This report describes efforts to use digital motion video compression technology to develop a highly portable device that would convert 1990-91 era IBM-compatible and/or MacIntosh notebook computers into full-color, motion-video capable multimedia training systems. An architecture was conceived that would permit direct conversion of existing laser-disk-based multimedia courses with little or no reauthoring. The project did not physically demonstrate certain critical video keying techniques, but their implementation should be feasible. This investigation of digital motion video has spawned two significant spaceflight projects at MSFC: one to downlink multiple high-quality video signals from Spacelab, and the other to uplink videoconference-quality video in realtime and high quality video off-line, plus investigate interactive, multimedia-based techniques for enhancing onboard science operations. Other airborne or spaceborne spinoffs are possible

Scott, D. W.

English

NASA Technical Reports Server

NASA
Technical
Memorandum
NASA TM - 10846o
s ?. ;/
PORTABLE COLOR MULTIMEDIA TRAINING SYSTEMS
BASED ON MONOCHROME LAPTOP COMPUTERS
(CBT-IN-A-BRIEFCASE), WITH SPINOFF IMPLICATIONS
FOR VIDEO UPLINK AND DOWNLINK IN SPACEFLIGHT
OPERATIONS
Center Director's Discretionary Fund Final Report
(Project Number 91-16)
By D.W. Scott
Mission Operations Laboratory
Science and Engineering Directorate
August 1994
(NASA-TM-108460) PORTABLE COLOR
MULTIMEDIA TRAINING SYSTEMS BASED
ON MONOCHROME LAPTOP COMPUTERS
(CBT-IN-A-_RIEFCASE)p WITH SPINOFF
IMPLICATIONS FOR VIDEO UPLINK AND
OOWNLINK IN SPACEFLIGHT OPERATIONS
Fina] Report (NASA. Marshall Space
Flight Center) 10 p
G3/61
N94-3 7556
Uncias
0019619
NASA
National Aeronautics and
Soace Administration
George C. Marshall Space Flight Center
MSFC- Form 3190 (Rev. May 1983)
https://ntrs.nasa.gov/search.jsp?R=19940033045 2020-06-16T11:38:27+00:00Z

REPORT DOCUMENTATION PAGE Form ApprovedOMB NO. 0704-0188
=Pub c reposing burden for this collection of information isestimated to average 1hour per response, includingthe time for reviewing instructions_searchingexist!ngdata sourc.e_,
gather ng and ma nta n ng the data needed, and completing and reviewing the collection of information. Send comments recjardlngthis burden esttmate or any other aspect ol"this
collectionof information, including suggestionsfor reducing this burden, to Washington Headquarters Serv ces,Directorate tor Information Operat ons and Reports, 1215 Jefferson
Davis Highway,Suite 1204, Arlington, VA 22202-4302, and to the Office of Managemen¢ and Budget,Paperwork Reduction Pro ect(0704-0188), Washington, DC 20503.
1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED '
August 1994 Technical Memorandum
i4.TITLEAND SUBTITLECenter Director's Discretionary Fund Final R__Fi_mNG NUMBERS
Portable Color Multimedia Training Systems Based on Monochrome
Laptop Computers (CBT-in-a-Briefcase), With Spinoff Implications
for Video Uplink and Downlink in Spaceflight Operations (CDDF 91-16)
6. AUTHOR(S)
D.W. Scott
7. PERFORMINGORGANIZATIONAME(S)AND ADDRESS(ES)
George C. Marshall Space Hight Center
Marshall Space Hight Center, Alabama 35812
19. SPONSORING/MONITORINGA ENCYNAME(S)AND ADDRESS(ES)
National Aeronautics and Space Administration
Washington, DC 20546
i8. PERFORMING ORGANIZATION
REPORT NUMBER
10. SPONSORING / MONITORING
AGENCY REPORT NUMBER
NASA TM - 108460
11. SUPPLEMENTARYNOTES
Prepared by Structures and Dynamics Laboratory, Science and Engineering Directorate.
12a. DISTRIBUTION/AVAILABILITY STATEMENT
Unclassified--Unlimited
12b. DISTRIBUTION CODE
13. ABSTRACT (Maximum 200words)
This report describes efforts to use digital motion video compression technology to develop
a highly portable device that would convert 1990-91 era IBM-compatible and/or Macintosh
notebook computers into full-color, motion-video capable multimedia training systems. An archi-
tecture was conceived that would permit direct conversion of existing laser-disk-based multimedia
courses with little or no reauthoring. The project did not physically demonstrate certain critical video
keying techiques, but their implementation should be feasible. This investigation of digitial motion
video has spawned two significant spaceflight projects at MSFC: one to downlink multiple high-
quality video signals from Spacelab, and the other to uplink videoconference-quality video in real-
time and high quality video off-line, plus investigate interactive, multimedia-based techniques for
enhancing onboard science operations. Other airborne or spaceborne spinoffs are possible.
14. SUBJECT TERMS
digital motion video, video compression, multimedia, uplink
17. SECURITY CLASSIFICATION 18.
OF REPORT
Unclassified
NSN 7540-01-280-5500
SECURITY CLASSIFICATION
OF THIS PAGE
Unclassified
19. SECURITY CLASSIFICATION
OF ABSTRACT
Unclassified
15. NUMBER OF PAGES
10
16. PRICE CODE
NTIS
20. LIMITATIONOFABSTRACT
Unlimited
Standard Form 298 (Rev. 2-89)
Prescribed by ANSI Std. Z39-18
298-102

TABLE OF CONTENTS
INTRODUCTION ..........................................................................................................................
APPROACH ...................................................................................................................................
DIRECT CONCLUSIONS .............................................................................................................
IMPLICATIONS FOR SPACEFLIGHT ......................................................................................
Page
1
2
5
5
ill _ P_A_E IILAHX J)I().TFJLI_ED

LIST OF ILLUSTRATIONS
Figure
1.
2.
3.
Title
CBT-in-a-briefcase video concept .............................................................................
Digital versus analog keying in a DVI TM environment ...................................
Equipment setup for CBT-in-a-briefcase development. ......................................
Page
2
3
4
iv

TECHNICAL MEMORANDUM
PORTABLE COLOR MULTIMEDIA TRAINING SYSTEMS BASED ON MONOCHROME
LAPTOP COMPUTERS (CBT-IN-A-BRIEFCASE), WITH SPINOFF IMPLICATIONS
FOR VIDEO UPLINK AND DOWNLINK IN SPACEFLIGHT OPERATIONS
INTRODUCTION
Computer-based training (CBT) covers a wide range of electronic teaching tools and
methods, but its classic form involves combining text, graphics, animation, motion video, and sound
to provide a highly interactive environment for the student. Properly authored CBT is engaging and
promotes better retention of knowledge than traditional teaching methods. (Plus, the "instructor" is
inexhaustible!) Versatility and speed in selecting and playing video clips or stills is typically pro-
vided by having the CBT computer send control signals to a laser-disk player. Output from the
laser-disk player may be displayed on a separate screen, but overlaying retrieved video on a portion
of the CBT computer's screen is generally preferred.
Laser-disk-based systems are somewhat bulky and moderately expensive, so using them in
NASA's mission training would involve centralization, hence scheduling complications. Many NASA
personnel, particularly flight crewmembers, have notebook computers. If a small, inexpensive add-on
device would convert those machines into training systems, students could work at their conven-
ience (time and place). Although the intended prototype would be briefcase-sized, later versions
could be miniaturized. Ideally, CBT output would be sent to an ordinary NTSC television, so the stu-
dent could train at home or in a hotel room as well as at the office.
The main advantage of laser-disk systems is virtually instant random access to video clips
and/or stills. "Editing" is extremely easy---one need only provide video frame numbers or time
synchronization codes and playback speed. (There are 30 frames per second in a standard television
signal). Most digital approaches require a distinct file for each clip or still, so converting a laser-disk-
based course could require significant re-authoring. An important goal of this project was to allow
direct conversion of a laser-disk-based course by digitizing the laser-disk image into a single file and
deriving digital byte offsets from analog frame counters. This could have significant implications where
large bodies of laser-disk courses already exist, such as in the airline and automotive industries.
Motion video digitizing and compression schemes work by sampling an analog image, con-
verting it from lines to pixels, then reducing the number of bits required to store the digital informa-
tion. Some approaches use add-in hardware boards, while others are software only. The differences
lie in image size, speed of motion, storage space required, and of course, price. With or without
hardware assistance, certain software techniques are typically used:
Cosine transforms
Averaging color pixels (humans are much more sensitive to detail than color)
Describing repeated pixels once, with a counter telling how many times to repeat it (intra-
frame coding)
Storing a reference frame, then describing only the changes to it until a certain percentage of
pixels have changed, when a new reference frame is stored (interframe coding)
Thefirst threecanbe donein real-time,while interframecodingtypically requiresoff-line
processing.
APPROACH
Originally, separate devices were to be developed for Macintosh and IBM environments, with
extensive software manipulation of digital video within each device. Investigation revealed that this
would require an excessively large hardware and software development capability. Since reasonably
inexpensive, commercially developed digitizing hardware was becoming available as this discovery ,
was made, the concept evolved towards a single device that could be driven by either platform. The
core of the effort involved (1) integrating decompressed video with graphics from an external laptop
computer and (2) making the discreet-file-based decompressor look like a continuous-stream laser-,
disk device in the eyes of the laptop computer. Video was the main focus, as audio capability is _
generally embedded in processors and file schemes capable of handling video. Converting signals
from VGA to NTSC was originally a research issue, but disappeared as inexpensive commercial
products proliferated. Figure 1 depicts the selected hardware architecture.
Color LCD Screen i
(Optional) I
s 1
_ I
Briefcase
System
Hard drive or(> devel) ROH
Combine video with
add effects
motion
¢ldeo
Intelo DVI ¢lrd
H 386 System Board,AT Bus
Figure 1.
VGA/NTSC Out
VGA Graphics, Animation,
Notebook Computer (Mac or PC)
i
(Serial) video indexing and control commands, including effects
CBT-in-a-briefcase video concept.
An 80386-with-ISA expansion board architecture was chosen for its simplicity and relative
ease of implementation. The Intel/IBM Action Media II expansion board used relies on Intel's Digi-
tal Video Interactive, or DVI TM, technology. DVV u relies on a pair of very fast graphics chips, one
for manipulating individual pixels, the other for processing entire frames of pixels. The board is
designed to be upgradeable via software improvements. An essential feature is the ability to "key"
the DVIrU-generated video (still or motion) to a VGA graphics signal generated internally or exter-
nally relative to the host PC. Figure 2 illustrates the two types of keying.
Although the DVI TM hardware was designed to support analog or external keying, establish-
ing a software environment for delving into the core of the project became an Achilles heel.
Resources for developing machine-level drivers for the DVI TM hardware were not available, and
certain machine-level documentation had not been made public until near the end of the project, so
we had to rely on commercially available development tools.
Digital _ Analog
Keying Keying
0011100
tYi;2;Card
Analog
Multiplexer
DVI
Delivery Board
40st Interface=
VRAM
t
Data from
video file
1001101
0011010
D/A I
/ ideo Card
BE ]B
I I Analog
I Multiplexer I
• _:Yit;fi e 1_m
ml
)etect "black" JlKeying I -lost Interfaces,
<SO mllllvolts) Lo_..L.ogic,..J _VI VRAM
Del ivery Board
Data from
video file
Legend
Analog Digital
Symbo I Entity Symbol
System video 1001101
0011010
(with keying field) oo111o0
I_ Decompressed video B
Signal Flow --_
Figure 2. Digital versus analog keying in a DVI TM environment.
Figure 3 shows the hardware setup used for attempts at analog (external) keying. A tower
configuration PC represented the device to be developed. (Note: The DVI TM video board includes a
dedicated SCSI controller designed specifically for CD-ROM players.)
Initially, Intel's DOS-based "AVSS" environment was used, but it failed to support external
keying. Experiments were then conducted with IBM's "Action Media Developer's Toolkit" under
OS/2, which relies on external keying because OS/2 does not support digital feature connectors on
display cards. However, the Microsoft C (Version 6.0) debugging environment was not compatible
with the then-current version of OS/2 (2.0). Working with an unmodified sample player program, the
audio track of a DVI TM motion video file would play when the notebook machine was connected, but
video display could not be obtained. It was essential that a graphics-type VGA signal (e.g., Windows,
3
as opposed to a DOS display) be present to provide enough sync information to satisfy certain drivers.
Audio playback was also obtained with a Macintosh Powerbook attached.
386/20MHz
Notebook PC
or Mac Powerbook
ff" w/VGA output
/_ Notebook
Y-cable t_ RGB&Sync,"
Keyed VGA N_. I
Output
_=_____LI DVI Video Board
'_== I I (w/CD-ROM control ler
AT Bus
System Video Board
SCSI Controller
Hard Disk (video files)
l CD-ROM (video files)
Figure 3. Equipment setup for CBT-in-a-briefcase development.
A DOS-based, Microsoft C-compatible environment called New World was obtained. Analog
keying support was lacking at rest, but, due to inputs from this project and other developers, the
manufacturer produced a new version that, according to its documentation, had the necessary
features. Unfortunately, a three-way clash occurred involving video output from the DVI TM board,
system video from the sample playback program we were working with, and debugger output. Use of
a third display card and monitor would probably have resolved the conflict, but this was not available.
Contact with other developers indicates that relatively little work has been done with external
keying for other than mundane support of the OS/2 operating system.
Without debug capability, investigation of keying colors and adjustments of other parameters
could not successfully be made. It is possible that the "black" voltages generated by the notebook
computers were higher than the 50-mV threshold that the ActionMedia II board uses for digital
keying. This consideration came to light in technical discussions with Intel after active research had
ended.
An important feature of the intended design was the ability to convert laser-disk-based
courseware with minimal re-authoring. This could be accomplished by digitizing and compressing the
laser-disk video as a single file and storing SMPTE time codes within the file. (DVI's TM AVSS file
structure provides for such substreams. Time codes can be extracted from the laser disk or gener-
ated during compression.)
4
Toward the endof thetime allottedfor research,hardwareconformingto the Motion Picture
ExpertsGroup (MPEG) beganto emerge.Theprincipal investigator(PI) did not havetime to work
with MPEG,but hasseendemonstrationsandnotedexcellentpicture qualityman order of magni-
tude higher thanDVI TM (in the PI's subjective opinion). Discussion with other investigators indi-
cates that analog frame numbers can also be encoded directly into the data stream of an MPEG-1
file during compression.
Concepts for integrating the proposed device with commercial authoring systems were dis-
cussed with several publishers. If hardware development had proceeded more smoothly, two or three
would have provided source code (under nondisclosure agreements) to allow the PI to develop driver
software. One small company became extremely interested in the project, provided extensive techni-
cal visits, and was eager to co-develop drivers. Unfortunately, the principal engineer passed on sud- ,
denly and the company closed.
DIRECT CONCLUSIONS
The intended device could be developed if a more robust debugging environment were estab-
lished. If developed, use of MPEG video is recommended due to higher quality compared to DVI TM.
There is still intrinsic value in being able to convert a "plain vanilla" notebook computer into
a full-color multimedia system, particularly if one has a significant investment in laser-disk-based
courseware. Two factors may reduce the intrinsic value for other environments:
( 1 ) Inexpensive digital video on everyday desktop computers and the sheer number of com-
puters may make CBT training sufficiently accessible.
(2) Decreasing cost of color notebook computers, subnotebooks, personal digital assistants,
and consumer devices.
IMPLICATIONS FOR SPACEFLIGHT
While contemplating video compression methods and data flow rates, the thought arose that
this technology might be used to uplink motion video to the space shuttle. A 128-kbit/sec bandwidth,
currently used for what amounts to fax transmissions, is available. Unfortunately, DVI TM requires
150 k.b.y._/sec for full-screen video, but it was thought that a smaller window might be transmitted.
Further examination has shown that commercial desktop video teleconferencing systems available
on AT-bus expansion cards would be better suited for this application, since they are designed to
run in the 56- to 128-kbit range. However, DVI TM and MPEG hold potential as a means of
transferring detailed full-screen video off-line, e.g. 10-minute transmission time to upload 1 minute
of video. Marshall Space Flight Center and Johnson Space Center are jointly sponsoring an effort to
demonstrate motion video uplink.
While discussing video uplink possibilities, the need for multiple-channel high-quality video
downlink from the shuttle (particularly during video-intensive Spacelab missions) surfaced. The PI
was able to identify other (non-DVI TM) compression schemes with extremely high resolution, using
about 6 megabits per second. Such wide-band channels are readily available via the Spacelab high
rate multiplexer. This has led to a flight project to downlink six motion video channels simultane-
ously on the USML-2 mission.
5
APPROVAL
PORTABLE COLOR MULTIMEDIA TRAINING SYSTEMS BASED ON MONOCHROME
LAPTOP COMPUTERS (CBT-IN-A-BRIEFCASE), WITH SPINOFF IMPLICATIONS
FOR VIDEO UPLINK AND DOWNLINK IN SPACEFLIGHT OPERATIONS
By D.W. Scott
The information in this report has been reviewed for technical content. Review of any informa-
tion concerning Department of Defense or nuclear energy activities or programs has been made by
the MSFC Security Classification Officer. This report, in its entirety, has been determined to be
unclassified.
/
./7, /.....
H'ir_,E_vli "_n _e ra fiL_ons L_oratory
6


Portable color multimedia training systems based on monochrome laptop computers (CBT-in-a-briefcase), with spinoff implications for video uplink and downlink in spaceflight operations

Portable color multimedia training systems based on monochrome laptop computers (CBT-in-a-briefcase), with spinoff implications for video uplink and downlink in spaceflight operations

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server