Looking for PVR Software

Does anyone know of any PVR software where you can timeshift backwards and record what is being viewed form the timeshift buffer? Most PVR softwares allow you to timeshift but once you hit record it will only record what is going into that capture device at that moment.

Thanks, JOe K.

That depends ALWAYS on the source signal.

The source is a DVD player from a composite distribution amp.

I want to take 10 second samples of video clips that I think are cool or funny (like amazing sports plays).

So I think the source would be BDA which is comprised of ATSC and DVB (I think).

The set up is video going from a composite video cable to my capture device then USB into my computer.

I can rewind but when I record it only records what is going through the device at that moment.