LG OLED C4 vs TCL P7K / P79K

The results of HDR materials are definitely among the better ones. Practically every film significantly exceeds the 700 nits barrier, which allows for a very realistic image. Of course, none of them surpasses the magical thousand, however, the combination of such results along with unlimited contrast and black effectively boosts the visual outcome. The last of the scenes, featuring a fullscreen sun burst, is indeed less bright than the others, although it still represents a respectable level. It's also worth mentioning the excellent coverage of the DCI-P3 colour palette, which will enable the achievement of exceptionally vivid colours.

When it comes to assessing HDR performance, we need to be clear and straightforward without any marketing fluff: the P7K/P79K is not and never was meant to be a champion in this area. The maximum peak brightness that this panel can generate hovers around just 300 nits. This represents a threshold, a sort of thin red line between what can be considered barely satisfactory HDR signal and what is, in reality, only slightly better than standard dynamic range (SDR), unfortunately leaning towards the latter. Synthetic tests confirmed this harsh reality – our measurements taken during movie sessions showed that the luminance in key bright scenes rarely exceeded 200-250 nits. Therefore, this is not a TV that would allow content created in a wide tonal range to truly shine, and that must be openly acknowledged.

Unfortunately, the issue of colour reproduction is presented just as conservatively. Although the manufacturer positions this model within the "QLED" family, owing to the use of a PFS LED filter, the results do not match the heightened expectations. The coverage of the wide DCI-P3 colour gamut reaches only 86%. Compared to the market, this is at best an average result, since most devices that utilise additional layers to expand the colour spectrum easily achieve values at a minimum of 90-92%.

The best factory mode implemented in the tested television was "Filmmaker". That was the one we used during all tests. This mode, in terms of colour reproduction, turned out to be quite decent, although other flaws effectively detracted from the enjoyment of the viewing experience. Starting with the most basic one, which is white balance, it was easy to notice that this was marked by a dominance of red, which completely altered the characteristics of the picture. We could see a strong yellowing of the whites and a shift of all colours to warmer tones. The gamma, which is a graph as equally important, if not more so, was quite severely reduced, resulting in a significant drop in contrast, except for the start of the graph, where the television insidiously lost details. That’s all regarding SDR materials. Looking closely at films with a wide dynamic range, we can observe exactly the same phenomenon of white balance yellowing as in films with a standard colour palette. The EOTF curve, which replaces the gamma chart for us, is practically perfect and cannot be faulted.

Every reliable assessment of image quality must start with selecting the most optimal, factory preset mode. In the case of the tested P7K/P79K model, the choice was made without hesitation for the "Film" mode. It is the mode that presents an image closest to the intentions of its creators, avoiding both the exaggerated brightness of the dynamic mode and the excessive dimming known from eco settings. And it must be admitted that, for a device in this price range, the factory calibration is surprisingly decent, although it is not without a few stumbles. The most noticeable shortcoming turned out to be the not entirely correctly set white balance. A slight dominance of the blue component gives the image a subtly cool, frosty character, straying from the ideal neutrality that the director intended to show us. The television handles the reproduction of greyscale in the standard dynamic range much better – the gamma curve is almost exemplary. The only slight reservation can be made for the darkest parts of the image, where a delicate deviation from the norm causes a loss of some detail in the shadows. The most significant challenge, however, for the TCL software was interpreting the HDR signal, as illustrated by the EOTF curve. The television follows its own, rather free path here – the darkest details are disproportionately brightened, followed by a noticeable slowdown in brightness increase for mid-tones. Fortunately, most of these imperfections are of a software nature, which can be eliminated. With that thought in mind, we proceeded to the process of professional calibration.

As we mentioned earlier, LG televisions are equipped with advanced tools for carrying out the calibration process. We used them to model the picture in line with what the director envisioned. And without modesty, we must admit that we achieved this phenomenally. Both SDR and HDR materials present a level that clearly indicates this is how a film should look. It's worth taking a look at the colour errors on the "ColorChecker" palette, where practically none of them exceed "1", except for two samples.

The calibration process turned out to be spot on, especially in the context of standard dynamic range (SDR) content. We successfully managed to eliminate the tendency of the television to showcase cool tones, restoring white to its natural neutrality. Moreover, the precise adjustment allowed us to correct a slight error in the gamma curve, enabling the darkest parts of the image to regain proper depth, without any signs of unnatural brightness. The results are measurable and impressive – in the ColorChecker test, the vast majority of colour reproduction errors fell below the perceptual threshold, achieving a deltaE value of below 2. This is a result that more expensive models would not be ashamed of. Unfortunately, in the case of HDR content, we encounter a wall in the form of the panel's structural limitations. And although we managed to bring the colours into line, the software's specifics mean that the television still adapts brightness in its own way, as evidenced by the persistent, non-standard EOTF curve. To summarise, calibration adds tremendous value, but it is important to be aware that it won't overcome certain physical barriers. The slightly elevated blacks, resulting from the lack of local dimming, and limited peak brightness mean that HDR content won't always be able to showcase its full potential. This is simply not the main task of this display; its true strength, especially after professional tuning, lies in viewing SDR material.

Once again, we will take a look at the feature responsible for gentle gradation, but we will also address the one that aims to enhance the quality of lower-quality materials. The default smoothing of tonal transitions, as we could see, was not the worst, but it can be improved further. The function has a slider that allows us to adjust its intensity. We recommend using the former, as it produces very good results and does not blur important details.

Image scaling on LG C4 is quite good, however, it cannot be said to be without flaws. The image is slightly sharper by default, although not in a very noticeable way. While jagged edges of trees can be seen, it is not a major issue when compared to other manufacturers.

After a series of harsh evaluations, thankfully, it’s time for some praise, and this is deserved by the TCL AiPQ image processor for its work in the field of digital processing and content scaling. It should be noted right away that we are not talking about the level known from flagship models; nonetheless, in the price segment represented by the P7K/P79K, the results achieved are more than solid. The function that smooths tonal transitions performs particularly well, effectively eliminating posterization, which are the characteristic bands often visible in materials with higher compression, for instance, from choose.tv. The algorithm can elegantly remove unwanted gradients, which ultimately looks really good. The television also handles upscaling competently, which means the task of raising low-resolution materials to 4K standard. The resulting image, although it may seem a bit too sharp out of the box, is fortunately not a problem. The software allows for free adjustment of this parameter using a sharpness slider, allowing the final appearance to be easily tailored to personal preferences.

The maximum refresh rate we can set on the LG G4 is 144 Hz. Naturally, this is only possible when connecting the TV to a very powerful PC. Otherwise, we will operate at a maximum refresh rate of 120 Hz, which is recommended if we primarily want to watch sports or content with a lot of motion dynamics. For those who require high fluidity of the image, the manufacturer has implemented a multi-level motion smoother called "TrueMotion". It has been divided into two separate sliders that adjust the sharpness of moving images (De-Blur) and judder (De-Judder). Both sliders can be set in the range of 0 to 10, with each degree affecting the level of smoothing, allowing everyone to find their sweet spot.

The panel of the LG OLED C4 features an average response time of less than 1 ms (which directly results from our measurements), enabling the achievement of an extremely clear image, unattainable for LCD TVs, which can have response times of up to several milliseconds. This is clearly evident in the images from the "UFO Test," which show no trailing blur behind the object.

The issue of fluidity and sharpness of motion image is inextricably linked to the fundamental parameter of the panel, and in the case of the TCL P7K/P79K, we are dealing with a panel that has a native refresh rate of 60 Hz. This specification at the outset defines its capabilities and makes it hard to unequivocally recommend it to enthusiasts of dynamic sports broadcasts. During quick camera movements, the image loses sharpness, and the panel also shows a slight tendency to smudge, which may be noticeable to more sensitive viewers. Fortunately, not everything in this aspect has been left to chance. The manufacturer has implemented a simple motion smoothing system, which is primarily used in film materials recorded at 24 or 30 frames per second. Thanks to a dedicated slider, the user can decide on the final nature of the motion – from maintaining a fully cinematic, slightly jerky image, to achieving a very smooth, almost theatrical effect. It is a simple yet effective tool that allows one to adjust the viewing experience to their own preferences.

We can now say that LG C4, like practically every OLED television from the manufacturer, is exceptionally good in terms of cooperation with consoles and PCs. Thanks to the implementation of four full-bandwidth HDMI 2.1 ports at 48 Gbps, the manufacturer has embedded all the features that enhance gaming comfort, including simultaneous support for FreeSync and G-Sync technologies. With such a tandem, players with graphics cards from AMD or nVidia can safely choose C4. However, what should please gamers demanding the highest possible quality the most is the simultaneous implementation of HDR Dolby Vision and HGIG mode. The former is particularly important as it operates with extremely low input lag in all settings.

A standard feature in televisions from the Korean manufacturer is also the implementation of GameBar, allowing for quick adjustments of settings "on the fly," without the need to exit the game. It also allows for image adjustments for people with visual impairments, which is an incredibly nice touch. Another important piece of information is that when VRR technology is enabled, we won’t experience a drop in contrast. This is, of course, due to the design of the panel and the absence of conventional backlighting. It is, however, normal for shades of grey to flicker slightly, although this is a characteristic feature of this function regardless of the manufacturer and television.

In summary: LG C4, just like all the manufacturer's OLEDs equipped with high-refresh-rate panels and HDMI 2.1 connections, creates a harmonious whole with consoles. In practice, it is a complete television, and if we expect the highest possible efficiency in gaming, C4 will be an ideal choice.

Although on paper the native 4K@60Hz matrix might suggest that the TCL P7K/P79K is not a TV tailored for gamers, the reality turns out to be surprisingly different. On the contrary, the manufacturer has ensured a rich set of features that make it a very friendly companion for next-generation consoles. Onboard, we find key technologies such as ALLM, which provides automatic switching to low-latency mode, and VRR, or variable refresh rate, which eliminates screen tearing. The list is rounded off with support for Dolby Vision Gaming and a simple yet functional Game Bar. However, the real and extremely pleasant surprise is something else. It turns out that the TV effortlessly supports a high refresh rate signal of 120Hz, but at lower resolutions – 1080p and 1440p. This is fantastic news for console owners, who know how rarely games run in native 4K at a full 120 frames per second. The option to choose between higher resolution and doubled smoothness is therefore an incredibly sensible compromise.

In summary, while the P7K/P79K may not be the target screen for the most passionate, tournament gamers, it offers a package of options for casual or occasional console users that is hard to find among many competitors at this price point.