U.S. patent application number 10/880272 was filed with the patent office on 2004-12-02 for system, method and article of manufacture for late synchronization during the execution of a multimedia event on a plurality of client computers.
This patent application is currently assigned to InterActual Technologies, Inc.. Invention is credited to Collart, Todd R., Getsin, Evgeniy M., Lewis, Michael J..
Application Number | 20040244041 10/880272 |
Document ID | / |
Family ID | 32713728 |
Filed Date | 2004-12-02 |
United States Patent
Application |
20040244041 |
Kind Code |
A1 |
Getsin, Evgeniy M. ; et
al. |
December 2, 2004 |
System, method and article of manufacture for late synchronization
during the execution of a multimedia event on a plurality of client
computers
Abstract
A system, method and article of manufacture are provided for
delayed synchronization of an event on a plurality of client
apparatuses. First, a plurality of client apparatuses are connected
via a network and an event is stored in memory on the client
apparatuses. The event is then simultaneously played back on the
client apparatuses utilizing the network. During the simultaneous
playback, a request may be received from one of the client
apparatuses for that particular client to be included in the
synchronized event. In response to the request, information is
transmitted to the requesting client apparatus utilizing the
network. This information is adapted for identifying a location in
the memory where the event is currently being played back on the
remaining client apparatuses. This allows the simultaneous playback
of the event on the requesting client apparatus.
Inventors: |
Getsin, Evgeniy M.; (Los
Altos, CA) ; Lewis, Michael J.; (Aurora, CA) ;
Collart, Todd R.; (Los Altos, CA) |
Correspondence
Address: |
FITCH EVEN TABIN AND FLANNERY
120 SOUTH LA SALLE STREET
SUITE 1600
CHICAGO
IL
60603-3406
US
|
Assignee: |
InterActual Technologies,
Inc.
San Jose
CA
|
Family ID: |
32713728 |
Appl. No.: |
10/880272 |
Filed: |
June 28, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10880272 |
Jun 28, 2004 |
|
|
|
09488613 |
Jan 20, 2000 |
|
|
|
6769130 |
|
|
|
|
Current U.S.
Class: |
725/89 |
Current CPC
Class: |
G06F 21/10 20130101;
H04L 65/604 20130101 |
Class at
Publication: |
725/089 |
International
Class: |
G06F 015/16 |
Claims
What is claimed is:
1. A method for delayed synchronization of an event on a plurality
of client apparatuses, comprising the steps of: connecting a
plurality of client apparatuses via a network; providing an event
stored in a memory storage device on each of the plurality of
client apparatuses; transmitting information from a host apparatus
to the plurality of client apparatuses to start a synchronized
event, wherein the synchronized event includes playback of the
event on each of the plurality of client apparatuses; receiving a
request from an additional client apparatus during the synchronized
event; and transmitting additional information from the host
apparatus to the additional client apparatus to allow the
additional client apparatus to join the synchronized event; wherein
only the host apparatus can transmit the additional information to
allow the additional client apparatus to join the synchronized
event.
2. A method as recited in claim 1, wherein said information
includes a history of simultaneous playback.
3. A method of claim 1, wherein said client apparatus is a
computer.
4. A method as recited in claim 1, wherein said request is received
utilizing said network.
5. A method as recited in claim 1, wherein said synchronized event
includes at least one of a movie, a concert, and a theatrical
event.
6. A method as recited in claim 1, wherein said memory storage
device includes a DVD.
7. A method as recited in claim 1, wherein said information
includes chapter information associated with said memory storage
device.
8. A method as recited in claim 1, wherein said information
includes title information associated with said memory storage
device.
9. A method as recited in claim 1, wherein said information
includes start time information associated with said memory storage
device.
10. A method as recited in claim 1, wherein said information
includes stop time information associated with said memory storage
device.
11. A method as recited in claim 1, wherein said information
includes DVD command information associated with said memory
storage device.
12. A method as recited in claim 1, wherein said information
includes client apparatus capability information associated with
said memory storage device.
13. A method as recited in claim 1, wherein said information
includes user information associated with said memory storage
device.
14. A method as recited in claim 1, wherein said network is a wide
area network.
15. A method for synchronizing an event, comprising the steps of:
providing an event stored in a first memory storage device on a
first client apparatus; providing the event stored in a second
memory storage device on a second client apparatus; connecting the
first client apparatus and the second client apparatus to a host
apparatus utilizing a computer network; and transmitting
information from the host apparatus to the first client apparatus
and the second client apparatus utilizing the network for allowing
the simultaneous playback of the event on each of the first client
apparatus and the second client apparatus; wherein only the host
apparatus can transmit the information to the first client
apparatus and the second client apparatus for allowing the
simultaneous playback of the event on each of the first client
apparatus and the second client apparatus.
16. A method as recited in claim 15, wherein said information
includes a history of the simultaneous playback.
17. A method of claim 15, wherein said client apparatus is a
computer.
18. A method as recited in claim 15, wherein said event includes at
least one of a movie, a concert, and a theatrical event.
19. A method as recited in claim 15, wherein said memory storage
device includes a DVD.
20. A method as recited in claim 15, wherein said information
includes chapter information associated with said memory storage
device.
21. A method as recited in claim 15, wherein said information
includes title information associated with said memory storage
device.
22. A method as recited in claim 15, wherein said information
includes start time information associated with said memory storage
device
23. A method as recited in claim 15, wherein said information
includes stop time information associated with said memory storage
device
24. A method as recited in claim 15, wherein said information
includes DVD command information associated with said memory
storage device.
25. A method as recited in claim 15, wherein said information
includes client apparatus capability information associated with
said memory storage device.
26. A method as recited in claim 15, wherein said information
includes user information associated with said memory storage
device.
27. A method as recited in claim 9, wherein said network is a wide
area network.
28. A method for delayed synchronization of an event on a plurality
of client apparatuses, comprising the steps of: connecting a
plurality of client apparatuses via a network; providing an event
stored in a memory storage device on each of the plurality of
client apparatuses; transmitting information from a host apparatus
to the plurality of client apparatuses to start a synchronized
event, wherein the synchronized event includes playback of the
event on each of the plurality of client apparatuses; receiving a
request from an additional client apparatus during the synchronized
event; and transmitting information from the host apparatus to the
additional client apparatus to allow the additional client
apparatus to join the synchronized event; wherein the information
to allow the additional client apparatus to join the synchronized
event also includes a history of the synchronized event.
29. A method of claim 28, wherein said client apparatuses are
computers.
30. A method as recited in claim 28, wherein said request is
received utilizing said network.
31. A method as recited in claim 28, wherein said synchronized
event includes at least one of a movie, a concert, and a theatrical
event.
32. A method as recited in claim 28, wherein said memory storage
device includes a DVD.
33. A method as recited in claim 28, wherein said information
includes chapter information associated with said memory storage
device.
34. A method as recited in claim 28, wherein said information
includes title information associated with said memory storage
device.
35. A method as recited in claim 28, wherein said information
includes start time information associated with said memory storage
device
36. A method as recited in claim 28, wherein said information
includes stop time information associated with said memory storage
device
37. A method as recited in claim 28, wherein said information
includes DVD command information associated with said memory
storage device.
38. A method as recited in claim 28, wherein said information
includes client apparatus capability information associated with
said memory storage device.
39. A method as recited in claim 28, wherein said information
includes user information associated with said memory storage
device.
40. A method as recited in claim 28, wherein said network is a wide
area network.
41. A method for synchronizing an event, comprising the steps of:
connecting a first client apparatus to host apparatus utilizing a
computer network, wherein the first client apparatus accesses an
event stored in a first memory storage device; connecting a second
client apparatus to the host apparatus utilizing the computer
network, wherein the second client apparatus accesses the event
stored in a second memory storage device; and transmitting
information from the host apparatus to the first client apparatus
and the second client apparatus utilizing the network for allowing
the simultaneous playback of the event on each of the first client
apparatus and the second client apparatus; wherein only the host
apparatus can transmit the information to the first client
apparatus and the second client apparatus for allowing the
simultaneous playback of the event on each of the first client
apparatus and the second client apparatus.
42. A method as recited in claim 41, wherein said information
includes a history of simultaneous playback.
43. A method of claim 41, wherein said client apparatus is a
computer.
44. A method as recited in claim 41, wherein said request is
received utilizing said network.
45. A method as recited in claim 41, wherein said synchronized
event includes at least one of a movie, a concert, and a theatrical
event.
46. A method as recited in claim 41, wherein said memory storage
device includes a DVD.
47. A method as recited in claim 41, wherein said information
includes chapter information associated with said memory storage
device.
48. A method as recited in claim 41, wherein said network is a wide
area network.
Description
RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. patent
application Ser. No. 09/488,613, filed Jan. 20, 2000, entitled A
SYSTEM, METHOD, AND ARTICLE OF MANUFACTURE FOR LATE SYNCHRONIZATION
DURING THE EXECUTION OF A MULTIMEDIA EVENT ON A PLURALITY OF CLIENT
COMPUTERS, now pending, which is incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates to network synchronization and
more particularly to synchronizing the playback of a multimedia
event on a plurality of client apparatuses.
BACKGROUND OF THE INVENTION
[0003] Systems such as the Internet typically are point-to-point
(or unicast) systems in which a message is converted into a series
of addressed packets which are routed from a source node through a
plurality of routers to a destination node. In most communication
protocols the packet includes a header which contains the addresses
of the source and the destination nodes as well as a sequence
number which specifies the packet's order in the message.
[0004] In general, these systems do not have the capability of
broadcasting a message from a source node to all the other nodes in
the network because such a capability is rarely of much use and
could easily overload the network. However, there are situations
where it is desirable for one node to communicate with some subset
of all the nodes. where it is desirable for one node to communicate
with some subset of all the nodes. For example, multi-party
conferencing capability analogous to that found in the public
telephone system and broadcasting to a limited number of nodes are
of considerable interest to users of packet-switched networks. To
satisfy such demands, packets destined for several recipients have
been encapsulated in a unicast packet and forwarded from a source
to a point in a network where the packets have been replicated and
forwarded on to all desired recipients. This technique is known as
IP Multicasting and the network over which such packets are routed
is referred to as the Multicast Backbone or MBONE. More recently,
routers have become available which can route the multicast
addresses (class D addresses) provided for in communication
protocols such as TCP/IP and UDP/IP. A multicast address is
essentially an address for a group of host computers who have
indicated their desire to participate in that group. Thus, a
multicast packet can be routed from a source node through a
plurality of multicast routers (or mrouters) to one or more devices
receiving the multicast packets. From there the packet is
distributed to all the host computers that are members of the
multicast group.
[0005] These techniques have been used to provide on the Internet
audio and video conferencing as well as radio-like broadcasting to
groups of interested parties. See, for example, K. Savetz et al.
MBONE Multicasting Tomorrow's Internet (IDG Books WorldWide Inc.,
1996).
[0006] Further details concerning technical aspects of multicasting
may be found in the Internet documents Request for Comments (RFC)
1112 and 1458 which are reproduced at Appendices A and B of the
Savetz book and in D. P. Brutaman et al., "MBONE provides Audio and
Video Across the Internet," IEEE Computer, Vol. 27, No. 4, pp.
30-36 (April 1994), all of which are incorporated herein by
reference.
[0007] Multimedia computer systems have become increasingly popular
over the last several years due to their versatility and their
interactive presentation style. A multimedia computer system can be
defined as a computer system having a combination of video and
audio outputs for presentation of audio-visual displays. A modem
multimedia computer system typically includes one or more storage
devices such as an optical drive, a CD-ROM, a hard drive, a
videodisc, or an audiodisc, and audio and video data are typically
stored on one or more of these mass storage devices. In some file
formats the audio and video are interleaved together in a single
file, while in other formats the audio and video data are stored in
different files, many times on different storage media. Audio and
video data for a multimedia display may also be stored in separate
computer systems that are networked together. In this instance, the
computer system presenting the multimedia display would receive a
portion of the necessary data from the other computer system via
the network cabling.
[0008] Graphic images used in Windows multimedia applications can
be created in either of two ways, these being bit-mapped images and
vector-based images. Bit-mapped images comprise a plurality of
picture elements (pixels) and are created by assigning a color to
each pixel inside the image boundary. Most bit-mapped color images
require one byte per pixel for storage, so large bit-mapped images
create correspondingly large files. For example, a full-screen,
256-color image in 640-by-480-pixel VGA mode requires 307,200 bytes
of storage, if the data is not compressed. Vector-based images are
created by defining the end points, thickness, color, pattern and
curvature of lines and solid objects comprised within the image.
Thus, a vector-based image includes a definition which consists of
a numerical representation of the coordinates of the object,
referenced to a corner of the image.
[0009] Bit-mapped images are the most prevalent type of image
storage format, and the most common bit-mapped-image file formats
are as follows. A file format referred to as BMP is used for
Windows bit-map files in 1-, 2-, 4-, 8-, and 24-bit color depths.
BMP files contain a bit-map header that defines the size of the
image, the number of color planes, the type of compression used (if
any), and the palette used. The Windows DIB (device-independent
bit-map) format is a variant of the BMP format that includes a
color table defining the RGB (red green blue) values of the colors
used. Other types of bit-map formats include the TIF (tagged image
format file), the PCX (Zsoft Personal Computer Paintbrush Bitmap)
file format, the GIF (graphics interchange file) format, and the
TGA (Texas Instruments Graphic Architecture) file format.
[0010] The standard Windows format for bit-mapped images is a
256-color device-independent bit map (DIB) with a BMP (the Windows
bit-mapped file format) or sometimes a DIB extension. The standard
Windows format for vector-based images is referred to as WMF
(Windows meta file).
[0011] Full-motion video implies that video images shown on the
computer's screen simulate those of a television set with identical
(30 frames-per-second) frame rates, and that these images are
accompanied by high-quality stereo sound. A large amount of storage
is required for high-resolution color images, not to mention a
full-motion video sequence. For example, a single frame of NTSC
video at 640-by-400-pixel resolution with 16-bit color requires
512K of data per frame. At 30 flames per second, over 15 Megabytes
of data storage are required for each second of full motion video.
Due to the large amount of storage required for full motion video,
various types of video compression algorithms are used to reduce
the amount of necessary storage. Video compression can be performed
either in real-time, i.e., on the fly during video capture, or on
the stored video file after the video data has been captured and
stored on the media. In addition, different video compression
methods exist for still graphic images and for full-motion
video.
[0012] Examples of video data compression for still graphic images
are RLE (run-length encoding) and JPEG (Joint Photographic Experts
Group) compression. RLE is the standard compression method for
Windows BMP and DIB files. The RLE compression method operates by
testing for duplicated pixels in a single line of the bit map and
stores the number of consecutive duplicate pixels rather than the
data for the pixel itself. JPEG compression is a group of related
standards that provide either lossless (no image quality
degradation) or lossy (imperceptible to severe degradation)
compression types. Although JPEG compression was designed for the
compression of still images rather than video, several
manufacturers supply JPEG compression adapter cards for motion
video applications.
[0013] In contrast to compression algorithms for still images, most
video compression algorithms are designed to compress full motion
video. Video compression algorithms for motion video generally use
a concept referred to as interframe key frame. Successive frames
are compared with the key frame, and only the differences between
the digitized data from the key frame and from the successive
frames are stored. Periodically, such as when new scenes are
displayed, new key frames are digitized and stored, and subsequent
comparisons begin from this new reference point. It is noted that
interframe compression ratios are content-dependent, i.e., if the
video clip being compressed includes many abrupt scene transitions
from one image to another, the compression is less efficient.
Examples of video compression which use an interframe compression
technique are MPEG, DVI and Indeo, among others.
[0014] MPEG (Moving Pictures Experts Group) compression is a set of
methods for compression and decompression of full motion video
images that uses the interframe compression technique described
above. The MPEG standard requires that sound be recorded
simultaneously with the video data, and the video and audio data
are interleaved in a single file to attempt to maintain the video
and audio synchronized during playback. The audio data is typically
compressed as well, and the MPEG standard specifies an audio
compression method referred to as ADPCM (Adaptive Differential
Pulse Code Modulation) for audio data.
[0015] A standard referred to as Digital Video Interactive (DVI)
format developed by Intel Corporation is a compression and storage
format for full-motion video and high-fidelity audio data. The DVI
standard uses interframe compression techniques similar to that of
the MPEG standard and uses ADPCM compression for audio data. The
compression method used in DVI is referred to as RTV 2.0 (real time
video), and this compression method is incorporated into Intel's
AVK (audio/video kernel) software for its DVI product line. IBM has
adopted DVI as the standard for displaying video for its Ultimedia
product line. The DVI file format is based on the Intel i750
chipset and is supported through the Media Control Interface (MCI)
for Windows. Microsoft and Intel jointly announced the creation of
the DV MCI (digital video media control interface) command set for
Windows 3.1 in 1992.
[0016] The Microsoft Audio Video Interleaved (AVI) format is a
special compressed file structure format designed to enable video
images and synchronized sound stored on CD-ROMs to be played on PCs
with standard VGA displays and audio adapter cards. The AVI
compression method uses an interframe method, i.e., the differences
between successive frames are stored in a manner similar to the
compression methods used in DVI and MPEG. The AVI format uses
symmetrical software compression-decompression techniques, i.e.,
both compression and decompression are performed in real time. Thus
AVI files can be created by recording video images and sound in AVI
format from a VCR or television broadcast in real time, if enough
free hard disk space is available.
[0017] Despite these compression algorithms, it is very difficult
to simultaneously multicast multimedia material due to bandwidth
restraints. This problem is unavoidable with present technology
since such large amounts of data must be transferred over networks
such as the Internet from a single host server to numerous client
computers.
SUMMARY OF THE INVENTION
[0018] A system, method and article of manufacture are provided for
delayed synchronization of an event on a plurality of client
apparatuses. First, a plurality of client apparatuses are connected
via a network and an event is stored in memory on the client
apparatuses. The event is then simultaneously played back on the
client apparatuses utilizing the network. During the simultaneous
playback, a request may be received from one of the client
apparatuses for that particular client to be included in the
synchronized event. In response to the request, information is
transmitted to the requesting client apparatus utilizing the
network. This information is adapted for identifying a location in
the memory where the event is currently being played back on the
remaining client apparatuses. This allows the simultaneous playback
of the event on the requesting client apparatus. In one embodiment
of the present invention, the request may be received utilizing the
network.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The invention will be better understood when consideration
is given to the following detailed description thereof. Such
description makes reference to the annexed drawings wherein:
[0020] FIG. 1 is a schematic diagram of a hardware implementation
of one embodiment of the present invention;
[0021] FIG. 2 illustrates a flowchart delineating a method for
synchronizing an event on a plurality of client apparatuses in
accordance with one embodiment of the present invention;
[0022] FIG. 3 illustrates a flowchart delineating a method for
storing synchronization information for subsequent playback of an
event in accordance with one embodiment of the present
invention;
[0023] FIG. 4 illustrates a flowchart setting forth a method for
providing overlays during a synchronized event on a plurality of
client apparatuses in accordance with one embodiment of the present
invention;
[0024] FIG. 5 illustrates a flow diagram for delayed
synchronization of an event on a plurality of client apparatuses in
accordance with one embodiment of the present invention;
[0025] FIG. 6 illustrates a flow diagram for providing information
on a synchronized event on a plurality of client apparatuses in
accordance with one embodiment of the present invention;
[0026] FIG. 7 illustrates a method for creating a synchronizer
object in order to playback an event simultaneously on a plurality
of client apparatuses in accordance with one embodiment of the
present invention;
[0027] FIG. 8 illustrates a flowchart for affording a scheduler
object adapted to facilitate the playback of an event
simultaneously on a plurality of networked client apparatuses in
accordance with one embodiment of the present invention;
[0028] FIG. 9 is a flowchart delineating a method for identifying a
plurality of events which are played back simultaneously on a
plurality of networked client apparatuses in accordance with one
embodiment of the present invention;
[0029] FIG. 10 shows a flowchart delineating a technique for
interfacing a plurality of different types of playback devices of
client apparatuses which are networked to simultaneously playback
an event in accordance with one embodiment of the present
invention;
[0030] FIG. 11 illustrates the manner in which a layer factory is
created in accordance with one embodiment of the present
invention;
[0031] FIG. 12 illustrates the manner in which user requests are
processed in accordance with one embodiment of the present
invention;
[0032] FIGS. 13-16 illustrate various class/component diagrams in
accordance with one embodiment of the present invention;
[0033] FIG. 17 illustrates a logical sequence diagram in accordance
with one embodiment of the present invention;
[0034] FIG. 18 illustrates a logical sequence diagram that shows
server side collaboration in accordance with one embodiment of the
present invention; and
[0035] FIG. 19 illustrates a logical sequence diagram showing
client side collaboration in accordance with one embodiment of the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] FIGS. 1-19 illustrate a system for synchronizing an event on
a plurality of client apparatuses. Prior to use, an event is stored
in memory on at least one of the client apparatuses. Such client
apparatuses are adapted to be connected to a network along with a
host computer(s). In operation, information is transmitted from the
host computer to the at least one client apparatus utilizing the
network. This information allows for the simultaneous and
synchronous playback of the event on each of the client
apparatuses.
[0037] In various embodiments, the client apparatuses may take the
form of computers, televisions, stereos, home appliances, or any
other types of devices. In one embodiment, the client apparatuses
and the host computer each include a computer such as an IBM
compatible computer, Apple Macintosh computer or UNIX based
workstation.
[0038] A representative hardware environment is depicted in FIG. 1,
which illustrates a typical hardware configuration of a workstation
in accordance with a preferred embodiment having a central
processing unit 110, such as a microprocessor, and a number of
other units interconnected via a system bus 112. The workstation
shown in FIG. 1 includes a Random Access Memory (RAM) 114, Read
Only Memory (ROM) 116, an I/O adapter 118 for connecting peripheral
devices such as disk storage units 120 (i.e. DVD playback device)
to the bus 112, a user interface adapter 122 for connecting a
keyboard 124, a mouse 126, a speaker 128, a microphone 132, and/or
other user interface devices such as a touch screen (not shown) to
the bus 112, communication adapter 134 for connecting the
workstation to a communication network (e.g., a data processing
network) and a display adapter 136 for connecting the bus 112 to a
display device 138. The workstation typically has resident thereon
an operating system such as the Microsoft Windows NT or Windows/95
Operating System (OS), the IBM OS/2 operating system, the MAC OS,
or UNIX operating system. Those skilled in the art will appreciate
that the present invention may also be implemented on platforms and
operating systems other than those mentioned.
[0039] A preferred embodiment is written using JAVA, C, and the C++
language and utilizes object oriented programming methodology.
Object oriented programming (OOP) has become increasingly used to
develop complex applications. As OOP moves toward the mainstream of
software design and development, various software solutions require
adaptation to make use of the benefits of OOP. A need exists for
these principles of OOP to be applied to a messaging interface of
an electronic messaging system such that a set of OOP classes and
objects for the messaging interface can be provided.
[0040] OOP is a process of developing computer software using
objects, including the steps of analyzing the problem, designing
the system, and constructing the program. An object is a software
package that contains both data and a collection of related
structures and procedures. Since it contains both data and a
collection of structures and procedures, it can be visualized as a
self-sufficient component that does not require other additional
structures, procedures or data to perform its specific task. OOP,
therefore, views a computer program as a collection of largely
autonomous components, called objects, each of which is responsible
for a specific task. This concept of packaging data, structures,
and procedures together in one component or module is called
encapsulation.
[0041] In general, OOP components are reusable software modules
which present an interface that conforms to an object model and
which are accessed at run-time through a component integration
architecture. A component integration architecture is a set of
architecture mechanisms which allow software modules in different
process spaces to utilize each others capabilities or functions.
This is generally done by assuming a common component object model
on which to build the architecture. It is worthwhile to
differentiate between an object and a class of objects at this
point. An object is a single instance of the class of objects,
which is often just called a class. A class of objects can be
viewed as a blueprint, from which many objects can be formed.
[0042] OOP allows the programmer to create an object that is a part
of another object. For example, the object representing a piston
engine is said to have a composition-relationship with the object
representing a piston. In reality, a piston engine comprises a
piston, valves and many other components; the fact that a piston is
an element of a piston engine can be logically and semantically
represented in OOP by two objects.
[0043] OOP also allows creation of an object that "depends from"
another object. If there are two objects, one representing a piston
engine and the other representing a piston engine wherein the
piston is made of ceramic, then the relationship between the two
objects is not that of composition. A ceramic piston engine does
not make up a piston engine. Rather it is merely one kind of piston
engine that has one more limitation than the piston engine; its
piston is made of ceramic. In this case, the object representing
the ceramic piston engine is called a derived object, and it
inherits all of the aspects of the object representing the piston
engine and adds further limitation or detail to it. The object
representing the ceramic piston engine "depends from" the object
representing the piston engine. The relationship between these
objects is called inheritance.
[0044] When the object or class representing the ceramic piston
engine inherits all of the aspects of the objects representing the
piston engine, it inherits the thermal characteristics of a
standard piston defined in the piston engine class. However, the
ceramic piston engine object overrides these ceramic specific
thermal characteristics, which are typically different from those
associated with a metal piston. It skips over the original and uses
new functions related to ceramic pistons. Different kinds of piston
engines have different characteristics, but may have the same
underlying functions associated with it (e.g., how many pistons in
the engine, ignition sequences, lubrication, etc.). To access each
of these functions in any piston engine object, a programmer would
call the same functions with the same names, but each type of
piston engine may have different/overriding implementations of
functions behind the same name. This ability to hide different
implementations of a function behind the same name is called
polymorphism and it greatly simplifies communication among
objects.
[0045] With the concepts of composition-relationship,
encapsulation, inheritance and polymorphism, an object can
represent just about anything in the real world. In fact, one's
logical perception of the reality is the only limit on determining
the kinds of things that can become objects in object-oriented
software. Some typical categories are as follows:
[0046] Objects can represent physical objects, such as automobiles
in a traffic-flow simulation, electrical components in a
circuit-design program, countries in an economics model, or
aircraft in an air-traffic-control system.
[0047] Objects can represent elements of the computer-user
environment such as windows, menus or graphics objects.
[0048] An object can represent an inventory, such as a personnel
file or a table of the latitudes and longitudes of cities.
[0049] An object can represent user-defined data types such as
time, angles, and complex numbers, or points on the plane.
[0050] With this enormous capability of an object to represent just
about any logically separable matters, OOP allows the software
developer to design and implement a computer program that is a
model of some aspects of reality, whether that reality is a
physical entity, a process, a system, or a composition of matter.
Since the object can represent anything, the software developer can
create an object which can be used as a component in a larger
software project in the future.
[0051] If 90% of a new OOP software program consists of proven,
existing components made from preexisting reusable objects, then
only the remaining 10% of the new software project has to be
written and tested from scratch. Since 90% already came from an
inventory of extensively tested reusable objects, the potential
domain from which an error could originate is 10% of the program.
As a result, OOP enables software developers to build objects out
of other, previously built objects.
[0052] This process closely resembles complex machinery being built
out of assemblies and sub-assemblies. OOP technology, therefore,
makes software engineering more like hardware engineering in that
software is built from existing components, which are available to
the developer as objects. All this adds up to an improved quality
of the software as well as an increased speed of its
development.
[0053] Programming languages are beginning to fully support the OOP
principles, such as encapsulation, inheritance, polymorphism, and
composition-relationship. With the advent of the C++ language, many
commercial software developers have embraced OOP. C++ is an OOP
language that offers a fast, machine-executable code. Furthermore,
C++ is suitable for both commercial-application and
systems-programming projects. For now, C++ appears to be the most
popular choice among many OOP programmers, but there is a host of
other OOP languages, such as Smalltalk, Common Lisp Object System
(CLOS), and Eiffel. Additionally, OOP capabilities are being added
to more traditional popular computer programming languages such as
Pascal.
[0054] The benefits of object classes can be summarized, as
follows:
[0055] Objects and their corresponding classes break down complex
programming problems into many smaller, simpler problems.
[0056] Encapsulation enforces data abstraction through the
organization of data into small, independent objects that can
communicate with each other. Encapsulation protects the data in an
object from accidental damage, but allows other objects to interact
with that data by calling the object's member functions and
structures.
[0057] Subclassing and inheritance make it possible to extend and
modify objects through deriving new kinds of objects from the
standard classes available in the system. Thus, new capabilities
are created without having to start from scratch.
[0058] Polymorphism and multiple inheritance make it possible for
different programmers to mix and match characteristics of many
different classes and create specialized objects that can still
work with related objects in predictable ways.
[0059] Class hierarchies and containment hierarchies provide a
flexible mechanism for modeling real-world objects and the
relationships among them.
[0060] Libraries of reusable classes are useful in many situations,
but they also have some limitations. For example:
[0061] Complexity. In a complex system, the class hierarchies for
related classes can become extremely confusing, with many dozens or
even hundreds of classes.
[0062] Flow of control. A program written with the aid of class
libraries is still responsible for the flow of control (i.e., it
must control the interactions among all the objects created from a
particular library). The programmer has to decide which functions
to call at what times for which kinds of objects.
[0063] Duplication of effort. Although class libraries allow
programmers to use and reuse many small pieces of code, each
programmer puts those pieces together in a different way. Two
different programmers can use the same set of class libraries to
write two programs that do exactly the same thing but whose
internal structure (i.e., design) may be quite different, depending
on hundreds of small decisions each programmer makes along the way.
Inevitably, similar pieces of code end up doing similar things in
slightly different ways and do not work as well together as they
should.
[0064] Class libraries are very flexible. As programs grow more
complex, more programmers are forced to reinvent basic solutions to
basic problems over and over again. A relatively new extension of
the class library concept is to have a framework of class
libraries. This framework is more complex and consists of
significant collections of collaborating classes that capture both
the small scale patterns and major mechanisms that implement the
common requirements and design in a specific application domain.
They were first developed to free application programmers from the
chores involved in displaying menus, windows, dialog boxes, and
other standard user interface elements for personal computers.
[0065] Frameworks also represent a change in the way programmers
think about the interaction between the code they write and code
written by others. In the early days of procedural programming, the
programmer called libraries provided by the operating system to
perform certain tasks, but basically the program executed down the
page from start to finish, and the programmer was solely
responsible for the flow of control. This was appropriate for
printing out paychecks, calculating a mathematical table, or
solving other problems with a program that executed in just one
way.
[0066] The development of graphical user interfaces began to turn
this procedural programming arrangement inside out. These
interfaces allow the user, rather than program logic, to drive the
program and decide when certain actions should be performed. Today,
most personal computer software accomplishes this by means of an
event loop which monitors the mouse, keyboard, and other sources of
external events and calls the appropriate parts of the programmer's
code according to actions that the user performs. The programmer no
longer determines the order in which events occur. Instead, a
program is divided into separate pieces that are called at
unpredictable times and in an unpredictable order. By relinquishing
control in this way to users, the developer creates a program that
is much easier to use. Nevertheless, individual pieces of the
program written by the developer still call libraries provided by
the operating system to accomplish certain tasks, and the
programmer must still determine the flow of control within each
piece after it's called by the event loop. Application code still
"sits on top of" the system.
[0067] Even event loop programs require programmers to write a lot
of code that should not need to be written separately for every
application. The concept of an application framework carries the
event loop concept further. Instead of dealing with all the nuts
and bolts of constructing basic menus, windows, and dialog boxes
and then making these things all work together, programmers using
application frameworks start with working application code and
basic user interface elements in place. Subsequently, they build
from there by replacing some of the generic capabilities of the
framework with the specific capabilities of the intended
application.
[0068] Application frameworks reduce the total amount of code that
a programmer has to write from scratch. However, because the
framework is really a generic application that displays windows,
supports copy and paste, and so on, the programmer can also
relinquish control to a greater degree than event loop programs
permit. The framework code takes care of almost all event handling
and flow of control, and the programmer's code is called only when
the framework needs it (e.g., to create or manipulate a proprietary
data structure).
[0069] A programmer writing a framework program not only
relinquishes control to the user (as is also true for event loop
programs), but also relinquishes the detailed flow of control
within the program to the framework. This approach allows the
creation of more complex systems that work together in interesting
ways, as opposed to isolated programs, having custom code, being
created over and over again for similar problems.
[0070] Thus, as is explained above, a framework basically is a
collection of cooperating classes that make up a reusable design
solution for a given problem domain. It typically includes objects
that provide default behavior (e.g., for menus and windows), and
programmers use it by inheriting some of that default behavior and
overriding other behavior so that the framework calls application
code at the appropriate times.
[0071] There are three main differences between frameworks and
class libraries:
[0072] Behavior versus protocol. Class libraries are essentially
collections of behaviors that you can call when you want those
individual behaviors in your program. A framework, on the other
hand, provides not only behavior but also the protocol or set of
rules that govern the ways in which behaviors can be combined,
including rules for what a programmer is supposed to provide versus
what the framework provides.
[0073] Call versus override. With a class library, the code the
programmer instantiates objects and calls their member functions.
It's possible to instantiate and call objects in the same way with
a framework (i.e., to treat the framework as a class library), but
to take full advantage of a framework's reusable design, a
programmer typically writes code that overrides and is called by
the framework. The framework manages the flow of control among its
objects. Writing a program involves dividing responsibilities among
the various pieces of software that are called by the framework
rather than specifying how the different pieces should work
together.
[0074] Implementation versus design. With class libraries,
programmers reuse only implementations, whereas with frameworks,
they reuse design. A framework embodies the way a family of related
programs or pieces of software work. It represents a generic design
solution that can be adapted to a variety of specific problems in a
given domain. For example, a single framework can embody the way a
user interface works, even though two different user interfaces
created with the same framework might solve quite different
interface problems.
[0075] Thus, through the development of frameworks for solutions to
various problems and programming tasks, significant reductions in
the design and development effort for software can be achieved. A
preferred embodiment of the invention utilizes HyperText Markup
Language (HTML) to implement documents on the Internet together
with a general-purpose secure communication protocol for a
transport medium between the client and the Newco. HTTP or other
protocols could be readily substituted for HTML without undue
experimentation. Information on these products is available in T.
Berners-Lee, D. Connoly, "RFC 1866: Hypertext Markup Language--2.0"
(November 1995); and R. Fielding, H, Frystyk, T. Berners-Lee, J.
Gettys and J. C. Mogul, "Hypertext Transfer Protocol--HTTP/1.1:
HTTP Working Group Internet Draft" (May 2, 1996). HTML is a simple
data format used to create hypertext documents that are portable
from one platform to another. HTML documents are SGML documents
with generic semantics that are appropriate for representing
information from a wide range of domains. HTML has been in use by
the World-Wide Web global information initiative since 1990. HTML
is an application of ISO Standard 8879; 1986 Information Processing
Text and Office Systems; Standard Generalized Markup Language
(SGML).
[0076] To date, Web development tools have been limited in their
ability to create dynamic Web applications which span from client
to server and interoperate with existing computing resources. Until
recently, HTML has been the dominant technology used in development
of Web-based solutions. However, HTML has proven to be inadequate
in the following areas:
[0077] Poor performance;
[0078] Restricted user interface capabilities;
[0079] Can only produce static Web pages;
[0080] Lack of interoperability with existing applications and
data; and
[0081] Inability to scale.
[0082] Sun Microsystem's Java language solves many of the
client-side problems by:
[0083] Improving performance on the client side;
[0084] Enabling the creation of dynamic, real-time Web
applications; and
[0085] Providing the ability to create a wide variety of user
interface components.
[0086] With Java, developers can create robust User Interface (UI)
components. Custom "widgets" (e.g., real-time stock tickers,
animated icons, etc.) can be created, and client-side performance
is improved. Unlike HTML, Java supports the notion of client-side
validation, offloading appropriate processing onto the client for
improved performance. Dynamic, real-time Web pages can be created.
Using the above-mentioned custom UI components, dynamic Web pages
can also be created.
[0087] Sun's Java language has emerged as an industry-recognized
language for "programming the Internet." Sun defines Java as: "a
simple, object-oriented, distributed, interpreted, robust, secure,
architecture-neutral, portable, high-performance, multithreaded,
dynamic, buzzword-compliant, general-purpose programming language.
Java supports programming for the Internet in the form of
platform-independent Java applets." Java applets are small,
specialized applications that comply with Sun's Java Application
Programming Interface (API) allowing developers to add "interactive
content" to Web documents (e.g., simple animations, page
adornments, basic games, etc.). Applets execute within a
Java-compatible browser (e.g., Netscape Navigator) by copying code
from the server to client. From a language standpoint, Java's core
feature set is based on C++. Sun's Java literature states that Java
is basically, "C++ with extensions from Objective C for more
dynamic method resolution."
[0088] Another technology that provides similar function to JAVA is
provided by Microsoft and ActiveX Technologies, to give developers
and Web designers wherewithal to build dynamic content for the
Internet and personal computers. ActiveX includes tools for
developing animation, 3-D virtual reality, video and other
multimedia content. The tools use Internet standards, work on
multiple platforms, and are being supported by over 100 companies.
The group's building blocks are called ActiveX Controls, small,
fast components that enable developers to embed parts of software
in hypertext markup language (HTML) pages. ActiveX Controls work
with a variety of programming languages including Microsoft Visual
C++, Borland Delphi, Microsoft Visual Basic programming system and,
in the future, Microsoft's development tool for Java, code named
"Jakarta." ActiveX Technologies also includes ActiveX Server
Framework, allowing developers to create server applications. One
of ordinary skill in the art readily recognizes that ActiveX could
be substituted for JAVA without undue experimentation to practice
the invention.
Synchronization Overview
[0089] FIG. 2 illustrates a flowchart delineating a method for
synchronizing an event on a plurality of client apparatuses. First,
in operation 200, an event is stored in memory on at least one of
the client apparatuses. In various embodiments, the memory may take
the form of an electromagnetic medium, or any type of optical
storage device, i.e. CD-audio. In a primary aspect of the present
invention, the memory includes a digital video disc (DVD) (audio or
video). Further, for reasons that will soon become apparent, the
information includes chapter information associated with the DVD.
In such embodiment where the memory is portable, the user may be
required to purchase the memory, i.e. DVD, in order to participate
in a synchronized event, thus increasing the sale of DVD's.
[0090] It should be noted that the event need not be necessarily
stored in memory on all of the client apparatuses, but rather
stored on one or some of the client apparatuses and streamed to the
remaining client apparatuses at variant rates. This may be feasibly
accomplished if the client apparatus(es) containing the stored
event has a high-bandwidth connection with the remaining client
apparatuses. For example, the client apparatus(es) containing the
stored event may include a server that has a connection to a
plurality of televisions via a cable network, i.e. WEBTV. Similar
functionality may be achieved via a broadcast medium. The present
invention is thus flexible by having an ability to host user events
and corporative events.
[0091] In one embodiment, the event includes a video and audio
presentation such as movie, a concert, and/or a theatrical event.
It should be noted, however, that the event may included any
recording capable of being played back for entertainment,
education, informative or other similar purposes.
[0092] In use, the client apparatuses and a host computer are
adapted to be connected to a network. Such network may include a
wide, local or any other type of communication network. For
example, a wide area network such as the Internet may be employed
which operates using TCP/IP or IPX protocols.
[0093] In operation 202, information is transmitted from the host
computer to the appropriate client apparatuses utilizing the
network. This information allows for the simultaneous and
synchronous playback of the event on each of the client
apparatuses. In one embodiment, the information may also include a
start time when the playback of the event is to begin on each of
the client apparatuses. Further, an ending time may be included
when the playback of the event is to end on each of the client
apparatuses. Still yet, "play" command information may be sent to
the client apparatuses at the start time. As an option, input may
be received from the user, and used to alter the playback of the
event. The host server, or synchronization server, can also control
various streams of a variant rate and different hardware associated
with those streams.
[0094] The present invention thus has the ability to synchronize
video playback for one or multiple (thousands) users from one or
multiple physical locations, and to synchronize with external
video, audio and/or data streams.
[0095] Users of the present invention are at multiple physical
locations and host servers may also be at different locations. The
present invention is thus a scalable system which is capable of
servicing an unlimited number of users. Since the content is local
to the user machine, no high network bandwidth is required.
[0096] History Download Capabilities
[0097] FIG. 3 illustrates a flowchart delineating a method for
storing synchronization information for subsequent playback of an
event. Initially, in operation 300, an event is stored in memory on
at least one of the client apparatuses, as set forth earlier. These
client apparatuses are adapted to be connected to a network along
with a host computer during use.
[0098] In operation 302, information is stored on the host
computer(s) for allowing the simultaneous playback of the event on
each of the client apparatuses. In one embodiment, the information
may include a history and data associated with the synchronous
playback. In particular, the history may include any overlaid
material(as will be described hereinafter in greater detail), any
specific commands affecting the playback of the information, or any
other type of general information, i.e. start time, end time,
etc.
[0099] In operation 304, the information may be downloaded
utilizing the network at any time after the synchronous playback of
the event. Such downloaded information may then be used for
playback after the simultaneous playback of the event. As such, the
present invention has the ability to allow users to download a
history and data associated with a particular synchronization event
and play it later.
[0100] Overlay Synchronization
[0101] FIG. 4 illustrates a flowchart setting forth a method for
providing overlays during a synchronized event on a plurality of
client apparatuses or any other source. First, in operation 400, a
plurality of client apparatuses are connected via a network. In
operation 402, an event may be simultaneously played back on the
client apparatuses utilizing the network, as set forth earlier.
[0102] During the playback of the event, visual and/or audio
material may also be overlaid on the event based on input received
from at least one of the client apparatuses. See operation 404.
This may be accomplished by transmitting the overlay material from
one of the client apparatuses to the host computer or any other
server, and multicasting the same to the remaining client
apparatuses.
[0103] As an option, the overlay material may include annotations
on a display of the client apparatus. For example, the overlay
material may include sketches which are inputted by way of a
stylus-based input screen or a keyboard or the like, along with a
voiceover inputted by way of a microphone or voice synthesizer.
Such capability may also be quite valuable in an educational
environment.
[0104] In one embodiment, the overlay material may also be
displayed on each of the client apparatuses utilizing the network.
This allows each of the users to experience the overlay in
real-time during the simultaneous playback of the event. As an
option, the user inputting the overlay material may select which
users may experience the overlay material. The client apparatus
that provided the overlay material may also be identified to the
users experiencing the overlay material.
[0105] It should be noted that various bi-directional communication
may be enabled for allowing data to travel to and from the server.
For instance, the playback of the event on the client apparatuses
may be altered in any feasible way based on input from a user.
[0106] Late Synchronization
[0107] FIG. 5 illustrates a flow diagram for delayed
synchronization of an event on a plurality of client apparatuses.
First, in operation 500, a plurality of client apparatuses are
connected via a network and an event is stored in memory on the
client apparatuses. The event is then simultaneously played back on
the client apparatuses utilizing the network, as set forth earlier.
Note operation 502.
[0108] During the simultaneous playback, a request may be received
from one of the client apparatuses for that particular to be
included in the synchronized event, as set forth in operation 504.
This request may be received after the synchronized event has
already begun while it is still playing. Further, the request may
be submitted via a site on a network, i.e. website.
[0109] In response to the request, information is transmitted in
operation 506 to the requesting client apparatus utilizing the
network. This information is adapted for identifying a location in
the memory where the event is currently being played back.
This-allows the simultaneous playback of the event on the
requesting client apparatus.
[0110] The end users are thus able to come in at a later time and
to be synchronized with the event. Targeted synchronization and
various filters criteria can be applied to target different
audiences. Also language and cultural differences can be taken into
account. Still yet, the present invention may be adapted to address
users on different hardware platforms (MAC, PC, set-top boxes).
This may be accomplished by identifying the user using a cookie, a
user profile which is identified by way of a log in, or a Burn Cut
Area (BCA) of the disc.
[0111] An example setting forth details relating to identifying
DVDs will now be set forth. First, a content owner (such as studio)
requests use of the BCA on their DVDs. Based on request, the
replicator (examples include WAMO, Panasonic, Nimbus, Technicolor,
Pioneer, Crest) adds unique BCA number to every DVD. Adding BCA
number to each DVD requires a special (YAG) laser. This may be the
very last step in the manufacturing process. The BCA numbers for a
specific DVD must then be entered into InterActual's BCA database.
Information to track includes: DVD title, i.e. "Lost in Space"; BCA
#/range, i.e. 12345687890; and Shipping Packaging/Tracking
Container, i.e. Box 52221 to Hollywood Video.
[0112] After the BCA number is added to the DVDs, the DVDs are
packaging/boxed for distribution to either the Distributor or the
Retailer. It should be noted that many companies take multiple
forms, so the replicator and distributor may be one in the same.
Also, some retailers are large/important enough to get shipments
directly from replicator. The way in which the DVDs are
packaging/shipped is very important because one must track the BCA
numbers to actual shipping containers (box, etc.). Therefore
tracking information must also be added to the BCA database.
[0113] If packaged DVDs are then sent to distributor, the
distributor also has mechanisms, i.e. scanners, input device, and
monitoring devices, in place for tracking based on their
distribution. For example, Deluxe may receive a "package" of
100,000 copies of "Lost in Space." However, the distributor ships
10,000 to Retailer A and 5,000 to Retailer B. The distributor
should be able to "input" retailer A and B's distribution
information into the system. Ideally, this becomes a
seamless/automated process.
[0114] Once the DVDs reach the retailer (either from the replicator
or distributor), then DVDs may be further divided and distributed
to local stores/outlets. In such a situation, the retailer should
be able to automatically "track" distribution of these DVDs through
to their stores. Over time, all three entitities (replicator,
distributor, and retailer) are able to add tracking information to
BCA database. Due to complexity and dependencies on existing
business systems, the retail tracking concept will be rolled out in
phases: replicator first most likely with key retail accounts. The
distributors will be brought in. Retailers will then begin to
embrace the ability to track based on local outlet/store.
[0115] By the foregoing design, easy deployment is thus afforded
and minimal hardware is required to allow the synchronization of
content without significant capital investments and with a very
efficient control mechanism. The content delivery does not rely on
high network bandwidth and is independent from the
synchronization.
[0116] Internet Server Application Program Interface (ISAPI)
extensions will be used on the server. ISAPI extensions provide a
mechanism to maintain a temporary or permanent connection with the
users. These connections allow the Synchronization Server to
process request and to send the appropriate DVD commands. The
permanent connections are known as "Keep Alive" connections. ISAPI
extension can also be used as an HTTP interface to a more
traditional server, with all data returned as text.
[0117] On the client side the approach is to use, but not limited
to Java 1.1 applets, to initiate event start-up for the
Synchronization server. The advantage of using Java 1.1 applets is
to achieve platform independence for existing and future
Java-enabled devices. JavaScript will be used to provide user
interface navigation by "wrapping" the applet.
[0118] An ISAPI (Internet Server Application Program Interface) is
a set of Windows program calls that let one write a Web server
application that will run faster than a Common Gateway Interface
(CGI) application. A disadvantage of a CGI application (or
"executable file," as it is sometimes called) is that each time it
is run, it runs as a separate process with its own address space,
resulting in extra instructions that have to be performed,
especially if many instances of it are running on behalf of
users.
[0119] Using ISAPI, you create a Dynamic Link Library (DLL)
application file that can run as part of the Hypertext Transport
Protocol (HTTP) application's process and address space. The DLL
files are loaded into the computer when HTTP is started and remain
there as long as they are needed; they don't have to be located and
read into storage as frequently as a CGI application.
[0120] Existing CGI applications can be converted into ISAPI
application DLLs without having to rewrite their logic. However,
they do need to be written to be thread-safe so that a single
instance of the DLL can serve multiple users.
[0121] A special kind of ISAPI DLL is called an ISAPI filter, which
can be designated to receive control for every HTTP request. One
can create an ISAPI filter for encryption or decryption, for
logging, for request screening, or for other purposes.
[0122] One can write ISAPI server extension DLLs (ISAs) that can be
loaded and called by the HTTP server. Users can fill out forms and
click a submit button to send data to a Web server and invoke an
ISA, which can process the information to provide custom content or
store it in a database. Web server extensions can use information
in a database to build Web pages dynamically, and then send them to
the client computers to be displayed. An application can add other
custom functionality and provide data to the client using HTTP and
HTML.
[0123] One can write an ISAPI filter. The filter is also a DLL that
runs on an ISAPI-enabled HTTP server. The filter registers for
notification of events such as logging on or URL mapping. When the
selected events occur, the filter is called, and one can monitor
and change the data (on its way from the server to the client or
vice versa). ISAPI filters can be used to provide custom encryption
or compression schemes, or additional authentication methods.
[0124] Both server extensions and filters run in the process space
of the Web server, providing an efficient way to extend the
server's capabilities.
Overall Component Design
[0125] The various functional components of the software associated
with the present invention will now be set forth. Such components
include a Java/JavaScript Component, Synchronizer Component,
LayerImpl Component, Business Layer Component, Configuration
Manager Component, and DBConnect Component.
[0126] Java/JavaScript Component
[0127] FIG. 6 illustrates a flow diagram for providing information
on a synchronized event on a plurality of client apparatuses in
accordance with one embodiment of the present invention. First, in
operation 600, a plurality of client apparatuses are connected via
a network, as set forth earlier. Next, an application program is
embedded on a site on the network in operation 602. Such
application program may take the form of a JAVA applet, and the
site may include a website on the Internet.
[0128] In use, information is requested from a server on the
network utilizing the application program. See operation 604. Such
information relates to an event to be played back simultaneously on
the client apparatuses and may include general information such as
a start and stop time of the event, or more specific information
about the event itself.
[0129] In response to such request, a script is received for
displaying the information. Note operation 606. The script may take
any form such as Perl, REXX (on IBM mainframes), and Tcl/Tk, and
preferably includes a JAVAscript.
[0130] In one embodiment of the present invention, the JAVA applet
may be further adapted to send a request to retrieve command
information from the server for use with a playback device of one
of the client apparatuses. The commands may be adapted to playback
the event on the playback device simultaneous with the playback of
the event on the remaining client apparatuses. Further, the
commands may include a start time when the playback of the event is
to begin on each of the client apparatuses.
[0131] The JAVA applets and JAVAscript are used to communicate with
the playback device of the client apparatuses. In one embodiment,
the playback device includes a PCFriendly TM video player
manufactured by Interactual.RTM..
[0132] The Java applet is embedded within a web page and uses HTTP
protocol to communicate to the synchronization server. The applet
could request event information from the server, and display it to
the user via JavaScript. The applet could also send a
"BroadcastVideoEvent" request to retrieve DVD commands that can be
passed to the video component, as set forth hereinabove.
[0133] Synchronizer Component
[0134] FIG. 7 illustrates a method for creating a synchronizer
object in order to playback an event simultaneously on a plurality
of client apparatuses. The synchronizer object is portion of the
software that actually implements the synchronization procedure.
First, in operation 700, a request is received utilizing a network
for viewing an event. Next, the request is queued in memory in
operation 702.
[0135] In response to the request, in operation 704, an object is
created which is adapted to playback the event on a client
apparatus simultaneous with the playback of the event on the
remaining client apparatuses upon the receipt of an activation
signal. As an option, the activation signal may be provided using a
clock of the client apparatus, or located at a different location,
i.e. server. To accomplish this, the object identifies a start time
when the playback of the event is to begin on each of the client
apparatuses.
[0136] In operation 706, the object is sent to one of the client
apparatuses utilizing the network for being stored therein. In
accordance with a primary aspect of the present invention, the
object may be adapted to playback the event which is stored in
memory of the client apparatus. This may be accomplished by
activating a digital video disc (DVD) player.
[0137] In summary, when the Synchronizer component receives a
"Broadcast VideoEvent" from the applet, it then places the request
in the thread queue for processing. To process a request, the
thread creates a "call back" object, if one does not exist for this
event. The thread then adds the request to the "call back" object
queue. This "call back" object will be invoked when it is time to
play the DVD. The Synchronizer component creates a Call Back COM
object, LayerSink. The Synchronizer component is also responsible
for creating the LayerFactory interface which will be set forth
hereinafter in greater detail.
[0138] LayerImpl Component
[0139] FIG. 8 illustrates a flowchart for affording a scheduler
object adapted to facilitate the playback of an event
simultaneously on a plurality of networked client apparatuses. The
present method ensures that critical information is tracked during
the synchronization of the event. Such critical information not
only ensures proper synchronization, but also enables various
peripheral features.
[0140] First, in operation 800, various values are determined
including a current time, a start time when an event is to start,
and a stop time when the event is to end. Thereafter, a length of
the event is calculated based on the start time and the stop time
in operation 802. As an option, the current time is determined by
querying a clock of one of the client apparatuses.
[0141] If any portion of the length of the event takes place during
a predetermined threshold period, a command is stored in memory in
operation 804. The command may be adapted to automatically begin
playing back the event at the start time. In one embodiment, the
threshold period includes the time the users can be queued before
the event. As an option, chapter information may be stored in the
memory if any portion of the length of the event takes place during
the predetermined threshold period. This allows the command to
automatically begin playing back the event at a predetermined
chapter.
[0142] In operation 806, a loop is created at the start time during
which a lapsed time of the event is tracked. This information may
be used for various tracking purposes to decide when to issue
commands to the user. In another embodiment, a second loop may be
created upon the beginning of a chapter during which information on
a next chapter is retrieved.
[0143] The "call back" object (LayerSink) is thus responsible for
creating and communicating with the LayerImpl component. The
LayerImpl component acts as a scheduler, determining when to issue
commands to the user.
[0144] LayerImpl will issue different DVD commands, based on the
type of decoder the user has in their PC. LayerImpl will
differentiate between the decoders by using the decoder information
submitted from the client. The LayerImpl will pass the correct DVD
command to the client, based on the decoder's capabilities. For
example, if the decoder does not support the TimePlay event, then
the server may send a ChapterPlay event and wait appropriately.
[0145] The following is an enumerated summary of the steps the
component uses to determine when the users will receive the DVD
commands:
[0146] 1. Retrieves the current time, and the time the event starts
and ends.
[0147] 2. Calculates the length of the event.
[0148] 3. If the event is within a threshold period (i.e. the time
users can be queued before the event), then store the first DVD
command in memory. Also, store the Chapter information in
memory.
[0149] 4. Create a loop that processes request until the event has
completed.
[0150] 5. In the loop, calculate the lapsed time of the event.
[0151] 6. In the loop, retrieve the next chapter information.
[0152] 7. Create another loop that will loop until time for the
next chapter to be played.
[0153] 8. When the next chapter is ready to play, send the command
that was retrieved from the Chapter table.
[0154] Business Layer Component
[0155] FIG. 9 is a flowchart delineating a method for identifying a
plurality of events which are played back simultaneously on a
plurality of networked client apparatuses. This features is
important since a host server may be synchronizing more than one
event at once, or during overlapping times. Such events must
therefore be distinguished.
[0156] First, in operation 900, a plurality of events are stored in
memory on a plurality of client apparatuses. Each of the events is
assigned a unique identifier which is stored in the memory.
[0157] In operation 902, the client apparatuses are adapted to be
coupled to a host computer via a network, as set forth hereinabove.
In operation 904, the identifier of the event which is stored in
the memory of the client apparatuses is then retrieved utilizing
the network. Such identifier is subsequently compared with an
identifier of a scheduled event, as set forth in operation 906. If
the comparison renders a match, the playback of the event is begun
on the appropriate client apparatuses. Note operation 908.
[0158] CbusinessLayer thus differentiates events by the disk and
location ids, uploaded by the client to guarantee backwards
compatibility. As set forth earlier, late arrivals can always
re-sync with the event.
[0159] Configuration Manager Component
[0160] FIG. 10 shows a flowchart delineating a technique for
identifying playback devices of a plurality of client apparatuses
which are networked to simultaneously playback an event. The
present technique is important since the playback devices of the
various client apparatuses may differ in make and model. Thus,
different commands are required therefor.
[0161] In operation 1000, a type of the playback devices of the
client apparatuses is first identified. Such "type" may refer to a
make, model, or any other distinguishing characteristic of the
particular playback devices. A command associated with the
identified type of the playback device is then looked up in a
look-up table. Note operation 1002. Such table may be located at
the host server, or at any other location such as the client
apparatuses.
[0162] Thereafter, in operation 1004, the command is sent to the
corresponding client apparatus for beginning the playback of the
event simultaneously with the playback of the event on each of the
remaining client apparatuses.
[0163] This component is thus responsible for identifying what type
of reference player is hosting the event. The reference player can
be the database, which contains the DVD commands or a real time
player. When the initial DVD is command is requested, the
"Synchronizer" table is queried for the host type. From that point
forward, the scheduler would know from whom to receive data.
[0164] DBConnect Component
[0165] This component is responsible for communicating with the
Synchronizer tables, and for providing access methods for the
retrieved data. All interaction from the tables is on a read-only
basis. The LayerImpl component communicates with this component to
retrieve DVD commands and event information.
[0166] Even though current implementation may be based on a
Microsoft platform, hard dependencies on Microsoft or any other
3rd-party development tools may be avoided. To address such issues,
the following considerations may be made throughout the code:
[0167] MFC specific code may be avoided. Instead, STL may be used.
ATL and/or MFC code may be encapsulated into separate classes and
portioned from the rest of the code. Class implementations may use
aggregation pattern to delegate business logic to the portable
classes. Database connection classes may be separated and the
communication protocol may be separated with respect to portability
to Oracle and other platforms.
[0168] FIGS. 11 and 12 illustrate the order of events among the
various components of the present invention. In particular, FIG. 11
illustrates the manner in which a layer factory is created. As
shown, an event is first checked in a database server after which a
business layer is created in a WEB server in a manner set forth
hereinabove. The foregoing components are then created. FIG. 12
illustrates the manner in which user requests are processed. As
shown, communication is afforded with the video player on the
client machine by means of JAVAscript and JAVA applets. The WEB
server, in turn, communicates DVD commands to the video player via
the JAVA applets, and also interfaces the database server via the
various components thereof which were set forth hereinabove.
[0169] Alternate Embodiments
[0170] To support future enhancements, further components may be
included with extendibility as the major objective. Various future
enhancements of the product and how they will be addressed will now
be set forth.
[0171] Hosted Real Time Players
[0172] While spirals may retrieve pre-recorded DVD commands from
the database, alternate spirals may support a consumer as a host.
The architecture may also support plug-in components. Alternate
spirals may support the RealTimeConnector component, which accepts
host user request and forwards them to the clients. The instant
architecture supports the DBConnector which accepts events from the
database.
[0173] Keep Alive Connections
[0174] Clients may maintain connections throughout the event. This
allows the host to send a various number of commands to the client
of the event. Although the spiral disconnects users once a PLAY
command has been issued, the Synchronizer class (which will be set
forth later) adds each connection to a Thread Pool. This pool of
connections can be left open during the life of the event.
[0175] Logging Participants
[0176] Each request may be logged into the database to provide a
reference for the future.
[0177] DVD Positioning
[0178] As an option, connections may be pooled to allow the
synchronization server to direct consumer's machines to the certain
locations throughout the entire event.
[0179] Synchronization events in alternate spirals may be defined
as a combination of play from location event and the actual event.
This way, one describes each event in the unambiguous way on the
client side and synchronizes it with the server. For example, a
situation may be considered where one fast forwards after a movie
is played for 15 min and thereafter plays the scene in the movie.
In such situation, one has to submit the information to the client
player, indicating that it (player) has to start time play from 15
min into the movie and fast-forward to the certain location. A
better way would be to analyze what is the next event after fast
forwarding occurred and perform a combination for the play from
location and next event. This design would require significant
changes to the client infrastructure, including video object,
remoteagent and provider and should be taken into consideration in
any alternate client design.
Classes/Component Diagrams
[0180] FIGS. 13-16 illustrate various class/component diagrams. In
particular, FIGS. 13-16 illustrate a Synchronizer Class Diagram
1300, Layerlmpl Class Diagram 1400, Business Layer Class Diagram
1500, and DBConnect Class Diagram 1600, respectively.
[0181] Sequence Diagrams
[0182] FIG. 17 illustrates a logical sequence diagram 1700. As
shown, when the server receives a user request, it analyzes the
authentication information of the request (date/time, disc id, user
id, and BCA number) and the appropriate synchronization event
stored in the database. The database contains an event start
threshold value measured in milliseconds. This threshold defines
the amount of time prior to an event that a consumer is eligible to
"connect" for the start of the event.
[0183] If the date/time of the user request lies within the event
start threshold, the user is put into wait queue and receive the
appropriate data when the time elapses. Note steps 1,2,3,5,6,7 of
the Logical Sequence diagram. Otherwise, a message is sent
informing the user when the event will occur. Note step 4 of the
Logical Sequence diagram.
[0184] Server side collaboration diagram
[0185] FIG. 18 illustrates a logical sequence diagram 1800 that
shows server side collaboration. As shown, server ISAPI extension
receives a BroadcastVideoEvents request. It calls IA_BusinessServer
via BeginProcess, to retrieve configuration information.
Configuration information contains a playback connector. Playback
connector identifies whether the server will have to communicate
with a reference player or will it perform playback from the
database.
[0186] At step 6, ISAPI extension will call IA_BusinessServer
CompareTime method and based on the results will send to the user a
predefined web page indicating to retry later or return control to
the web server, notifying it (web server) to keep the connection
open. At this point connection is pooled and will be processed by
the IA_BusinessServer at a time of the event.
[0187] Client Collaboration Diagram
[0188] FIG. 19 illustrates a logical sequence diagram 1900 showing
client side collaboration in accordance with one embodiment of the
present invention.
Classes/Interfaces Definition
[0189] Definitions of one embodiment of the various classes
associated with the software which implements the present invention
will now be set forth.
[0190] Class Applet1
[0191] Purpose:
[0192] This is the class that implements the applet. The browser
will use it to bootstrap our applet.
[0193] Responsibilities:
[0194] Request a BroadCastVideo event and to gather event status
information.
[0195] Collaborations:
[0196] BroadCastEvent, CITIEncrypt
[0197] Base Class and Implemented Interfaces:
[0198] Javax.Applet
[0199] Public Interface:
[0200] getchapter Returns the current chapter the reference player
is playing.
[0201] Return type: String
[0202] Parameters: void
[0203] Pre-conditions: None.
[0204] Post-conditions: None.
[0205] getTitleInfo Returns the current title the reference player
is playing
[0206] Return type: String
[0207] Parameters: void
[0208] Pre-conditions: None.
[0209] Post-conditions: None.
[0210] getStartTime Returns the time the event is scheduled to
start
[0211] <SS:MM:HH:DD:MM:YYYY>
[0212] Return type: String
[0213] Parameters: void
[0214] Pre-conditions: None.
[0215] Post-conditions: None.
[0216] getStartTimeSec Returns the time the event starts in
seconds.
[0217] Return type: String
[0218] Parameters: void
[0219] Pre-conditions: None.
[0220] Post-conditions: None.
[0221] getStartTimeMinReturns the time the event starts in
minutes.
[0222] Return type: String
[0223] Parameters: void
[0224] Pre-conditions: None.
[0225] Post-conditions: None.
[0226] getStartTimeHrReturns the time the event starts in
Hours.
[0227] Return type: String
[0228] Parameters: void
[0229] Pre-conditions: None.
[0230] Post-conditions: None.
[0231] GetStartTimeDay Returns the time the event starts in
days.
[0232] Return type: String
[0233] Parameters: void
[0234] Pre-conditions: None.
[0235] Post-conditions: None.
[0236] GetStartTimeMnth Returns the time the event starts in
months.
[0237] Return type: String
[0238] Parameters: void
[0239] Pre-conditions: None.
[0240] Post-conditions: None.
[0241] GetStartTimeYr Returns the time the event starts in
year.
[0242] Return type: String
[0243] Parameters: void
[0244] Pre-conditions: None.
[0245] Post-conditions: None.
[0246] GetLenOfEvent Returns the length of the event.
[0247] Return type: String
[0248] Parameters: void
[0249] Pre-conditions: None.
[0250] Post-conditions: None.
[0251] GetExpiredTime: Returns lapse time of the event.
[0252] Return type: String
[0253] Parameters: void
[0254] Pre-conditions: None.
[0255] Post-conditions: None.
[0256] getServerTime: Returns the servers current time
<SS:MM:HH:DD:MM:YYYY>.
[0257] Return type: String
[0258] Parameters: void
[0259] Pre-conditions: None.
[0260] Post-conditions: None.
[0261] getServerTimeSec: Returns the servers current in
seconds.
[0262] Return type: String
[0263] Parameters: void
[0264] Pre-conditions: None.
[0265] Post-conditions: None.
[0266] getServerTimeMin: Returns the servers current in
minutes.
[0267] Return type: String
[0268] Parameters: void
[0269] Pre-conditions: None.
[0270] Post-conditions: None.
[0271] getServerTimeHr: Returns the servers current in hours.
[0272] Return type: String
[0273] Parameters: void
[0274] Pre-conditions: None.
[0275] Post-conditions: None.
[0276] getServerTimeDay: Returns the servers current in day.
[0277] Return type: String
[0278] Parameters: void
[0279] Pre-conditions: None.
[0280] Post-conditions: None.
[0281] getServerTimeMnth: Returns the servers current in month.
[0282] Return type: String
[0283] Parameters: void
[0284] Pre-conditions: None.
[0285] Post-conditions: None.
[0286] getServerTimeYr: Returns the servers current in year.
[0287] Return type: String
[0288] Parameters: void
[0289] Pre-conditions: None.
[0290] Post-conditions: None.
[0291] startProc: Calls the ISAPIs "ServerInfo" method.
[0292] Return type: void
[0293] Parameters: String disk id, String location id
[0294] Pre-conditions: None.
[0295] Post-conditions: None.
[0296] msgEvent: Calls BroadCastEvent applet.
[0297] Return type: void
[0298] Parameters: void
[0299] Pre-conditions: None.
[0300] Post-conditions: None.
[0301] Class BroadCastEvent
[0302] Purpose:
[0303] This is the class that invokes the Synchronizer.
[0304] Responsibilities:
[0305] Sets the JavaScript with the command returned from the
server.
[0306] Collaborations:
[0307] CITIEncrypt
[0308] Base Class and Implemented Interfaces:
[0309] Java.Thread
[0310] Class CDBConnect
[0311] Purpose:
[0312] This is the class provides a public interface for components
to request information from the DB tables.
[0313] Responsibilities:
[0314] Opens the database and Synchronizer, Chapter_Disk
tables.
[0315] Queries the Synchronizer by the specified disk id and
location id.
[0316] Queries the Chapter_Disk by disk id.
[0317] Provides the next chapter that is scheduled to play.
[0318] Queries the Decoder_Capabilities table to determine if the
requested player is time or chapter play.
[0319] Collaborations:
[0320] DBSyncSet
[0321] DBReferenceSet
[0322] CDBChapterSet
[0323] CDecoderCapabilities
[0324] Base class and implemented interfaces:
[0325] Public Interface:
[0326] Get_NextChapter: Returns the next chapter to play.
[0327] Return type: String
[0328] Parameters: long time, long title, BSTR Chapter
[0329] Pre-conditions: None.
[0330] Post-conditions: None.
[0331] chkEvent: Checks if an event is scheduled for the disk and
location id.
[0332] Return type: String
[0333] Parameters: long time, long title, BSTR Chapter
[0334] Pre-conditions: None.
[0335] Post-conditions: None.
[0336] get_initialDVDCommand: Returns the first DVD command to
play.
[0337] Return type: String
[0338] Parameters: BSTR &
[0339] Pre-conditions: None.
[0340] Post-conditions: None.
[0341] get_nextDVDCommand: Returns the next DVD command to
play.
[0342] Return type: String
[0343] Parameters: BSTR &
[0344] Pre-conditions: None.
[0345] Post-conditions: None.
[0346] decoderArray: Returns an array of decoder types.
[0347] Return type: String
[0348] Parameters: long**, long**
[0349] Pre-conditions: None.
[0350] Post-conditions: None.
[0351] Class CCConfigMgrImpl
[0352] Purpose:
[0353] This is the class provides a public interface for components
to determine the type of reference player hosting the event.
[0354] Responsibilities:
[0355] Opens the database and Synchronizer, Chapter_Disk
tables.
[0356] Queries the Synchronizer by the specified disk id and
location id.
[0357] Stores the reference player type.
[0358] Collaborations:
[0359] CConfigMgrRecSet
[0360] Base Class and Implemented Interfaces:
[0361] Public Interface:
[0362] get_hostType: Returns the reference player host type.
[0363] Return type: String
[0364] Parameters: short
[0365] Pre-conditions: None.
[0366] Post-conditions: None.
[0367] Class threadFunctor
[0368] Purpose:
[0369] This class provides a threading model that classes can use
to derive.
[0370] Responsibilities:
[0371] Calls the CreateEvent function, which opens a named or
unnamed event objec.
[0372] Calls_beginthread, which creates a thread begins execution
of a routine at
[0373] start_address. The routine at start_address must use the
_cdecl calling convention and should have no return value. When the
thread returns from that routine, it is terminated
automatically.
[0374] Calls the WaitForSingleObject function, which checks the
current state of the specified object. If the object's state is
nonsignaled, the calling thread enters an efficient wait state.
[0375] Calls the ResetEvent function, which sets the state of the
specified event object to nonsignaled.
[0376] The state of an event object remains nonsignaled until it is
explicitly set to signaled by the SetEvent or PulseEvent
function.
[0377] Collaborations:
[0378] CConfigMgrRecSet
[0379] Base Class and Implemented Interfaces:
[0380] Public Interface:
[0381] start: Starts the thread.
[0382] Return type: void
[0383] Parameters: void
[0384] Pre-conditions: None.
[0385] Post-conditions: None.
[0386] stop: Stops the thread. Calls CloseHandle for the thread and
event.
[0387] Return type: void
[0388] Parameters: void
[0389] Pre-conditions: None.
[0390] Post-conditions: None.
[0391] Class Isapithread
[0392] Purpose:
[0393] This creates an ISAPI thread.
[0394] Responsibilities:
[0395] Adds a request to a vector.
[0396] Creates the sink object.
[0397] Stores the request into sink object.
[0398] Sends the time information to JavaScript.
[0399] Collaborations:
[0400] LayerSink
[0401] factorySink
[0402] Base Class and Implemented Interfaces:
[0403] threadFunctor
[0404] Public Interface:
[0405] addrequest: Adds the request to its vector.
[0406] Return type: void
[0407] Parameters: void
[0408] Pre-conditions: None.
[0409] Post-conditions: None.
[0410] getBLayerInfo: Responsible for getting information about the
event.
[0411] Return type: void
[0412] Parameters: std:string&,std::string&,
ChttpServerContext*
[0413] Pre-conditions: None.
[0414] Post-conditions: None.
[0415] Class factorySink
[0416] Purpose:
[0417] Manages the layerSink and businessLayerProp objects.
[0418] Responsibilities:
[0419] Stores a layerSink object.
[0420] Returns the "businesssLayerProp" <Business Layer
Properties>
[0421] Creates the "businessLayerProp" <Business Layer
structure>
[0422] Collaborations:
[0423] LayerSink
[0424] businessLayerProp
[0425] Base Class and Implemented Interfaces:
[0426] Public Interface:
[0427] construct: Stores a layerSink object.
[0428] Return type: void
[0429] Parameters: void
[0430] Pre-conditions: None.
[0431] Post-conditions: None.
[0432] notifyCreateLayer: Responsible for creating a
"businessLayerProp".
[0433] Return type: void
[0434] Parameters: BSTR, BSTR, DATE, DATE, LONG
[0435] Pre-conditions: None.
[0436] Post-conditions: None.
[0437] Class layerSink
[0438] Purpose:
[0439] layerSink represents a sink interface and stores a queue of
requests. It creates a connection point object.
[0440] This call back object, allows asynchronously processing.
[0441] Responsibilities:
[0442] Acts as the client sink object.
[0443] Sends the results to the user
[0444] Creates the "BusinessLayer" and makes it a connection point
object.
[0445] Closes the users connection.
[0446] Creates a Factory interface by calling "createFactory".
[0447] Creates a connection point for the factory.
[0448] Stores the LayerSink in the FactorySink object.
[0449] Creates a connection point (call back) by calling AtlAdvise,
between the connection point container and the client sink object.
This allows the client to receive events.
[0450] Calls the connectable objects "getServerLayer". This method
fires an event to the clients sink object.
[0451] Create a business layer,
[0452] Store the request in its vector.
[0453] Release the Sink Object (client)
[0454] Calls AtlUnadvise to terminates the ability of the client to
receive events.
[0455] Collaborations:
[0456] Base Class and Implemented Interfaces:
[0457] Public Interface:
[0458] construct: Creates a connection point.
[0459] Return type: void
[0460] Parameters: void
[0461] Pre-conditions: None.
[0462] Post-conditions: None.
[0463] addRequest: Adds the request to its vector.
[0464] Return type: void
[0465] Parameters: BSTR, BSTR, DATE, DATE, LONG
[0466] Pre-conditions: None.
[0467] Post-conditions: None.
[0468] createBusinessLayer: Creates a business layer. Create the
connection point.
[0469] Return type: void
[0470] Parameters: businessLayerProp &
[0471] Pre-conditions: None.
[0472] Post-conditions: None.
[0473] updatetime: This call back function translates the time and
sends the command to
[0474] the user.
[0475] Return type: void
[0476] Parameters: long,long
[0477] Pre-conditions: None.
[0478] Post-conditions: None.
[0479] Class CBusinessLayer
[0480] Purpose:
[0481] Creates a layerthread object. This object is responsible for
providing access methods, which provide event information.
[0482] Responsibilities:
[0483] The "Synchronizers" createBusinessLayer method creates a
class object from the "IBusinessLayer" interface. <The class
object is part of the LayerImpl project>
[0484] The BusinesLayers class object <m_ilayer>calls its
"Initialize" method. <Note: m_ilayer is the connection point
object. It identifies the "Sink Interface".
[0485] It then calls the "Initialize" method of the connection
point.
[0486] The "Initialize" method then calls the "ChkValidEvent"
method, which then creates a layerthread object.
[0487] Collaborations:
[0488] CBusinessLayer
[0489] layerthread
[0490] Base Class and Implemented Interfaces:
[0491] Public Interface:
[0492] Initialize: Calls the "ChkValidEvent" method which kicks of
a layer thread.
[0493] Return type: void
[0494] Parameters: void
[0495] Pre-conditions: None.
[0496] Post-conditions: None.
[0497] Class layerthread
[0498] Purpose:
[0499] This object acts as a scheduler, processing request from its
queue.
[0500] Responsibilities:
[0501] Send DVD commands to the user.
[0502] "Syncs" up late corners to the events.
[0503] Collaborations:
[0504] CBusinessLayer
[0505] CDBConnect
[0506] Base Class and Implemented Interfaces:
[0507] Public Interface:
[0508] startThread: Processes requests from the queue
[0509] Return type: void
[0510] Parameters: void
[0511] Pre-conditions: None.
[0512] Post-conditions: None.
[0513] Class CLayerFactory
[0514] Purpose:
[0515] This object manages businesslayer objects. Business layer
objects communicate with the reference player and notify the user
which DVD command to play.
[0516] Responsibilities:
[0517] Send DVD commands to the user.
[0518] "Syncs" up late corners to the events.
[0519] This object Implements the IID_LayerFactory interface.
[0520] This COM object is the servers Connectable Point object.
[0521] This server object supports connections to sink interfaces.
These sink interfaces reside on the client side and are equivalent
to the "call back" functions in Windows.
[0522] Collaborations:
[0523] CBusinessLayer
[0524] CDBConnect
[0525] Base Class and Implemented Interfaces:
[0526] Public Interface:
[0527] getServerLayer: "Fires" an event to create a business layer
with the properties
[0528] retrieved from the pipe object.
[0529] Return type: void
[0530] Parameters: void
[0531] Pre-conditions: None.
[0532] Post-conditions: None.
[0533] put_set_layer: call the "CLayerFactoryImpl" add( ) method.
Supplying the "businesslayer" object.
[0534] This will added to shared memory queue and written to a
file.
[0535] Return type: void
[0536] Parameters: void
[0537] Pre-conditions: None.
[0538] Post-conditions: None.
[0539] FinalConstruct: Calls the "CLayerFactoryImpl" FinalConstruct
COM class object.
[0540] Return type: void
[0541] Parameters: void
[0542] Pre-conditions: None.
[0543] Post-conditions: None.
[0544] Although only a few embodiments of the present invention
have been described in detail herein, it should be understood that
the present invention may be embodied in many other specific forms
without departing from the spirit or scope of the invention.
Therefore, the present examples and embodiments are to be
considered as illustrative and not restrictive, and the invention
is not to be limited to the details given herein, but may be
modified within the scope of the appended claims.
* * * * *