Samsung Galaxy S24 Ultra’s HDR playback ruined my movie

The Samsung Galaxy S24 series arguably has the best hardware specs in the industry, from fast processors to strong build quality. The gorgeous AMOLED display, in particular, has been a highlight of the series’ long run, but after watching several hours of HDR movies on my new Galaxy S24 Ultra, I was a bit disappointed.

At first, I thought it had something to do with my movie files, so I went to YouTube and found some HDR videos to test those out. When watching SDR content, everything looked just as I expected. However, despite Samsung claiming a peak brightness of 2,600 nits, when using HDR the image appears dim and the highlights aren’t even that bright. Overall, the speech was uneventful.

So I tested it with my Google Pixel 8 Pro and Apple iPhone 15 Pro, and found that the S24 Ultra’s peak brightness was consistently lower than both devices. In fact, much lower. When the peak white display covers 50% of the screen, the brightness is nearly 40% lower than that of the iPhone. Just to give you an idea, even compared to the older iPhone 11 Pro Max (which claims a peak brightness of just 1,200 nits), the Galaxy S24 still looks dimmer and has lower contrast when displaying real-world content.

I reran the test more than four times (I lost count at the time); I went into settings to enable high-brightness mode, made sure to test the phone with and without adaptive brightness enabled, and checked out vivid mode and natural mode . I even ran HDR10 and HDR10+ video just to make sure it didn’t have anything to do with HDR10+’s dynamic metadata, but it didn’t seem to make a difference.

It wasn’t until I started looking into ambient light levels that the problem became clear. HDR content on the S24 series always has some form of adaptive brightness enabled. In the video above, you can see that when I increased the room brightness, the monitor’s brightness went up in clear steps, even with adaptive brightness turned off, and shouldn’t interfere with the brightness in such a drastic way when displaying HDR content.

This can lead to some annoying effects. If you’re viewing HDR content indoors using only indirect light, Samsung’s software will reduce the display’s brightness regardless of your settings. Not only does this result in an image that lacks the sparkling highlights that OLED excels at, but it also makes the darker parts of the image darker than they should be.

This is a mistake. The whole point of HDR is to control contrast as much as possible, so the screen shouldn’t interfere with the creator’s intended contrast for a particular scene.

The exception is increasing brightness for accessibility reasons. I guess if you’re watching a movie or TV show outside in bright, direct light, it’s better to see an enhanced image than no image at all. Still, I only see this as an accessibility feature that should be turned on and off, rather than a default feature used in all viewing scenarios.

Perhaps worse, you can also see a slight change in screen color, turning a subtle blue into a more vivid and intense hue. It looks like Samsung is trying to trick my eyeballs into liking it more, but that compromises accuracy and respect for the original picture.

We reached out to Samsung to ask it to explain this behavior and whether it was intentional. Here’s what Samsung had to say:

“Adaptive brightness drives display adjustments based on ambient light levels. Samsung Galaxy devices process HDR video to adaptively adjust the display’s brightness based not only on the current display brightness but also on the viewing conditions. This is to provide users with enhanced visibility and A more immersive viewing experience that best showcases the high dynamic range of HDR video resources.”

So this is intentional, Samsung’s software compensates for ambient viewing conditions to try and improve the look of HDR video. I’m not convinced it works very well.

Every Samsung device we’ve tried, including the regular Galaxy S24, S24 Ultra, and S23 Ultra, performed very similarly. Without a switch to turn this feature on and off, adaptive brightness appears to be how Samsung handles HDR video on all of its flagship phones.

On the plus side, environmental adaptability helps improve visibility, especially outdoors where sunlight can make the display difficult to see. The fact that Samsung’s display isn’t as super-bright as those phones that claim the ridiculous number of 4,000 nits of peak brightness isn’t necessarily a problem in itself. It is important to maintain a consistent contrast ratio combined with high brightness. However, this requires adaptability to be handled in the right way.

Unfortunately, Samsung’s technology produces visual artifacts. For one, you can often see the brightness increase as the ambient light changes. This can be distracting halfway through the movie, especially when you’re riding public transportation and entering tunnels that temporarily change the ambient light. Annoyingly, the transition isn’t nearly as smooth as the default auto-brightness, which scales in a more pleasant way. It was so sudden.

In addition to this, shadow fragmentation, color casts, and a relatively dim rendering caused by indoor lighting can also reduce the quality (and purpose) of HDR video. Eventually, a switch that turns HDR adaptive brightness on and off will suit both worlds. HDR’s “Filmmaker Mode” doesn’t need to add much, given the plethora of existing display options. Samsung, is this all?