8K Video – Do We Really Need it?
So, 8K video is here.
I know, it’s been “here” for a while. But, it’s now available in a consumer device made by a tech giant. Yes, 8K video is available to the masses.
Meanwhile, the way we consume video itself means the masses (including me) actually watch video at less quality than we used to. Yes, because while TVs with bigger screens and more pixels are themselves more affordable and more available, we’re watching more streamed video on them. And streamed video has to be compressed to stream it (like streamed music).
How compressed the video needs to be depends a lot on the speed of your internet connection. So, while we may now all be able to shoot 8K video, the question is – how will we watch it?
What is 8K video?
8K resolution is approximately 8000 pixels wide, per frame or image. In addition, 8K UHD (7680 × 4320) is the highest resolution defined in the Rec. 2020 (UHDTV) standard. Putting it simply, 8K has more detail in the image than a lower resolution, like 4K or 2K.
Meanwhile, the display on my ageing MacBook Pro (2015) is 2880 x 1800. So it can’t even display 4K video (3840 × 2160 – aka 2160p) let alone 8K or higher. And even if I had a higher resolution monitor, does the source of the video stream 8K? And can my internet connection carry the data at fast enough speeds?
Thing is, the new Samsung S20 phones come with QHD+ resolution screens. That’s 2560 x 1440 pixels. So, while you can shoot 8K video on one of these devices, you can’t view it in 8K.
Let’s be clear, the S20 range have some of the highest quality smartphone screens known to humanity, with up to a 120hz refresh rate. By comparison, the iPhone 11 Pro Max screen contains a maximum of 2688 x 1242 pixels (limited to a 60hz refresh rate).
What does 8K video look like?
It’s hard to visualise numbers (at least for me), so check out the chart below. Presuming your TV is HD, now see how much bigger it would need to be (if the pixels remained the same size) to display 8K video.
I was browsing YouTube to see if I could find samples of video shot on the new Samsung Galaxy S20 range of phones. OK, so there’s now a bunch of videos uploaded claiming to be S20 8K footage, most likely trying to catch the wave of interest after the Samsung launch. And probably some them are fake.
Thing is, I haven’t yet found one which allows the 8K setting on YouTube (which has been available for years). The problem is going to be that 1000s of people will rush to YouTube, expecting to be blown away by the quality. What they find will most likely be too much for their playback system to handle.
Samsung’s own 8K demo video is set at 1080p
Even Samsung’s own demo video of the 8K function is only available on YouTube at a max of 1080p. The video only really demonstrates how to set the camera to shoot 8K, rather than show it – because, realistically, how can they?
It’s also interesting to note that Samsung are focusing this 8K video feature as a way of shooting stills. The idea being, shoot a clip of 8K video then select a frame from that video, so you get the perfect shot. As opposed to shooting a bunch of still frames and hoping one of them is good.
So, it’s almost like Samsung know consumers have no real need for 8K video and so they’ve come up with a way of using it for stills. And the photo shooting specs of a smartphone are still far more of a consumer attraction than video.
But are consumers really going to scroll through hundreds or thousands of frames of 8K video hunting for the best frame? Isn’t it actually easier just to take say 5 snaps and then choose the best? Plus, most of us give up when there’s too much to choose from.
Qualcomm’s 8K video test is in 8K
A few days ago, Snapdragon processor manufacturer Qualcomm shared a video on YouTube shot using the new Snapdragon 865. This is the processor which will ship with many of the Samsung S20 range of smartphones.
I tried watching it with the YouTube setting at 8K and what I got was lagging, pixilation, and bursts of clear crisp video. Plus, the fan on my MacBook kicked, in as it does when the processor has a lot of work to do.
No HDR
The image signal processor (ISP) in the Snapdragon 365 is the Spectra 480. This is the technology that allows 200 MP photos and 8K video. However, it only supports HDR in 4K resolution and below.
As HDR is a great tool for adding extra dynamic range to smartphone-shot video, that leaves us with an interesting dilemma. Do you want the extra pixels that your system might not be able to handle (and almost nobody can watch)? Or would you like the extra dynamic range, helping keep parts of your image blowing out or disappearing into the shadows.
600 MB per Minute
Since the Samsung launch, the Verge came up with the clickable headline that 8K video uses up 600MB of memory per minute. Samsung also say five minutes of 8K footage would take up around 3GB of space. But with the new phone capable of 1.5TB (or 1,500GB) internal storage. That would allow for 2500 minutes of video (well, not quite, because there will be other demands on that memory).
Of course, how much memory is used also depends on other factors such as bitrate.
To make a comparison, I recorded 1 minute of 4K video on my Samsung S9, at the highest bitrate (using FiLMiC Pro) and 25fps, using the AVC (h.264) compression setting. The file comes out at 866MB, which would be 4.3GB per 5 minutes. So that’s actually significantly more than Samsung’s quote for 8K.
But the h.265 compression codec reduces video file sizes further. So I recorded another 1 minute clip, this time using the HEVC (h.265) codec. The file size came out at 563MB. Which is still only slightly smaller than the Samsung quote of 600MB per minute.
Are Samsung restricting bitrates on 8K so that the smartphone can cope with it? Why else might it create smaller files than 4K? Thing is, if they did crush the bitrate for compression purposes, 99.9% of users would never notice as they can’t view 8K anyway.
As mentioned above, 8K video on the S20 phone screen itself won’t look any different to 4K. The only real way to see what it looks like is to view it on an 8K TV or monitor. And a quick search revealed to me that a Samsung 8K TV costs over $2000.
Maximum 5 Minutes
The new Samsung devices will create 8K video clips at a maximum of 5 minutes. Not only that, but it will be limited to 24fps. No 60fps, or even 30fps. There will also be no stabilisation available at 8K, says Samsung (more reason to keep your gimbal).
Two possible uses for it
For more serious video shooters, there are reasons for capturing higher resolution video. Here’s 2 of them:
- reframing: clips higher resolution the final master allows you to crop and reframe the clips, individual. For example, to move closer to the subject. Or perhaps you didn’t like the original framing.
- CGI: higher image detail can really help out with any motion tracking you are doing.
Beyond the marketing
So, 8K video might not be much practical use for most of us at this point. However, what goes mostly unsaid is the implication of processors with 8K video capability. The Snapdragon 365 is more powerful therefore it will be able to handle 2K and 4K video much better.
Quite often when shooting 4K video, especially at maximum bitrates and frame rates, our smartphones start to overheat. This sometimes causes third party apps to crash. Files get lost, corrupted or come out at the wrong frame rate.
Meanwhile, having a more powerful image processor means we can shoot at higher resolutions more reliably. Of course, this doesn’t sell smartphones to the masses. Or rather, it doesn’t create the instant online buzz that a new high benchmark achievement does.
So, once the interest in seeing the glory of 8K video reaches it’s eventual ‘dip to black’, the rest of us can quietly get on with shooting 4K video more reliably.
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