There is no information for the settings of the camera nor the firmware version of it and neither what/which card was used. But since it was just posted by an ordinary Japanese K-5 user (I believe), we would assume that the original 1.0 firmware was used, since the new firmware has not yet been released.
Okay, let me do a quick summary then, on what can be counted/observed from the video clips:-
RAW: 19 frames; Time to Write: ~12 seconds
JPEG: 24 frames; Time to Write: ~16 seconds
So, it seems that if a fast card (a very fast one?) is used, it may help, in case of the K-5!
Monday, November 01, 2010
K-5 Continuous Burst YouTube Demos (Both RAW and JPEG)