LG OLED G4 vs TCL A400 PRO

The LG G4 excels in delivering an incredibly vivid HDR experience, positioning it as one of the best models in its class. Equipped with second-generation Micro Lens Array (MLA) technology, it achieves a remarkable peak brightness of 1474 nits in real-world scenes. While it may not match Mini LED-backlit LCD TVs in full-screen white scenes, the overall performance is outstanding. The fine details in HDR content shine brightly, a distinct advantage of OLED technology over non-OLED displays. With this impressive brightness and wide DCI-P3 colour gamut coverage, HDR content is brought to life with unmatched engagement and immersion.

The TCL A400 Pro is a moderately bright TV. Its peak brightness reaches about 600 nits. That level already allows for a real HDR effect and in many movies it does produce a noticeably more attractive picture than SDR. However, it is not a level that overwhelms by brightness alone. The A400 Pro is not one of those TVs that "attack" the viewer with a powerful flash in every dramatic scene. The biggest limitation is visible with small bright elements on a dark background. Due to rather aggressive control of the dimming zones, the TV can significantly reduce their brightness — in extreme cases down to around 100 nits. That means small lights, sparks, stars, or single highlights can be much less visible than they should be. That said, this is not done without reason. The A400 Pro does this to keep blacks as deep as possible and to limit haloing around bright objects. It's a deliberate compromise: the TV more often chooses deeper blacks over maximally bright, point-like highlights. On one hand this is understandable, especially with a limited number of dimming zones, but on the other hand you should be aware that the HDR effect will not always be as strong as the peak brightness alone would suggest.

On the plus side, the colors are worth noting. The PFS LED filter used here, marketed by the manufacturer as QLED, produces suitably saturated colors. Our measurements showed about 94% coverage of the DCI-P3 gamut and about 74% of BT.2020, which is a solid result for this class.

Before calibration, the "Filmmaker" mode on the TV had a noticeable red and green colour dominance, resulting in a warm-yellow hue across both SDR and HDR content. This warm tone, typical of modes like "Cinema" and "Filmmaker," led to a yellowish cast that was evident when switching from the "Standard" mode.

Looking at the brightness characteristics, the Gamma chart showed decent performance for mid-tones and bright whites, but it struggled with the darkest details, which tended to merge into a black blob. HDR content, as represented by the EOTF curve chart, displayed a drop in contrast due to excessive brightness, which overshadowed fine details and negatively affected the overall image quality. Additionally, the "ColourChecker" chart revealed that colours were under-saturated, contributing to a less accurate and vibrant visual experience.

This provided a good foundation to build on, but calibration was needed to bring out the full potential of the "Filmmaker" mode and address these issues.

As standard, we carried out color measurements in the best-calibrated mode, Filmmaker Mode, the one that is supposed to be closest to the creators’ intent. The A400 Pro, of course, also offers other picture modes, but in practice they suffer from much larger color errors and alter the image character more strongly. We won’t go into those modes in detail in this part of the test. So how does the factory color reproduction perform? In short: really very well. In fact, looking at our measurement results, it’s excellent. Both the white balance and the luminance response were set surprisingly precisely. The errors were so small that during testing we genuinely rubbed our eyes in disbelief. Such good out-of-the-box settings don’t happen often, even in TVs operating in Filmmaker Mode. All the more reason to praise TCL, because the A400 Pro right out of the box can produce an image very close to how the source material should look. The results were so good that you could easily think someone had already paid extra attention to that unit and tried to calibrate it.

Our nitpicking really comes down to just one thing. In SDR content the image was slightly brighter than the reference for a dark room, because the factory gamma was set closer to 2.3 than to 2.4. It’s not a big error and most viewers probably won’t even notice it.

However, it should be noted that we’re talking about our specific review sample. With factory colors there can always be some variation between units, production batches, or screen sizes. So we don’t assume that every A400 Pro will look identical straight out of the box.

The manufacturer has been offering extensive support for the calibration process in its LG televisions for many years. Therefore, we used 2- and 20-point grayscale adjustments along with an advanced CMS (Colour Management System) to optimise the display. As shown, the calibration procedure greatly improved each parameter. The results included studio-quality colour reproduction, enhanced detail in dark areas, corrected brightness characteristics, and accurate colour saturation. This led to a near-perfect match with the reference image—the one the film director saw on the preview monitor. It’s also worth mentioning that LG G4 televisions are unique in offering even deeper image adjustments through 3D LUT matrices, a feature primarily suited for post-production or graphics studios.

Despite its excellent factory tuning, we couldn't resist checking how the TCL A400 Pro would respond to a professional calibration. Since the starting point was so good, we were even more curious whether we could squeeze even more out of this TV. And here we have to boast: we managed to bring our unit to absurdly low color errors. Results below 1 are something you don't see every day, even on very good TVs. Such results are more often associated with professional reference monitors than with a lifestyle TV for the living room. In terms of white balance and color reproduction, the A400 Pro after calibration simply performed outstandingly. The only thing we can pick at after a deeper analysis concerns the brightness behavior. The TV can manipulate luminance levels depending on the content being displayed, and quite often the image is a bit darker than it should be according to the standard. This most likely stems from the way the Mini-LED backlight and local dimming algorithms work in this model. However, that doesn't spoil the overall impression, because in terms of color precision alone the A400 Pro after calibration reached a level we really didn't expect.

The LG G4 does not perform well with materials rich in tonal transitions, leading to a pronounced posterization effect. However, the manufacturer has included a smoothing system called "Gentle Gradation," with three levels: Low, Medium, and High. These settings are effective at smoothing bright colours, though less so for darker tones. It is recommended to use the Low setting, as the higher levels can distort the director's intentions by removing film grain.

When it comes to upscaling lower-quality material, the television's performance is quite good, delivering a sharp and clear image. However, attention should be paid to the jagged edges of fine details and the occasional halo effect around figures. This occurs due to the sharpening imposed by the LG G4, even when the lowest setting is selected (0). This is a noticeable change from the LG G3, which did not apply such strong sharpening, even at setting 0.

Digital video processing is unfortunately one of the weaker points of the TCL A400 Pro. That doesn't mean the TV performs badly, but it's hard to call it anything clearly above standard. The upscaling itself is adequate: edges are smoothed fairly well, the image doesn't look overly sharp or pixelated, and lower-quality content can be watched without major discomfort. At the same time the overall look is slightly soft and it lacks the precision that the best image processors in more expensive TVs can deliver.

Much worse, however, is its handling of tonal transitions caused by heavy compression. TCL equipped the A400 Pro with a "Gradual Smoothing" feature that in theory should reduce visible color banding and artifacts in lower-quality content. In practice 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's best to leave this feature off. The A400 Pro handles basic image scaling decently, but if you often watch heavily compressed content with visible posterization, this model won't be one of the best choices.

The LG G4 offers a maximum refresh rate of 144 Hz, achievable when connected to a powerful PC. For most users, however, the TV operates at a maximum of 120 Hz, ideal for watching sports or other content with fast motion. To improve image fluidity, the television includes the "TrueMotion" motion smoothing system, which features two separate sliders: De-Blur (for the sharpness of moving images) and De-Judder (for judder reduction). These sliders allow users to adjust the level of smoothing between 0 and 10, ensuring everyone can find the ideal setting.

With a response time of 0.78 ms, the LG G4 delivers exceptionally clear images, outperforming LCD televisions, which can have much slower response times. This results in no trailing blur behind moving objects, as shown in the "UFO Test." The TV also provides precise control over motion smoothing, which is especially beneficial during fast-paced video game sequences. Thanks to OLED technology, the G4 eliminates ghosting, ensuring a crisp and clear image even during the most dynamic sports or action scenes.

The TCL A400 Pro is equipped with a 144 Hz panel, but in practice we're most interested in how it performs at 120 Hz. That's the refresh rate used by most consoles today, as well as many sports broadcasts and high-frame-rate content. In this range the TV performs quite well. Motion clarity is really good, especially after properly configuring the motion smoothing. The "Motion Clarity" feature improves smoothness. Its settings include two sliders that let you tailor the motion smoothing to your preferences — separately for lower- and higher-frame-rate material. That way you can achieve either a more cinematic look or a noticeably smoother picture. If you don't want to tweak settings manually, you can use presets such as low, medium, high, cinema, or nature.

The LG G4 TV supports all the features encompassed by the HDMI 2.1 standard, making it a gaming powerhouse. During testing, every feature activated seamlessly, ensuring a smooth experience for both console gamers and PC users. Notably, the HGIG mode (HDR Gaming Interest Group) is implemented correctly, allowing games mastered to brightness levels higher than the TV’s maximum luminance to map tones accurately, preserving the game’s original visual integrity.

A notable highlight is the dedicated GameBar, which can be accessed at any time to quickly check or adjust game settings. More importantly, enabling VRR (Variable Refresh Rate) does not compromise contrast—a common issue in TVs with local dimming or Mini LED backlighting. This is thanks to the OLED panel’s self-emissive pixels, which maintain consistent contrast. However, a slight grey flicker may appear when VRR is enabled, though this is standard across OLEDs.

In summary, the LG G4, like most OLED TVs, is ideal for gaming and online competitions. Its HDMI 2.1 ports offer a full 48 Gbps bandwidth, supporting features such as VRR, ALLM (Auto Low Latency Mode), G-Sync, FreeSync, and HDR Dolby Vision gameplay, ensuring an exceptional gaming experience.

When it comes to features for gamers, the TCL A400 Pro performs excellently. The TV has practically everything you can expect from a gaming TV today: 4K support at high refresh rates, VRR, ALLM, correct implementation of HDR formats in games, including Dolby Vision, and HGiG. Because of that it works well with both next-gen consoles and PCs. Another plus is the inclusion of a Game Bar, a special panel with the most important settings for gamers. From it you can quickly check basic signal information, refresh rate, and active features, and also adjust the look and behavior of some settings to your own preferences. This is a solution that 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 ports out of four, and one of them also functions as eARC. In practice this means that if someone wants to connect two next-gen consoles and a soundbar, they may hit some limitations. In that scenario you'll have to either swap devices or use extra equipment, for example an AV receiver or a soundbar with HDMI inputs. Despite this, it's hard not to rate the A400 Pro very highly as a gaming TV. The gaming feature set here is really powerful.