LG 4K OLED

LG HDR OLED TV
Hands-on with LG's 4K OLED TVs (and HDR)

22 Jan 2015 | Rasmus Larsen |

LG unveiled a range of new flat and curved OLED TVs at CES 2015. We had some quality time with the new amazing TVs during a tech demo in which LG’s plans for HDR (high dynamic range) were demonstrated and discussed. Here are our hands-on impressions.

Hands-on with LG’s 4K OLED TVs

LG is currently selling a few Full HD OLED TVs, but the entire 2015 line-up will consist of Ultra HD models. The details are available here so let us jump straight to what we learned.

What LG wanted to demonstrate in particular was how good a 4K HDR picture can look on an OLED TV, stating that “OLED is ideal for HDR”. We were not allowed to take photos during the tech room session, so what you see here are photos from the booth area. However, we can say that we were pretty blown away by the HDR demonstrations on LG’s OLED TVs. HDR takes the amazing picture quality of an OLED TV to the next level.

HDR on LG’s 4K OLED TV


Some of the Dolby Vision LCD TVs we saw at CES can go into much higher brightness peaks and most the highlights are so bright that you cannot discern details with the naked eye. However, the LCD TVs also tend to eliminate details around the bright spots – details that are supposed to be there.

With an LCD TV you need full-array local dimming (FALD) zones to do HDR, but as you probably know there are only a few hundred zones. So when the LCD TV is reproducing a very bright spot, for example the sun, it needs to fully activate the zone behind this part of the picture, which means that it will often overexpose the area around the bright spot. LG’s OLED TVs do not, and we noticed how the OLED TVs can reproduce bright spots and still maintain a perfect balance in the rest of the image. Why? Because every single pixel in an OLED panel can go from perfect, zero black to 800 nits (current peak brightness of the new 4K OLED TVs). This corresponds to having a local dimming zone behind every single of the 8 million pixels in an LCD panel. Impossible.

We also saw some HDR demos running on LCD TVs without full-array local dimming systems. It was not very pretty. Do not expect to enjoy HDR content on those kinds of TVs even if it is advertised in the specifications.

Another big difference between HDR on a LCD and OLED is evident in the darkest areas of the picture. Again, this is one of the disadvantages of LCD local dimming zones that dim in areas where the picture is dark, which also means that many “shadow details” disappear. When comparing LCD and OLED side-by-side the difference is dramatic. Black is truly black on the OLED - no tricks - and there are far more details in the dark areas of the picture.

SUHD vs. other display technologies


We not only noticed this during LG’s tech room session, but also during Samsung’s S’UHD tech room demo, where Samsung was comparing “a Full HD OLED TV from a competitor” (take a wild guess) to the new JS9500 TV. Even though it was Samsung’s own demo, the difference was dramatic. The OLED simply blew the JS9500 away in some of the darker demo scenes, including a scene with fireworks, a scene in space, and a “night in the city” scene. More on that in a later hands-on article.

After seeing a lot of HDR demos at CES 2015, including some of the very impressive Dolby Vision demos, we still have to say that LG’s was the most impressive. All because of OLED technology, which feels like it was made for HDR with its perfect blacks and beautiful colors. We will of course be reviewing lots of 2015 TVs soon, so the final verdict is still pending, but OLED continues to impress us.

Technical details

We talked with one of LG’s engineers from the research lab in South Korea. He told us that LG has done a lot of research into HDR on OLED TVs. Currently, their 4K OLED TVs can peak at around 800 nits (10% window), which is close enough for the open HDR standard. The Blu-ray association recommends that picture highlights only on very rare occasions exceed 1000 nits. Dolby wants to go far higher with Dolby Vision.

It is important to emphasize that HDR has still not left the testing phase. There are several approaches to HDR right now and LG’s OLED TVs will not support all of them (not Dolby Vision), but the TVs can process the new PQ (Perceptual Quantizer, EOTF) gamma format.

We will not go into the full details about PQ here, but the short version is that it is a new way to map the gamma curve on a digital display, and required for proper HDR. We are now putting the analog age and legacy behind us. PQ is included in the open SMPTE ST2084 standard for HDR, which is supported by the Ultra HD Blu-ray standard.

HDR on LG’s 4K OLED TV


LG is still not 100% sure how HDR will be implemented in its OLED TVs as PQ gamma is still a very recent development. As with all other light sources, longevity goes down as brightness goes up on an OLED panel, which is obviously something that must also be taken into account. LG tells us that the HDR function on the new 4K OLED TVs will be added through a software update once they have decided exactly how to approach it.

Additionally, LG told us that the new 4K OLED TVs use true 10-bit panels – no dithering – and that the built-in HEVC decoder can process 4K HDR at 10-bit, too. LG also confirmed to us that its 4K OLED TVs will support Netflix’s 4K HDR streaming when it launches later this year. In practice, HDR is added on top of the standard 4K stream via metadata and requires 20-30% extra bandwidth. This is true for Netflix’s HDR implementation as well as BDA’s HDR implementation in Ultra HD Blu-ray.

HDR is coming and LG is sending a clear message. OLED is not only ready; it is “the best TV for high dynamic range”.



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