HK1083549A - Method of and apparatus for synchronizing interactive contents - Google Patents

Description

Method and apparatus for synchronizing interactive content

Technical Field

The present invention relates to a method and apparatus for synchronizing interactive contents, and more particularly, to a method and apparatus for synchronizing and reproducing interactive contents.

Background

Currently, internet-based markup languages allow users to process various text and multimedia elements (elements) and to construct web pages more animated and colorful than ever before. Recently, it has become possible to reproduce specific audio-visual (AV) content, such as Digital Versatile Disc (DVD) content, in synchronization with various multimedia data. A widely used hypertext markup language (HTML) can generate a markup document using defined tags and attributes to reproduce AV contents and multimedia elements within the markup document, but there is no method to reproduce a specific multimedia element and AV contents synchronously. According to the related art, by using an extensible markup language (XML), such as Synchronized Multimedia Integration Language (SMIL), and a time attribute, the start and end points of the reproduction time width of multimedia elements included in a browser can be processed as tags and attributes. However, a technique of controlling navigation by synchronizing already reproduced contents has not been available. Further, in order to control each element to implement such synchronization, many marks and attributes are required, whereby the generation of a mark-up document becomes complicated.

Disclosure of Invention

The present invention provides a method and apparatus for efficiently synchronizing and reproducing various multimedia elements, in which a specific multimedia content, such as a Digital Versatile Disc (DVD) content, and a multimedia content synchronized with the specific AV content are simultaneously navigated through information about multimedia elements related to whether the multimedia elements are synchronized with the AV content, included in the AV/interactive content, in response to a user input.

According to an aspect of the present invention, there is provided an apparatus for synchronizing interactive contents. The device includes: a synchronized multimedia element determining unit that determines whether multimedia elements included in the interactive contents are synchronized with audio-visual (AV) contents; and an Application Program Interface (API) transmitting unit that transmits an API corresponding to the interactive control command to an AV content reproducing engine that reproduces the AV content and a multimedia element reproducing engine that reproduces the multimedia element determined by the synchronized multimedia element determining unit to be synchronized with the AV content.

According to another aspect of the present invention, there is provided an apparatus for synchronizing and reproducing interactive contents. The device includes: an interactive contents synchronization unit which determines whether multimedia elements included in the interactive contents are synchronized with audio-visual (AV) contents and transmits an Application Program Interface (API) corresponding to the interactive control command; an AV content reproducing engine which receives the API transmitted from the interactive content synchronizing unit and reproduces the AV content according to the received API; and a synchronized multimedia element reproducing engine which receives the API transmitted from the interactive contents synchronizing unit and reproduces the multimedia elements determined to be synchronized with the AV contents by the interactive contents synchronizing unit.

According to another aspect of the present invention, there is provided a method for synchronizing interactive contents, which includes: determining whether multimedia elements included in the interactive contents are synchronized with audio-visual (AV) contents; and transmitting an Application Program Interface (API) corresponding to the interactive control command to an AV content reproducing engine that reproduces the AV content and a synchronized multimedia reproducing engine that reproduces the multimedia elements determined to be synchronized with the AV content.

According to another aspect of the present invention, there is provided a method for synchronizing and reproducing interactive contents, which includes: determining whether multimedia elements included in the interactive contents are synchronized with audio-visual (AV) contents, and transmitting an Application Program Interface (API) corresponding to the interactive control command; receiving the API and reproducing the AV content according to the received API; and reproducing the multimedia elements determined to be synchronized with the AV contents.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

Fig. 1 is a diagram of an apparatus for synchronizing and reproducing interactive contents according to an embodiment of the present invention;

fig. 2 illustrates a configuration of an apparatus for synchronizing interactive contents according to an embodiment of the present invention;

FIG. 3 illustrates an exemplary markup document expressing interactive contents according to the present invention;

FIG. 4 illustrates an exemplary markup document expressing interactive contents according to the present invention;

FIG. 5 illustrates an Application Program Interface (API) corresponding to an interactive control command in accordance with the present invention;

FIG. 6 illustrates an exemplary markup document expressing interactive contents according to the present invention;

fig. 7 illustrates control commands with respect to an AV content reproducing engine and a plug-in player according to the present invention;

fig. 8 is a flowchart of a method of synchronizing and reproducing interactive contents according to another embodiment of the present invention;

FIG. 9 is a flow diagram of a method of synchronizing interactive content according to another embodiment of the present invention;

FIG. 10 is a detailed flowchart of operation 91 of FIG. 9; and

fig. 11 is a detailed flowchart of operation 92 of fig. 9.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.

Fig. 1 is an illustration of an apparatus for synchronizing and reproducing interactive contents according to an embodiment of the present invention.

The apparatus for synchronizing and reproducing interactive contents includes a content reading unit 11, a content buffer 12, an interactive content synchronizing unit 13, an AV content reproducing engine 14, a synchronized multimedia element reproducing engine 15, and an unsynchronized multimedia element reproducing engine 16.

The content reading unit 11 reads AV/interactive contents including AV contents and interactive contents from a storage medium, such as a DVD read only memory (DVD-ROM) and a compact disc ROM (CD-ROM), or reads the AV/interactive contents by downloading the AV contents and interactive contents from the internet. The content buffer 12 buffers the AV/interactive contents read by the content reading unit 11. The content buffer 12 is required for stably reproducing AV/interactive contents, and the content buffer 12 may not be required in an ideal environment where the reading speed is very high.

The interactive contents synchronizing unit 13 analyzes the interactive contents included in the AV/interactive contents buffered by the contents buffer 12. At this time, the interactive contents including information controlling reproduction of the AV contents and the multimedia elements included in the AV/interactive contents previously read from the contents buffer 12 are then analyzed. In an ideal environment, it is possible to directly analyze interactive contents included in AV/interactive contents read by the content reading unit 11. Generally, the interactive contents represent a technology that allows a user to interactively control the contents of a DVD image and is mainly based on Enhanced Navigation (ENAV) suggested in the DVD Forum (http:// www.dvdforum.org).

The interactive contents synchronizing unit 13 interprets the interactive contents included in the parsed AV/interactive contents, determines whether multimedia elements included in the AV/interactive contents are synchronized with the AV contents, receives an interactive control command from a user, and transmits an Application Program Interface (API) corresponding to the received interactive control command to the AV contents reproducing engine 14 and the synchronized multimedia element reproducing engine 15. Here, AV contents are basic contents for synchronization, and other contents are synchronized with the AV contents. AV content, which is basic content for synchronization, is generally DVD content. The determination of which multimedia elements should be synchronized with the AV content is done by interpreting the interactive content. Thus, these synchronized multimedia elements can be controlled independently of other multimedia elements. In other words, the corresponding API is transmitted to the AV content reproducing engine 14 that reproduces the AV content and the synchronized multimedia element reproducing engine 15 that reproduces the multimedia elements that have been determined to be synchronized with the AV content. Here, the API denotes a method predetermined by an operating system or other application program to request the operation of the operating system or other application program. The API is implemented by calling a function that provides a connection to a particular subroutine in the program.

The AV content reproducing engine 14 receives the API transmitted from the interactive content synchronizing unit 13 and reproduces the AV content according to the received API. The synchronized multimedia element reproducing engine 15 receives the API transmitted from the interactive contents synchronizing unit 13 and reproduces the multimedia elements determined to be synchronized with the AV contents by the interactive contents synchronizing unit 13 according to the received API. If the user inputs an interactive control command, such as reproduction or stop, by pressing a specific key on the remote controller, the interactive contents synchronization unit 13 receives the interactive control command and transmits an API corresponding to the received interactive control command to the AV contents reproduction engine 14 and the synchronized multimedia elements reproduction engine 15. Then, the AV content reproducing engine 14 and the synchronized multimedia element reproducing engine 15 receive the transmitted API, and reproduce the AV content and the multimedia elements, respectively, according to the received API. In this way, the AV contents and the multimedia elements are reproduced while being synchronized with each other according to the intention of the manufacturer of the AV/interactive contents.

The asynchronous multimedia element reproducing engine 16 reproduces multimedia elements that are determined not to be synchronized with the AV contents by the interactive contents synchronization engine 13. Multimedia elements, such as banner advertisements, reproduced asynchronously with the AV content may be reproduced repeatedly and continuously.

The synchronized multimedia element rendering engine 15 and the unsynchronized multimedia element rendering engine 16 are included in the interactive content rendering engine. In addition, a reproduction engine for a still image browser is also included in the interactive contents reproduction engine. Accordingly, an AV image (generally, a DVD image) implemented by AV contents, a browser implemented by interactive contents, and multimedia elements are mixed together and then displayed on a single screen of a display device.

Fig. 2 illustrates a configuration of an apparatus for synchronizing interactive contents according to an embodiment of the present invention.

The apparatus for synchronizing interactive contents includes a synchronized multimedia element determining unit 21 and an API transmitting unit 22.

The synchronized multimedia element determining unit 21 analyzes and interprets the interactive contents including the AV contents and the multimedia elements, and determines whether the multimedia elements included in the interactive contents are synchronized with the AV contents. Here, the AV content is generally DVD content, the interactive content is expressed by a markup document, and the means for synchronizing the interactive content is implemented by a browser. The information indicating whether the multimedia element is synchronized with the AV content may be included in the markup document in the form of a metatag, a newly defined tag or attribute, a script, or binary data.

The synchronized multimedia element determining unit 21 includes an interactive content analyzing unit 211 and an interactive content interpreting unit 212.

The interactive contents analysis unit 211 analyzes the interactive contents expressed by the markup document and creates a Document Object Model (DOM) tree. The DOM tree represents a logical tree structure by modeling elements included in a structural document like a markup document as a single object. The interactive content interpretation unit 212 interprets the DOM tree created by the interactive content analysis unit 211, and determines whether an element in each node of the DOM tree is a multimedia element synchronized with AV content.

The API transmitting unit 22 receives an interactive control command from a user and transmits an API corresponding to the received interactive control command to the AV content reproducing engine 202 that reproduces the AV content and the synchronized multimedia element reproducing engine 203 that reproduces the multimedia elements determined to be synchronized with the AV content by the synchronized multimedia element determining unit 21. The interactive control commands include a play command, a stop command, a previous screen view command, and a next screen view command. Typically, interactive control commands are input by a user through an input of, for example, a remote control. The synchronized multimedia element rendering engine 203 may be implemented by a browser displaying interactive contents, but is typically implemented by a plug-in player. The plug-in allows files of various formats that cannot be displayed in the browser to be displayed in the browser's window by using software programmed by a third party. In other words, the plug-in allows opening of files of various formats called by the markup document. Because the plug-in runs in the web browser, the web browser appears to display files that cannot actually be displayed in the web browser without opening a browser window. For example, a plug-in player using a plug-in may be a WINDOWS media player, a flash player, a real player, etc. Since multimedia elements are mainly audio files, real moving image files, and moving image files reproduced by WINDOWS media player, flash player, or real-time player, they can be reproduced using an applet player.

More specifically, the API sending unit 22 includes an interactive control command receiving unit 22l and an interactive control command corresponding API sending unit 222.

The interactive control command receiving unit 221 receives interactive control commands such as a play command, a stop command, a previous screen view command, and a next screen view command. The interactive control command corresponding API transmitting unit 222 transmits an API corresponding to the interactive control command received from the interactive control command receiving unit 221 to the AV content reproducing engine 202 that reproduces the AV content and the synchronized multimedia element reproducing engine 203, such as WINDOWS media player, flash player, real player, which reproduces the multimedia elements, such as audio files, real moving image files, and moving picture moving image files, which are determined to be synchronized with the AV content by the synchronized multimedia element determining unit 21.

In other words, the interactive control command corresponding API transmission unit 222 forms the DOM tree by analyzing the interactive contents, and thus recognizes elements in each node of the DOM tree. At this time, the interactive control command corresponding API transmitting unit 222 responds to the interactive control command input by the user through the remote controller. If the elements in each node of the DOM tree can be processed in the browser, the browser displays the elements. If the elements in each node of the DOM tree cannot be processed in the browser, they are displayed using the corresponding plug-in player that allows them to be displayed. Once a user inputs an interactive control command through a specific key input using a remote controller, an event corresponding to the control command occurs. If the intention of the corresponding event is a play command, a stop command, a previous screen view command, or a next screen view command, i.e., navigation, the interactive control commands the corresponding API transmitting unit 222 to transmit an API corresponding to the input event to the AV content reproducing engine 202 and the synchronized multimedia element reproducing engine 203, i.e., the plug-in player, which reproduces multimedia elements synchronized with the AV content. At this time, when the DOM tree is first formed, the API is not transmitted to a plug-in player reproducing multimedia elements that are not synchronized with AV content by using the identified information synchronized with the AV content. Accordingly, only multimedia elements synchronized with the AV contents can be reproduced in synchronization with the AV contents.

Fig. 3 illustrates an exemplary markup document expressing interactive contents according to the present invention.

The markup document of fig. 3 is provided by a manufacturer of AV/interactive contents to allow a browser to recognize whether multimedia elements need to be synchronized with the AV contents when the AV/interactive contents include the multimedia elements in addition to the AV contents.

Referring to fig. 3, the markup document indicates that reproduction of the DVD content is defined in the first < object > tag assuming that two flash animation files and AV content (hereinafter, DVD content) are reproduced using the < object > tag. In the second and third < object > tags, reproduction of the flash animation file is defined. The manufacturer uses the < meta > tag to indicate that multimedia metadata included in the markup document needs to be synchronized with DVD content. Further, the manufacturer defines the "name" attribute of the < meta > tag as "synchronization _ id" and the "content" attribute of the < meta > tag as "2". Therefore, it can be seen that after interpreting the markup document, the flash animation file included by the < object > markup having the attribute "id-2" needs to be synchronized with the DVD content.

Since DVD content can be reproduced in the form of video object units (VOBUs), multimedia elements, such as audio files and motion picture files, reproduced simultaneously with the DVD content can additionally require schedule information in the form of VOBUs. In the present invention, since the technology of the multimedia element reproducing in synchronization with the DVD content is well known, the manner of the multimedia element reproducing in synchronization with the DVD content is not discussed. Accordingly, the flash animation file included in the second < object > tag is separated from the AV content, and the flash animation file included in the third < object > tag should be reproduced in synchronization with the AV content. In addition, information on a plug-in player that can reproduce a corresponding multimedia element is provided by using a "type" attribute.

Fig. 4 illustrates an exemplary markup document expressing interactive contents according to the present invention.

The markup document of fig. 4 is provided by a manufacturer of AV/interactive contents to allow a browser to recognize whether multimedia elements need to be synchronized with the AV contents when the AV/interactive contents include the multimedia elements in addition to the AV contents.

Referring to fig. 4, which is similar to fig. 3, the markup document indicates that AV content (here, DVD content) is supposed to be reproduced using an < object > tag. In the first < object > tag, reproduction of the DVD content is defined. In the second and third < object > tags, reproduction of the flash animation file is defined. However, in contrast to the markup document shown in fig. 3, information regarding synchronization with AV content is not recorded in a specific markup such as a < meta > markup. Instead, a "synchronization" attribute is newly defined in the < object > tag, and thus DVD content that needs to be synchronized with AV content can be identified. As shown in FIG. 4, "synchronization" includes Boolean expressions as attribute values. If the Boolean expression is "true", the flash animation file needs to be synchronized with the AV content. If the Boolean expression is "false," the flash animation file does not need to be synchronized with the AV content. Therefore, the flash animation file included in the second < object > tag is separated from the AV content, and the flash animation file included in the third < object > tag needs to be reproduced in synchronization with the AV content. Also, information on a plug-in player that can reproduce a corresponding multimedia element is provided by using a "type" attribute.

In fig. 3 and 4, information on synchronization with AV content is defined in the form of < meta > tag and attribute, respectively. However, information on synchronization with AV content may be defined in a new mark or a programming language such as Java script. In other words, information regarding synchronization with AV content may be included in a markup document using various methods. Manufacturers of AV/interactive contents include information on whether multimedia elements included in their AV/interactive contents need to be synchronized with the AV contents in a markup document. Accordingly, the browser implemented by the present invention can control both multimedia elements and AV content by using corresponding information on synchronization with the AV content in response to a user input.

Fig. 5 illustrates an API of an interactive control command corresponding to the present invention.

In order to respond to a case where a user wants to navigate AV contents through a user input device such as a remote controller, an API corresponding to the interactive control command should be included. At this time, when the API corresponding to a specific key-in event from the remote controller refers to the RCKeyEvent interface, the RCKeyEvent interface provides specific information related to the remote controller. The key code attribute represents a key code value previously assigned to a key on the remote controller, and the key name represents a name of the key on the remote controller. The RCKeyEvent interface shown in fig. 5 is used in the DOM tree.

The RCKeyEvent of fig. 5 may occur through "rckeyress", "rckeydown", or "rckeyup". In RCKeyEvent, the minimum key codes required to navigate AV content in the ENAV mode suggested in the DVD Forum (http:// www.dvdforum.org) are "12", "13", "16" and "17". When the keys assigned with "12", "13", "16", and "17" are pressed in the ENAV mode, the corresponding APIs are transmitted, and thus the AV content reproducing engine 14 and the synchronized multimedia element reproducing engine 15 shown in fig. 1 can be controlled. According to the present invention, other multimedia elements that need to be reproduced in synchronization with AV content should be controlled so that the multimedia elements can be navigated in the same manner as AV content is navigated. In other words, a control command corresponding to a navigation event occurring in the user input device should be transmitted to the plug-in player and the AV content reproducing engine 14, which reproduce each multimedia element.

Accordingly, when the user presses "PlayPause", "Stop", "Prev", and "Next" keys, to which key codes "12", "13", "16", and "17" are assigned, in the ENAV mode, the browser transmits corresponding APIs to a plug-in player and an AV content reproducing engine that reproduce multimedia elements in synchronization with AV content.

Fig. 6 illustrates an exemplary markup document expressing interactive contents according to the present invention.

Referring to fig. 6, in a markup document, flash animation files that do not need to be synchronized with AV content and windows media moving picture files that need to be synchronized with AV content are designated as multimedia elements instead of AV content. The flash player and the windows media player are designated as plug-in players reproducing the flash animation file and the windows media moving image file.

Fig. 7 illustrates control commands regarding the AV content reproducing engine 14 and the plug-in player according to the present invention.

Referring to the table of fig. 7, if an event corresponding to "Play" is initialized by a user in an ENAV mode, the browser transmits an API named dvdvdvvideo. In other words, according to the table of fig. 7, predetermined corresponding APIs are transmitted to all the reproducing engines and plug-in players which reproduce multimedia elements. However, as described above, since the browser knows which multimedia elements are synchronized with the AV content through information on synchronization with the AV content included in the markup document, the API is not transmitted to the multimedia elements that do not need to be synchronized with the AV content. Accordingly, AV contents and multimedia events that need to be synchronized with the AV contents are controlled in the same manner in response to a navigation event of a user.

Fig. 8 is a flowchart of a method of synchronizing and reproducing interactive contents according to an embodiment of the present invention.

The method of synchronizing and reproducing the interactive contents is as follows.

In operation 81, AV/interactive contents including AV contents and interactive contents are read from a predetermined storage medium or read by downloading from the internet. In operation 82, the read AV/interactive contents are buffered. In an ideal environment where the read speed is very high, operation 82 may be omitted. In operation 83, the interactive contents included in the read AV/interactive contents are analyzed or the interactive contents included in the buffered AV/interactive contents are directly analyzed in an ideal environment, the analyzed interactive contents are interpreted, and it is determined whether multimedia elements included in the interactive contents are synchronized with the AV contents. If it is determined in operation 84 that the multimedia elements included in the interactive contents are synchronized with the AV contents, interactive control commands are received from the user and APIs corresponding to the received interactive control commands are transmitted in operation 85. In operation 86, the transmitted API is received and the AV content is reproduced according to the received API. In operation 87, the transmitted API is received and multimedia elements synchronized with the AV content are reproduced according to the received API. If it is determined in operation 84 that the multimedia elements included in the interactive contents are not synchronized with the AV contents, the multimedia elements are reproduced independently of the interactive control commands.

Fig. 9 is a flowchart of a method of synchronizing interactive contents according to an embodiment of the present invention.

The method of synchronizing interactive contents is as follows.

In operation 91, the interactive contents including the multimedia elements are analyzed and interpreted, and it is determined whether the multimedia elements included in the interactive contents are synchronized with the AV contents. Here, the AV content is generally DVD content, and the interactive content is expressed by a markup document. In the markup document, information on whether the multimedia element is synchronized with the AV content may be included in the form of a < mata > tag, a newly defined attribute, a script, or binary data.

In operation 92, when an interactive control command is received from a user, an API corresponding to the received interactive control command is transmitted to the AV content reproducing engine 202 that reproduces AV content and the synchronized multimedia element reproducing engine 203 that reproduces multimedia elements determined to be synchronized with the AV content, shown in fig. 2. Here, the interactive control command may be a play command, a stop command, a previous screen view command, or a next screen view command, and the synchronized multimedia element reproducing engine 203 is a plug-in player. The plug-in player may be a windows media player, a flash player, or a real player. The audio file, the real moving image file, and the moving image file are multimedia elements reproduced in a windows media player, a flash player, or a real player, not AV content.

Fig. 10 is a detailed flowchart of operation 91 of fig. 9. Operation 91 of fig. 9 is as follows.

In operation 101, interactive contents expressed by a markup document are analyzed and a DOM tree is created. In operation 102, the created DOM tree is interpreted, and it is determined whether an element in each node of the created DOM tree is a multimedia element synchronized with AV content.

Fig. 11 is a detailed flowchart of operation 92 of fig. 9. Operation 92 of fig. 9 is as follows.

In operation 111, an interactive control command, such as a play command, a stop command, a previous screen view command, or a next screen view command, is received from a user. In operation 112, an API corresponding to the received interactive control command is transmitted to an AV content reproducing engine 202 that reproduces AV content and a synchronized multimedia element reproducing engine 203, such as a windows media player, a flash player, or a real player, that reproduces multimedia elements, such as audio files, real moving image files, and animation moving image files, that are determined to be synchronized with the AV content.

The embodiments of the present invention can be embodied as computer readable codes on a computer readable medium and can be implemented in a general digital computer that executes a program using the computer readable medium.

The data structure used in the embodiments of the present invention may be recorded in a computer-readable medium using various recording apparatuses.

The computer-readable medium includes, but is not limited to, magnetic storage media (e.g., ROM, floppy disks, and hard disks), optical read media (e.g., CD-ROMs and DVDs), and carrier waves (e.g., transmission through the internet).

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Industrial applicability

According to the present invention, in response to a user input, a specific AV content, such as a DVD content, and a multimedia content synchronized with the specific AV content are simultaneously navigated by including information indicating whether multimedia elements in AV/interactive contents including the multimedia elements are synchronized with the AV content. In addition, various multimedia elements can be efficiently synchronized and reproduced. To achieve such synchronization, it is only necessary to specify a flag or an attribute defined to include information on synchronization with AV content. Accordingly, the user can conveniently generate the markup document.

Claims (40)

1. An apparatus for synchronizing interactive content, the apparatus comprising:

a synchronized multimedia element determining unit that determines whether multimedia elements included in the interactive contents are synchronized with audio-visual (AV) contents; and

an Application Program Interface (API) transmitting unit that transmits an API corresponding to the interactive control command to an AV content reproducing engine that reproduces the AV content and a multimedia element reproducing engine that reproduces the multimedia element determined by the synchronized multimedia element determining unit to be synchronized with the AV content.

2. The apparatus of claim 1, wherein the AV content is Digital Versatile Disc (DVD) content, and the interactive content is expressed by a markup document and/or is a resource referenced in the markup document.

3. The apparatus of claim 2, wherein the synchronized multimedia element determining unit analyzes and interprets the interactive contents expressed by a markup document including information on whether the multimedia elements are synchronized with the AV contents, and determines whether the multimedia elements included in the interactive contents are synchronized with the AV contents, the information included in the markup document being a meta tag, a newly defined attribute, a script, or binary data.

4. The apparatus of claim 3, wherein the synchronized multimedia element determination unit comprises:

an interactive contents analysis unit which analyzes interactive contents expressed by the markup document and creates a Document Object Model (DOM) tree; and

an interactive content interpreting unit that interprets the DOM tree created by the interactive content analyzing unit and determines whether an element in each node of the created DOM tree is a multimedia element synchronized with the AV content.

5. The apparatus of claim 1, wherein the interactive control command is a play command, a stop command, a previous screen view command, or a next screen view command, and the synchronized multimedia element reproduction engine is a plug-in player.

6. The apparatus of claim 5, wherein the plug-in player is a WINDOWS media player, a flash player, or a real player.

7. The apparatus of claim 6, wherein the multimedia elements include audio files, real moving image files, and animation moving image files reproduced in a WINDOWS media player, a flash player, or a real player.

8. The apparatus of claim 7, wherein the API sending unit comprises:

an interactive control command receiving unit which receives an interactive control command from a user as a play command, a stop command, a previous screen viewing command, or a next screen viewing command; and

an interactive control command corresponding API transmitting unit which transmits an API corresponding to the interactive control command received by the interactive control command receiving unit to an AV content reproducing engine which reproduces the AV content and a multimedia element reproducing engine which reproduces the audio file, the real moving image file, and the moving image file determined as the multimedia element synchronized with the AV content by the synchronized multimedia element determining unit as a WINDOWS media player, a flash player, or a real player.

9. An apparatus for synchronizing and reproducing interactive contents, the apparatus comprising:

an interactive contents synchronization unit which determines whether multimedia elements included in the interactive contents are synchronized with audio-visual (AV) contents and transmits an Application Program Interface (API) corresponding to the interactive control command;

an AV content reproducing engine which receives the API transmitted from the interactive content synchronizing unit and reproduces the AV content according to the received API; and

and a synchronized multimedia element reproducing engine which receives the API transmitted from the interactive contents synchronizing unit and reproduces the multimedia elements determined to be synchronized with the AV contents by the interactive contents synchronizing unit.

10. The apparatus of claim 9, further comprising a content reading unit which reads AV/interactive contents including AV contents and interactive contents from a predetermined storage medium or reads the AV/interactive contents by downloading from the internet.

11. The apparatus of claim 10, wherein the interactive contents synchronizing unit analyzes the interactive contents included in the AV/interactive contents read by the contents reading unit.

12. The apparatus of claim 10, further comprising a content buffer buffering the AV/interactive contents read by the content reading unit.

13. The apparatus of claim 12, wherein the interactive contents synchronizing unit analyzes and interprets the interactive contents included in the AV/interactive contents buffered by the contents buffer, and determines whether multimedia elements included in the interactive contents are synchronized with the AV contents.

14. The apparatus of claim 9, further comprising a non-synchronized multimedia element reproducing engine that reproduces multimedia elements determined by the interactive contents synchronizing unit not to be synchronized with the AV contents.

15. A method of synchronizing interactive content, the method comprising:

determining whether multimedia elements included in the interactive contents are synchronized with audio-visual (AV) contents; and

an Application Program Interface (API) corresponding to the interactive control command is transmitted to an AV content reproducing engine that reproduces the AV content and a synchronized multimedia reproducing engine that reproduces the multimedia elements determined to be synchronized with the AV content.

16. The method of claim 15, wherein the AV contents are Digital Versatile Disc (DVD) contents, and the interactive contents are expressed by a markup document and/or are resources referenced in the markup document.

17. The method of claim 16, wherein the step of determining whether multimedia elements included in the interactive contents are synchronized with the AV contents further comprises parsing and interpreting the interactive contents expressed by a markup document including information on whether the multimedia elements are synchronized with the AV contents, and determining whether the multimedia elements included in the interactive contents are synchronized with the AV contents, the information included in the markup document being a meta tag, a newly defined attribute, a script, or binary data.

18. The method of claim 17, wherein the determining whether multimedia elements included in the interactive contents are synchronized with the AV contents comprises:

analyzing interactive contents expressed by the markup document and creating a Document Object Model (DOM) tree; and

the DOM tree created by the interactive content analysis unit is interpreted, and it is determined whether an element in each node of the created DOM tree is a multimedia element synchronized with AV content.

19. The method of claim 15, wherein the interactive control command is a play command, a stop command, a previous screen view command, or a next screen view command, and the synchronized multimedia element reproduction engine is a plug-in player.

20. The method of claim 19, wherein the plug-in player is a WINDOWS media player, a flash player, or a real player.

21. The method of claim 20, wherein the multimedia elements include audio files, real moving image files, and animation moving image files reproduced in a WINDOWS media player, a flash player, or a real player.

22. The method of claim 21, the step of transmitting the API comprising:

receiving an interactive control command as a play command, a stop command, a previous screen view command, or a next screen view command from a user; and is

An API corresponding to the received interactive control command is transmitted to an AV content reproducing engine that reproduces AV content and a multimedia element reproducing engine that reproduces multimedia elements determined to be synchronized with the AV content, which is a WINDOWS media player, a flash player, or a real player, a real moving image file, and a moving image file.

23. A method of synchronizing and reproducing interactive contents, the apparatus comprising:

determining whether multimedia elements included in the interactive contents are synchronized with audio-visual (AV) contents, and transmitting an Application Program Interface (API) corresponding to the interactive control command;

receiving the transmitted API and reproducing the AV content according to the received API; and

the transmitted API is received and the multimedia elements determined to be synchronized with the AV content are reproduced.

24. The method of claim 23, wherein the determining whether multimedia elements included in the interactive contents are synchronized with the AV contents further comprises:

the AV/interactive contents including the AV contents and the interactive contents are read from a predetermined storage medium or read by downloading the AV/interactive contents from the internet.

25. The method of claim 24, wherein the step of determining whether multimedia elements included in the interactive contents are synchronized with the AV contents comprises analyzing the interactive contents included in the read AV/interactive contents.

26. The method of claim 24, further comprising buffering the read AV/interactive contents.

27. The method of claim 26, wherein the step of determining whether multimedia elements included in the interactive contents are synchronized with the AV contents comprises parsing and interpreting the interactive contents included in the buffered AV/interactive contents, and determining whether the multimedia elements included in the interactive contents are synchronized with the AV contents.

28. The method of claim 23, further comprising reproducing multimedia elements that are determined not to be synchronized with the AV contents.

29. A computer-readable recording medium having embodied thereon a program for a method of synchronizing interactive contents, wherein the method comprises:

determining whether multimedia elements included in the interactive contents are synchronized with audio-visual (AV) contents; and

an Application Program Interface (API) corresponding to the interactive control command is transmitted to an AV content reproducing engine that reproduces the AV content and a synchronized multimedia reproducing engine that reproduces the multimedia elements determined to be synchronized with the AV content.

30. A computer-readable recording medium having embodied thereon a program for executing a method of synchronizing and reproducing interactive contents, the method comprising:

determining whether multimedia elements included in the interactive contents are synchronized with audio-visual (AV) contents, and transmitting an Application Program Interface (API) corresponding to the interactive control command;

receiving the transmitted API and reproducing the AV content according to the received API; and

the transmitted API is received and the multimedia elements determined to be synchronized with the AV content are reproduced.

31. A method for synchronizing data streams, comprising:

receiving a data stream;

analyzing the data stream into AV content and interactive content;

interactive contents are identified to correspond to synchronized interactive contents synchronized with the AV contents and non-synchronized interactive contents not synchronized with the AV contents.

Receiving a navigation control command; and

the AV content and the synchronized interactive content are selectively decoded based on a result of the identification of the synchronized interactive content and corresponding to the received navigation control command.

32. The method of claim 31, further comprising:

selectively decoding the non-synchronized interactive content.

33. The method of claim 31, wherein the selectively decoding comprises selectively decoding the AV content and the synchronized interactive content using an Application Program Interface (API) corresponding to the navigation control command.

34. The method of claim 31, further comprising:

buffering the received data stream allows AV contents and interactive data in the data stream to be more stably reproduced.

35. The method of claim 31, wherein the AV content comprises a Digital Versatile Disc (DVD).

36. The method of claim 35, wherein the interactive contents allow a user to control the DVD AV contents based on an Enhanced Navigation (ENAV) command.

37. The method of claim 36, wherein the selectively decoding is controlled such that the synchronized interactive content is navigable in the same manner as the AV content in response to the navigation control command.

38. The method of claim 31, wherein the interactive contents comprise a markup document including information of control of selective decoding of multimedia elements in the AV contents and the interactive contents.

39. The method of claim 38, wherein the selectively decoding further comprises:

creating a Document Object Model (DOM) tree from the parsed interactive content; and

each node of a DOM tree representing multimedia elements synchronized with AV content is identified.

40. The method of claim 39, further comprising:

a plug-in corresponding to the multimedia elements synchronized with the AV content is identified, wherein the plug-in is used to selectively decode the multimedia elements synchronized with the AV content.