That's simply not true!
What's happening is that the samsung h.264 codec is outputting the video in a manner which
is inefficient to play back raw on a computer.
This isn't a deal breaker though, just get yourself a copy of Quicktime Pro (currently version 7 as of 05/04/10) NOT quicktime X that ships with Snow Leopard.
Open the video file, and select the entire clip, then choose File --> Export
Make sure to export with the h.264 codec if all you want to do is upload to youtube, then check the settings to make sure you're exporting 1920 x 1080 and at the same fps as captured (30).
Make sure to select the "Deinterlace" option checkbox in video settings and you're all set, leave the audio alone.
Export it to a .mov file and there you go, silky smooth 1080P video that's good enough to eat!
Note: Quicktime Pro is GPU accelerated too, and YES you do have to buy it from Apple for $29.00
but if you're playing around with 1920 x 1080 HD source, then you will have that $29.00 to spend on an essential tool like QT Pro because your storage needs will dictate your purchasing of hundreds of dollars of raid 5 or raid 1 hardware, unless you don't plan on keeping the video you worked so hard to create. In which case why spend the effort to edit it at all? Just do the work in-camera.
