Did YouTube do away with 4K?

Searching for 4k (4096 horizontally by 2306 or some other number vertically) videos on Youtube today, I realized there aren't any. Including those that certainly were 4K last time I watched them - probably 6 months to a year ago.

If you are interested in videos with resolutions higher than 1080p, you may remember that YouTube announced support for full 4K resolutions in their official blog post of July 2010, "What's bigger than 1080p? 4K video comes to YouTube". No subsequent blog posts seem to announce any changes to supported resolutions. In my blog post shortly after YouTube's announcement of 4K support, I pondered about the reasons YouTube decided to support 4K given the extreme rarity of computer systems and devices that were capable of displaying it. My guess was YouTube was future-proofing itself and playing with possibilities.

Here is the playlist I assembled of 4K 2K clips. In quite a few of them, you see the posted resolution of 4096xN where "N" is the vertical resolution number usually between 2160 and 3072. All of these videos now only play at 2048x1536. You can verify that by right-clicking on the video and selecting "Show video info".

Do you know why and when YouTube decided to stop supporting full 4K videos?

(A 2K video sample. To watch it in full 2K glory, click "Play" first; then select "original" in video settings - the wrench symbol in the bottom right of the player box. Make it full screen. Pause and wait till it buffers if you don't have a particularly fast Internet connection. It helps if your monitor is large with a native resolution higher than 1080p.  How's the viewing experience?)

P.S. 4K is not the same as 4096P, and 2K - is not 2048p.  In "4K", "2K" and similar designations, the number such as 4096 stands for horizontal resolution, i.e. 4096 pixels horizontally by 1536 vertically.  Designations such as 1080p (along with 720p, 480p, 1080i, etc.) refer to vertical resolutions (e.g. 1920 horizontally by 1080 vertically).  In the old analog TV days, signal resolution was also measured horizontally, i.e. in the number of vertical lines, like today's 4K.

YouTube Goes 4K: Why?

YouTube started hosting 4K clips, and I am stumped: why offer something that very, very few people can use? Here are my tops reasons to not host 4K clips:

1. My monitor is too small. The official YouTube blog post says that "the ideal screen size for a 4K video is 25 feet". Yes, 25 feet. That's 6 times your average Joe's 50-inch TV and most apartment walls are 10 to 14 feet unless you feel like finding an empty wall at Ralph's... good luck.
   
   Wait, here is an idea. You go buy a 4K Red One camera ($25-50K with lenses and accessories), shoot an awesome 4K video, upload it to YouTube and... watch it on your iPhone? Oh wait, it's less than 4 inches and you need 25 feet of real estate to view it. Then go to your nearest Imax theater - they should let you fire up your 4K YouTube video after hours, right? Or, rent one of those 4K projectors and a 25' screen for something like $5K a day... There, enjoy your 4K movie. Don't forget the popcorn.
   
   Seriously, most high resolution monitors max out at 1080p and there are very, very few monitors or projection screens out there that can display 4K. None of them are accessible to regular mortals outside of 4K post production houses and Malibu celebrity row. People attempting to view 4K clips on their supposedly high end systems will be disappointed to not being able to see the 4K quality.
   
   Ouch.
   
   
2. My computer is too slow. The vast majority of computers will choke on 4K. My 3-year-old office machine (Intel Core 2 6600 2.4GHz CPU, 4GB RAM, GeForce 8800GTS graphics, Vista 64) sure does choke: choppy playback, severe compression artifacts. The monitor is the 30-inch HP LP3065 with 2560x1600 resolution. In 1080p mode, it's smooth and gorgeous. In 4K mode - horrible. Here is the 4K clip I tried - see if your results are better. I hope they are.
   
   Ouch 2.
   
   (Added 2010-07-10 10:57am) Current computers with high performance multi-core Intel and AMD CPUs will likely play back 4K videos in their "original" mode smoothly. HP Z800 with dual Xeon E5530 CPUs and NVidia Quadro CX card had no issues although the visual quality of the video in the original mode is still noticeably worse than in 1080p mode and even 720p mode: not as sharp, with visible gradients and pixelized lines. According to Pavel P who commented on this post, his 27" iMac with Core i7 CPU had no issues either. I can only guess that the "original" 4K mode is worse than 1080p because of Adobe Flash player processing: it may simply not know what to do with such high quality video.
   
   
3. YouTube says you need a "super-fast broadband" to video 4K videos although my crude calculations show that they stream at about 6Mbs, which means even a home-brew 3Mbs DSL is fast enough if you don't mind a little waiting. It took me about 4 minutes to fully download a 3-minute 4K video over a 6Mbs DSL. So to me, broadband speed isn't that big of an issue. The real issue is that most people can't enjoy the 4K quality.

Bottom line, virtually nobody can enjoy the full 4K quality. Why offer this 4K support then?

For YouTube, it's most likely a test of the potential market, a somewhat cruel tease akin to putting you in an F-22 Raptor and taxiing you around the airstrip but no flying. Lots of tease, no release, excuse my parallel. These 4K videos may be useful to few of us with access to the right display and computer equipment, and to ubergeeks to stress-test their uber-duper gaming or editing systems - but certainly not to the vast majority of YouTube users.
(F-22 Raptor image by Rob Shenk)

Another reason is future-proofing YouTube. Making the 4K option available today rather than sometime in the future, eliminates the inconvenience of re-uploading 4K clips in the future. After all, there aren't too many 4K cameras out there; 4K production (and post-production) is expensive, and the impact on YouTube's servers because of hosting 4K will be minuscule. Letting users upload 4K clips today is a smart move even if few people can enjoy them at full quality.

Have you tried YouTube's 4K videos? How do they look? Can your computer play back YouTube's 4K videos smoothly in their "original mode"? Is that "original" mode better quality than the 1080p mode? Let me know - post a comment, and tell me this:

• which 4K clip(s) you tried, and in what mode (original, 1080p, etc.)?
• the resolution of your monitor
• the CPU, RAM and GPU in your system
• What OS you are running (e.g. Windows Vista Business 64-bit), and Flash player version (right-click on the video, click on "About Adobe Flash Player")
• What was the effective frame rate of the video, and how many frames were dropped during playback? (Right-click on the video during playback and choose "Video Info")
• How is the quality of the video in "original" mode vs. 1080p and 720p?

Enjoy your tests!

Sample 4K video below. Click to open it on YouTube page and select "original" quality.

Optimizing HD uploads for YouTube

YouTube has become a very popular video sharing site, and recently, it started to let users upload HD videos. While these HD videos won't match Blu-ray or Dish HD quality, they still look fantastic compared to standard YouTube videos, which, to be honest, look crappy at best.

The questions often comes up, how to best save an HD video, to upload it to YouTube?

While YouTube's "Optimizing your video uploads" help article does recommend a resolution of 1280x720 for 16x9 HD videos, and lists recommended codecs (H.264, MPEG-2 or MPEG-4 preferred), it does not recommend a specific bitrate. What's a man to do, when a 5-minute video can be as big as 700MB in HDV format, and take many hours to upload?

Experimenting with various bitrates and types of encoding helped me narrow down the optimum settings for YouTube's HD videos.

YouTube re-compresses the videos anyway, so bigger files will not always produce better quality. I.e. uploading raw HDV videos (at 19-25Mbs) will be horrendously slow over a standard DSL connection, and the quality will not be visibly higher vs. videos encoded at 3Mbs H.264.

Certainly, a 25Mbs video will look better than a 3Mbs one, before it's uploaded to YouTube. Once it's uploaded, however, YouTube will "process" it, making it as small as possible while trying to maintain its quality, and once processed, a 25Mbs video is unlikely to look any better than a 3Mbs one.

I did a number of test encodes and uploads, starting at 500Kbs and ending at 7Mbs. After a 3Mbs "sweet spot", all tests looked very similar on YourTube, in HD mode. There were still barely noticeable differences between a 3Mbs and a 4Mbs test videos, but they were insignificant to my eye, and I did look really hard in full screen mode, on a 30" professional LCD monitor. After 4Mbs, these differences disappeared altogether. In other words, a 7Mbs video looked exactly the same as a 4Mbs one.

The encoding was done with a Adobe Media Encoder (part of Adobe Premiere Pro CS3), using Mpeg4 H.264 codec, single pass VBR (Variable Bit Recording).

To summarize, 3Mbs Mpeg4 (H.264) VBR (Variable Bit Recording) seems to be the optimum setting for most videos, to encode for YouTube HD. Any higher, and it's unlikely that YouTube HD viewers will feel it. At 2Mbs, it's not bad but you will see more compression artifacts than at 3Mbs, and 1.5Mbs will make YouTube think it's HD, but the quality will not be that great.

The resultant files are not exactly small, about 22MB per minute of video, but still far smaller than raw HDV, which is 142 to 187MB per minute. At 3Mbs, a 5-minute video will be about 110MB in size, and take about 25 minutes to upload over a 3Mb/768Kb DSL connection. A similar HDV video will take close to 3 hours to upload.