Wednesday, January 9, 2013

UPDATED! 4K Resolution: Will it Ever Matter for Online Video?

CES 2013 is going on this week, and we have a few representatives from Vertigo in attendance.  While we're used to seeing 3D technology hyped and over-hyped at CES, the word on everyone's lips this year seems to be "4K".  

4K televisions are being displayed by multiple manufacturers, and are being touted as the last HD resolution you'll ever need in your home.  The $17,000 LG 84LM9600 will be the largest LCD on the market, and the first with 4K resolution:

4K is the next frontier in High Definition video resolution: it refers to 4096x2304 pixels, four times the definition of 1080p.  Another similar consumer-targeted resolution of 3840x2160 is being marketed as "Ultra HD" - the technical standard being named "Quad HD".  

How big does 4K "feel"?  Take a look at this image, keeping in mind that MOST content that you watch on your HDTV via cable or satellite is 720p, and Blu-Ray discs are 1080p:

That's a pretty impressive increase in pixels.  Both 4K and 2K come to us from the world of cinema.  George Lucas pioneered shooting digitally to avoid the cost of film stock, and originally shot "Attack of the Clones" in full 1080p HD.  Digital Cinema Initiatives was formed in 2002 to determine global standards for digital cinema, and devised two standards: 2K (slightly larger than 1080p HD) and 4K.

So, what does all of this mean for online video?  In short, we won't be seeing it for a long time, for 2 key reasons:

1) You don't need it:
Geoffrey Morrison's CNET article entitled "Why 4K TVs are stupid" goes into a good level of mathematical detail about why 1080p is really more resolution than the human eye can see anyway unless you're closer than 6 feet to your TV.  The human eye with 20/20 vision can resolve 1 arcminute, or 1/60th of a degree.  Doing some trigonometry based on your distance from your TV and its screen size can tell you whether a resolution greater than 1920x1080 even matters.

Other sources indicate a small sliver of distance/size where Ultra HD/4K may make a difference for you.

Of course, we're talking about online video, and TVs aren't the only display in town.  What about Macs, PCs, tablets, and mobile devices?  Panasonic has demonstrated an Ultra HD tablet intended for architects and other workers who may need super high resolution in a tablet form factor:

This could eventually lead to 4K screen technology in the home, but the bottom line is still that the price will have to reduce dramatically before the dubious value proposition to most consumers is anywhere near worth it.

2) You can't stream it:
Those of us with high-speed internet at home typically see speeds around 10Mbps.  This can fluctuate, and while streaming 720p content is usually a pretty consistent experience these days, streaming 1080p content is often a buffer-fest. 

1080p content (1920x1080 pixels) has 2.25 more pixels per frame than 720p content (1280x720), and consequently takes about 2.25 times greater bandwidth to download.

4K content (4096x2304 pixels) has 10.24 more pixels per frame than 720p content.  Roughly, this means you'd need a connection providing around 45Mbps in order to stream 4K content. 

In a world where home internet providers are moving towards monthly usage caps, the massive size of the video being downloaded is perhaps more of a challenge than even the daunting speed requirements.

One factor that could help here is the upcoming H.265 High Efficiency Video Coding standard. With claims of double the efficiency of H.264, 4K content comes a bit closer to the reach of users at home.

Do you think 4K will be relevant to our work in online video in the next few years?

My expert video compressionist friend Alex Zambelli did a lengthy analysis describing why H.265 will actually get us very close to being able to stream 4K some time soon.  Check out his post here.  The key exerpt (below) is that you cannot take current bandwidth requirements for 720p/1080p and do simple multiplication based on the number of pixels - the relationship is non-linear:

I believe that the relationship between bit rate and picture size is not linear, but closer to a power function...
In other words, I believe that as the pixel count gets higher a DCT-based video codec requires fewer bits to maintain the same level of visual quality.

Thanks for the detailed analysis, Alex!


  1. Updated to mention the H.265 HEVC standard...

  2. Here's my response, Bob:

    A bit lengthy, but it wouldn't fit into a comment. :)

    1. Thanks for the analysis, Alex! You're right that I did make the mistake of assuming a linear relationship. I've updated this post to include a link to your article.

  3. Honestly I don't know if 4K will be needed for online. Higher quality 1080p would be great. At this point it would be nice if resolution just froze for a couple decades like TV used to be when it was SD for decades. As a content creator the last thing I want to be doing is constantly chasing the next resolution standard, in fear that my production will be outdated in 5 years because it's not shot in 4K then 8K, etc.

    I shot my first feature film back in 2003 on a DV camera. It was what we could afford. Today on modern HDTVs and computer screens it doesn't look so hot. There will never be an HD version. But being shot in standard definition has less to do with the frame size and more to do with the camera and format it was shot on. Even today most people are perfectly happy with DVDs of Hollywood movies that originated on film or HD. The quality is tight and scales up to HD decently.

    But I do feel like we are getting to a maximum point where frame size resolution won't matter anymore. In fact I would say that we're already there with 2k/1080p. Aside for some die hards who sit at the front of the movie theater and like to point out pixels, the fact that you can take a 1080p image and show it on a regular movie theater screen as a standard way of displaying movies to paying customers or take that same resolution and put in on a home TV or a smart phone, is pretty remarkable. So I don't see the absolute desire to display 4K. I do see the desire to shoot with it though.

    I don't think most people will rush out to buy a 4K TV. It will be something they end up with when they buy a new TV, just because at a certain point all TVs will be 4k. It will just be cheaper to make them all 4K. But I don't think most people will care or see the difference.

  4. I think the next revolution will actually be 3D again. I form of 3D that doesn't require glass and allows to to see around objects on screen toa certain degree. Maybe five or ten degrees left and right and to a lesser degree up and down. Only because think people move their head sup and down less than they do left to right.

    It's much more natural and the way that we see objects in the real world.

    Apple is already experimenting with this on iOS7. When you tilt the device a certain way the background moves around independent of the icons. So you can see more of the background. While we won't tilt TV and movie screens around, we will tilt our heads. So we will see what our brains expect us to see when we shift our perspective, a different perspective.

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