UPDATE: For the authoritative take on Microsoft's new flagship console, Digital Foundry's full Xbox Series X review is now live.
One of the greatest strengths of Xbox Series S and X is its backwards compatibility. Revisiting old classics, from the original 2001 Xbox, 360 and the Xbox One - Microsoft has maintained a through line across its console legacy. Not only are legacy titles playable, they're enhanced too with higher resolutions, smoother frame-rates, clearer texture filtering and faster load times. Auto HDR is the latest enhancement, drawing on a machine learning algorithm to add HDR to the majority of its back-compat titles on all Xbox systems. The question is - how good is it? Can it really compare to a native HDR implementation?
When well implemented, high dynamic range can transform the look of a game. Genuine HDR is not a given for new releases, even today. For the likes of Hellblade, Final Fantasy 15 or Sekiro, the effect elevates the image and heightens the realism of their lighting. Supporting displays with a high enough peak brightness - ideally 600 nits or more - bring out details that would normally be hidden in standard dynamic range. The sun's outline in Sekiro becomes more defined against a cloudy sky; Hellblade's overcast greys come out clearly with subtler gradients. Meanwhile dark detail pops out in caves or long grass. Fire takes on a more believable peak brightness in Resident Evil 3, while for racing games like Dirt 5, headlamps hit a realistic peak brightness on night-time tracks. Put simply: HDR lets us see a wider contrast of tones in bright and dark detail - plus a wider spectrum of colour in-between.
But what of the games that don't have HDR support? That's where Auto HDR steps in and while results vary, it hits more than it misses. Batman: Arkham Knight is an interesting example in that Auto HDR is pretty much the best enhancement back-compat adds to the game. It still renders at the same 1440x1080 resolution as the original Xbox One release and performance improvements can only see it run at a capped 30fps. You get more consistent frame-rates than the original Xbox One release, but One X effectively sorted its overall performance profile. For Series X enhancements, Auto HDR is the biggest boost you'll get beyond that.
Rocksteady's interpretation of Gotham City is just perfect for the new feature. On street lights, car headlamps, and the streaks of rain - all these points contrast against a city that's constantly in darkness. To explain, Auto HDR attempts to interpret the original standard range image. It's an algorithm calibrated by Microsoft on a per-game basis, to boost elements on-screen towards a peak brightness value we'd expect of HDR. We're told the feature will be disabled on certain titles, based on whether or not it's a clear improvement. So for example, Grand Theft Auto 4 had issues with unnatural, blown-out clothes and ultra-white road markings when we checked it during the first phase of the Series X preview - and its subsequent removal might have been a response to our feedback. It's worth stressing that all of this is pre-release, and Microsoft is still refining the Series X features constantly. The quality, and range of support may change by the time you receive your console.
There's no question, the quality of Arkham Knight's image is boosted with Auto HDR enabled. I ended up playing for hours like this - and while yes, it's still peaking at 1080p and 30fps on Series X - as was the limit on base Xbox One, the colours have far more pop. Rocksteady's work here is a unique case though. Clearly the game's colour palette helps; having a city set in perpetual night means HDR highlights are easy to define - on sparks from the batmobile, explosions, or shop signs. The aesthetic is consistent across the length of the game, making it easier for an algorithm to work in post.
Another similar example is MGS5 Ground Zeroes. At least for the main mission, the night setting keeps the lighting simple to interpret and tweak. On muzzle flashes, explosive barrels and searchlights, these elements get a satisfying push to take advantage of a display's peak brightness in HDR. It doesn't work so well across the board, of course. In fact, MGS5 Ground Zeroes flags one major issue with Auto HDR's approach in general; the treatment of logos. Any static splash-screen with pure white elements, text, or subtitles in-game hit a searing brightness level. With Auto HDR enabled, sadly, these parts can end up looking unnatural.
Another brilliant example is in Panzer Dragoon Orta. As an original Xbox game, and one of its finest visual showcases, it still preceded the use of HDR by many years - and so it's fascinating to see how it combines with the effect. In action, the first night-time mission genuinely shines. Again, the setting is at night for this mission, bringing out lightning strikes, rain, fire, and all projectiles. It looks great, especially with the resolution boosts that comes with X support. The only downside in this case is that splashes appear overly bright on water bodies - unnaturally paper white. And again, intro logos present at extreme brightness. But that's it, and the rest of play unfolds beautifully. Likewise, games like Mirror's Edge Catalyst benefit: its clear, saturated whites offset against red markers.
I'd also recommend checking out Geometry Wars 2. This is a classic Xbox 360 game with a visual style that's easy-to-work with: a pure black background setting the stage for crisp, neon twin-stick shooting. Every colour gets punctuated by Auto HDR. It's a game that benefits from the hyper-real, exaggerated lighting, and it wouldn't be a stretch to imagine this as the intended result from Bizarre Creations, if it was possible at the time. The conclusion? Whether it's an arcade-style game, or something more realistic, Auto HDR works best where the visual tone of a game is kept simple, consistent. Geometry Wars 2 is easily one for the best showcases for the mode.
I've tried a range of other games with mixed results: Perfect Dark Zero and Apex Legends deliver on the bright highlights we'd expect of HDR. In fact, Rare's Xbox 360 launch title plays to its strengths with a wide contrast, and while the visuals are of its time, it's simple enough to work. There are other, less exciting examples. I tried Fallout 4, and even the original 360 Crackdown. In each of these cases they're not as impactful as I'd hoped. Crackdown has huge potential, but the result with Auto HDR enabled isn't as vibrant as the true calibrated HDR of its sequel Crackdown 3.
All of which leads us to what doesn't work. At least for now, Dark Souls 2: Scholar of the First Sin has a few issues with overexposure. The skies of Majula, and especially around Heide's Tower looks so saturated with light that the game can be unpleasant to look at. It's nicely attuned to interlinking caves, darker dungeons and forests at least but in the open areas, Auto HDR creates a blindingly bright effect. Dark Souls 2 also makes clear the limits of interpreting an SDR picture: it doesn't truly add extra detail in bright areas, or darkened spots on the screen. Where an actual HDR picture has the colour depth to mark out the sun in the sky clearly, games like Dark Souls 2 still show less defined gradients. This is an outlier though. Gears of War Ultimate Edition works well, as does Sunset Overdrive with its colour-saturated effects.
Regardless of the quality of Auto HDR in gameplay, there are a few nitpicks that need addressing. One small, final one I've seen in a few games: overlays are at times brighter than the gameplay itself - hitting a similar peak white point as logos and text. Super Meat Boy is an example of this issue. As a side note, LG 4K TVs have a similar problem with HUD elements when using a similar mode - called 'HDR effect'. It's comparable to Auto HDR in that it interprets the colour space to make whites hit your screen's peak brightness - and overlays like health bars just don't look quite right. Auto HDR is more refined for games at least, being lag free - but there can be similar issues.
All round, there are more hits than misses here and it's great to see Microsoft attempt to embellish older games way beyond their original spec. Back compat enhancements can be quite limited on some titles, while non-existent on others - Geometry Wars 2 shipped on Xbox 360 in what you might call a perfect state. It runs at 1080p, it locks to 60fps - so where can Microsoft take that experience beyond its original presentation? Its upcoming 2x frame-rate and increased resolution boosts at the system level are enticing features for the future, but right now, Auto HDR is a great win.
Again, all of this is being tweaked and optimised ahead of launch. From our experience so far though, the Auto HDR option is by no means a one size fits all solution - but when it works, it really works. To get the most from the setting, you'll have to manually decide when to enabled it via the Xbox system options. For the future, perhaps an override option would work best when looking at your game library, to make sure it only switches on select titles. Still - it's a fascinating option to have, filling a gap for games that deserved HDR support on release and adding it convincingly to titles that predate the concept. More than that it's another reason to rediscover the Xbox's best games, bolstered and enhanced on its latest hardware - and we're looking forward to seeing more of the compatibility team's work.