Pausing Live TV?
One of the main features of a DVR, and one that is hyped heavily in product advertisements, is the ability to "pause live television." This feature has caused more than a few people to scratch their heads, wondering exactly how this is done.
The phrase "pause live TV" is a bit misleading. When you hit the pause button on a DVR remote, the box instantly begins recording the program. It also freeze-frames the current image, giving the appearance of a paused videotape. When you hit play (un-pause), the recorded program begins playing.
DVRs allocate a certain portion of the hard drive to a live TV buffer. They are constantly recording, and generally keep the past hour or so in the buffer. This means that if you walk into the room 10 minutes into a movie, you can rewind by 10 minutes and catch the beginning -- provided the DVR was on the desired channel (the buffer is emptied each time you change the channel, and the DVR starts recording again).