LG B8 Review (OLED65B8PUA; OLED55B8PUA)

The LG B8's picture quality is comparable to the rest of the LG line-up of OLED TVs for 2018, except when it comes to removing posterisation artifacts that are present in low-bitrate content. The reason being is the B8 has the Alpha 7 processor, and uses a two step noise reduction process instead of the quad-step (in which the decontouring filters are applied twice) but only the step-up OLED models with the Alpha 9 processor are able to perform. Nevertheless, thanks to the 10-bit panel, the B8 is able to achieve smooth color gradation, provided the content you're watching is not overly compressed (and doesn't have in-source posterisation).

1. OLED Panel

Strengths	Perfect black level (0 cd/m2) Infinite intra-image contrast ratio Pixel-level dimming No blooming or halos Wide viewing angles
Weakness	Somewhat prone to image retention when static images are left on display for long periods of time
Potential Solutions	Automatic compensation cycle for correcting voltage irregularities (performed by default by the TV at given intervals) Pixel Refresher (longer compensation cycle) Screen Shift Logo Luminance Adjustment

The B8's resolution is 3840x2160 so it has nearly 8.3 million pixels. Since OLED is an emissive technology, each of these pixels is producing its own light, and can be individually brightened, dimmed, or turned off so that no light is emitted. This leads to a minimum luminance level of 0 cd/m², and an infinite intra-image contrast ratio. The pixel-level dimming ability on the B8 means that there are no blooming artifacts (halos around bright objects against a dark background). Furthermore, the B8 doesn't exhibit any dirty screen effect when the camera is panning across the scene due to the fact that it doesn't have a backlight. Another advantage of having the light source almost immediately to the front panel is the wide viewing angles on the B8. One downside to the OLED is that it's somewhat prone to image retention in case of a static image is being displayed for long periods of time. That being said, the B8 is automatically configured to perform a short compensation cycle after accumulating a couple of hours of on-time. This allows the B8 to measure the voltages in different areas of the panel, and correct any irregularities which may be visible in the form of either image retention or uneven uniformity. You can manually initiate a longer compensation cycle that takes about an hour or so for more comprehensive correction but it's generally not advisable to use the Pixel Refresher option often (i.e. more than once per year).

2. WRGB Pixel Layout

Strength	Allows for relatively high peak brightness
Weakness	Bright colors are not fully saturated

The B8 has four subpixels but not all of them are used at the same time. In addition to the standard red, green and blue subpixels, there is a white one. This layout allows the B8 to reach relatively high peak brightness output but the presence of a white subpixel impacts the B8's ability to fully saturate bright colors. The reason being is that light from the white subpixel has a broad spectrum, and remains unfiltered, so when mixed with the otherwise pure primary colors (thanks to the use of color filters), it tends to dilute them, thus reducing color saturation. This becomes obvious at higher luminance levels, however, so mid-tones and shadows are not affected. Therefore, the B8 is able to show fully saturated dark colors, for example.

3. Auto Brightness Limiter

Strength	ABL is not activated up until ~150cd/m2
Weakness	Dims the screen based on the content's APL
Potential Solution	Calibrate to less than 150cd/m2 if possible (i.e. in case you are not watching TV under bright lighting conditions)

SDR content is typically mastered to 100cd/m², so the absence of ABL on the B8 up until 150cd/m² means that you can have a reference image quality in terms of luminance level. In other words, if you calibrate the B8 to less than 150cd/m², the brightness output will be the same irrespective of the content's APL (average picture level). Otherwise, content with preponderance of bright elements (such as hockey) will be dimmer than low-to-mid APL content (such as movies and TV series) due to the Auto Brightness Limiter on the B8.

4. HDR

Strengths	Multiple HDR formats are supported: Dolby Vision, HDR10, HLG, Advanced HDR by Technicolor DCI-P3 color gamut is covered almost entirely (except at higher luminance levels) Accurate PQ EOTF tracking Minimal tone-mapping when MaxCLL (Maximum Content Light Level) is 1,000cd/m2 Highlight detail resolved when MaxCLL is 4,000cd/m2 (via tone-mapping)
Weakness	Mid-tones and shadows are compressed with HDR10 when MaxCLL is 4,000cd/m2
Potential Solution	Dynamic Tone Mapping

The B8 supports all major HDR formats such as Dolby Vision, HDR10 and HLG. Furthermore, Advanced HDR by Technicolor is also supported. Only omitted is the HDR10+ compatibility. Unlike HDR10, the HDR10+ includes dynamic metadata but so does Dolby Vision which the B8 supports, as previously mentioned. The B8 can display HDR10 content that is mastered to 1,000cd/m² with minimal amount of tone-mapping. Considering that the B8 is able to cover the DCI-P3 color gamut almost entirely, it can render colors in mid-tones and shadows that are faithful to the intent of the content creators. Only some of the brightest highlights are not properly saturated due to the WRGB subpixel layout. It should also be said that due to the fact that HDR10 only includes static metadata, meaning only scenes with highlights can be optimally rendered, the B8 is prone to compressing mid-tones and shadows even in the absence of highlights. This is especially noticeable in HDR10 content mastered for 4,000cd/m². In order to avoid any unnecessary darkening of the image, you can use the Dynamic Tone Mapping functionality.

5. Motion & Gaming

Strengths	Instant Pixel Response Time 120Hz Refresh Rate Black Frame Insertion Low Input Lag (~21ms)
Weakness	Stutter with low frame rate content
Potential Solution	Frame Interpolation (although it may cause a soap opera effect)

The B8's instant pixel response time means that there is no dark trails following fast moving objects, or any other ghost images but it may cause stuttering when watching low frame rate content (e.g. 24fps movies). You can solve this by engaging the motion compensated frame interpolation but this may create the soap-opera effect (i.e. motion appears unnaturally smooth). The TruMotion has a User setting under which you can granually adjust both the De-Judder and De-Blur.

6. Inputs

Strengths	4 HDMI 2.0 ports (full-bandwidth) 3 USB 2.0 ports
Weaknesses	No HDMI 2.1 ports (e.g. no HFR via HDMI) No USB 3.0 ports
Potential Solution	HFR (4K@120fps) is supported via USB

Although the B8 doesn't have any HDMI 2.1 ports, so it cannot accept 4K@120fps via HDMI, it should be said that it has a HEVC decoder conforming to the Main10 profile at Level 5.2 so it supports HFR content via USB. Specifically, HEVC files with maximum bitrate of 60Mbps and resolution of 3840×2160 at 120 fps can be decoded. The eARC (enhanced audio return channel) is also part of the HDMI 2.1 specification, meaning the B8 doesn't support it. Nevertheless, it's possible to pass-through Dolby Atmos via the existing HDMI ARC on the B8.

7. Audio

Strengths	2 full-range drivers, 2 subwoofers 40 Watts sound power output (20 Watts are allocated for the subwoofers) Dolby Atmos: decoder as well as pass-through via HDMI ARC
Weakness	Down-firing speakers
Potential Solution	Sound Tuning functionality

Due to the down-firing speakers, dialogues and voices are not projected optimally. However, the B8 has a Sound Tuning feature that uses the built-in microphone in the MagicRemote in order to optimize the sound on your TV based on where its placed and the acoustics of the room. The B8 has a Dolby Atmos decoder so you can listen Dolby Atmos tracks directly via the TV's 2.2 channel system. But the B8 doesn't have any height speakers so it can only try to emulate 3-dimensional sound via its stereo speakers. Alternatively, you can pass-through Atmos tracks to a compatible receiver or a soundbar via the TV's HDMI ARC.