Length time different

[Blindeagle]

So doing some editing in sony vegas and when i render as mepg it says the time length is 29 seconds when i hover over the file in my documents. While in sony vegas its actually 30 seconds, however if i render in mp4 it says time is 30 seconds when i hover over the file and in sony vegas it is 30 seconds but why is the mepg format wrong? or is that how it is?

 

[Blindeagle]

Ah i see i will check but i think i kept the frame rate the same so pal at 25 frames