Build a White-Box TiVo

The following shot shows the solution I chose for this Recipe: a WinTV viewer application, bundled with the Hauppauge PVR-250 package. What's most cool is that it is resizable. That is, the user has the option of viewing the image in the corner while they do something else with the rest of the screen. In essence, it's a TV inside a PC screen:

PVR Features

Dedicated set-top boxes like TiVo and ReplayTV have added a rich new set of features for TV viewers. People want to pause a live program to answer the phone or go to the fridge. They can also "timeshift," which is recording scheduled programs for later viewing, and burn their favorite programs onto DVDs. The public loves PVR features, and they are willing to pay big dollars for the dedicated hardware -- plus a hefty monthly service fee.

Turning a PC into a PVR can cost less than $200 and provide even more features that your clients could get from TiVo or ReplayTV. Unlike the set-top solutionyour PC-PVR will give your clients the choice of full-featured software packages, like SnapStream's BeyondTV and SageTV; upgradabilty; and control over captured video so they can edit and burn DVDs or render video for streaming to Web-enabled devices across a network. PVRs also let your clients watch live or recorded TV in a resizable or full-screen window while running other PC applications. Some PVR programs even offer the ability to mark and skip through commercials -- not a happy thought for the advertisers.

As the next image shows, users can operate the Sage Scheduler from SageTV like a VCR to schedule a recording while they're out:

As the next image shows, users can play back captured programs in DVD-quality with the Sage Recordings application from SageTV.

What makes a PC a PVR?

TV on the PC monitor is not a new idea. In fact, TV tuner cards have been around since the days of DOS. But while it was interesting to view the TV signal in a tiny window, there was not much that could be done to practically capture and store the massive amounts of data associated with a video broadcast. Back then, PCs had limited bus speed and disk space. But all that has changed. Today, as hardware and operating systems like Microsoft's Windows-XP have become more video friendly, the concept of integrating TV onto the PC has come into its own. Microsoft even has a special version of XP with integrated video software called XP-Media Center Edition or MCE, for which vendors including Dell and HP are building muscular PC packages to support the new media "experience" -- a favorite word to describe integrated media on these beefy PCs.

Fortunately, a basic PC-based PVR does not require either MCE or a high-powered PC. In fact, the major differences between a PC built for a general office application and a PVR are the additions of a TV tuner card, PVR software, and an appropriately sized disk. (Okay, you'll want that DVD burner, too.) I'll detail all of them below.

• The TV tuner card is the heart of a PC-based PVR. Tuner cards convert the analog signal coming from the user's cable service provider into digital data to be compressed and stored on a local disk. The digital signal is also converted back to analog for display on your PC screen. In addition to providing 125 cable channels, the tuner cards used in PVRs can do hardware encoding, dbx-TV stereo decoding, and video capture from other sources like VCRs and video cameras -- handy for transfering that library of family videos to DVD.
• PVR software provides all the cool features. Most tuner cards also come bundled with some pretty impressive digital video recording and playback software. They also include modest video editing, DVD authoring and, of course, scheduling software to allow users to record their favorite programs daily, weekly, or one time only. Scheduling is accomplished through a network connection to an Electronic Programming Guide, or EPG, which comes free with some software. You can't beat that price!
• How much disk space will a PVR consume? It depends. Space requirements and performance characteristics will vary with the quality of the video captured and compression method used. This is because processing a signal with a data rate of 12 Mbits/sec. will require more speed, processing power, and disk space than at 4.4 Mbits/sec. At a DVD quality of 4 Mbits/sec. and using MPEG-2 compression, a typical one-hour show will use about 2 GB of hard disk space. The chart below projects that out to illustrate what your disk requirements might look like.

How long does it take to record? The more recordered, the longer it takes. The following table shows the relationship between gigabytes and hours needed:

Putting It All Together

Listed below are the components I used to build my PVR. Where appropriate, I've added insights to my choices.

By the way, I also installed the TV tuner card and software on an older Pentium III/600-Mhz system with reasonable results, proving that building a PVR from an upgraded system makes good sense. For an upgrade, consider a tuner card that provides hardware encoding (see notes below on TV tuner card), and make sure your disk is sized appropriately and fast enough (7200 rpm is preferred) for your set-up.

Parts List and Assembly

1. Locate a system to upgrade, or assemble a PC to meet requirements for tuner card and software. Here's what I recommend:

• Case/Power Supply/Cables: Antek Sonata. Quality case with quiet, 380-watt power supply. I use this case wherever noise may be an issue.
• Motherboard: Intel 865PERL. Rock-solid board with great 5.1 audio and network.
• Video: GeForce MX400 w/128MB nVidia GeForce MX4000 with 128 MB of DDR Memory.
• Stay with common nVidia (GeForce 2 or above) or ATI (Radeon 7500 or above) chipsets of at least w/64M. The card must be DirectX9.0-compatible and support overlay.
• CPU: Intel P4/2.6 MHz. While PIII/500 CPUs are sufficient to build a basic PVR, capturing or viewing TV while running applications requires more. Celeron or AMD Athlon 600 MHz also are supported by most software.
• Memory: 512 MB DDR 400.
• DVD/CD Burner: Plextor P67-1100 DVD++/-R/RW. No special requirements other than must be R/RW
• Disk: Maxtor Ultra Series SATA. 80 GB for the OS and software, 200-GB SATA for data. Space requirements vary with the amount of captured video you want to store and the compression scheme. For example: MPEG1 (Video CD) uses 0.65GB/hour, whereas DVD Standard Play uses 3.1 GB/hr.
• While it's not necessary for your basic PVR, consider the use of RAID (an option with the above motherboard/disk combination) or made-for-video IDE and SCSI drives that use 1:1 interleaving and track caching for the best performance while doing more aggressive video work.
• Partition disks so that video data will reside on one partition and OS/swap on another or separate disk. For example, if using one disk, partition with all software loaded into a smaller "C" partition and a large "D" partition for video recording.
• Operating System: Windows XP-Home Edition.

2. Install tuner card and utilities.

For your TV tuner card, I recommend the WinTV-PVR250 from Hauppauge Computer Works (card with bundled software and remote).

Another good option for a tuner card with integrated video is ATI's All-In-Wonder RADEON 9600, which is a 128 MB Video Card with remote (integrated tuner and video card). It's especially good if you need a video card anyway.

Your choice of tuner card (and digital TV software) will naturally depend on what you wish to accomplish with your PVR. Your choice affects the base configuration of the PC. Some tuner cards (like Hauppauge) have on-board MPEG2 encoding, and some (like ATI) do not. Having the tuner card do the MPEG encoding onboard significantly offloads the PC's CPU, so check the manufacturer's requirements carefully. Tuner cards are also available to handle digital cable signals and support ATSD/HDTV formats. USB-2 versions are available, too.

By the way, some PVR software will support multiple cards. That way, your clients can record one program while watching another.

3. Load and configure third-party software and peripherals.

• PVR Software: Hauppague bundles the basic WinTV with the PVR-250 package, but Snapstream's BeyondTV and Sage are two other outstanding packages. For all three choices, installation is simple and carefully guided. Your final configuration will require connection to the Internet to locate the scheduling server.
• Remote: Again, Hauppauge bundles one with their PVR-250 package, as does ATI with the All-in-Wonder 9600. Snapstream now also has one called Firefly, and there are Streamzap, ATI, and X10, too. Check compatibility if this feature doesn't come bundled with your software.

Tuning Tips for Digital Video

At the first sign of choppy playback, "dropouts," or degraded performance on your PVR, check the following:

• Do not use DoubleSpace or other disk compression.
• Make sure DMA is checked for your drives in Device Manager.
• Defragment your disks often.
• Keep your running processes to a minimum.
• Check for any virus or spyware running. Keep the box clean.
• Pick an appropriate level of data compression. Higher data rates (better quality) use more CPU horsepower and disk space.

Conclusions

If you haven't seen TV on your PC screen lately, then building a Personal Video Recorder will be a blast. Your clients will really love the special features of the software and the affordable pricing.

While each of the third-party software packages has its advantages, all provide basic PVR features, perform well, and are available on a trial basis. So you can decide which interface suits you best.

PVRs are also used closed-circuit surveillance systems, courtroom recording, news gathering, and other commercial pursuits. Think you have an application for digital video recording? Sage software is customizable and extensible. Information on their Software Development Kit (SDK) is available by e-mail.

For more information on PVRs, read Digital Television and the PC (PDF format) by the Hauppauge Computer Works. Also, an ongoing source of information for the industry is HTPC News. For the really adventurous, there is MythTV, a suite of programs that let you build the mythical home-media convergence box using Open Source software and operating systems.

Good luck building your personal video recorders!

ANDY MCDONOUGH is a professional musician, composer, voice actor, engineer, and educator happily freelancing in New Jersey.

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