Did you know: 4K vs 1080p, chroma sub-sampling and why you should record in 4K even if your TV does not support it yet

Different chroma sub-sampling

Different chroma sub-sampling


4K video is the new buzz word in the world of media and entertainment: you can already see a lot of fairly affordable 4K TVs, and most importantly, content is slowly, but surely starting to arrive. However, if we had to look at the current state of things, the large majority of people still use 1080p or even lower-resolution TV and notebook screens.

So even now that most top-shelf Android smartphones are capable of recording 4K video, should you really waste your precious phone storage for those larger files, if you cannot see the difference on your 1080p monitor?

We’re here to tell you about one important reason to choose to shoot in 4K, and decide whether to keep the original recording, or downscale to 1080p and still see some tangible benefits.

At first, you might think that a 4K video downscaled to 1080p should look just like native 1080p. However, this is not exactly so. The reason for this is chroma sub-sampling, a common practice in most smartphones and cameras alike to encode video files using less resolution for chroma (aka color, as opposed to luma aka light).

The default chroma subsampling on cameras (and YouTube for that matter) is referred to as 4:2:0. Before looking into this, let’s just freshen your mind that rather than speaking about RGB in pixels for video, we’re more commonly dealing with Y’CbCr. Y stands for luma, the value that says how bright a pixel is, while Cb and Cr refer to the actual color. However, in order to save precious megabytes (or sometimes gigabytes), it has been figured out that as long as you have the luma value for each pixel, you can then share the color value between every four. Thus, you lose 75% of the color information, hence some degradation, but still achieving acceptable quality of recordings. This type of encoding is what is called 4:2:0 chroma sub-sampling, and this is what smartphones and most cameras record into.

In still image we speak about RGB, while for video, we refer to Y'CbCr

In still image we speak about RGB, while for video, we refer to Y'CbCr


While 4K recordings do adhere to the same 4:2:0 rule, once you downsample them (coincidentally, 4 times), every one of those remaining pixels will carry its full color information. This results in downscaled 4K to 1080p video actually looking better since it’s 4:4:4 (retaining full color information) rather than 4:2:0 (retaining only 25% of the color info).

So if you’re still wondering whether there is benefit to recording in 4K now, in times when our monitors and TV have not made the switch just yet, the answer is a resounding yes, at least for those looking for maximum quality.

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39 Comments

1. XperiaFanZone

Posts: 2277; Member since: Sep 21, 2012

Certain fans are against the 4k feature because their phones don't have such feature. Anyways, would a 1080p video look better on a 720/768p screen, than the 720p video?

10. Neo_Huang

Posts: 1067; Member since: Dec 06, 2013

Probably not, since 1080 is not a multiple of 720.

18. vincelongman

Posts: 5623; Member since: Feb 10, 2013

Na 1080p still would probably look better as its most likely a higher bitrate Especially video from online, such as YouTube where 1440p looks better than 1080p on my 1080p monitor

30. cezarepc

Posts: 718; Member since: Nov 23, 2012

I was about to bash you but checked for myself... and I agree. Tried watching a 4K (and also 1440p) youtube video on my 1080p monitor just now and the difference is definitely noticeable.

26. kent-gaga

Posts: 609; Member since: Apr 10, 2012

not really sure but i think it's a yes

29. jaytai0106

Posts: 1888; Member since: Mar 30, 2011

I'm pretty sure it still looks better when you play a 1080p content on a 720p monitor/tv. I have 720p monitor at work and when I watch youtube video, I could tell the diferent between 720p and 1080p quality.

32. kevin91202

Posts: 640; Member since: Jun 08, 2014

who has a 720p screen? iFans? wait. they have a whopping 750p.

2. ArtSim98

Posts: 3535; Member since: Dec 21, 2012

What is this? Am I dreaming? Am I in heaven? No. This is real. An actually interesting and factual article by PA! :D

17. techperson211

Posts: 1280; Member since: Feb 27, 2014

About to say the same thing. This is really one of those article that gave PA a thumbs up.

3. fzacek

Posts: 2486; Member since: Jan 26, 2014

There should be an option in the phone camera to change the chroma sub-sampling ratio...

4. _Bone_

Posts: 2155; Member since: Oct 29, 2012

Recording in 60fps is far more beneficial. While 4K or downsampled 1080p indeed offers more crisp quality, without motion blur or any filmic effect to smoothen movement out, 30 sharp images of movement per second makes stuttery videos. It's just not enough. Add that most computers and many TVs and players can play back at 1080p/60 RIGHT NOW compared to laggy 4K support and only 1080p displays around, I see no benefit of sharper stuttery video over a smoother one. I'm completely right here. Watch a dynamic 4K video in 30fps on a 4K screen and an 1080p one at smooth 60, and 90 ppl. out of a 100 will say the latter had more quality.

5. ArtSim98

Posts: 3535; Member since: Dec 21, 2012

Naah, you're not right there ;)

6. vuyonc

Posts: 1088; Member since: Feb 24, 2014

+1000. Smoothness > sharpness.

11. Neo_Huang

Posts: 1067; Member since: Dec 06, 2013

So you can notice the difference between 30 FPS and 60 FPS?

21. _Bone_

Posts: 2155; Member since: Oct 29, 2012

Of course, humans can see between 50 and 200 in extreme cases but follow me on this: imagine a panning shot left to right changing the whole field of view in 2 seconds.Displayed on a 4K playback it means each pixel of your content (say a baby's face) will move 64 pixels every frame (3840 pixels / 60 frames), so no matter that you have millions of pixels of a baby, your hand naturally moves and every still frame will be dozens of pixels apart from the previous. This looks crap. All the 4K videos 30frame with handheld movement suffers from this and 60 fps looks so much smoother cause the pixels of your subject changes less per frame. I can't explain it more. Just search YouTube for phone recording at 4k30f and 1080p60f, the latter will look so much better.

27. ArtSim98

Posts: 3535; Member since: Dec 21, 2012

Lol you kidding? Heck you can see difference between 60 and 100

31. vincelongman

Posts: 5623; Member since: Feb 10, 2013

Seems like Ubisoft has brainwashed youhttp://30vs60.com/http://www.30vs60fps.com/https://frames-per-second.appspot.com/ Even the difference between 60 and 120 fps is noticeable Though you need a 120+ Hz monitor and something capable of producing 120 fps That's why the James Cameron's next Avartar film is going to be filmed in 120 fps Hopefully the film companies don't pay the reviewers to write BS this time like the hobbit Film companies dont want higher fps because it costs them more, e.g. they need better equipment and they need to make more frames for CGI IMO we need both 4K and 60 fps (or even higher, e.g. 120 or 240 fps)

15. pepeo

Posts: 11; Member since: Mar 27, 2014

yeah but if you take in consideration that no phone on the planet has smooth constant 60fps recording rate, this is useless. galaxy k zoom and xperia z3 for example has terrible 60fps recording, reaching a minimum of 20fps in some recordings. if you use a software to monitor the video fps you will see the totally unconsistent framerate over time. i didnt test the i6 yet, but i hope it can bring consistent recording. also, 4k and 1080p60 are arcaic in phones yet since they doesnt support h.265, so the bitrates are huge, resulting in enormous file sizes. i hope manufacturers make use of qualcomm s810 with h.265 encoding capabilities.

23. _Bone_

Posts: 2155; Member since: Oct 29, 2012

Of course many phones record smooth constant 60fps video, they actually use less than half of 4K bitrate (which is 4 times the data of an 1080p video). 60fps doesn't overheat and there is no 5 minute limit which is bad if you actually want to record anything worthy, family or friend event, concert etc. Right now, until 4K60f arrives without overheating or limits, 4K is a gimmick you cannot even enjoy while you can actually use and play back 60fps video TODAY with it's full glory and 60fps will look better than 4K30f tomottow.

33. kevin91202

Posts: 640; Member since: Jun 08, 2014

Well, at least not with a smartphone camera. 2160p 30fps looks better than 1080p 60fps.

7. AlikMalix unregistered

I will give 4k praise when it's smooth enough not to notice the jitter when comparing to 60fps.

16. shuaibhere

Posts: 1986; Member since: Jul 07, 2012

That is when apple adds it right???

8. Micah007

Posts: 266; Member since: Oct 09, 2014

Glad smartphones are adapting 4K. The bigger screens help maximize the experience.

9. dorfoz

Posts: 156; Member since: Oct 18, 2011

There's nothing wrong with paving the way for future phones to have this. (lol like iPhones, which are ALWAYS late on new tech)

12. 0xFFFF

Posts: 3806; Member since: Apr 16, 2014

Exactly. You can't make as much profit if you use new chips in your products.

14. clevername

Posts: 1436; Member since: Jul 11, 2008

What do you mean? Apple only releases new, innovative, and magical features. I know you THINK you've seen 4k, but when apple releases i4K on the iPhone 9sPro+ it'll be the REAL 4k.

13. darkoman4

Posts: 181; Member since: May 30, 2014

The main reason is the future. I wish some of my old videos taken in the 80s were of better quality. Same will happen 30 years from now. I'll be happy I recorded them in 4K even though I don't have 4K TV to watch them now.

19. lalalaman

Posts: 638; Member since: Aug 19, 2013

Reason s why I won't shoot in 4k: 1.4k takes way too much memory to shoot 2.U can't shoot 4k for more than 5min on a smartphone >>>^http://www.phonearena.com/news/Sony-Xperia-Z2-wont-let-you-record-more-than-5-minutes-of-4K-video-and-neither-will-Note-3-and-S5_id56633 3.Battery drain 4.Coz I don't have a 4k recording phone:(

24. slh163

Posts: 140; Member since: May 19, 2014

i would say your main reason is number 4. the rest is just excuses that mostly the ifans bring it. while there are dying to have this feature on there phones.

20. Bogdan86

Posts: 48; Member since: Oct 06, 2014

i have a S5, and my opinion is that 1080P 60 fps is the best looking of them all, yes 4K is really sharp, but only if i put the phone down and don't move it. for movement, 1080p60 is incredible. if only there were 4K and 60 fps or even 1440p with 50 fps like the new goPro.

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