1. Color
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The C8 is able to properly saturate dark colors as well as colors in mid-tones but when it comes to bright colors in HDR highlights, the saturation is less than optimal. The reason is that the C8 uses a WRGB pixel layout which includes a white subpixel next to the traditional red, green and blue ones. This increases the brightness output capability on the C8 but also causes a narrow spectrum red, green or blue to mixed with a wide spectrum white which leads to bright colors appearing slightly washed-out. Nevertheless, not all four subpixels are active at the same time meaning the suboptimal color saturation can only be observed at higher luminance levels. In other words, it's limited only to HDR highlights whereas the HDR shadows and most of the mid-tones are unaffected (and can reach up to 99% DCI-P3 color gamut coverage) since they don't have to be rendered any brighter than what SDR content is usually mastered for (i.e. a light level of 100cd/m2). This also means that the C8 is able to show fully saturated colors with SDR content since the BT.709 color gamut, which is smaller than the DCI-P3, is fully covered in the entire brightness range (0-100cd/m2) of SDR content. The Cube 3D LUTs (Look-up Tables) on the C8 are of 33x33x33 size, meaning that each look-up table can store 35,937 color data points used for direct color corrections as well as color interpolation (for any of the 1.07 billion color shades without a corresponding entry in the 3D LUT). The relatively high number of reference data points reduces the number of color interpolation the C8 has to perform (so there is less chance of any errors to occur during color calculations), hence the C8 has the True Color Accuracy Pro.
2. Picture processing
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The C8 has the Alpha 9 picture processor thanks to which is able to perform a number of advanced image processing tasks such as object depth enhancement in which the main object is separated from the background so that textures and edges can be individually analyzed and processed accordingly. The sharpness enhancement of the edges improves the clarity of the object against the background, thus the perceived image depth is heightened while at the same time fine detail in textures is not only preserved but also boosted. Furthermore, the Alpha 9 chip is powerful enough to carry out a quad-step image noise reduction process with two of the steps being dedicated specifically to banding removal. Combining the noise reduction and decountoring filters in one process however leads to some fine detail in the image being obscured (by the noise reduction filters) when you attempt to smoothen out the gradation. That being said, considering that in-source countouring artifacts are typically found only in low bitrate content, so the MPEG Noise reduction feature, which controls the banding removal on the C8, may not be needed very often.
3. Brightness output
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In terms of brightness headroom, the C8 can get up to 4 times brighter than the level SDR is mastered for (which typically is 100cd/m2), provided the content has low-to-mid APL (average picture level). Considering that most movies and TV series have low-to-mid APL, the brightness headroom on the C8 is sufficient for the vast majority of SDR content to be watched even under bright lighting conditions. That being said, the C8 has an Auto Brightness Limiter (ABL) which adjusts the brightness of the screen depending on the content's APL (Average Picture Level). Content with preponderance of bright elements (i.e. high APL) is therefore dimmer on the C8 than low-to-mid APL content but only in case you've calibrated your TV to more than 150cd/m2. The ABL is not used for any light levels less than that, meaning you can achieve a reference image quality with SDR content if you calibrate to 100cd/m2 or 120cd/m2, for example, which is adequate for dimly or even moderately lit rooms. If you plan on watching high APL content (such as hockey) under high ambient light conditions, however, the C8 can only get up to 1.5 times brighter than what SDR is mastered for, which may not be sufficient to overcome excessive ambient light.
4. HDR
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Considering that the C8 can reach up to 900cd/m2 in small specular HDR highlights, HDR10 content that is mastered to 1,000cd/m2 can be displayed with minimal amount of tone-mapping. Although HDR10 content with MaxCLL of 4,000cd/m2 requires more significant amount of tone-mapping on part of the C8, detail in the highlights is nevertheless preserved (instead of clipped). In order to achieve this, however, the C8 needs to compress mid-tones and shadows, which leads to slightly darker image, even in the absence of highlights (due to the HDR10 including only static metadata that doesn't change for entire duration of the content). In order to avoid any unnecessary darkening of the image when the scene has no highlights, you can use the Dynamic Tone Mapping on the C8 that analyzes the video signal and generates dynamic metadata on the fly. This process is not needed with Dolby Vision format, which the C8 also supports, because the dynamic metadata in this case has been generated during the creation of the Dolby Vision content, so not only provides scene-by-scene optimization but also preserves the intended look of the content.
5. Motion & Gaming
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Thanks to the 120Hz native refresh rate and the instantaneous pixel response time, the C8 exhibits no motion blur that is caused by slow pixel transitions, so there are no dark trails or ghost afterimages following fast moving objects. That being said, since the C8 uses the sample-and-hold method of rendering and displaying frames, meaning a static frame is hold until the next refresh cycle which may cause individual frames to appear blurred together because the eyes are constantly moving as they track a moving object whereas the object remains static on the screen until the next refresh cycle. In order to prevent the sample-and-hold induced type of motion blur, the C8 has a Black Frame Insertion capability but this technique may cause visible flickering of the screen, in addition to lowering the brightness output. Nevertheless, the clarity of moving objects can be improved significantly with the Black Frame Insertion. Furthermore, the C8 has the ability to generate additional frames and insert them between original ones in order to increase the smoothness of motion. The frame interpolation can be particularly useful for minimizing stutter in low frame rate content but it may also create a pronounced soap opera effect. The input lag on the C8 is approximately 21ms for both 1080p and 4K sources, making this TV suitable for gaming.
6. Audio
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Although the down-firing speakers on the C8 cannot convey dialogues and voices optimally, it should be said that there is a cutout in the C8's table top stand thanks to which the sound can be reflected towards the front of the TV, thus somewhat improving the clarity of voices and dialogues (at least when the C8 is mounted on a table top surface). Furthermore, you can use the Sound Tuning option on the C8 for acoustic room correction. Thanks to the built-in microphone in the MagicRemote, the TV placement can be determined, and the sound of the TV optimized depending on the acoustic of the room. The C8 has a Dolby Atmos decoder but it lacks any height speakers, so any Dolby Atmos tracks you listen to need to be emulated by the stereo speakers in the C8's 2.2 channel system which is comprised of 2 full-range drivers and 2 sub woofers. Alternatively, the C8 allows you to pass-through Atmos tracks to a compatible receiver or a soundbar via the TV's HDMI ARC for more immersive 3-dimensional sound stage (provided you have height speakers) than using the C8's built-in speaker system.
7. Inputs
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The C8 has 4 full-bandwidth HDMI 2.0 inputs, and HDCP 2.2 is supported on all of them. Furthermore, there are 3 USB 2.0 ports. The C8 is equipped with a HEVC decoder conforming to the Main10 profile at Level 5.2, meaning that HEVC files with maximum bitrate of 60Mbps and resolution of 3840×2160 at 120 fps can be decoded. Due to the lack of HDMI 2.1 ports, however, HFR is only supported via USB. Although the C8 doesn't support eARC (enhanced audio return channel) which is part of the HDMI 2.1 specification, it's still possible to pass-through Dolby Atmos via the C8's HDMI input labeled as ARC.
8. OLED Panel
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Since OLED is emissive technology, the C8 has wide viewing angles. Furthermore, the C8 has the ability to control the luminance of each pixel individually. In addition to being independently brightened or dimmed, the OLED pixels can be turned off independently from one another. Not only does it lead to a black level of 0 cd/m2 (and an infinite intra-image contrast ratio) but also rules out the possibility of any blooming artifacts (halos around bright objects against a dark background) to occur. It should be said, however, that OLED TVs can exhibit image retention in case of a static image is displayed for long periods of time. The C8 has a number of features designed to either prevent image retention from occurring in the first place (e.g. Screen Shift and Logo Luminance Adjustment) as well as correcting existing one. The latter is achieved by the means of C8 measuring the voltages in different areas of the panel automatically at given intervals, and correcting any irregularities that may manifest themselves in the form of either image retention or uneven uniformity. The Pixel Refresher option allows you to start a longer compensation cycle that takes about an hour or more to complete if more comprehensive correction is needed but it's generally not advisable to use the Pixel Refresher option often (i.e. more than once per year).
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