This is not a definitive assessment but just some useful tips from finding out the hard way! Hopefully you will have seen my first fractal video release, Aridcadabra? It's not bad in terms of detail, with reference to the quality drop after posting on to youtube, but that wasn't how it started off on my draft posting. I will pass on lessons learned!
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First of all, brace yourself. You create that stunning quality video on your PC/laptop and excitedly you post it on you tube ...then wham!! What the smeg happened, it's a pixelated mess! This will happen most notably when you post video with a lot of fast moving high detail, like I did with the Aradcadabra video. Youtube get millions or whatever videos posted on it a year. It has to compress. It will compress, be prepared. On normal camcorder footage you probably won't notice too much but detailed stuff, you will. Youtube compresses using various codecs and one method it uses it assigning blocks to areas. If that area doesn't change much it saves that block for the next whatever frames. Great on a blank wall or sky but on a smooth detailed 3D fractal or similar, not so good. It can cause jumpy pixellation.
What can you do? You have to understand Youtube wants to compress as much as it can. For all standard format videos it uses something called an AVC codec that serves it well. If you play a youtube video use right click on the video and then click stats for nerds. The codec and other detail is seen there. However the AVC codec is not going to work well for detailed video so YouTube can assign a much better codec; the VP09. Click 'stats for nerds' most good quality specialist videos on YouTube and you see they have the VP09 codec. Youtube doesn't give the codec to everyone as it takes up a lot more resources than using the AVC; if you post your normal video you don't get it, you are stuck with the AVC codec.
Here is a comparison of standards for you to see. It's a portion of a frame (about 40% of it) from my Aridcadabra 3D fractal video. You can see what it looked like on my home computer, the first youtube 1080P upload with the AVC codec and then the finished 1080P youtube upload with the VP09 codec.
Quite some difference. I was very sad and confused when I first saw the AVC version. I guess you might be experiencing the same, and why you are reading this?
So how did I get the VP09 codec? I think higher profile Youtube users get it automatically but you can also get it. All you have to do is post a 'serious' video and youtube sees it as that if you post with a frame size greater than 1080P, that's all you need to do ....simples, only I didn't see this info anywhere on google/Youtube support, hence why I'm posting it here.
What you then have to do with, say, your 4k video is upload ...and wait ..and wait ... and wait. Depending on video length it will take an age. My 6 min 4k video took over 24 hours from start of upload to processing the 4k video (I read in blogs some people had even worse times). My upload was in a *.mov format and 40Gb in size, so you can see why Youtube compress to save space and allow the video to stream efficiently. The shock was that it released the 1080P before the 4K was processed, after a few hours after upload had finished and it was with the AVC codec. Panic, was it going to stay like that!? No, when the 4k gets rendered Youtube uses the VP09 codec and then it uses that for the 1080P version, so the 1080P gets upgraded ...phew. It is best that you make your video unlisted until the 4k render has finished, so that your friends and fans don't see the terrible AVC codec version and think your video sucks. Wait! Be patient it will get there!
Good luck! I hope this has helped you. I will post more video rendering tips on this blog over time. Stay tuned in; register, comment and please please sub my Youtube channel and like my facebook page ...it's free and hopefully will be useful to you ..and hopefully you'll enjoy some of the videos. I hope to publish full length music videos at about 1 per month ...I hope!!
Cheers - Steve, Nepenthes Sloth