Tutorial: Publishing HDR Video to YouTube
I’ll be straight with you: What I know about producing HDR wouldn’t fill a thimble. But included in that thimble is how to publish HDR videos from your iPhone to YouTube, with an intermediate step through Adobe Premiere Pro. If that journey is of interest, come along.
Let’s start with what Dolby Vision is and why you should care.
About Dolby Vision
Dolby Vision is Dolby’s high dynamic range (HDR) specification that’s included in many premium 4K and larger HDR TV sets. As you know, HDR uses an expanded range of brightness and expanded color space to produce a more vivid image. Apple added an HDR to its Super Retina displays on the iPhone X and added Dolby Vision capture and playback on the iPhone 12.
There are a couple of things about HDR you should keep in mind when shooting and playing it back. First, HDR may look pretty dingy on strandard dynamic ranger (SDR) displays because they can display only a portion of the color and brightness that make up the file. SDR displays also use a different transfer function than HDR, which controls how the color and brightness data in each pixel is displayed on the screen. So displaying HDR on SDR displays is not optimal.
Second, HDR has multiple characteristics that you’re probably not familiar with, some of which you can see in Figure 1 (below), an explainer video from this Dolby page. As explained in the video, the iPhone uses Dolby Vision Profile 4 which is a 10-bit 4:2:0 HEVC-encoded video, which uses the HLG transfer characteristic and BT 2020 color primaries. You don’t need to know what HLG or BT 2020 is or does, but as you’ll see, you’ll want to keep these as consistent as possible in Adobe Premiere Pro through project setup and output.
Figure 1. The iPhone stores in Dolby Vision profile 4 as defined above.
In your iPhone, you choose whether to shoot in HDR format in the Camera settings as shown in Figure 2 (below). If you don’t select the HDR option you shoot in SDR.
Figure 2. Choosing HDR/Dolby Vision capture on your iPhone
Which format should you use? If you’re shooting video to include in an HDR production, to upload to YouTube, or for display on your own HDR TV, you should go HDR. If you’re shooting for an SDR production, I recommend choosing SDR for simplicity.
Once you shoot your video, you may find that transferring it from phone to computer is more challenging than you might imagine. That’s because of...
Dirty Secret Number 1: Apple Makes it Hard to Export HDR
My own beef with Apple is that when they attempt to make things simple for novice users, they often make them incomprehensible for users who know what they are doing. (Or at least users like me.) Apple’s market cap proves that they’re right and I’m wrong, but it’s frustrating to spend two hours trying to figure out why the video that’s clearly Dolby Vision on your iPhone copies down to your computer as SDR video.
First, I tried connecting my iPhone to my Windows computer with a cable and dragging the video file from iPhone to my hard drive. I checked the video in MediaInfo and saw that not only was it not HDR, but it also wasn’t even HEVC. After two hours of searching, I learned that you have to either use iTunes on Windows or Photos on the Mac or iCloud photos. And you need to select Keep Originals in the Photos app (Figure 3, below) to transfer Dolby Vision rather than SDR H.264.
Figure 3. Check Keep Originals to copy Dolby Vision-encoded videos to your computer.
Obviously, this decision makes sense for novice users who might download the Dolby Vision-encoded video, play it on their SDR screen, and recoil in horror at the dingy and washed-out appearance. But the first thing you should do after downloading the video is check in MediaInfo that you’ve downloaded the HDR version. As shown on the left in Figure 4 (below), if you’ve got AVC-encoded video with BT. 709 color primaries, you’ve done something wrong. If you’ve got HEVC with BT. 2020 color primaries, HLG transfer characteristics, and BT.2020 non-constraint matrix coefficients, you’re in business.
Figure 4. Check if you’ve actually downloaded the Dolby Vision file.
Dirty Secret Number 2: YouTube Makes it Hard to Know if You Uploaded HDR
At this point, you can upload the Dolby Vision file to YouTube you should end up with an HDR file. There are two caveats, however.
First, Grasshopper, you must be patient. If you click the link in the caption for Figure 5 (below), you’ll load an HDR tutorial of my daughter baiting a hook in sunny Florida. Note that while the video was playable immediately after upload, as normal, the HDR version didn’t become available for about four hours. So, if you upload and immediately check if the video is HDR, it won’t be.
Figure 5: This YouTube video is HDR.
Second, there is no indication that the video is HDR in the video details screen in YouTube Studio, which is frustrating. And if you play the video on an SDR display, there’s no indication that there’s an HDR option.
Of course, if you play the video on an HDR display you can tell it’s HDR right away, as an HDR emblem will appear on the upper right of the screen. You can also see HDR in the quality options and the BT 2020 color space in the Stats for Nerds screen shown in Figure 5. And yes, that’s 10-bit VP9 displaying HDR; YouTube doesn’t encode in HEVC and isn’t using Dolby Vision.
The other easy way to get HDR from iPhone to YouTube is to upload the video via the YouTube app. That’s how I got this version of the hook-baiting tutorial up on YouTube.
Note that YouTube’s video editor doesn’t currently edit HDR footage, so you can’t upload and edit in the YouTube editor. You should be able to perform some edits with iMovie, upload to YouTube and produce HDR output, but I didn’t experiment with that workflow.
On to Premiere Pro.