With 245,000 visitors, 1,645 exhibitors and exhibit floor space totaling 150,000 square meters IFA is one of the world’s leading trade shows for Consumer Electronics and Home Appliances. Organized by The German Association for Entertainment and Communications Electronics in cooperation with Messe Berlin, it took place from September 4th to September 9th.
This year HDR (High Dynamic Range), touted as the next big thing in display technology, replaced 4K as the primary talking point in television sets on display at the Berlin show. In developing HDR for video engineers borrowed a page from their colleagues in photography, where HDR is used to produce brighter and more detailed photos by taking multiple exposures and then combining them, delivering more detail in the brightest and darkest parts of a scene that would otherwise be lost. HDR is also available on smartphones, for example there is an HDR mode on the Samsung Galaxy S5.
Dynamic Range, the ”DR” in HDR, is the difference between the darkest image and the brightest image that can be displayed. Brightness is measured in a unit called a nit. On a normal sunny day, the illumination of ambient daylight is about 107,000 Lux or 30,000 nits. But today's TV broadcasts are constrained to about 100 nits. When the maximum brightness is restricted, brighter colors quickly look washed out, limiting the quality of the viewing experience.
This separation between bright and dark used to be described by the term “contrast ratio”, measured in foot-Lamberts, but since there is no regulation on how to measure contrast ratio, TV marketers became, shall we say, creative in presenting their numbers. One thing is certain, the higher the dynamic range of a TV display, the more realistic images it can create. A high-contrast image can appear to have some of the depth and realism of 3D, even if it is not actually 3D.
HDR allows a TV to display a much wider dynamic range of brightness levels, achieving deeper blacks and much brighter whites and colors, which can be rendered with a richer and larger palette. More detail will be visible, too, in dark shadows. For the general consumer it is believed that the picture differences made possible by HDR will be more noticeable than those brought about by the higher resolution of 4K UHD pictures. Unlike 4K UHD, which provides more pixels for greater resolution, HDR improves the individual pixels. 4K UHD and HDR are not mutually exclusive; displays can and will feature both technologies.
At IFA all of the big TV brand names had HDR-capable televisions to show off, including LG, Samsung, Sony, Philips and Panasonic.
For example, LG Electronics launched three HDR TVs at IFA, all employing Organic Light Emitting Diode (OLED) technology. LG claims that OLEDs and HDR are a perfect match because of all current display technologies used in TVs, only OLED panels can deliver a nearly absolute black to make the colors of HDR look even better. Unlike LCD screens, which produce the color black by fully closing the pixel shutter (the back light remains shining but is being blocked), an OLED display instead turns the pixel off entirely to produce the color black.
That said, at IFA, Philips demonstrated it is possible to render HDR images through an LCD display, but you have to be clever about it. To achieve HDR-rendering in its 65-inch model 65PUS9600, Philips employed direct LED backlighting with full-array local dimming (FALD) to control light in zones. Local dimming dims the area of the screen that needs it, while keeping the bright parts of the screen bright. With 16 columns and 16 rows of individually dimmable segments, the Philips set was said to have the highest number of dimmable zones of any 65 in., LED backlit LCD television on the market.
Since LG’s new EF9500 set has the ability to process HDR content through both streaming video and devices connected to the set’s HDMI 2.0a port, at IFA the company showed how HDR content could come from a number of sources. BBC Research & Development transmitted HDR content streamed by the EBU (European Broadcasting Union) using an adaptive bitrate streaming technology, MPEG DASH, also known as Dynamic Adaptive Streaming over HTTP. This technology enables HDR content streaming over the Internet to be delivered from conventional HTTP web servers. LG and its partners also demonstrated the transmission of satellite HDR content over an Astra satellite and visitors to the LG booth could experience HDR content delivered by means of Broadcom’s set-top box, which delivers HDR content via HDMI.
Overall, HDR content is being developed at a faster rate than content for 4K UHD TVs. Amazon has already begun streaming HDR content and Netflix should follow suit sometime early next year. Ultra HD Blu-ray discs will be available with HDR content and satellite and terrestrial broadcasters will follow (though there is not yet a standard for sending HDR signals over the air). For theatrical presentations and TV, Dolby Vision is mastering content at 4,000 nits, which will result in more detailed images with greater contrast in both the cinema and at home.
LG said its new HDR TVs meet the just announced Consumer Electronics Association (CEA) guidelines defining what constitutes an HDR Compatible Display. CEA’s Video Division Board last month defined an HDR Compatible Display as meeting the following minimum attributes:
- Includes at least one interface that supports HDR signaling as defined in CEA-861-F and CEA-861.3 providing metadata extensions. This means the TV needs to be capable of reading HDR metadata— the data about the HDR picture that is added on top of the regular picture signal. These standards establish protocols, requirements, and recommendations for the utilization of uncompressed digital interfaces by consumer electronics devices such as Digital Televisions (DTVs), digital cable, satellite or terrestrial set-top boxes (STBs).
- The display must receive and process the HDR10 Media Profile from IP, HDMI or other video delivery sources. The HDR10 Media Profile has been selected as a base layer format for the next generation Ultra HD Blu-ray disks by the Blu-ray Disc Association.
- Applies an appropriate Electro-Optical Transfer Function (EOTF) before rendering the image. EOTF stands for Electro-Optical Transfer Function and it describes how to turn digital code into visible light.