Thursday, February 16, 2017

Review OLED65E7P vs OLED65G7P

The LG OLED65E7P and OLED65G7P have identical picture quality. The differences between them therefore are limited to the design of the integrated sound bar and the speaker configuration. The OLED65G7P's sound bar functions as a stand, and it can be folded back when wall mounting your TV. On the other hand, the OLED65E7P's sound bar cannot be folded back in case of the TV being wall mounted. When placed on a table-top surface, there is a clearance beneath the OLED65E7P's sound bar due to the fact this model has a stand that is joined at an angle, which provides certain elevation. The OLED65G7P doesn't have a separate stand.

The TV design, however, is identical. Both models use the Picture-on-Glass design. The ultra-thin OLED module of the OLED65E7P and OLED65G7P is directly applied to their glass back. The sound bar on the OLED65G7P, however, has a total audio power output of 60 Watts over 4.2 channels. In contrast, the OLED65E7P's integrated soundbar delivers 40 Watts of amplification over 2.2 channels. Both models have a Dolby Atmos decoder. You can listen to soundtracks in this object-based audio format through the TV's integrated sound bar, or pass-through the bitstream output to a compatible receiver.

It's no secret that OLED TVs have self-illuminating pixels. When individual pixels are turned off, no light is emitted, hence the perfect black level. What's more interesting, though, is how bright the OLED65E7P and OLED65G7P can get. On a full-filed white (100% window size), they can reach around 150 nits. This may not seem much by itself but it's significant in the context of SDR content, which is typically mastered to 100 nits. The OLED65E7P and OLED65G7P hence are able to cover the entire brightness range of DVDs, regular Blu-ray discs, TV broadcasts, etc.

It should be said, though, that most SDR content doesn't have a high average picture level (i.e. a preponderance of bright elements). Instead, low-to-mid APL (average picture level) is most common. Which is why the luminance output for 25% and 50% window sizes is more relevant, especially if you plan on using your TV in bright environments since it'd give you a good indication of how much extra brightness they can output in case an overall brighter picture is needed. The OLED65E7P and OLED65G7P can reach about 320 nits (50% window size), and approximately 430 nits (25% window size), meaning that you can watch them under high ambient light conditions without them appearing too dim. That being said, they have an auto brightness limiter, which explains why the nit count is lower when the window size is bigger (i.e. high Average Picture Level), and vice versa.

As expected, both models have considerably higher brightness in small specular highlights. This only concerns HDR (High Dynamic range) content, though. For example, the OLED65E7P and OLED65G7P are capable of circa 720 nits (10% window size), and approximately 900 nits (5% window size) when in HDR Vivid mode. Evidently HDR doesn't make the entire picture brighter but only small areas of it, so that the dynamic range can be enhanced. HDR content in the HDR10 format is usually mastered to either 1,000 nits or 4,000 nits.

Although the OLED65E7P and OLED65G7P cannot reach 4,000 nits of peak luminance, it should be said that the authoring guideline for Ultra HD Blu-ray discs says that only specular highlights can be over 1,000 nits. Furthermore, approximately half of the code words in the 10-bit HDR10 signal correspond to 0-100 nit range. This means that both models don't have problems reproducing the shadows and most mid-tones in HDR10 content, even if it is mastered to 4,000 nits. Although some mid-tones may be above 100 nits (depending on the creative intent), only specular highlights that exceed the peak brightness capability of both models are compressed.

In order to avoid unnecessary compression, the OLED65E7P and OLED65G7P utilize Active HDR processing. HDR10 content is analyzed on a frame-by-frame basis, and dynamic metadata is generated as needed. HDR10's static metadata defines maximum content light level for the entire content. Based on the maxCLL value, the dynamic range is compressed regardless if the scene has highlights or not. By applying dynamic metadata, the OLED65E7P and OLED65G7P can perform scene-by-scene optimization, meaning that they no longer need to compress the dynamic range in scenes with no highlights.

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