Are you asking why it always says that the remaining time available is 29m59s, even though you have an enormous 64GB card in the camera, and you're expecting to be able to record more than half an hour of video?
If so, I believe the camera restricts the possible length of each video recording (file) to 29m59s for some legal reason. I don't know the details but I read a long time ago that in certain countries, the government (or someone) would slap on a hefty tax if the camera was capable of recording more than that. Adding that tax to the retail price would price the camera out of its intended market, which would be A Bad Thing for Canon - and potential customers.
That's what I read, anyway.
Martin - Who never shoots video