The popularity of livestreaming has exploded since 2019, with general entertainment, concerts, gaming, sporting events and corporate presentations leading the way. In early December 2020, streaming giant YouTube became the first major platform to support HDR livestreams. We’ll take a look at everything you need to know about HDR and how to stream in this format.
What is HDR?
Before we dive into livestreaming HDR, let’s take a look at what HDR is exactly, and why it’s seeing a huge surge in popularity both in capture and display.
Over the last 20 years, there has been a multitude of video formats and features that TV manufacturers and movie theaters have pushed as “the next big thing.” High definition — both 1080p and 720p — and 4K have been the most successful, while 3D and high frame rates fizzled out. Remember “The Hobbit“ 3D 48p debacle?
However there is one format that looks like it’ll be sticking around for a while, and that’s HDR — or high dynamic range. It’s often said that going from standard dynamic range to HDR is more impressive visually than going from 1080p to 4K.
Essentially, an HDR image — video or still — shows more details in the shadows while not blowing out the highlights. In addition, there is a wider color gamut, which results in a more realistic appearance to what’s being displayed on a proper HDR-compatible TV, monitor or mobile device.
SDR displays between 6 and 10 stops of light, while HDR goes even further to 13 stops, minimum. Our eyes can see 20 stops of light, a contrast ratio of 1 million to 1, so HDR clearly wins here. When comparing color gamut between the two formats, HDR covers more than twice what SDR does, 76% of the CIE 1931 color chart vs. 36%.
Technically speaking, HDR requires a 10-bit color depth and Rec. 2020 wide color gamut. Meanwhile, SDR only needs 8-bit color depth and Rec. 709, which is an industry-standard. Be sure to read our in-depth article covering HDR, which also discusses formats such as HDR10, Dolby Vision and HLG.
HDR is clearly a superior format, but it’s quite data-heavy, whether editing it on an NLE timeline, watching a film via a 4K Blu-ray with an HDR-compatible TV or streaming on YouTube.
HDR livestream technical requirements
We recently discussed the technical requirements needed to understand livestreaming, including video bitrates and resolution, internet upload speeds, protocols and more. Streaming 1080p or 4K requires a computer and internet connection strong and fast enough to ensure the video viewed doesn’t stutter and have audio sync issues.
With HDR, a better internet connection and video compression is needed, such as an upload speed of at least 50 Mbps. Some popular streamers pay for 1 Gbps download and upload to ensure their streams aren’t interrupted. As of right now, the only platform that supports HDR livestreaming is YouTube, and they have special requirements to effectively stream.
Under normal circumstances, software such as the popular OBS Software is the preferred app to livestream. However, at the moment the only software that’s compatible with streaming HDR is Mirillis Action!, as OBS doesn’t support the settings necessary for HDR, such as 10-bit encoding.
It’s recommended to use Mirillis Action! version 4.12.2 or later — it’s only available for Windows — a PC with Intel 10th Generation graphics or later, an AMD Radeon RX 5700 or later graphics card or an NVIDIA GeForce GTX 10-series or later card.
HDR streaming is easy from the Action! app. Just log into YouTube, click the video recording tab, select HDR10 under Hardware acceleration, choose YouTube under Live Streaming and start streaming. Make sure the default setting of variable bitrate is selected in the YouTube Live Control Room.
If you decide to use a hardware encoder, it must support HEVC, 10-bit encoding, HLS output, BT.2020 color space and more. The only hardware encoders supported by YouTube are Cobalt and Telestream. Visit the YouTube HDR livestreaming page for all the details.
When it comes to livestreaming HDR, the gaming community is really the first to truly benefit. Many games support HDR, and as long as the gamer’s PC is compatible, including the monitor, they’ll be able to livestream their in-game experiences in HDR. Even if the viewers who don’t have an HDR-compatible monitor can still watch the livestream in SDR without much trouble.
It’s fun to livestream something as simple as taking a walk outside in nature in HDR, which allows the format to really shine. Streaming a simple setup of someone presenting in a studio may not take full advantage of everything HDR has to offer, and the bandwidth required to stream and view the video may not be worth it.
Sporting events broadcast over the Internet are where HDR livestreaming will really grow in popularity. Imagine watching the 24-hour Le Mans as cars race by in glorious HDR, or taking in a college or NFL football game. Golf, soccer and other sports will also benefit from HDR.
What the viewers need to watch HDR livestreams
Mobile and tablets are the most common devices to watch any kind of livestreams. Many of the newer models support HDR playback. The iPhone 8 or later, iPad Pro 12.9-inch 3rd generation and newer iPads support HDR viewing. The iPhone 12 and iPhone 12 Pro cameras can capture in HDR. Additionally, most newer Android devices, including those from Samsung and LG, can support HDR playback.
For those watching from a computer, it needs to support HDR without grinding the system to a halt. You also need a monitor that supports HDR. There are plenty of monitors from manufacturers such as Dell, Acer, ASUS, HP, Lenovo and others.
Most laptops and all-in-one computers, like Apple iMacs, iMac Pros, MacBook Pros and MacBook Airs — all 2018 or later — and Windows PCs from nearly all manufacturers, support HDR. Just make sure to select HDR in the monitor settings. It needs to be manually done, or the livestream will playback in SDR with tone mapping so it looks good visually.
HDR livestreams can be viewed via the YouTube app on a television that supports HDR, from manufacturers like Samsung, LG, TCL and others. You can also use the Chromecast Ultra, though the Apple TV doesn’t yet support HDR playback from YouTube.
It’s still early days for HDR livestreaming. As it grows in popularity, more platforms will support it beyond just YouTube, including Twitch and Facebook. Additionally, more apps will be updated to support the technical specifications needed to stream it. While gamers are the first to enjoy the benefits of streaming HDR, other avenues will follow suit.