Tutorial: Publishing HDR Video to YouTube
YouTube’s HDR Specifications
Before we import our video into Adobe Premiere Pro, let’s begin with the end in mind and consider what YouTube needs from a metadata perspective. As shown in Figure 6 (below), it’s pretty simple; PQ or HLG transfer function, Rec. 2020 color primaries, and Rec. 2020 non-constant luminance matrix. This matches the right side of Figure 4, which is why YouTube successfully (if not promptly) converted the Dolby Vision upload to HDR.
Figure 6. YouTube’s HDR requirements
So, our goal in Premiere Pro is to output a file that matches these specs as closely as possible in project setup and output. In addition, since we know Dolby Vision uses the HLG transfer function, we should opt for HLG over PQ wherever possible.
Working in Premiere Pro
Here’s what we’re doing in Premiere Pro and what we’re not doing. What we’re not doing is color grading. Unless you have an expensive HDR setup for Premiere Pro, you won’t be able to accurately gauge the color and brightness of the video that you’re editing. So, if your video looks good on the iPhone, you shouldn’t adjust these aspects in Premiere Pro, even if the video looks a bit dingy in the Premiere Pro user interface. You should expect that.
Assemble your footage as normal, but expect that any color-related edits, whether color adjustments or adding a title, may look funky when viewed on an HDR display. So you should probably do as little of that as possible and budget time to preview your edits in HDR somewhere before publishing your video.
Let’s start in Premiere Pro by setting up your project.
Here are the steps involved. FYI, I referenced a PDF manual that’s strangely only available on Larry Jordan’s website. Larry’s article is useful if you’ll be attempting color and brightness adjustments, but I’m sticking to the bare-bones details and we take a completely different approach with output.
1. Set HDR Graphics white. This sets the target luminance of solid white color; the default should be fine, but click File > Project Settings > General, scroll to the bottom, and make sure 203 is selected (Figure 7, below).
Figure 7. Setting the target luminance of white
2. Import your content and create your sequence. My normal technique for creating a sequence is to drag the video onto the New item icon so the new sequence inherits the characteristics from the source file (Figure 8, below).
Figure 8. Creating the sequence
If you right-click the sequence and choose Sequence Settings, you should see that the working color space is Rec. 2100 HLG (Figure 9, below). Mission accomplished there. If you’re working with PQ-based source, that option would be selected, and I would use the PQ-based options going forward rather than HLG.
Figure 9. Sequence settings are what we want.
3. Enable Display Color Management (Figure 10, below). According to the aforementioned PDF file, Display Color Management “uses the ICC profile for your monitor to apply a colorimetric conversion from the sequence working color space (or media color space in the case of the source monitor) to the monitor color space.” In English, it brightens the video to make it look less dingy, though it affects only that display, not the output. I found it useful, but it’s your choice. Access the switch by clicking Preferences > General.
Figure 10. Enabling Display Color Management
5. Set scopes to HDR. If you’ll be adjusting color and/or brightness, set the scopes to the appropriate color space by right-clicking the scope, choosing Color Space, and Rec. 2100 HLG (for Dolby Vision). This will change the scope from 8-bit to 10-bit automatically (see Figure 11, below, bottom right).
Figure 11. Setting the color space for the scopes
As mentioned, if you venture into these edits, tread lightly and remember to budget time to gauge the output on an HDR monitor before finalizing them. Note that any 32-bit effect should work with HDR footage (Figure 12, below).
Figure 12. All 32-bit effects (Gaussian Blur above) should work with HDR footage.
Exporting HDR For Upload
Most articles and posts on HDR output recommend using the QuickTime preset and ProRes output. I checked this, and it worked, but my 38-second test file was 1.5 GB in size, adding up to about 24 GB for a ten-minute video. Upload speeds have increased and all, but that’s a little rich for my blood.
After much testing, I learned that YouTube is pretty forgiving, and converted a range of files to HDR. The simplest and most upload efficient output format for me was the HEVC (H.265) format using the HEVC - Match Source - HLG preset (Figure 13, below), which I used as-is. Lovely to have an Easy Button at the end of a long and arduous project.
Figure 13. This output preset worked for me.
Figure 14 (below) shows the MediaInfo data from the Premiere Output and the Original.
Figure 14. The Premiere Output matched the Dolby Vision output in color primaries, transfer characteristics, and matrix coefficients.
And here’s the final video. If you watch on an HDR-capable display, you’ll see that it is HDR.
So, there you have it. As I admitted at the start, I’m not an expert at HDR production, so if I missed anything or suggested anything stupid, send me a note at janozer [at] gmail.com.
For you anglers out there, no, my daughter didn’t catch anything, but the sky and sea in Delray Beach in December were every bit as vivid and colorful as the HDR video shows. If you see any mistakes in her tutorial, please keep it to yourself.