Is it practical to create video products in-house? Yes, but be prepared to spend an enormous amount of time trying to get the different hardware components to talk to each other.
Stanford Diehl
The Digital Video Revolution has arrived, but don't expect a lot of fanfare: Everyone's too busy getting the hardware to work. In the age of MTV and sound-bite presidential campaigns, video's power is obvious, but capturing video at the PC desktop and delivering it across the enterprise is still fraught with the glitches and the gotchas of the PC architecture.
That's no reason to let the revolution pass you by. Digital video is essential for producing CD-ROM-based products that can hold in-house training programs, presentations, and other types of corporate data. Digital video excels at handling small v
ideo segments like these, and with CD-ROM players on many desktops, it's often easier to view a CD-ROM in the workplace than a VHS tape.
Over the next several months, expect an explosion of motion-video hardware, mainstream playback boards, and turnkey capture solutions to hit the market. When Windows 95 finally ships, it will provide an integrated multimedia architecture along with 32-bit versions of the Indeo and Cinepak codecs.
What's more, almost every major graphics chip vendor--including S3, Tseng Labs, Western Digital, and Brooktree--has or will soon release a Windows accelerator that incorporates on-chip motion-video acceleration. This, along with the new DCI (Display Control Interface) drivers, will make full-motion video a standard capability of most Windows accelerators (for a review of hardware video architectures, see "Video for Free," February BYTE).
BYTE set up a desktop video production suite and created an in-house multimedia product to find the requirements, the problems
, and the issues of desktop video production. We looked at video from the corporate perspective rather than the professional broadcast angle. Without contracting professional video services or hiring a video specialist, can a corporation build video production capability on the PC desktop?
The answer, we concluded, is yes. But in the process, we ran into one configuration hassle after another trying to mix together the various components, such as a 24-bit Windows accelerator, a motion-video capture card, a hardware compression module (often a separate card requiring a unique interrupt and address), a 16-bit sound card, and a CD-ROM drive or CD-ROM recorder.
We also learned that while digital video may be all the rage today, you need to look past the hype. Analog video can be a better solution if VHS tape will carry your message from the president, customer profile, or other long-length subject. For details, see "What It Takes" and "Analog, Hands On."
BYTE Video Productions
Our video workshop started with the idea of capturing the valuable technical information that companies present to BYTE each day in product demonstrations. We set up cameras to record the give and take among industry representatives and BYTE editors. We trained one camera, a pro/am-level Sony Hi8 Handycam, on the main presentation speaker. The second camera, a professional-class Panasonic OmniMovieHQ SuperVHS, filmed a wide-angle shot of all the demonstration participants. A scan-converter piped the on-screen computer presentation to a Sanyo SuperVHS tape deck. The tapes that resulted held a treasure of industry insights, demonstrations of exciting new products, and unguarded revelations of limitations and bugs.
We planned to send the edited video package to editors in our worldwide bureaus, to freelance authors, or to anyone else who needed the information. The target market drove not only how we scripted the content but also the development platform. We chose two different output targets: a
nalog videotape and digital video on CD-ROM. The sidebar "What It Takes" shows our digital-video and analog-video production platforms.
CD-ROM products work best for nonlinear delivery of information. You click buttons on the CD-ROM title's interface to launch short video clips (
see the screen
). We broke our video content into several clips and organized them by subject. Click on one button, for instance, and you can see a selection of sample video transitions shown in one vendor demonstration. These video clips played samples of transitions and on-screen tutorials on how to create the transitions with a selection of digital-editing software.
Capture Conflicts
To digitize our taped demonstrations, we first used the Orchid Videola Premium. After trying almost every configuration combination imaginable, we got the video capture working--or so we thought. When we dumped the captured clip into Adobe Premiere (our editing software), the video was consecu
tive frames of solid pink.
Orchid technical support came up with a solution: Go into Gateway's BIOS setup and disable BIOS shadowing. That trick let us capture some excellent video clips using Orchid's Motion JPEG compression (an optional daughtercard is required for M-JPEG).
Unfortunately, the Videola requires a VGA feature connector, which limits your desktop resolution to 640 by 480 pixels. (In theory, you should be able to get up to an 800- by 600-pixel resolution desktop, but we never got stable output at the higher resolution.) Adobe Premiere and other digital video editors present a full desktop with an assortment of tool palettes and windows. You also must work with a time line packed with video strips, transition effects, and audio waveforms. It's simply too much interface for anything less than a 1024- by 768-pixel resolution desktop.
Many alternatives can replace the feature-connectors (faster local-bus architectures such as PCI [Peripheral Component Interconnect], better compr
ession schemes, integrated chips that combine Windows acceleration with motion-video support, and architectural solutions such as VESA Media Channel). At this point, we don't recommend a feature-connector solution.
The best answer is a turnkey solution. We solicited Smart and Friendly's MPEG Creation Station, a well-conceived bundle of products that comprises all the pieces you'll need to generate MPEG titles. Smart and Friendly offers the MPEG Creation Station as a turnkey system, but when we started our project, the components were only available separately. That's a lot of stuff to get working in a single PC.
We ran into problems trying to get the Fast Movie Machine to work (the capture component of the MPEG Creation Station). The Movie Machine supports an optional Motion-JPEG board that occupies its own slot, interrupt, and address space. When we first installed it, the motion-video input displayed on screen, but it wasn't aligned in the capture window. When we tried to load the alignment co
ntrols, we were unceremoniously bumped out of Windows. A few configuration options later, we got the video capture to work well, but when we played back the captured clip, compression didn't work properly. We finally resorted to a second machine, but it didn't work either.
Vendors and developers in the digital-video field told us conflicts are normal. We heard plenty of other horror stories, usually solved by a technical-support engineer who knew the vagaries of the specific combination of hardware components. Here are a few tips:
--
Keep a good configuration log.
Write down the interrupts and addresses occupied by each component in the system, and keep track of which combinations have failed.
--
Get to know MSD (Microsoft Diagnostics),
the configuration utility that ships with DOS. It can return valuable information about open interrupts and addresses.
--
Get the capture and compression component working first,
before adding sound ca
rds, CD-ROMs, and network interfaces.
--
Plug the network card in last and use the 3Com EtherLink III,
if possible. It shipped with our 100-MHz Gateway. It's the closest thing to true plug-and-play that we've ever run across.
--
Install VFW (Video for Windows) 1.1d and keep your software setup routines from reinstalling VFW run time (if possible).
Some installation software will overwrite your current VFW drivers and downgrade you to an older version. It happened to us more than once. VFW 1.1 is a significant upgrade from 1.0, and you'll need it.
--
Call technical support before you lose your wits
or kick your dog. Have your log handy so that you can report your current hardware setup, including interrupt and address configurations.
Andrew Hudson, president of North Coast Software (makers of the PhotoMorph video-effects package), suggested the miroVideo DC1 capture and compression card. His company was happy with it, and the card's
installation routine automatically senses available interrupts and addresses--well, sort of. Configuration glitches remained. Without a true plug-and-play architecture, software can't reliably find the best configuration options, but the miroVideo performed better than most. The bottom line is it worked reliably with all our other hardware.
The card captured video through the S-Video port without dropping any frames, and it supported high-quality Motion-JPEG compression on-board (the compression hardware didn't require an additional board or daughtercard). For us, the miroVideo was the solution.
Video Assembly
Finally, it was time to capture video (see
"Capture Tips"
). We had filmed two hour-long demonstrations, and we had three tapes of each session: one wide-angle view, one zoom of the main demonstration presenter, and one video capture of the demonstration computer screen. We captured short video clips from the assembled content. We quickly realized
that the 500 MB free on our 1-GB hard drive would not suffice; thus, we installed Adaptec's PCI SCSI Master drive controller and a fresh Micropolis 4110 1-GB drive before proceeding. For your video-capture station, 4 GB is not an unreasonable recommendation, and if you really want optimum performance from a storage system, invest in one of the high-capacity audio/video hard drives, which are optimized for multimedia applications.
On the surface, you can capture raw video as easily as plugging your video source into the capture card and firing up your capture driver. But for optimal playback on target systems, you need to consider many performance issues.
VFW will drop frames from a video clip if the playback system can't keep up. Your video clips will look better on your target systems if you select a capture rate that your target hardware can handle. It is better to run a video at 12 fps without dropping frames than to play it back at 15 fps with dropped frames. A lower frame rate stretches the
display of each frame, smoothing out the overall playback quality. Dropped frames result in extremely jerky motion. So select the highest frame rate that your target system can play back without dropping frames.
Here's the rub: Playback on any system can achieve only the maximum frame rate you've configured for your captured sequence. If your capture rate is at 12 fps, the quality will look the same on a 33-MHz 486 as it does on a 90-MHz Pentium with a motion-video accelerator. If you up the frame rate, you degrade playback quality on your low-end target; lower the frame rate, and you waste any special playback acceleration at the high end. MPEG solves the problem with dynamic frame rate support, but your target systems will require MPEG decompression hardware. We'll address those issues in a moment. First, let's look at VFW.
Optimizing Video Compression
To optimize frame-rate and compression parameters to a targeted throughput rate, start from your VFW capture driver.
As you can see from the
Video for Windows Format
screen, VFW gives you some important output options. First, you can select a target throughput rate. If your target is a single-speed CD-ROM drive, select a throughput rate of 150 Kbps. You can also adjust the compression quality. Start at 100 percent quality and scale it down if you exceed your targeted throughput rate. It will take trial-and-error to tune performance properly. Luckily, you can capture your original video sequence and then save it with different parameters (using the VFW driver "Save As" option).
Normally, you should avoid recompression because each compression pass results in some quality degradation. But most boards use only intraframe compression during capture. Recompression to a lower frame rate takes advantage of intraframe and interframe compression, improving overall quality. (For more compression details, see "Compression Scorecard".)
A Step at a Time
To avoid quality degra
dation in real-time video capture, you could install at least 64 MB of memory and capture small clips directly into RAM. A more practical way to avoid real-time compression is with
step-frame
capture. Here, your capture driver receives the first frame of the video clip from the video source. The driver then compresses the frame, taking as much time as it requires. After compressing the frame, the driver advances the video source one frame and begins processing the next image. Step-capture rates are often specified in a ratio; for instance, a 20-to-1 compression rate requires 20 minutes to process 1 minute of real-time video. Use step-capture if you have the hardware and software to support it (you'll need a deck or a camcorder that your driver can control through MCI (media control interface). An emerging standard for device control is LANC, a protocol for controlling consumer devices remotely. When you're shopping for a consumer or "prosumer" camcorder, look for a LANC connector. Our Sanyo deck ship
ped with an MCI driver for computer-control through the serial port.
At the moment, MPEG is not a viable solution for corporate video production. It is simply too much work and expense to outfit all your playback systems with MPEG decompression hardware. Until recently, RealMagic distributed the only inexpensive MPEG playback solution. But there's a bigger issue. MPEG has not been a standard long enough to rely on. Buying an MPEG decompresssion board does not necessarily mean you will be able to play back all the titles developed with different flavors of MPEG.
MCI-based MPEG and DCI drivers should provide the impetus for mainstream MPEG playback. Most major graphics card vendors are readying inexpensive MPEG modules that integrate with existing Windows accelerators. Diamond Computer, Jazz Multimedia, miro, and other vendors have already announced or shipped mainstream MPEG playback options for their standard Windows-accelerator cards. You won't need to buy a separate video adapter and connect t
o your MPEG decompressor through a feature connector. You can buy it all together and slip it into one slot.
Microsoft and other vendors are addressing MPEG's incompatibility problems by standardizing on an MPEG implementation that will be incorporated into MCI. MPEG uses bidirectional interframe compression (an intermediate frame can refer to the previous key frame and to the subsequent key frame to optimize compression), a capability not supported in VFW. So in the immediate future, MPEG can't plug into VFW as an installable codec. You'll have to implement MPEG via MCI calls. But that's not a major roadblock. The VFW Developer's Kit ships with a Visual Basic Custom Control for accessing MCI devices from Visual Basic programs. In fact, building a simple Visual Basic-based interface for corporate video delivery is fairly easy to design and implement.
With MPEG, you'll be able to dynamically adjust the playback rate, sending 30 fps to a hardware-assisted target or delivering only key frames to a
low-end platform. And, of course, MPEG can take advantage of DCI by passing unscaled YUV (shorthand for broadcast signals that define luminance, hue, and saturation) data to an available DCI-enabled video accelerator.
For practical advice on optimizing compression for video playback, see Jan Ozer's excellent book,
Video Compression for Multimedia
(Academic Press, 1995). It is full of good tips and tricks, and it also comes bundled with Doceo's VCS (Video Compression Sampler), an invaluable tool for optimizing video compression and playback. VCS displays a video clip's throughput rate so that you can easily see how well your clips conform to a throughput target. You can even pinpoint specific frames where your compression is breaking down.
Post-Processing
We found some outstanding software tools for editing our digital video clips. Adobe Premiere 4.0 is an obvious choice. PhotoMorph can create slick digital transitions and dump the results to an AVI (Audio Video
Interleave) file. You can then drop the clip directly into Premiere or any other tool that supports the AVI format.
Star Media Systems recently began shipping a remarkable editor called Video Action Pro. This first release offers tools for video editing, animation, digital effects and transitions, filtering, chroma-keying, audio mixing, and title generation from a single interface. Very impressive.
With all this software power, it's easy to get carried away with special effects. For corporate video production, stick to the basic transitions: hard-cut, dissolve, and a few selected wipes. Don't use effects or transitions just for their own sake. Each technique should serve a clear purpose that's related to the content of your project.
That's a Wrap
Our video project still needs a nip here and a tuck there. We've captured key clips and created a prototype interface, but we still have to toil with authoring environments and spit the results out to our CD-ROM recorder.
For now, we have our capture station producing high-quality digital video.
We believe in-house video production is viable for corporate content. Although you still need professional video services for broadcast-ready production, such as TV advertisements and public-relations promos, desktop video is effective for training and other corporate-video content. But it isn't yet Plug and Play. You'll need computer-savvy people who, preferably, have also dabbled in video. In the ramp-up phase, you might even need an outside consultant, but once you're up and running, the payoff can be significant. Video is an effective way to distribute information. Welcome to the revolution. Stay tuned.
-- Compress at the highest rate that your target system can play
back without dropping frames
-- Capture at the highest possible rate and then recompress to the target rate
-- Select the driver's VCR checkbox to enable time-base correction
-- Make sure your hard dr
ive is large and fast (1 to 4 GB and 6-Mbps
sustained data transfer rate)
-- Capture at 160 by 120 pixels if your target systems support
hardware scaling
-- Use step-frame capture if your video source supports it
-- Compress with Indeo 3.23 for software-only playback
-- Develop with MPEG if your targets support MPEG playback
WHERE TO FIND
Adobe Systems
Mountain View, CA
(415) 961-4400
fax: (415) 961-3769
Communications Specialties, Inc.
Hauppauge, NY
(516) 273-0404
fax: (516) 273-1638
Consumer Technologies Northwest, Inc.
Beaverton, OR
(503) 643-1662
fax: (503) 671-9066
Doceo Publishing, Inc.
Norcross, GA
(404) 564-5545
fax: (404) 564-5652
Fast Electronic
Redwood City, CA
(415) 802-0772
fax: (415) 802-0746
Gateway 2000
North Sioux City, SD
(800) 846-4289
(605) 232-2000
fax: (605) 232-2023
miro
Palo Alto, CA
(415) 855-0940
fax: (415) 855-9004
North Coast Software
Barrington, NH
(603) 664-6000
Orchid Technology
Fremont, CA
(510) 683-0300
fax: (510) 490-9317
Panasonic Consumer Affairs
Secaucus, CA
(201) 348-9090
Sampo Technology
Norcross, GA
(404) 449-6220
Sanyo Fisher Corp.
Compton, CA
(310) 605-6527
fax: (310) 605-6529
Smart and Friendly
Van Nuys, CA
(818) 994-8001
fax: (818) 988-6581
Sony Corporation of America
Montvale, NJ
(201) 368-9272
Star Media Systems
Naperville, IL
(800) 775-3314
fax: (708) 355-4843
screen_link (56 Kbytes)
Digital Video is best deployed by launching small video clips from a CD-ROM interface. We used Asyme
trix's Compel to prototype our video project.
screen_link (46 Kbytes)
Video for Windows lets you select a throughput rate for video output. Note also the compression slider for output quality.
Stanford Diehl is director of BYTE Reviews and aspiring creative director of BYTE Video Productions. Previously, he designed computer-based training courses for a major industrial contractor. He has been installing, configuring, and testing computer hardware and software for over 10 years. You can reach him on the Internet or BIX at
sdiehl@bix.com
.
BYTE's Video Workshop
