New user help with Kaffeine

Hello,
I use Linux and have a tv tuner card that I would like to use to record live tv.
I have done this in the past using Windows but, not Linux.
I set Kaffeine up to record a two hour show and it only recorded about an hour. I went back and checked my record schedule and it was set correct for the full two hours. I don’t understand.
Any Ideas?

Thank You,

Does your setup use a screensaver? (You didn’t mention what linux OS and DE.)