LG 55 B4 vs Xiaomi S Pro 2026

The HDR brightness performance of the LG B4 is impressive, even though it doesn't surpass 1000 nits. Its luminance stability is consistently strong across various scenarios, delivering a reliable viewing experience. The only instance where the TV shows slight weakness is in scenes with large areas of bright white, which has long been a challenge for OLED technology. However, perfect contrast, deep blacks, and excellent brightness ensure a fully immersive HDR experience. Furthermore, the TV’s remarkable 99% coverage of the DCI-P3 colour gamut enhances its colour vibrancy, making images appear rich and visually striking. This level of colour accuracy and brightness balance firmly places the LG B4 among the top choices for HDR content.

When it comes to HDR quality, the Xiaomi S Pro 2026 is undoubtedly a really bright TV. On our synthetic measurement charts, we were able to generate a peak brightness of around 1400 nits. This is not only a very good result but even spectacular, considering the price of this model. However, as we always repeat, for our editorial team, measurements and experiences from the content we watch every day—movies and series—are more important. So let's analyze how Xiaomi handles film material. Unfortunately, the result is somewhat mixed. When very bright scenes appear on the screen, the S Pro 2026 truly shows its full potential and can achieve real brightness of 800-1000 nits on bright elements. Moreover, even smaller objects can "burn" the eyes— in scenes from the movie Sicario 2, small metallic elements of the helicopter were really bright. The problem is this—and here the story comes full circle back to our assessment of contrast—that in such scenes, we cannot count on absolutely cinematic black. In our opinion, this compromise is too significant; high visibility of details in bright areas should not come at the expense of such a substantial boost in black levels. And even though the HDR effect itself can be striking here, it is important to remember that when very difficult, mixed scenes appear on the screen, we may feel a slight disappointment. Exactly the one we mentioned in the previous paragraph regarding dimming issues in HDR mode. On a positive note, it is worth adding that the S Pro 2026 is equipped with an additional PFS filter (which works similarly to a QLED layer), effectively broadening the color palette coverage. As a result, measurements showed a DCI-P3 color gamut coverage of up to 94%. This gives us the confidence that in most colorful scenes, the image will look rich and appropriately saturated.

The best factory preset offered by LG B4 is the "Filmmaker" mode, which we used throughout our testing. Straight out of the box, the TV delivered fairly accurate colour reproduction. However, the most significant issue in both SDR and HDR content was the white balance. In SDR, there was a noticeable red dominance, giving the image a distinct yellow tint, particularly evident in skin tones and whites. In HDR, this red hue persisted, but the lack of blue also introduced a greenish tint in certain scenes. Additionally, we observed some inconsistencies in grayscale and colour accuracy. Despite these shortcomings, the overall picture quality was still solid for most viewing scenarios.

Of course, we conducted all our measurements in "Film" mode, which is usually the best and most accurate choice you get straight out of the box. And we have to say it bluntly: even though this is the best mode, it is still very far from ideal. First of all, the television has a clear tendency to give the image a cool, bluish tint – this is due to a poorly set white balance. Additionally, there is a problem with how the S Pro 2026 manages its brightness right after being taken out of the box, which results in an overly bright image. These two flaws contribute to really huge colorimetric errors (Delta E). In HDR content, they were able to exceed our expected error scale of "10" (meaning values close to 20). For reference – the threshold of perceivable error by the human eye is a Delta E value of around 3. Results at the level of 20 mean that the image significantly deviates from what the director intended.

LG B4 has long been known for offering advanced calibration tools, and it remains one of the few manufacturers that allows such in-depth image adjustments. Thanks to these tools, we calibrated the device to an exceptional standard. The result was incredibly low deltaE errors, considered at a reference level. Both SDR and HDR content now display exactly as the filmmaker intended. This level of precision is one of the reasons LG TVs are frequently used as preview monitors in graphic design and post-production studios.

So how does the S Pro 2026 perform after our calibration treatment? We must admit that after calibration, the television becomes a really pleasant device for watching everyday content. As you can see in the graphs, we managed to bring both white balance and gamma values to nearly perfection in HD (SDR) material. Most importantly, the colorimetric errors have become practically invisible to the human eye. In this scenario, the S Pro 2026 is simply a great television that, after professional calibration, can provide a lot of enjoyment while watching. However, it is worth noting clearly – our efforts helped little in 4K HDR mode. Despite calibration, the television still interprets the image rather strongly "in its own way," which is clearly seen in the measurement of the EOTF curve (luminance tracking). It's a bit of a shame, because this shows that the problem lies not in the panel itself, but in the software. Underdeveloped image management algorithms in HDR content can, unfortunately, disqualify this television for many more discerning users.

In this section, we will revisit the smooth transition function while also examining how the TV handles lower-quality content. As we’ve found, the setting responsible for smooth gradation is generally effective, though it does have its drawbacks. While the function works well in SDR content, it becomes less useful in HDR content. Even at the lowest setting, it can blur important details, so we advise against using it in such cases.

The image scaling on the LG B4 is assessed moderately positively. While there is no noticeable edge doubling, the image tends to be somewhat "soft." This can be adjusted by tweaking the sharpness slider to improve the clarity.

Let's start with the issue we addressed in the previous paragraph: can a TV even fix the problem of poor tonal transitions in dark scenes? Theoretically, yes – in the menu, we find a feature with the promising name "Color Contour Removal." Well, "theoretically." Unfortunately, in practice, this setting – regardless of which of the three power levels is selected – yielded absolutely no real results. So we have a feature that, in practice, only exists in the menu. Moving on to the quality of upscaling (scaling the image from a lower resolution to 4K), unfortunately, we have more bad news for you. The S Pro 2026 handles this task very poorly. Interestingly, the phenomenon of "overscan" (slight image cropping) is not a big issue here. The problem is that the TV simply displays a very raw, unprocessed image. Its attempt to upscale the signal to a higher resolution looks simply poor and lacks any "smart" enhancement. There is no denying it – the whole digital image processing is the true Achilles' heel of this model.

The maximum refresh rate on the LG B4 is 120 Hz, the bare minimum for those requiring high image fluidity. The manufacturer has equipped the TV with a multi-stage motion smoother called "TruMotion." This feature is split into two sliders: one controls the sharpness of moving images (De-Blur) and the other adjusts judder (De-Judder). Both sliders can be set between 0 and 10, with each level affecting the smoothness, so users can easily find their preferred setting.

The LG OLED B4 panel boasts an impressive average response time of 0.1 ms (based on our measurements), delivering an exceptionally clear image that surpasses the capabilities of LCD TVs, which often have response times of several milliseconds. This is particularly noticeable in the "UFO Test" images, where no trailing blur is visible behind moving objects.

On paper, the specification of the S Pro 2026 looks impressive. The television is equipped with a native 144 Hz panel, capable of displaying images up to 288 Hz in a dedicated gaming mode. These are amazing results, but what interested us the most, in the context of everyday use, was how the television handles motion blur and how the image looks at 120 Hz. After all, this is the frequency used today by consoles like PlayStation 5, Xbox Series X/S, and it is desired by sports fans. Generally speaking, the panel "holds up." The matrix is fast enough to meet these challenges, and objects displayed at native 120Hz fluidity are shown correctly. As for the software, the television is equipped with a motion smoothing system, but with a key caveat – it only works for input signals up to 60 Hz. This means it is mainly suitable for classic television, movies, and series. Thanks to this, we can adjust the fluidity of the image to our own preferences – from a very smooth, "theatrical" approach to setting the slider to "zero" and maintaining a fully cinematic character.

The LG B4 has four full HDMI 2.1 ports, each providing 48Gbps bandwidth. This ensures smooth activation of all relevant features without issues, making the television highly suitable for gaming. With its low input lag and extensive functionality, including well-implemented HGIG mode and Dolby Vision gaming with low latency, the B4 is a strong contender for gamers who demand high quality.

A standout feature is GameBar, which allows for on-the-fly adjustments without interrupting gameplay, as well as image adaptations for those with visual impairments. Another key point is that when VRR technology is enabled, the television maintains its contrast, thanks to the OLED panel's structure, though slight flickering in grey shades is to be expected.

In conclusion, the LG B4 is an ideal choice for gamers, seamlessly combining high performance with excellent gaming features. Its 120Hz panel and HDMI 2.1 ports make it a standout option for those seeking top-tier gaming experiences.

For gamers, the Xiaomi S Pro 2026 is, on paper, an almost ideal proposition. It is equipped with two HDMI 2.1 ports, allowing us to unlock (although these options are somewhat hidden in the menu) the full suite of features: ALLM, VRR, and, crucially, the ability to work in 4K at 144 Hz. This last feature should particularly please owners of powerful PCs. The TV also has something akin to a gaming panel – and while it’s hard to call it a full-fledged "Game Bar," it does its job by displaying key information. It’s just a shame that in its default form, it covers a relatively large part of the screen.

However, our biggest issue with this model concerns how the S Pro 2026 handles gaming in HDR mode. To put it bluntly: it doesn’t handle it well. Due to the poorly implemented HGiG function (the HDR tone mapping standard for games), during the initial HDR calibration on the console, it’s very easy to "blow out" the image. If someone is unaware of this software flaw and follows the on-screen instructions, they will simply set the image incorrectly, with burnt-out details in bright areas. Another major problem is the Dolby Vision mode for gaming. While it does work, it generates such a high input lag that it becomes noticeable in dynamic titles. (All our latency measurements can be checked in the paragraph below). In summary: generally, it’s a really good screen for gamers, but with one small caveat. We would rather avoid HDR mode on it – unless we decide to manually adjust the brightness bar on the console "by eye," completely ignoring the instructions from the console's pictogram.