HDR Tools is a utility, included with the latest version of FCP X, that converts HDR media between color spaces. I first discovered it as I was working on my “HDR Media in Final Cut Pro X” webinar. Ever since, I wanted to share more about this with you.
As discussed in this article – The Basics of HDR Media Explained – different media use different color spaces. For example, HD media uses Rec. 709, while HDR uses one of several different “flavors” of Rec. 2020; the two most popular are Rec. 2020 PQ and Rec. 2020 HLG.
NOTE: Technically, PQ and HLG are called “transfer functions,” but it is easier to think of them as different color spaces. For this article, I’ll call both PQ and HLG “color spaces.”
The problem is that a camera can only shoot in one color space at at time. While some cameras are limited to a single color space, many cameras can shoot two: Rec. 709 plus one of the variations of Rec. 2020.
Larry’s Universal Rule of editing still applies, even when creating HDR projects: Set project settings to match the media format you need to deliver. This means that your project settings should match the codec, frame size, frame rate, and color space of your final deliverable. The closer they match, the easier it will be to create the final master.
The good news is that HDR Tools allows you to easily convert an HDR clip from one format to another. Here’s how it works.
HDR TOOLS EXPLAINED
Apple’s Help Files state:
You can use the HDR Tools effect to convert wide-gamut HDR video clips from one color space to another or to set the maximum brightness of a clip. For example, you might use the HDR Tools effect on any of the following kinds of wide-gamut HDR source clips:
CONVERT HDR TO REC. 709
A common use for shooting HDR media is to provide more flexibility in color grading traditional HD projects that use Rec. 709. HDR Tools can help.
Here, we have a Rec. 2020 HLG clip, which is properly identified by FCP X in the Info Inspector, with a Panasonic V-Log LUT applied.
This HDR clip is then edited into a Rec.709 project. When we look at it in the timeline, highlights are too hot (above 100 IRE) and shadows are too dark (below 0 IRE).
When we apply the HDR Tools effect, and set it to HDR to Rec. 709, both out-of-bound highlights and shadows are corrected.
Given that we still have access to the full-range of color correction tools, we can easily grade this image to look the way we want; in this case, a California cliff near sunset.
APPLYING HDR TOOLS
HDR Tools is located in Effects > Color. To apply it to a single clip, drag it from the Effects Browser on top of the clip. To apply it to a selected clip, or group of clips, double-click HDR Tools effect in the Effects Browser.
Select the clip you want to adjust, go to the Video Inspector and choose the setting that represents what you need to do. Apple’s Help files explain the four options to choose from:
In this example, I’m converting Rec. 2020 HLG to Rec. 709.
Then, after applying the conversion, use one of the color tools in FCP X to make your clip look the way you want. I generally apply HDR Tools first, then color correct after the Tools are applied.
BIG NOTE: HDR Tools is only needed when you are shooting HDR Media, then editing it into a project that does NOT match the settings that you shot. You don’t need to use HDR Tools for media that was shot using Rec. 709 color space.
CONVERT HLG MEDIA TO PQ
Here’s an HLG clip in a PQ timeline. Dark.
Here’s the same clip with HDR Tools > HLG to PQ applied. Slightly darker, but now the transform functions agree. You can color correct this to look the way you want.
NOTE: Remember, HDR media ALWAYS requires a color grade. Using HDR Tools does not remove the need for a color grade, it simply converts images between color spaces.
Another benefit of using HDR Tools when converting to PQ color space is that you can set the maximum brightness. For example, here, I’ve set maximum brightness to 2000. (The default is 1000.) This slider is essentially mapping the recorded brightness of a clip from one color space to another. The brightness levels can be overridden using any of the color tools in Final Cut.
NOTE: After working with this a bit, I’m not sure what this really does. When adding an HLG clip into a PQ timeline, the white levels will often far exceed the maximum setting in this slider. Whether that is a bug or user error, I have not yet figured out.
HDR Tools is designed to simplify converting HDR media between color spaces. If your media matches your project settings, you’ll never use this. But, when it doesn’t, it is nice to know this tool is available to help prep your clips for the final color grade. Remember, HDR Tools should be applied before any color grading.
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