Friday, May 27, 2005

Do-It-Yourself DVR

The Digital Home

A digital video recorder (DVR) can change your life. Well, your TV-viewing life, at least. TiVO is the most famous DVR on the market today, but there are plenty of PC-based hardware and software products that give you similar abilities and features and a lot more freedom.

For starters, you can now watch TV on your terms. No more staying up to the wee hours to catch an old movie or reruns of your favorite show. Instead, your DVR records it for you, and you can watch it whenever you choose. But a DVR is more than just a smarter VCR. It can also pause live TV and go into a time-shift mode, in which you can watch what was on the program a few seconds or minutes ago while the DVR continues to record in real time.

Buy or Build?

You could just go buy a TiVO—they're very well designed, and easy for everyone in the family to use. Midrange models are priced at around $200, plus $12.95 per month for the electronic program guide (EPG). But despite some recently added features, the TiVO remains by and large a closed system, and for copyright reasons, recorded video content is pretty much locked in the box.

Taking an existing PC and converting it into a DVR costs up to around $500, but before you run out and buy a TiVO, stop to consider how much more versatile a PC-based DVR will be. Along with letting you watch, time-shift, and record your favorite TV programs, a DVR system can also function as a media client or even a server on your home network. That means you can watch recorded TV programs from any PC on your home network. You can also show your digital photos on your TV, access your entire collection of ripped music, play PC games, surf the Web, and check e-mail. And the EPG service for Beyond TV (our DVR application of choice) is free.

Design and Components

For this project, we used a Dell Dimension 8200 system, which has a 2-GHz Pentium 4 CPU, 512MB of system memory, an ATI Radeon 9700 Pro 3D card, an Audigy 2 sound card, and a 30GB hard drive. This was a top-of-the-line system about two years ago, and is still competent today, even for processor-intensive chores. Part of what determines the minimum system requirements for a DVR system is whether you want to capture and time-shift HDTV content, which places more demands on the system (see "HD or Not HD").

To turn this PC into a DVR system, we added a TV tuner card, a remote control, a second hard drive, and DVR software. If your graphics card doesn't have a video output and you're connecting your PC-DVR to a standard-definition television, you'll need to upgrade your graphics card to one with good TV output. If you're not planning on playing games on this system, then you can opt for a modest $100 graphics card. But if you want to use your system for games as well, you should consider a card with a bit more power.

If you already have a large hard drive in your system, you may not need to add another. We recommend allocating at least 40GB for recorded video; add more if you like to archive a lot of programs. You may even want to consider a DVD burner so you can catalog shows to watch later without using up all your disk space.

As a DVR, this system can be driven entirely using SnapStream's Firefly PC remote control, so you don't necessarily have to buy a wireless keyboard/mouse combo. But if Web-surfing or e-mailing from your couch or easy chair is in your plans, you should consider adding those components.

Installing Hardware

Snapstream Firefly Unless you want to use an external TV tuner box and an external hard drive, you will need to open up your PC to bring this project to fruition. If you take your time and don't apply excessive force to anything inside your PC, the installation process should come off without a hitch.

Locate the screws for your PC's side panel and remove them, then open the case's side panel. Not all cases are created equal. For instance, our Dell Dimension 8200 has a case that you first lay on its side and then open like the hood of a car. Once you're inside your PC, you'll need to locate a free PCI slot to install the TV tuner card. After you seat the card in a PCI slot, screw the card into the back panel, so it won't come unseated when you connect cables to it.

Putting in the new hard drive is trickier, since you need to figure out where it can be installed. Most PC cases have room for more than one hard drive, so find where your system's current hard drive is mounted, and see if there's a space for another drive. If there is, you'll want to leave the drive with Microsoft Windows on it as the master drive, and set the new drive as the slave. This may require changing the jumpers on both your current and new hard drives.

Many hard drives are installed with jumpers set by default as if the drive were the only one on the machine. You may need to change your existing drive's jumpers to turn it into the master drive. Read through your new hard drive's documentation to determine the correct jumper settings to make it the slave. Next, connect the data ribbon cable and a power cable to your new hard drive.

Once those two items are installed, you can close your case back up. You'll need to connect a small patch cable that comes with the TV tuner card; it goes from the card's audio output to your sound card's line input. This is a crucial step, because without it you won't hear any audio, which needs to be routed to your TV's or sound system's speakers when you're watching live or recorded TV. Once you've connected this patch cable, you can reboot your system.

Before you connect the USB receiver for the Firefly remote, you need to install its driver software. When that is done, plug the USB receiver into an available USB port.

Getting Connected

Video: You have three options for video. If you have an HDTV, you can connect to it via either its VGA or DVI input straight from your graphics card. For a standard-definition TV, your choices are either the S-Video or composite video inputs of your TV. S-Video is the better option, as it does a superior job of carrying the video signal and delivers higher-quality images. If you have analog cable TV, you can connect it—or a TV antenna—directly to the TV tuner card. If you have a cable or satellite box, you need to connect it to either the TV tuner card's S-Video or composite video input, again preferably to the S-Video input. You'll also need to route audio output from your cable/satellite box into the TV tuner card's audio input.

You will want to set your computer's resolution fairly low. If you're using a standard-definition TV, set your PC's resolution no higher than 1,024-by-768. This is because SDTV images have an approximate pixel resolution of 640-by-480, and you don't want to stretch them much, because the image will begin to get either blurry or somewhat blocky. If you have an HDTV, we recommend running at its native pixel resolution (check your HDTV manual). This will usually be something like 1,280-by-720.

Audio: Ideally, you should connect your PC to your home theater receiver via a digital audio connection (called S/PDIF). This single wire can carry either two-channel stereo or multiple channels (5.1, 6.1, 7.1) of Dolby Digital or DTS.

If your sound card doesn't have a digital-audio output, you can connect its analog output to your receiver with a mini-jack-to-RCA patch cable. Your sound card probably came with one, but if not, they're inexpensive and easily found at a Radio Shack or other electronics stores. One note of caution: Some sound cards still put out a "DC thud," a noise burst when the PC is turned on and the sound card first gets power. When powering up your PC, either turn your receiver's volume down or select another input, as this noise-burst signal could damage your amp and speaker drivers. This DC thud only occurs when coming off a cold start; sound cards generally don't produce it when coming out of a sleep state.

Configuring Beyond TV

Recording Settings SnapStream's Beyond TV DVR is easy to use once you've run through its initialization wizard. There, you'll set an account up on SnapStream.Net so that you can receive the correct EPG grid, based on where you live and who your cable or satellite provider is. If you use antenna reception only, there's an option for that as well.

You can operate Beyond TV's user interface with either a mouse or the Firefly remote control. First, you need to configure the recording settings. With digital video, the tradeoff is usually between file size and video quality; higher quality will generally consume more hard-disk space. You get to choose between using MPEG-2 or the Windows Media Video file format. Both formats have four quality levels; we suggest you test each at the Better level. At that level, MPEG-2 records at a constant bit rate of 5.22 megabits/second—it fills 2.3GB of hard-disk space per hour, or 57GB for 25 hours of video. WMV's Better setting, at a variable bit rate of 1.76 Mbps, uses only 792MB of disk space per hour, or 19.8GB for 25 hours.

From the main menu, select Settings, and from there, select Recording Settings. Either file format will deliver good video quality; WMV does better with lower bit rates, but MPEG-2 is easier to use for creating DVDs. You also have the choice of adding SmartSkip information to the recordings, which allows you to easily skip past commercials. You can even have Beyond TV add this information after the program has been recorded.

Up and Running

Program Guide Your PC DVR system should now be ready to record and play back TV shows and movies. The Beyond TV interface makes your PC DVR easy enough for the whole family to use. Even better, those recorded programs can now be played on any PC on your home network. And remember, the computer can still do everything a PC can do—play games, music, home videos and DVDs; view pictures; surf the Web; and check e-mail, all from the comfort of your couch. But be warned: Once you try a DVR, you will soon become one of the converted.


Avcap DVR said...
This comment has been removed by the author.
Adam Scott said...

Thanks for this information i will use this for my Security System.