro as the place to polish the audio. My STP mixing strategy employs tracks that route into one or more subgroup buses and then a master output bus. Four to eight tracks of content in FCP might become twenty tracks in STP. Voice-over, sync-sound, SFX and music elements get spread over more tracks and routed to appropriate subgroups. These subgroups then flow into the master bus. This gives me the flexibility to apply specific filters to a track and have fine control over the audio.

I’ll usually apply a compressor across the master bus to tame any peaks and beef up the mix. My settings involve a low compression ratio and a hard limit at -10dB. The objective is to keep the mix levels reasonable so as to preserve dynamic range. I don’t want to slam the meters and drive the signal hard into compression. Even when I do the complete mix in Final Cut, I will still use Soundtrack Pro simply to compress the composite mix, because I prefer its filters. When you set the reference tone to -20dB, then these levels will match the nominal levels for most digital VTRs. If you are laying off to an analog format, such as Betacam-SP, set your reference tone to -12dB and match the input on the deck to 0VU.

Getting ready for broadcast

The video equivalent is the broadcast safe limiting filter. Most NLEs have one, including Avid Media Composer and both old and new versions of Final Cut. This should normally be the last filter in the chain of effects. It’s often best to apply it to a self-contained file in FCP 7, a higher track in Media Composer or a compound clip in FCP X. Broadcast specs will vary with the network or station receiving your files or tapes, so check first. It’s worth noting that many popular effects, like glow dissolves, violate these parameters. You want the maximum luminance levels (white peaks) to be limited to 100 IRE and chrominance to not exceed 110, 115 or 120, depending on the specs of the broadcaster to whom you are delivering. In short, the chroma should stay within the outer ring of a vectorscope. I usually turn off any RGB limiting to avoid artifacts.

It’s often a good idea to reduce the overall video levels by about five percent prior to the application of a broadcast safe filter, simply so you don’t clip too harshly. That’s the same principle as I’ve applied to the audio mix. For example, I will often first apply a color correction filter to slightly lower the luminance level and reduce chroma. In addition, I’ll frequently use a desaturate highlights or lows filter. As you raise midrange or highlight levels and crush shadows during color correction, the chroma is also driven higher and/or lower accordingly. Red, blues and yellows are most susceptible, so it’s a good idea to tone down chroma saturation above 90 IRE and below 20 IRE. Most of these filters let you feather the transition range and the percentage of desaturation, so play with the settings to get the most subtle result. This keeps the overall image vibrant, but still legal.

Let me interject at this point that what you pay for when using a music mastering specialist are the “ears” (and brain) of the engineer and their premium monitoring environment. This should be equally true of a video finishing environment. Without proper audio and video monitoring, it’s impossible to tell whether the adjustments being made are correct. Accurate speakers, calibrated broadcast video monitors and video scopes are essential tools. Having said that though, software scopes and modern computer displays aren’t completely inaccurate. For example, the software scopes in FCP X and Apple’s ColorSync technology are quite good. Tools like Blackmagic Design Ultrascope, HP Dreamcolor or Apple Cinema Displays do provide accurate monitoring in lower-cost situations. I’ve compared the FCP X Viewer on an iMac to the output displayed on a broadcast monitor fed by an AJA IoXT. I find that both match surprisingly well. Ultimately it gets down to trusting an editor who knows how to get the best out of any given system.

Navigating the formats

Editors work in a multi-standard world. I frequently cut HD spots that run as downconverted SD content for broadcast, as well as at a higher HD resolution for the internet. The best production and post “lingua franca” format today is 1080p/23.976. This format fits a sweet spot for the internet, Blu-ray, DVD and modern LCD and plasma displays. It’s also readily available in just about every camera at any price range. Even if your product is only intended to be displayed as standard definition today, it’s a good idea to future-proof it by working in HD.

If you shoot, edit and master at 1080p/23.976, then you can easily convert to NTSC, 720p/59.94 or 1080i/29.97 for broadcast. The last step for many of my projects is to create deliverables from my master file. Usually this involves creating three separate broadcast files in SD and two HD formats using either ProRes or uncompressed codecs. I will also generate an internet version (without bars, tone, countdown or slate) that’s a high-quality H.264 file in the 720p/23.976 format. Either .mov or .mp4 is fine.

Adobe After Effects is my tool of choice for these broadcast conversions, because it does high-quality scaling and adds proper cadences. I follow these steps.

A) Export a self-contained 1080p/23.976 ProResHQ file from FCP 7 or X.

B) Place that into a 720×486, 29.97fps After Effects D1 composition and scale the source clip to size. Generally this will be letterboxed inside of the 4×3 frame.

C) Render an uncompressed QuickTime file, which is lower-field ordered with added 2:3 pulldown.

D) Re-import that into FCP 7 or X using a matching sequence setting, add the mixed track and format it with bars, tone, countdown and slate.

E) Export a final self-contained broadcast master file.

F) Repeat the process for each additional broadcast format.

Getting back there

Archiving is “The $64,000 Question” for today’s digital media shops. File-based mastering and archiving introduces dilemmas that didn’t exist with videotape. I recommend always exporting a final mixed master file along with a split-track, textless submaster. QuickTime files support multi-channel audio configurations, so building such a file with separate stereo stems for dialogue, sound effects and music is very easy in just about any NLE. Self-contained QuickTime movies with discrete audio channels can be exported from both FCP 7 and FCP X (using Roles).

Even if your NLE can’t export multi-channel master files, export the individual submixed elements as .wav or .aif audio files for future use. In addition to the audio track configuration, remove any titles and logos. By having these two files (master and submaster), it’s very simple to make most of the future revisions you might encounter without ever having to restore the original editorial project. Naturally, one question is which codec to use for access in the future. The preferred codec families these days are Avid DNxHD, Apple ProRes, uncompressed, OP1a MXF (XDCAM) or IMX. FCP editors will tend towards ProRes and Avid editors towards DNxHD, but uncompressed is very viable with the low cost of storage. For feature films, another option to consider would be image sequences, like a string of uncompressed TIFF or DPX files.

Whichever format you standardize on, make multiple copies. LTO data tape is considered the best storage medium, but for small files, like edited TV commercial masters, DVD-ROM, Blu-ray and XDCAM media are likely the most robust. This is especially true in the case of water damage.

The typical strategy for most small users who don’t want to invest in LTO drives is a three-pronged solution.

A) Store all camera footage, elements and masters on a RAID array for near-term editing access.

B) Back-up the same items onto at least two copies of raw SATA or SSD hard drives for longer storage.

C) Burn DVD-ROM or BD-ROM copies of edited master files, submasters, project files and elements (music, VO, graphics, etc.).

A properly polished production with audio and video levels that conform to standards is an essential aspect of delivering a professional product. Developing effective mastering and archiving procedures will protect the investment your clients have made in a production. Even better, a reliable archive routine will bring you repeat business, because it’s easy to return to the project in the future.

Originally written for DV magazine/Creative Planet/NewBay Media, LLC

©2012 Oliver Peters