Problems with choppy video on Youtube and Vimeo

I have a problem with my video – after uploading it to Youtube or Vimeo, the video becomes choppy, especially when the camera is rotating.


However, the video is much smoother if I stream it from Youtube to VLC player, instead of watching it in a web browser (I tried the latest versions of IE, Chrome and Firefox; the best results gives Chrome, but still not perfect).


Here you can find this video; it’s very short (<2min):
http://www.youtube.com/watch?v=-STmBHxDouU
http://vimeo.com/73616262


I cannot find the source of the problem. I even zero’d my hard drive with DBAN and reinstalled Windows (I found some malware on my computer and I had codec packs installed, which according to some people can cause problems with video editing). But it did not help with video quality.


The video was made with Sony HDR-CX410VE camera (PAL). It is capable of shooting AVCHD Full HD videos, however this particular video was made in MP4 mode (1280x720, mp4, 25fps).


I edited the video with Camtasia Studio 8.1.2.
I put video quality to 100%, but I reduced resolution to 854x480 (no point in uploading in HD – I tried that, too – when video becomes so choppy). I put frame rate to automatic (so 25fps was preserved).


The result after editing was a 243MB mp4 file with bitrate of 17000 kb/s (Plenty! The video quality is just fine when I play it on my computer! Not that it’s exceptionally good, but it is not so choppy. It only sucks after uploading it online.)


I believe it is a web browser issue – that my video is not optimized for viewing it in a browser, but I don’t know how to fix that.


I am totally lost here. Please help :)