Monday, January 23, 2017

LG OLED65C7P vs OLED65E7P

The two main differences between the OLED65C7P and OLED65E7P are that the latter uses Picture-On-Glass design, and has an integrated sound bar. The picture quality, however, is identical.

Being OLED TVs, the OLED65C7P and OLED65E7P have a perfect black level since they can shut off individual pixels so that no light is emitted. At the other end of the brightness scale, they can reach approximately 150 nits on a full-field white (100% window size). Thus, they cover the entire luminance range of SDR content, which is usually mastered to 100 nits. The OLED65C7P and OLED65E7P are able to achieve reference picture quality in terms of contrast performance with SDR content. Regular Blu-ray, DVDs and broadcast TV are examples of Standard Dynamic Range content.

Watching SDR content under high ambient light conditions, however, would almost certainly necessitate increasing the overall brightness of the picture. On way to get an idea of how much luminance headroom there is on the OLED65C7P and OLED65E7P is to look at their brightness output for 25% and 50% window sizes because low-to-mid APL (average picture level) is representative of most SDR content. They can reach about 430 nits (25% window size), and approximately 320 nits (50% winodw size). Unless SDR content with high Average Picture Level (e.g. hockey, skiing, etc.) is to be watched in bright environments, the OLED65C7P and OLED65E7P have perfectly adequate brightness reserve for you to use when needed.

The extra brightness serves a completely different purpose in HDR content. It doesn't make the entire picture brighter but is instead reserved to be used only in small specular highlights. The OLED65C7P and OLED65E7P are capable of around 720 nits (10% window size) and approximately 900 nits (5% window size) when in HDR Vivid mode. Besides some panel to panel variation, it should be said that the peak brightness output is also affected by the D65 white point. For example, HDR Standard tracks more closely the D65 white point but the peak brightness output is lower than HDR Vivid.

The OLED65C7P and OLED65E7P support two HDR formats: HDR10 and Dolby Vision, in addition to HLG (Hybrid Log Gamma), which is a standard for future TV broadcasts in HDR. They are also ready support Advanced HDR by Technicolor via a future firmware update. Dolby Vision content is the only one that is accompanied by a dynamic metadata, which allows for scene-by-scene optimization. This, in turn, leads to more efficient tone-mapping, based on the specifics of individual scenes. Tone-mapping is carried out because Dolby Vision content is typically mastered to 4,000 nits whereas the OLED65C7P and OLED65E7P cannot reach such peak brightness, hence the need for quantization. Their dynamic range, however, is utilized efficiently during different scenes thanks to the dynamic metadata.

HDR10 content, on the other hand, includes only static metadata for the entire content. This is not a problem when the HDR10 content is mastered to 1,000 nits since the OLED65C7P and OLED65E7P can reproduce it with little or no tone-mapping but it becomes an issue when the content is mastered to 4,000 nits. In order to minimize the chance of exhibiting clipping of the highlights, the OLED65C7P and OLED65C7P feature Active HDR processing. HDR10 content is analyzed on a frame-by-frame basis, and dynamic metadata is generated as needed. The ensuing scene-by-scene optimization allows for more detail to be resolved in highlights. It has to be said, though, that the result may not be what the creators of the content wanted you to see. Because the dynamic metadata is not generated during post-production, it may or may not convey the director's vision faithfully. In contrast, Dolby Vision is an end-to-end propriety solution, and it faithfully reproduces HDR content.

Color reproduction is also extremely important for HDR content. The OLED65C7P and OLED65E7P cover the DCI-P3 color space almost entirely, thus they can display all the colors in HDR content such as UHD Blu-ray discs with little or no tone-mapping. Further, both models are capable of displaying over billion color shades thanks to the 10-bit panel they utilize. This makes possible smooth color gradation, without any banding. The BT.709 color space, which SDR content is graded in, is smaller than the DCI-P3, so it's no surprise that both models cover it entirely.

The native refresh rate is 120Hz on both of them, meaning there is no judder with 24p content. The nearly instantaneous pixel response time, and the motion compensated frame interpolation, which you can adjust to your liking, makes the OLED65C7P and OLED65E7P suitable for watching sports and action movies. The only thing that prevents them from achieving an absolutely perfect motion performance is the omission of black frame insertion. Such technique would have permitted the retinal persistence to be cleared, so that individual frames wouldn't appear blurred together in case of extremely fast-paced motion.

The OLED65C7P and OLED65E7P have an identical stand. Whilst there isn't a pedestal, the stand is joined at an angle, which ensures that there is some clearance beneath the bottom of the screen. The OLED65E7P, however, uses the Picture-On-Glass design, and has an integrated sound bar. The OLED65C7P omits both the sound bar and the glass back of its counterpart. The total audio power output is 40 Watts over 2.2 channel for both models. Further, they both include a Dolby Atmos decoder. You can either pass-through the bitstream output to a compatible receiver, or listen to Dolby Atmos soundtracks through the TV speakers.

The smart TV platform is webOS 3.5 on both of them.

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