TCL A400 PRO vs Philips OLED811

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.

Philips OLED811 uses a new generation of WOLED EX panels, also found in models such as the LG C6 and Samsung S90H. After calibration we measured around 1500 nits, which is a very good result for an OLED TV. You can see this clearly in films and series. All kinds of bright flashes have the right intensity, especially when they appear against a dark background. In such scenes the OLED811 can deliver truly impressive HDR. Of course, that does not mean you will see that level of brightness in every shot. When the screen is filled with a large amount of white or a wide explosion, brightness falls to around 600 nits. That is still a good result, but those scenes no longer have the same punch as small, bright elements on a dark background. This is a known limitation of OLEDs and the OLED811 is no exception.

Colours

Aside from HDR brightness, colours also matter and here Philips performs very well. It covers almost the entire DCI-P3 gamut, which contains most of the colours used in HDR films and series. You get saturated reds and lush greens, and when watching it’s hard to find major faults in that respect. It looks a little worse with the much wider BT.2020 gamut, whose most saturated shades are already out of reach for this panel. There is also the issue of the white subpixel that the WOLED panel uses to boost brightness. With very bright colours you can see a certain washout: the colour is bright but loses some of its intensity. It is precisely in such situations that QD-OLED panels from Samsung Display have the advantage. However, in most films and series this is not something that will immediately stand out.

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.

Film mode on the Philips OLED811 is sensibly set up straight out of the box. Most colour errors remain small, both in SDR and HDR, so you can sit down to watch without adjusting the settings first. There are no major inaccuracies that would immediately distract from the film. It falls a little short of perfection, though. The white balance shows a slight lack of red compared with green, so whites and greys can have a faint greenish tint. It is not a strong colour cast, but measurements clearly show it. There are also minor brightness deviations in SDR: some parts of the image are slightly brightened, and the darkest shades are not always reproduced evenly. In HDR the TV sticks much closer to the reference, although in places it gently lifts detail from the shadows. These are generally areas that could be improved. The factory film mode provides a good starting point, and calibration will reveal how much more can be gained from it.

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.

After calibration the Philips OLED811 produces an image very close to the reference. We managed to correct the white balance and eliminate the slight tint visible in the factory settings. Errors in the Color Checker measurements for SDR and HDR fell to around 1 to 2, and many samples are even below 1. That's a level at which differences from the reference image are hard to spot with the naked eye. We also improved the gamma, and only in the brightest whites is there a slight brightening remaining. In HDR the EOTF curve also tracks the reference closely, although the TV still tends to gently boost the brightness of small elements, such as stars or on-screen text. This gives the picture a little extra sparkle that shouldn't be there, but otherwise there's little to fault. It was already good out of the box, and after calibration we managed to refine most of the remaining shortcomings.

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.

OLED811 handles lower-quality material reasonably well, though it falls well short of perfection. The "Banding reduction" function helps to smooth tonal transitions and on the low setting gives a fairly good result. It does not remove bands between shades as effectively as similar solutions from some competitors, but at least it does not introduce new artefacts in the process. This is a sensible setting for everyday viewing. There is still some dissatisfaction, however, because the MediaTek Pentonic 800 chipset used here can, in other manufacturers' implementations, cope with the effects of heavy compression more effectively even at similarly low settings. Much therefore depends on how a given manufacturer makes use of its capabilities. We have a few more comments about the upscaling to 4K. There is a lot of detail, but the overall image looks rather soft. Edges are heavily smoothed, which robs the picture of a bit of sharpness and clarity. This can be partly corrected with the sharpness slider in the menu, though that will merely accentuate outlines rather than recover detail. On the plus side, there is no overscan; even with an SD signal the TV does not crop the edges of the picture.

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.

In terms of motion handling the OLED811 performs excellently. At 120 Hz, which is useful for console gaming and watching sport, the picture stays clear and moving objects do not leave noticeable smears. The fast response of OLED pixels helps here; this is clear in the UFO test, even on dark backgrounds. There are also motion smoothing controls. For films you can adjust the level of smoothing to suit your taste, ranging from preserving a cinematic character to much smoother motion. A separate blur reduction setting is useful for fast-paced material such as sports broadcasts.

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.

OLED811 has almost everything you could expect from a TV for gaming. It supports 120 Hz at Full HD, 1440p and 4K, and when connected to a PC it can reach 165 Hz. It also has VRR, which helps prevent screen tearing when frame rates fluctuate, and ALLM, which automatically switches to game mode. So you don't have to dig into the settings every time you power up your console.

Another plus is that HGiG works correctly, so once HDR is set on the console the TV doesn't apply its own changes to image brightness. There's also a Game Bar to check signal parameters and quickly change settings useful while gaming. The list even includes Dolby Vision for gaming, but there is a significant catch, which you can read about below.