Lastly, video. Both phones can record 4K video at 30fps - that's been the flagship standard for several generations. Starting with the S9+, Galaxies can also capture 4K at 60fps - the P20 Pro can't. Another limitation on the Huawei phone comes in the form of stabilization - or, rather, lack thereof in 4K. The Galaxy, on the other hand, will happily stabilize 4K/30fps footage.
The S9+ will also happily record multiple super slow-mo video bursts of sorts - you can have several 0.2s-long 720p/960fps segments within the same clip. The phone can also start slow-mo recording automatically once there's action in a pre-defined portion of the frame. The Huawei implementation is a lot clunkier with just a single super slow-mo recording in a fixed length clip that you need to time perfectly on your own.
Both phones will record in your choice of h.264 of h.265 codecs, depending on whether you prioritize compatibility or small file size. For that matter, the P20 Pro should be on top of your list if you want to save space - even when using the less efficient h.264 codec, it keeps bit rates surprisingly low.
For our tripod-mounted balcony videos the P20 Pro allocates 28.3Mbps of 2160p video (48.1Mbps on the Galaxy) and a tiny 5.6Mbps in 1080p/30fps (14Mbps on the Galaxy). This changes slightly when shooting handheld 4K clips (a bump to 33.8Mbps on the P20 Pro, no change on the Galaxy), and more dramatically in 1080p/30fps (13Mbps on the P20 Pro, no change on the Galaxy). We've always assumed that a variable bit rate should vary based on the intricacy of the content, and not on the mode of support, but hey - Huawei begs to differ.
Anyway, 4K videos come out good looking from both phones though they do differ somewhat. For example, Huawei's footage is more saturated, with the greens that dominate our test scene really popping out, and a cyan sky that really wasn't. Detail is comparable, though the Galaxy's more aggressive sharpening makes its videos appear crisper.
Both phones' videos are contrasty and well exposed. However, one issue we noted during the P20 Pro's review, which also manifested itself during this comparison is the Huawei's odd (and more than a little annoying) exposure pulsation - or rather, is it an issue of encoding?
That pulsation goes out of the way when you're examining stills, but examine them nonetheless.
The P20 Pro also has no answer to the Galaxy's 2160p/60fps mode. The higher frame rate comes at little to no cost in detail and if you can stomach the extra-large file size (some 72Mbps bit rate), there's no reason not to shoot in 60fps.
Moving on to plain old 1080p, the level of detail remains similar, though we're seeing a tiny bit extra in the Huawei's screen grabs, which borders on amazing, given the difference in bit rate. The P20 Pro's colors are still a bit over the top, and that's saying something considering we're comparing with a Samsung, and Samsungs like their colors punchy. Unfortunately, the pulsation is present in 30fps as well, though not in 60fps - go figure. It's worth pointing out that the 60fps videos from the P20 Pro actually come out at around 51fps, and 30fps ones are never really 30fps, but 29-ish fps.
On to the screengrabs for some pixel peeping, we know you like that.
Stabilization is very competent on both phones in 1080p - if anything, the P20 Pro manages to marginally better smooth out the shake from walking. The Huawei phone can't do much in 2160p though, where no electronic stabilization is available. The Galaxy S9+, meanwhile remains steady and unimpressed with this guy's marching walk and shaky hands.
In case you'd like to see how detail compares in these stabilized videos (well, not the Pro's 4K one, anyway) feel free to check out the screengrabs.
And since zooming in is a recurrent theme in this comparison, we figured we'd shoot some videos at the 2x and 3x settings on the two phones. Mind you, that means a native 2x and a digitally zoomed 3x on the Galaxy, and a digitally zoomed in 2x and sort of native 3x on the Huawei - we're still not 100% certain how the P20 Pro operates in all magnifications.
As the screengrabs below will show you, surprisingly or not, the Galaxy S9+ is the definitive winner in terms of captured detail in both zoom settings. And not just at 2x where it should have the upper hand in theory (as indeed it does in practice), but also in 3x, where we expected the P20 Pro to have an edge. Not only it doesn't, it's not even competitive.