Computer Buying
Computer Building
Cable / Satellite
How do PVRs/DVRs work?
A DVR can do amazing things. You can pause live TV, create your own "instant replays" and even start watching a recorded show from the beginning while the end is still recording. You can watch a program you previously recorded while one or more other shows record. Picking shows to record is often as easy as selecting them from the program guide. Some units even find shows for you based on what you normally watch.

A DVR is able to do all these things because of four things: It's actually small computer, it uses a contstantly updating onscreen guide, records programs onto a hard drive a hard drive and is always recording whatever you watch, even if you didn't tell the unit to do so.

One of the big selling points of a DVR is the ability to pause live TV as well as replay things you might have missed. This is accomplished by making use of a handy thing called a "buffer". When you tune to a channel, the DVR begins recording. At that point, you can pause the show. After a few seconds, you can jump backward. To save space for your recording, the buffer constantly records over the oldest portion with new video. Some units have a maximum buffer time of 30 minutes, while others can be 2 or 3 hours. This buffer actually delays the program by a second or two. You can see the effects of this by watching the same video without a DVR at the same time as the DVR video. Everything that happens on the non-DVR video happens slightly after on the DVR.

DVRs rely on a program guide that constantly updates itself. Some units dial in on a phone line to get this information (usually late at night), while many cable and satellite units get their listings through the same cable as the programming. The DVR uses this guide information to find the shows. They often use a unique code number assigned to every episode of every show. This way, the unit can figure out if you've already watched a show, even if the program description is missing.

Because a hard drive can read and write simultaniously, recording video to a drive means you can watch one part of a show while another part records. This is handy if you come home after a recording has already started. There's no waiting for the show to end. Just start watching the beginning while the rest records. Depending on when you tune in, you may actually catch up with the live show by the time it ends. In fact, many people actually delay the shows they watch (called "time-shifting") just so they can skim past the commercials.

Software | Hardware | Internet | Networking | Web Publishing | Computer Glossary | Computer Links
TVs and HDTV | Cable and Satellite | PVRs and DVRs | CD Technology | DVD Technology | MP3 Technology | Speakers
Receivers | Video Editing | Production Studio | Audio and Video Glossary | Audio and Video Links
Cables and Connectors | Home Tech | Power Protection

©Copyright 2003-2005 Kimberlite Productions
No part of this site may be reproduced or redistributed without written permission.

Some of the tips and advice may void your equipment or service warranty. When in doubt, consult your owners manual and/or seek professional assistance. GadgetFAQs.com does not recommend performing any task that may damage your equipment, void your warranty or viol ate applicable laws. Since laws vary, depending upon your location, check local regulations regarding any activity you choose to engage in.