HDR is one of the most exciting display technologies to be realized in recent years. Alongside higher refresh rates and resolutions, it's a truly-beautifying technique that can have a dramatic effect on how the TV, movies, and games you watch and play, look and feel. At it's most basic level, HDR just makes things look better. Colors pop more and whites and blacks are far starker.
But what does HDR mean, really? And what does it actually do?
What does HDR mean?
HDR stands for High Dynamic Range and is distinct from standard dynamic range, or SDR, from its use of a wider gamma curve. That's the information embedded in an image or video for how bright it should be at any given point on the display.
SDR's conventional gamma curve is based on the limits of cathode ray tube technology, which was the mainstay display technology used throughout much of the 20th century. With newer display technologies now powering the most capable of monitors and televisions, high dynamic range, or HDR, is possible.
What is HDR?
Like the term "HD," HDR has its own liberal and colloquial uses which make the understanding of what is HDR in relation to real-life displays, difficult to nail down. To fix that, organizations came up with their own standards, certifying displays as supporting HDR. In almost all cases, it's to do with the ability to display a wide gamut of colors and to reach a high brightness level, and contrast ratio, so that colors and whites can really pop, and blacks can seem deep and inky.
What is HDR and what does HDR mean for you? It depends on who you ask.
VESA 400 through to VESA 1000 certify that a display can handle HDR with a peak brightness the same as the nomenclature suggests, while HDR10 and Dolby Vision, have slightly different specifications. HDR10 specifies the 10-bit color, as well as high brightness and strong contrast, where Dolby Vision can handle up to 12-bit color, for a significantly broader color spectrum support.
A successor to HDR10, HDR10+ also implements dynamic metadata. Both it and Dolby Vision can adjust the strength of HDR's color and contrast enhancement on a frame by frame basis, making for a much richer image, no matter what it is.
What do you need for HDR?
HDR is another bandwidth-consuming component of a video signal, just like resolution, refresh rate, and chroma subsampling. Increasing one component will likely require you to decrease the quality of another component, especially when you’re pushing a high-resolution 4K monitor. See the chart below for an illustration of how video quality relates to bandwidth, and how that relates to what standard of HDMI or DisplayPort you’ll need. Notice how a 4K 30Hz HDR10 signal at 4:4:4 subsampling requires the same bandwidth as a 4K 60Hz HDR10 signal at 4:2:0 subsampling. In this case, you’re trading refresh rate off for color. At the extreme end with 4K 60Hz and HDR10 or Dolby Vision, you’ll need the new newest standard DisplayPort 1.4 or HDMI 2.1 source, display, and cable.
To watch or play HDR content, you need several key pieces of supporting equipment. First and foremost, an HDR display is a necessity, as it's what makes it possible to see the benefits of HDR technology. You also need an HDR-supporting source, such as a UHD Blu-Ray player, streaming service, or home console. Bear in mind, however, that the PS4 and PS4 Pro only support HDR10, while the Xbox One S and Xbox One X, support both HDR10 and Dolby Vision technologies.
Home PCs with recent-generation graphics cards and an HDR monitor can also take advantage, although support is a little flaky in Windows 10 at this time.
But no matter your hardware setup, you also need to get the HDR signal from the source to the display. That's where high-quality cables from companies like Cable Matters can really make a difference, since the extra bandwidth required to encode the HDR data is quite demanding, so any small issue in cable quality may result in your loss of an HDR image.
To run HDR content at 4K 60Hz resolution, you need an HDMI 2.1 or DisplayPort 1.4 cable. They not only support the latest HDR technologies but higher refresh rates and 8K resolution too.