LG OLED G4 vs TCL A400 PRO

LG G4 guarantees an incredibly vivid HDR effect, placing the television among the very best. The equipment of the highest model in the producer's 2024 portfolio with the second generation of micro-lens technology (MLA) has achieved a maximum brightness level of 1474 nits in real scenes. The only area where the product from the Korean manufacturer may lag behind LCD televisions with Mini LED backlighting is during the full-screen scenes featuring a lot of white. If we disregard the latter type of scene, the average result would be even higher. It is also worth mentioning scenes with very fine details, where each one shines at full intensity, which is not as evident in non-OLED televisions. The combination of such brightness and wide coverage of the DCI-P3 palette makes HDR materials more engaging than ever before.

The TCL A400 Pro is a moderately bright TV. Its peak brightness reaches around 600 nits. That level already allows for a real HDR effect, and in many films it does produce a noticeably more attractive picture than in SDR. However, it is not a level that overwhelms with sheer brightness. The A400 Pro therefore isn’t one of those TVs that ‘attack’ the viewer with a powerful flash in every eye-catching scene. The biggest limitation is seen with small bright elements on a dark background. Because of fairly aggressive local dimming control, the TV can significantly reduce their brightness, in extreme cases even to around 100 nits. This means that small lights, sparks, stars or individual highlights can be much less visible than they should be. It’s worth adding, however, that this isn’t without reason. The A400 Pro does this to maintain as deep a black level as possible and to limit the halo effect around bright objects. So it’s an intentional compromise: the TV more often opts for deeper blacks rather than maximally bright, point-like highlights. On one hand this can be understood, especially given the limited number of dimming zones, but on the other you should be aware that the HDR effect won’t always be as strong as the peak brightness alone might suggest.

On the plus side, the colours are a strength. The PFS LED filter used here, marketed by the manufacturer as QLED, allows for suitably saturated colours. Coverage of the DCI-P3 gamut measured around 94%, and BT.2020 around 74%, which is a solid result for this class.

The best factory mode in terms of colour reproduction was "Filmmaker". This was the one we used during our tests. Let's check how its characteristics looked before the calibration process. Looking closely at the white balance first, we can notice a significant dominance of red and green. As a result, the image had a warm yellowish hue. Such characteristics are typically observed in "Cinema", "Filmmaker" or similarly named modes. The effect of this colour balance was clearly visible in both SDR and HDR content, which after switching from "Standard" mode appeared distinctly yellow. Now, let's move on to two graphs that are responsible for the brightness characteristics and consequently the contrast of the image. The first one (Gamma), representing materials with a standard colour palette, performed decently. For most of the time, midtones and bright whites were reproduced very accurately; however, it noticeably lost the darkest details, which merged into a black blob. Conversely, HDR materials, represented by the EOTF curve graph, exhibited a significant drop in contrast due to a strong boost in brightness. The colours themselves also posed a problem, as can be seen on the "ColorChecker" graph, since they were noticeably under-saturated.

As standard, we performed colour measurements in the best‑tuned Filmmaker Mode, the mode that is designed to be closest to the creators' intentions. The A400 Pro of course also offers other picture modes, but in practice these come with considerably larger colour errors and interfere more with the character of the image. Therefore we will not deal with them in detail in this part of the test. So how does the out‑of‑the‑box colour reproduction fare? In short: really very good. Actually, looking at our measurement results, downright excellent. Both the white balance and the luminance response were set surprisingly precisely. The errors were so small that during measurements we genuinely rubbed our eyes in amazement. Such good factory settings do not happen often, even in TVs operating in Filmmaker Mode. All the more credit is due to TCL, because the A400 Pro right out of the box can deliver an image very close to how the source material should look. The results were so good that one could easily think someone had already given this unit extra attention and tried to calibrate it.

Our nitpicking really comes down to just one thing. In SDR content the image was slightly brighter than the dark‑room reference intends, because the factory gamma was set closer to 2.3 than to 2.4. This is not a large error and most viewers will probably not even notice it.

It should, however, be noted that we are talking about our specific test sample. With factory colours there can always be some variation between units, production batches or screen sizes. We do not assume, therefore, that every A400 Pro will look identical straight out of the box.

The manufacturer has implemented extensive support for the calibration process in its LG televisions for many years. We therefore used 2- and 20-point greyscale adjustments, as well as an advanced CMS (Colour Management System), and got to work. As you can see, thanks to the procedure carried out, each parameter has significantly improved. The use of tools allowed for the achievement of extremely beneficial effects, which include: studio colour reproduction, recovery of details in dark areas of the image, appropriate brightness characteristics, and suitable colour saturation. This brings us as close as possible to the reference image, which is what the film director saw on the preview monitor. It is worth noting that the LG G4 televisions alone allow for even deeper intervention in image quality thanks to the ability to calibrate with 3D LUTs. However, this is a solution recommended only for post-production or graphic studios.

Despite its superb factory calibration, we couldn't resist checking how the TCL A400 Pro would respond to professional calibration. Since the starting point was so good, we were all the more curious whether there was anything more to be had from the TV. And here we must boast: we managed to reduce our unit's colour errors to absurdly low levels. Measurements below a value of 1 are not something you see every day, even in very good TVs. Such results are more commonly associated with professional reference monitors than with a lifestyle TV for the living room. In terms of white balance and colour reproduction the A400 Pro therefore simply performed exceptionally well after calibration. The only gripe we have after closer analysis relates to the luminance behaviour. The TV adjusts luminance depending on the content being displayed and quite often the picture is slightly darker than the reference calls for. This is most likely due to the way the Mini-LED backlight and local dimming algorithms operate in this model. However, this does not spoil the overall impression, because in terms of colour accuracy alone the calibrated A400 Pro showed a level that was really hard to expect.

The tested television did not perform particularly well with materials rich in tonal transitions, as a result of which we could observe a strong posterisation effect. However, there is a partial remedy for this issue. The manufacturer has equipped the LG G4 with a smoothing system called "Gentle Gradation," which we can apply at three levels: Low, Medium, and High. Each of these options guarantees quite a high effectiveness of smoothing on light colours, although it is low on darker ones. We recommend primarily using the first one, as the other two interfere with the director's intentions by removing film grain.

When watching lower-quality materials, the efficiency of the television during upscaling is extremely important. The image from the tested television is sharp and clear. However, one should pay attention to the jagged edges of fine details and minor issues around characters, such as the creation of halo effects, which occurs due to the sharpening imposed by LG G4 even when the lowest value on the slider, that is 0, is set. It is worth noting that this represents a certain change compared to the LG G3, which did not impose such strong image sharpening, even when the appropriate slider was set to position 0.

Digital image processing is, unfortunately, one of the weaker points of the TCL A400 Pro. That does not mean the TV performs badly, but it is hard to call it anything clearly above average. The upscaling itself is adequate: edges are smoothed fairly well, the picture does not look overly sharp or "pixelated", and lower-quality content can be watched without much discomfort. At the same time, the overall image is slightly soft and lacks the precision offered by the best image processors in more expensive TVs.

Much worse, however, is how it handles tonal transitions caused by strong signal compression. TCL has equipped the A400 Pro with a "Gradual Smoothing" feature that, in theory, should limit visible colour banding and artifacts in lower-quality material. In practice, though, its effectiveness is very limited. It does not improve tonal transitions in any noticeable way, and at higher settings it can also smooth out image details, giving the picture an artificial, slightly blurred character. For that reason, we think it is best to leave this feature off. The A400 Pro copes decently with basic image scaling, but if you often watch heavily compressed content with noticeable posterisation, this model will not be among the best choices.

The maximum refresh rate that we can set on the LG G4 is 144 Hz. Naturally, this is only possible when the LG G4 is connected 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 high motion dynamics. For those requiring high image fluidity, the manufacturer has implemented a multi-level motion smoother called "TrueMotion". This 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 from 0 to 10, with each level affecting the degree of smoothness, allowing everyone to find their golden mean.

The LG OLED G4 panel features an average response time of 0.78 ms (as directly derived from our measurements), enabling an incredibly clear image, unattainable by LCD televisions, which can have response times of several milliseconds. This is perfectly illustrated by the images from the "UFO Test", which show no trailing blur behind the object. Moreover, the LG OLED G4 test revealed that the television offers the ability to precisely adjust the motion smoothing function, allowing users to select the ideal level of image interpolation. We particularly appreciated this during fast-paced actions in video games, where the LG G4 performed exceptionally well, minimising any blurring. Thanks to OLED technology, this model eliminates so-called ghosting, ensuring that the image remains sharp even in the most dynamic sporting or cinematic scenes.

The TCL A400 Pro is equipped with a 144 Hz panel, but in practice we are most interested in its behaviour at 120 Hz. That is the frequency most consoles are limited to today, as well as many sports broadcasts and high-frame-rate content. At that rate the TV performs quite well. The sharpness of moving objects is really good, especially after properly configuring the motion smoothing. The "Motion Clarity" function is responsible for improving smoothness. Its settings include two sliders that let you tailor how the motion smoothing operates to your preferences, separately for lower and higher frame-rate material. This makes it possible to achieve both a more cinematic look and a noticeably smoother picture. Those who do not want to fiddle with manual configuration can use presets such as low, medium, high, cinema or nature.

The LG G4 television supports all the features that make up the HDMI 2.1 standard. During testing, each of them activated without the slightest problem, which allows us to consider the television as designed for gaming. Their functionality will surely be appreciated by both console users and those connecting the LG G4 to a computer. It is also worth mentioning the correct implementation of the HGIG (HDR Gaming Interest Group) mode, which ensures that games mastered to brightness levels exceeding the maximum luminance of the LG G4 will correctly map tones, and the game's visuals will remain true to the original.

A nice touch is the existence of a special GameBar, which we can call up at any moment to check game parameters, but most importantly, to change them quickly. More importantly, enabling VRR technology does not degrade contrast, which is very common in televisions that feature local dimming or Mini LED backlighting. Of course, this is thanks to the OLED panel itself, characterised by pixel self-emission. As a matter of editorial obligation, we will only mention a slight grey flicker, which is somewhat normal after enabling VRR.

In summary, the LG G4, like practically all OLED televisions, is an ideal product for all kinds of games and online competitions. With fully-fledged HDMI 2.1 connections with a full bandwidth of 48 Gbit, features such as VRR, ALLM, G-Sync, FreeSync, or gaming in HDR Dolby Vision will bring much joy.

In terms of features for gamers the TCL A400 Pro performs brilliantly. The TV has practically everything you can expect from a gaming TV today: support for 4K at high refresh rates, VRR, ALLM, correct implementation of HDR formats in games including Dolby Vision, and HGiG. That means it works well with both next-generation consoles and a PC. Another plus is the presence of the Game Bar, a special panel with the most important settings for gamers. From it you can quickly check basic information about the signal, refresh rate or active features, and also adjust the appearance and behaviour of some settings to suit your preferences. This solution may not change picture quality by itself, but it greatly improves the convenience of using the TV while gaming.

The only thing to complain about is the number of full HDMI 2.1 ports. The A400 Pro has only two such connectors out of the four available, and one of them also serves as eARC. In practice this means that if someone wants to connect two next-generation consoles and a soundbar, they may run into some limitations. In that scenario you will have to either swap devices or use additional equipment, such as an AV receiver or a soundbar with HDMI inputs. Even so, it is hard not to rate the A400 Pro very highly as a TV for gamers. The gaming feature set here is truly powerful.