PC VCRs: 
    Desktop Video Recording and Time-Shifting
    (1/2001)

    by Douglas Dixon

     InterVideo WinDVR -- CyberLink PowerVCR -- Hauppauge WinTV-USB

Convergance! Consumer electronics products are bulking up with computer processing capabilities, from digital televisions with graphical displays and programming guides to the new digital VCRs. One of the most exciting functions of the new digital VCRs is the ability to "time-shift" a broadcast; since the video is recorded to hard disk and not on videotape, it can be both recorded live and also played back (from earlier in the same show) at the same time. Now you can "pause" a live broadcast while you answer the phone, and still see the full show when you are done with the call. You no longer need to worry about rushing home to catch the 8:00 p.m. show; you can get home at 8:15 and immediately start watching the recorded show while the rest of it is still being recorded. Try that with videotape!

But convergence goes both ways: a PC has a processor and memory and disk space, so with the addition of some TV tuner hardware a PC also can serve as a digital VCR. Two new products, InterVideo WinDVR and CyberLink PowerVCR, leverage the power and storage of the PC and access to Internet resources to provide the full range of digital VCR capabilities, and more: not just TV viewing and recording, but time-shifting, scheduling with a program guide, and even video editing and conversion.

InterVideo and CyberLink have developed these products as extensions of their DVD player products, WinDVD and PowerDVD, which support full-resolution playback of DVD MPEG video, in software, on Windows PCs. By optimizing MPEG compression and decompression, and with fast disk I/O on modern PCs, WinDVR and PowerVCR can support real-time full-rate full-resolution capture and playback of MPEG video and audio.

PC TV Hardware: Hauppauge WinTV-USB 

Of course, in order to watch TV on your PC, you need some sort of video capture hardware with a TV tuner. Your computer may already have a display card with TV tuner capability, like the ATI All-in-Wonder, in which case you are all set. Or you may want to install a PCI capture card to support high-resolution full-rate video capture. But these days, with the advent of the USB interface, you no longer even need to crack open your case to add new capabilities to your PC.

Previously, I described the Pinnacle PCTV-USB an example of how to easily add TV video to your PC. For this review, I used the WinTV-USB from Hauppauge, which provides TV tuning and video capture in a nice inexpensive and compact package. The unit is a translucent green box around 2 1/2 by 5 1/5 square by 1 inch high, with a street price around $79.

        Hauppauge WinTV-USB 

The WinTV-USB has input connectors for TV input from a coax cable (antenna or cable), plus direct video input from S-Video and audio line in. Hauppauge also provides an adapter to connect a composite cable to the S-Video connector. The USB cable both transfers data to your computer and also provides power, so no separate power cord or adapter is required. The final connector is audio line out, which is connected to your PC's sound card; the WinTV unit only transfers video on the USB cable, so your software must capture the associated audio from your sound card.

WinTV-USB ships with the WinTV2000 application for watching live TV. You can also capture snapshots of TV broadcasts or the video input as still images, and record video and audio clips to disk as AVI files. The product also includes Microsoft NetMeeting for videoconferencing over the Internet using a local video camera.

The WinTV-USB is available in versions for NTSC, PAL, and SECAM video formats, and also with an additional FM radio tuner. Hauppauge also has PCI card products in its WinTV line, but you just cannot beat these USB units for convenience, low hassle, and easy sharing between desktop PCs and even laptops.

Live TV: WinTV2000

The WinTV2000 application included with the WinTV-USB unit provides almost all the features you could want for TV viewing and video capture. When you first hook up the unit, the 125-channel cable-ready TV tuner can auto-scan for available channels, from cable or off-air. You can then edit the channel list and enter names for the channels. To check out what is currently being broadcast, you can use the channel surf option to display miniature thumbnails of 16 channels at a time.

        Hauppauge WinTV2000 

The main window has a control panel down the left side to change channels, adjust volume, and access the system controls. You can watch TV in the main window, and resize it to fit on your desktop or expand it to full-screen. To monitor the TV while you work, you can reduce the window size by displaying just the video without the controls, and also set the video window to always display on top of the desktop.

For more convenient control of the TV display, you can also use a separate "remote control" window to access the TV controls. It also has a slide-out tray with advanced options, including capturing still snapshots and VCR-like recording and playback via AVI files.

InterVideo WinDVR

PC-VCR applications like InterVideo WinDVR and CyberLink PowerVCR start with the basic TV tuning capabilities of applications like WinTV2000, and then add more extensive and more sophisticated digital VCR capabilities. WinDVR and PowerVCR have similar interface designs, with a resizable video window and a separate control panel. The control panels include TV tuning functions like channel selection and volume control, VCR functions like record and play, a display area for feedback on the current operation, and access to auxiliary functions like set-up options and the electronic control guide.

        InterVideo WinDVR 

WinDVR is the next entry in the WinCinema suite of multimedia software products from InterVideo. Building on the successful WinDVD player, InterVideo is developing a set of individual applications that consumers and OEMs can mix and match. Due in October are WinDVR, WinCoder, for MPEG capture, conversion to AVI, and simple editing, WinRip, a MP3 player / encoder / ripper that supports embedded data such as hyperlinks and song lyrics in the MP3 data files, and WinProducer, a more sophisticated timeline editor.

Trial versions of these products will be available from the InterVideo web site, with full versions priced from $29.95 to $49.95. The evaluation version described here is from September 2000.

The WinDVR interface consists of the main video player window and a separate control panel with controls for TV tuning, and VCR recording and time-shifting, channel surfing, EPG, scheduling, and still capture. The most common functions are also easily available through a pop-up menu. WinDVR provides a clean set of system setting dialogs to control the video display format and appearance, TV tuning formats, video and audio recording formats, disk usage for recording, and time-shifting mode.

CyberLink PowerVCR

CyberLink PowerVCR is a more integrated application that also includes video editing and conversion functions. The current retail version, PowerVCR II Deluxe, supports real-time capture of video in both MPEG-and MPEG-2 format, plus MPEG editing and AVI/DV/MPEG format conversion. The retail version includes PowerDVD, and is priced at $99. The version described here is version 2.0, from June 2000.

      CyberLink PowerVCR

The PowerVCR interface is controlled by the main control panel, which has a series of buttons to switch between the different program functions: TV tuning, playback, recording, editing, scheduling, and conversion. The control panel buttons and the main video window change format in the different modes, from simple video playback to editing and trimming files. PowerVCR also provides a separate TV tuner control for faster access to specific channels.

The PowerVCR system setting dialogs provide extensive information and control over program and system options, including gory detail on the Windows video and audio capture pipeline, display options for smoothing the video signal and removing noise, CPU-specific optimizations, and display hardware video overlay capabilities.

Recording

Even for video recording, WinDVR and PowerVCR go beyond basic Windows video capture using the AVI video file format, to support the MPEG-1 and MPEG-2 international standards. Based on the MPEG technology background of the InterVideo and CyberLink DVD player products, these applications can support real-time full-rate full-resolution capture and playback of 720x480 MPEG-2 video and MPEG audio.

To record a live broadcast, or from a connected video camera, simply press the record button on the control panel. You can specify the recording format and other parameters by using the options dialogs, in order to trade off video quality versus disk space for storage. Once the recording is complete, you can use the play button and other VCR controls to play it back.

WinDVR provides options for specifying the video and audio recording quality, in terms of video resolution and compressed bit rates. You can pick a general quality level, or define your own custom settings. It also has a nice interface for specifying both the hard disk drive to be used for storage, and the amount of available storage space to reserve for capture. PowerVCR provides an extensive list of pre-defined recording profile, with a wide range of MPEG-1 and MPEG-2 settings for different needs.

Time-Shifting

Beyond simple recording, the really cool feature that digital VCRs provide is time-shifting: the ability to pause a live broadcast, have it continue being recorded in the background, and then pick it up from where you left off. Or, you can do your own instant replays by skipping back to see a scene again, without missing the rest of the show.

With WinDVR and PowerVCR, time-shifting is just a different kind of recording, in which the live broadcast is compressed and saved to disk, and simultaneously the program is read back from disk and played (at a different point). The main interface for controlling the playback is a slider-like display at the top of the control panel. As the program is recorded, the slider grows to indicate the length of the recorded material. If you pause the playback, the slider bar keeps growing as more material is recorded. You can resume playback, or move the slider back to replay material that you want to see again, or move the slider forward, for example to skip ahead to catch up to the live broadcast.

WinDVR supports two forms of time-shifting: a "normal" mode for buffering up to a fixed amount of material (like 10 minutes) so you can pause briefly or do short relays, and a "record" mode that actually records the program while time-shifting, but with slower performance.

Scheduling - EPG

Watching and recording and time-shifting TV is fun, but how do you find what program to watch in the first place? Again, digital TVs and VCRs can provide an electronic program guide (EPG) to let you see what is on, and also schedule your favorite upcoming programs to be recorded. With an Internet connection, WinDVR and PowerVCR can provide access to EPGs over the Web. Given your zip code and local cable provider, these guides provide complete TV program and channel information for your system.

WinDVR accesses the EPG at TVGrid.com by launching a Web browser. In PowerVCR, the CyberLink "i-Power" button displays a Web portal page directly from within the application, with links to the Yahoo! TV coverage listings, and to additional information about PC video editing and capture.

However, the current versions of these applications do not integrate the Web TV listings directly into their scheduling functions. You still need to enter the information about what channel and time(s) you want to record. Again, you can specify the recording format to trade off video quality versus disk space.

Video Editing and Conversion

CyberLink PowerVCR also includes integrated video editing and conversion functions. With the MPEG Editor you can cut, trim, and merge a list of video clips. With the Converter, you can convert Windows AVI files into MPEG-1 and -2 formats.

InterVideo plans to provide similar functionality in its separate WinCoder application to capture, record, and transcode MPEG video.

Wrap-Up

InterVideo WinDVR and CyberLink PowerVCR are the next step in the evolution of software-based video processing on the PC platform. With today's processors and fast disks, it is feasible to be both encoding and decoding separate streams of high-quality video, and simultaneously recording and playing back data from disk. Of course, your performance may vary depending on your PC configuration, but a baseline system like a Pentium II 350 should be able to do at least real-time MPEG-1 recording.

The last hardware requirement is a TV tuner / video capture device such as the Hauppauge WinTV-USB. The USB video devices cannot provide full-resolution full-rate video over the USB cable, but they certainly provide an easy and inexpensive way to show video in a window on your PC. The main trick with USB is to make sure that your USB port is enabled in your PC's BIOS. You may also need to use the USB Legacy mode in the BIOS for full compatibility.

WinDVR and PowerVCR work with any Microsoft WDM-compliant TV tuner device, under Windows 98 or later. However, this is a new area for PC software and hardware, so some glitches can occur, especially in older machines. These applications can be slow to start up, with the need to configure the TV tuner hardware and start the USB data flow, and also can visibly delay when switching into recording or time-shift modes.

Since the WinTV-USB only provides video over the USB connection, I also occasionally needed to manually enable the Line-In audio on my system. Launching the application also seemed to disconnect my dial-in network connection.

So, are you ready to try out a taste of convergence for your PC, turning it into a digital VCR and MPEG video engine? If so, you can get started with simple hardware like the Hauppauge WinTV-USB for around $79. Then surf to the InterVideo and CyberLink web sites to download and try out the evaluation versions of these applications. You'll find it handy to be able to monitor the TV in a corner of your screen, and of course you will need the time-shifting function to catch up with things you missed because you were busy working.

References

Hauppauge - WinTV-USB 
    www.hauppauge.com

CyberLink - PowerVCR 
    www.cyberlink-usa.com 
    www.gocyberlink.com

InterVideo - WinDVR 
    www.intervideo.com