[sblantipodi]

Hi all,
I think that this is a topic widely discussed but it is still not clear to me.

Is OLED superior in terms of HDR over MiniLED monitors?

It’s clear that OLED is superior with blacks, they do not suffer from blooming and haloing, but how the reduced brightness afflicts the overall HDR quality.

Most HDR contents are mastered in HDR10 with static metadata, this means that low brightness can produce dull images.

This video shows the benefits of an high brightness screen.

https://youtu.be/NfHC8fVnOnA

I sincerely never compared an OLED near to a MiniLED monitor so I don’t know where the truth is.

Can you shed some light on this please?

[PCM2]

It’s a good question and we do draw comparisons between OLED and Mini LED solutions in our reviews. I don’t really think one technology is outright superior to the other for HDR, it depends on the scene and can also depend on your lighting in the room! It’s a good idea to have a dedicated thread like this to help focus these thoughts.

The advantage of OLED comes from its per-pixel illumination, providing the equivalent precision of a Mini LED solution with millions of dimming zones. Rather than the 500 – 2000 or so typically found on such models. This means they can provide high brightness to one pixel plus exceptionally low brightness to neighbouring pixels. It also means it can provide appropriate depth (assuming appropriate calibration) to various medium shades, with extremely precise control. This marries well with the 10-bit precision used for HDR10 content. In practice this can give a more defined look to various ‘structures’ and texture details in the scene, particularly where there are intricate mixtures of brighter and darker shade. There can be small bright or dark details which would both share a single dimming zone on a Mini LED solution. The OLED monitor doesn’t have to use a dimming algorithm which will cause a compromise, either dark-biasing to maintain good depth to the dark shades or bright-biasing to keep the bright shades nice and bright. You’re going to get some shades dragged down so they’re dimmer than intended or some shades brightened up too much on Mini LED models. ‘Haloing’ or ‘blooming’ can be observed if bright-biasing is too strong and a degree of this is inescapable with current Mini LED solutions. You’ll be aware of this from discussions on the X32 FP thread.

The OLED advantage tends to be most noticeable for scenes where there’s mainly medium to dark content with a few interspersed bright elements – and is most noticeable in a dimly lit room, too. The limitation with OLED models is that they draw more power the brighter each pixel is. So in scenes where bright shades dominate, they’ll employ an ABL (Automatic Brightness Limiter) which will dim the screen universally. It won’t just cap the maximum brightness and everything else will look the same because of some neat re-mapping by the monitor, it will dim the whole image much as you alluded to in your initial post. This graph illustrates this well, comparing the AW3423DW with QD-OLED panel to the 34M2C7600MV with 1152-zone Mini LED backlight and VA LCD panel. It’s worth reading the HDR section of the review for further points of comparison between how this difference manifests in ‘real world content’. It also draws some comparisons with the PG32UQX, which is extremely impressive in its ability to pump out high brightness even where bright shades strongly dominate – giving great ‘pop’ to daylight scenes in HDR games and videos, even in a bright room.

Another OLED limitation to be aware of affects WOLED models (LG Display panel technology) which use an unfiltered white subpixel for their brightness. This completely dominates when high brightness is outputted under HDR and has a significant dilutive effect on the filtered light shining through the red, green and blue subpixels. It means the colour volume is greatly reduced and the monitor is not able to output bright and strongly saturated shades – only bright or strongly saturated shades. The ASUS PG27AQDM is one such example. QD-OLED (Samsung Display panel technology) doesn’t share this limitation as it outputs blue light from an OLED light source, with red and green light emitted from red and green Quantum Dots that are ‘excited’ by this OLED light source. This also boosts the colour gamut somewhat compared to WOLED panels, but not as much as the Quantum Dot backlights commonly used on Mini LED models. With the Acer X32 FP, ASUS PG32UQX and ViewSonic XG321UG being good examples of what sort of gamut can be achieved with them. 🙂

This is why I’m personally looking forward to technologies which should combine the advantages of OLED and Mini LED. ‘NanoLED’ (QDEL) is a technology which will use Quantum Dots for all subpixels in a self-emissive fashion. The luminance efficiency this provides and lack of organic material means we can expect reduced burn-in risk, higher brightness and colour gamut improvement compared to current OLED technologies. The use of Micro LED arrays to vastly improve upon the Mini LED zone count is also a technology we might be able to look forward to at some point. Though expense and power requirements are currently prohibitive, amongst other things. I’m sure we will see good improvement on both the OLED side and Mini LED side in the nearer term, too.

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