EP1938322A2

EP1938322A2 - Apparatus for reproducing data, method thereof, apparatus for recording the same, method thereof and recording medium

Info

Publication number: EP1938322A2
Application number: EP06769354A
Authority: EP
Inventors: Kun Suk Kim; Jea Yong Yoo
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2005-08-22
Filing date: 2006-08-21
Publication date: 2008-07-02
Also published as: WO2007024077A2; EP1938322A4; WO2007024077A3

Abstract

In one embodiment, the method includes determining which one of a primary subtitle associated with a primary video stream and a secondary subtitle associated with a secondary video stream to display based on management information stored in a memory. The secondary video stream represents the picture-in-picture presentation path with respect to a primary presentation path represented by the primary video stream. The primary video stream is recorded on a recording medium. The determined subtitle is selectively reproduced based on the management information.

Description

[DESCRIPTION]

APPARATUS FOR REPRODUCING DATA, METHOD THEREOF, APPARATUS FOR

RECORDING THE SAME, METHOD THEREOF AND RECORDING MEDIUM

Technical Field

The present invention relates to a method and an apparatus

for reproducing data from and/or recording data in a

recording medium or storage and the recording medium.

Background Art

Recently, optical discs capable of recording large-scale data

as record media are widely used. To meet the rising demand

for video data of high image quality and audio data of high sound quality, HDTV and MPEG2 have been provided. For

instance, if video data amounting to one HDTV movie is stored

in a disc with MPEG2 image quality, a high-density recording

medium having at least 20Gbyte data storage capacity is demanded.

To meet this demand, Blu-ray disc, HD-DVD (high-definition

digital video versatile disc) and the like have been

developed as next generation recording media. And, many

efforts have been made to develop an optical record player

according to high definition recording medium specifications.

However, despite the increasing possibility in recording and

reproducing at least two kinds of video stream data simultaneously due to the development of high definition

recording media, a suitable reproducing method has not been

proposed so far.

Disclosure of Invention

The present invention relates to a method of managing

reproduction of at least one picture-in-picture presentation

path.

In one embodiment, the method includes determining which one

of a primary subtitle associated with a primary video stream

and a secondary subtitle associated with a secondary video stream to display based on management information stored in a

memory. The secondary video stream represents the picture-in-

picture presentation path with respect to a primary

presentation path represented by the primary video stream.

The primary video stream is recorded on a recording medium.

The determined subtitle is selectively reproduced based on

the management information.

In one embodiment, the management information includes a flag

indicating which one of the primary subtitle and the

secondary subtitle to display.

In one embodiment, a state of the flag is set based on an

instruction. For example, the instruction may be received

from a user, from an application program interface, or etc.

In one embodiment, the method may further include determining whether to display subtitles based on the management

information. Here, the management information may include a

flag indicating whether to display subtitles. In one

embodiment, a state of this flag is set based on an

instruction. For example, the instruction may be received

from a user, from an application program interface, or etc.

In another embodiment, a management table is reproduced from

a recording medium. The management table indicates a number of secondary subtitle entries. A secondary subtitle stream

number identifying a selected one of the number of secondary

subtitle entries as the secondary subtitle is stored in a

memory. The secondary subtitle identified by the stored

secondary subtitle stream number is associated with a

secondary video stream, and the secondary video stream

represents the picture-in-picture presentation path with

respect to a primary presentation path represented by a

primary video stream. The secondary subtitle is reproduced based on management information stored in the memory.

The present invention also relates to a reproduction

apparatus.

In one embodiment, the apparatus includes a memory unit

configured to store management information. The management

information indicates which one of a primary subtitle

associated with a primary video stream and a secondary

subtitle associated with a secondary video stream to display. The secondary video stream represents the picture-in-picture presentation path with respect to a primary presentation path

represented by the primary video stream. The primary video

stream is recorded on a recording medium. A controller is

configured to control reproduction of one of the primary subtitle and the secondary subtitle based on the management

information.

The present invention is further related to a recording

medium having a data structure for managing reproduction of

at least one picture-in-picture presentation path.

In one embodiment, the recording medium includes a primary video subtitle number area storing a number identifying a

primary subtitle associated with a primary video stream, and a secondary video subtitle number area storing a number

identifying a secondary subtitle associated with a secondary video stream. The secondary video stream represents the

picture-in-picture presentation path with respect to a

primary presentation path represented by a primary video

stream. The recording medium also includes a first flag area

storing a first flag indicating which of the primary subtitle

and the secondary subtitle to display.

The present invention further relates to a method and an

apparatus for recording the data structure for managing

reproduction of at least one picture-in-picture presentation

path. Brief Description of Drawings

The accompanying drawings, which are included to provide a

further understanding of the invention and are incorporated

in and constitute a part of this application, illustrate

embodiment ( s ) of the invention and together with the

description serve to explain the principles of the invention.

In the drawings :

FIG. 1 is a diagram of one embodiment of reproducing data within a recording medium and/or storage via an optical

record player;

FIG. 2 is a diagram of a file structure recorded in an

optical disc as a recording medium of the present invention;

FIG. 3 is a diagram of a recording structure of an optical

disc as a recording medium of the present invention;

FIG. 4 is a diagram for explaining a reproduction of a

secondary video according to an embodiment of the present invention;

FIG. 5 is a schematic block diagram of an overall

configuration of an optical record player according to an

embodiment of the present invention;

FIG. 6A and FIG. 6B are schematic block diagrams of a

playback system according to one embodiment of the present

invention;

FIG. 7 is a diagram of a data reproducing apparatus utilizing a playback system according to an embodiment of the present

invention;

FIG. 8A is an exemplary diagram of a status memory unit

provided to a reproducing apparatus according to an

embodiment of the present invention;

FIG. 8B is an exemplary diagram of PSR2 as a part of the

status memory unit shown in FIG. 8A;

FIGs. 9A to 9C are exemplary diagrams for explaining

reproduction of a subtitle according to embodiments of the present invention;

FIG. 10 is an exemplary diagram of syntax of a table including information for a presentation graphic or text

subtitle stream according to an embodiment of the present invention; and

FIG. 11 is a flowchart of a method of reproducing data according to an embodiment of the present invention.

Best Mode for Carrying Out the Ivnention

Reference will now be made in detail to example embodiments

of the present invention, which are illustrated in the

accompanying drawings. Wherever possible, the same reference

numbers will be used throughout the drawings to refer to the same or like parts.

For the purposes of example only, an optical disc such as a

DVD, Blu-ray disc (BD), HD-DVD, NFR (near field recording) disc, etc., will be used as an example recording medium in

describing the present invention, but it will be understood

that the present invention is not limited to optical discs as

the recording medium. For further convenience of explanation,

the present invention more particularly takes a "Blu-ray disc

(BD) " as an example of a record medium. Yet, it is apparent

that the technical idea of the present invention is

identically applicable to other record media including HD-DVD and the like.

In the present invention, "Storage" may be a storage means

provided within an optical record player such as shown in FIG.

1, and means an element which can randomly store information

and data. In particular, the storage currently used in

general, includes a "hard disc", "system memory", "flash

memory" or the like, which does not put limitation on the

scope of the present invention.

The "Storage" may be utilized as a means for storing data

associated with a recording medium. The data associated with

the recording medium to be stored within the storage may

include data externally downloadable such as from the

internet .

It will also be apparent that data directly read out of a

recording medium, in part, or a generated system data (e.g.,

metadata, etc.) associated with reproduction of data recorded

in the recording medium may be stored within the storage. "Contents" in the following description may be data provided

by a record medium author as contents configuring a title.

And, a party, who provides content, is generically named a

"content provider (CP)".

For convenience of explanation of the present invention, the

data recorded within the recording medium shall be called

"original data" and the data obtained outside the recording

medium and associated with the recording medium shall be called "additional data". The original and additional data

are classified according to acquisition methods only. So, data existing outside an optical disc and having any kind of

attribute associated with original data can be called

additional data.

"Title" as used in the following description may be a unit

of reproduction configuring an interface with a user. Each

title is linked to a specific object. And, a stream

associated with the corresponding title recorded within a

disc is reproduced according to a command or program within

the object. In particular, for explanation convenience of the

present invention, a title having a moving picture, movie and

interactive information according to MPEG2 compression among

titles recorded within a disc shall be named a "HDMV Title".

And, a title having moving picture, movie and interactive

information executed by a Java program among titles recorded

within a disc shall be named a "BD-J Title". "Subtitle" as used in the following description means a

graphic or text reproduction unit associated with the title.

The "subtitle" may be played back in a plane different from a

plane in which the title is played back.

"PiP (Picture-in-Picture) " used in the following description

means a function of playing a secondary video on an image of

a primary video that is being reproduced.

The above-explained terminologies are replaceable by any

terms indicating the same functions, respectively.

FIG. 1 shows one embodiment of reproducing data within a

recording medium and/or storage via an optical record player. Referring to FIG. 1, "Optical record player" 10 according to

the present invention enables recording or playback of an

optical disc according to various specifications. And, the

optical record player 10 can be designed to record/play an optical disc (e.g., BD) of a specific specification. Moreover,

the optical record player 10 can be made to play an optical

disc only. In the following description of the present

invention, by considering interactivity between a Blu-ray

disc (BD) and a peripheral device, a BD-player reproducing a

Blu-ray disc (BD) or a BD-recorder recording/playing a Blu-

ray disc (BD) will be taken as an example. And, it is

apparent that the "optical record player" 10 includes a

"drive" loadable within a computer or the like.

The optical record player 10 according to the present invention is equipped with a function of recording/playing an

optical disc 30 and a function of receiving an external input

signal, performing signal-processing on the received signal,

and delivering a corresponding image to a user via another

external display 20. In this case, no limitation is put on

the external input signal. And, a DMB (digital multimedia

broadcast) signal, an Internet signal or the like can be a representative one of the external input signals. In case of

the Internet, as an easily accessible medium, specific data

from the Internet can be downloaded via the optical record player 10.

The original data and the additional data will be explained

in detail as follows. For instance, if a multiplexed AV stream for a specific title is recorded as original data

within an optical disc and if an audio stream (e.g., English)

different from the audio stream (e.g., Korean) of the

original data is provided as an additional data from the

Internet, a request for downloading the audio stream (e.g.,

English) as the additional data from the Internet to

reproduce together with the AV stream of the original data,

or a request for downloading the audio stream (e.g., English)

as the additional data from the Internet to reproduce only,

may be made by a user. To enable the requests, association

between the original data and the additional data is

regulated and a systematic method of managing/reproducing the data according to the user' s request is provided.

To realize the user's requests, a file structure between the

original data and the additional data is provided. File and

data structures usable for a Blu-ray disc (BD) are explained

in detail with reference to FIG. 2 and FIG. 3 as follows.

FIG. 2 is a diagram of a file structure recorded within an

optical disc as a recording medium according to an embodiment

of the present invention. In particular, FIG. 2 shows a file structure for reproduction management of original data recorded within a disc.

Referring to FIG. 2, at least one BDMV directory exists below

one root directory. An index file ("index") and an object

file ("MovieObject") as general file (higher file)

information to secure interactivity with a user exist within

the BDMV directory. And, the BDMV directory includes a playlist directory ("PLAYLIST") , a clipinfo

directory ("CLIPINF") , a stream directory ("STREAM") , an

auxiliary directory ("AUXDATA") , a BD-J object

directory ("BDJO") , a metadata directory ("META") , a backup

directory ("BACKUP") and a JAR director. The BACKUP directory has information of data actually recorded within a disc and

information about a method of reproducing the recorded data.

The other directories, and the files included in each of the

directories, are explained in detail as follows.

The JAR directory includes JAVA program files. The metadata directory ("META") includes a metadata file as

data about a data. Namely, in the metadata directory ("META") ,

a search file, a metadata file for Disc Library and the like

exist as the metadata files to use for efficient search or

management of data.

The BD-J object directory ("BDJO") includes a BD-J Object file

for reproducing a BD-J Title.

The auxiliary directory ("AUXDATA") includes auxiliary files containing information for a disc playback. For instance, the

AUXDATA directory may include a sound file ("Sound.bdmv")

providing click sound in case of an execution of interactive graphic and font files ("11111. otf" and "99999. otf")

providing font information in case of a disc playback.

In the stream directory ("STREAM") , AV stream files recorded

within a disc in a specific format exist. Each of the streams

is recorded as MPEG-2 transport packets in general, and

".m2ts" is used as an extension of a stream file (01000.m2ts,

02000.m2ts, etc.). In particular, a stream generated from

multiplexing video, audio and graphic information together is

named an AV stream and at least one or more AV stream files

construct a title.

A "Presentation graphic" stream may be applicable to HDMV and

BD-J modes and includes information to provide a

supplementary image to the associated presentation. The

presentation graphic stream typically provides a subtitle and/or other animation graphics during HDMV or BD-J

reproduction .

A "Text subtitle" stream is a subtitle based on text provided

by a content provider who produces a subtitling application

that uses a character code sequence (text) added to style

information. A "Text subtitle" stream is stored as an Out-Of-

Mux stream separate from a main AV stream, and can provide a

subtitle stream without affecting attributes of audio and video reproductions associated with a content provider, in

bandwidth.

The above-explained "presentation graphic" stream or "text

subtitle" stream may be reproduced by a reproduction player.

Yet, both of the "presentation graphic" stream and the "text

subtitle" stream may be prohibited from being simultaneously reproduced.

The clipinfo directory ("CLIPINF") includes clip information

files (01000. clpi, 02000. clpi, etc.) one-to-one corresponding

to the stream files, respectively. In particular, a clip

information file ("*.clpi") includes attribute information

and timing information of the corresponding stream file. In

particular, the stream file ("*.m2ts") and the clip

information file ("*.clpi") corresponding to the stream file

(*.m2ts) are called collectively a "clip". Namely, a "clip"

is the data containing both of the stream file ("*.m2ts") and

the clip information file ("*.clpi"). The playlist directory ("PLAYLIST") includes playlist files

("*.mpls"). A playlist is a group of playing intervals for

reproducing clips. And, a playing interval is called a

Playltem. Each of the playlist files ("*.mpls") includes at

least one Playltem and SubPlayltem (SPI) designating a

playing interval of reproducing a specific clip. The Playltem

and SubPlayltem (SPI) have information about a reproduction

start time (IN-Time) and reproduction end time (OUT-Time) of a specific clip. So, the playlist can be called a set of

Playltems. And, metadata for managing a reproduction of a

secondary video is included within the playlist file.

Moreover, the metadata includes a reproduction time,

reproduction position and size of the secondary video in

association with the reproduction of the secondary video.

A reproduction process within PlayList file by at least one

Playltem is called "main path" and a reproduction process

within PlayList file by each SubPlayltem is called "sub path".

The main path provides a master presentation of a playlist

and the sub path provides auxiliary presentations associated

with the master presentation. The main path should exist

within the PlayList file and at least one sub path may exist

according to a presence of SubPlayltem (SPI) .

In the present invention, video data reproduced by the main

path is also called primary video, and video data reproduced

by the sub path is also called secondary video. A function of reproducing both of the primary and secondary videos by an

optical record player may be "PiP (Picture in Picture) .

The backup directory BACKUP stores a copy of the index file

("index") recording information associated with a disc

playback among data of the file structure, object files

(MovieObject, BD-J Object), unit key file, all playlist files

("*.mpls") within the playlist directory PLAYLIST, and all

clip information files ("*.clpi") within the clipinfo

directory CLIPINF. Since the loss of the files may be fatal to the disc playback, the BACKUP directory stores these files

for backup.

It is apparent that the file structure of the present

invention is not limited to the above-explained names and

positions. Namely, the directories and files should be

understood not by their names and positions but by their meanings .

FIG. 3 is a diagram of a data record structure written on an

optical disc as a recording medium according to an embodiment

of the present invention, which shows how the aforesaid file

structure associated information is recorded within a

corresponding disc.

Referring to FIG. 3, in view from an inner circumference of a

disc, there exist a file system information area as system

information for managing an entire file, an area ("database

area") in which PlayList and clip information files are written to reproduce a recorded AV stream (*.m2ts), and an AV

stream area in which a stream configured with

audio/video/graphic or a JAR file is recorded.

And, an area for recording file information for reproducing

contents within the stream area and the like is called a

"Reproduction management area" and corresponds to the file

system information area or the database area. In some cases,

reproduction information of a stream can be recorded in a

header of a stream within the stream area. In this case, the header corresponds to the management area as well. So,

information associated with playback or reproduction

management can be recorded in the "reproduction management

area".

An area for recording file information for reproducing

contents within the stream area and the like is called a

"Reproduction management area" and corresponds to the file

system information area or the database area. In some cases,

reproduction information of a stream can be recorded in a

header of a stream within the stream area. In this case, the

header corresponds to the management area as well. So,

information associated with reproduction management can be

recorded in the "Reproduction management area". And, main

data and auxiliary data (e.g., AV streams and at least one or

more text subtitle streams) are stored within a stream area.

In this case, the main data includes audio data, video data and graphic data. The auxiliary data (e.g., text subtitle) is

not multiplexed with the main data but is independently

stored within the stream area. Each area shown in FIG. 3 is

exemplarily proposed. And, it is apparent that the present

invention is not limited to the arrangement structure of the

areas shown in FIG. 3.

FIG. 4 is a diagram of a reproduction mode of secondary video according to embodiments of the present invention.

One embodiment of playing a secondary video on an image of a

primary video that is being played is explained with reference to FIG. 4 as follows.

Referring to FIG. 4, another video data associated with a

primary video 410 can be requested to be output to a same

display unit 20 while the primary video is being played back.

For instance, in the course of playing a movie or documentary, in case that a director's commentary for a shooting process

is to be provided to a user, a video showing the commentary

can be played back as a secondary video 420 together with the

primary video 410. In doing so, the secondary video 420 may

be played together with the playback of the primary video 410.

In some cases, a playback of the secondary video 420 may

start in the middle of reproducing the primary video 410. And,

it is also possible to display the secondary video 420 at a

different position or size on a screen according to a

playback process. Moreover, it is also possible to start or end a corresponding playback separately from a playback of

the primary video 410. The primary video 410 can be played

together with an associated audio 410a and the secondary

video 420 can be played together with an associated audio

420a.

Information for a play timing point, play position, size of

the secondary video and a stream constructing the secondary

video is provided to play back the secondary video. And,

information for defining an audio stream, presentation graphic or text subtitle stream (e.g., PiP PG textST stream)

reproduced together with the secondary video and information for defining a permitted reproduction combination of the

streams are provided as well. Moreover, an optical record player is provided with a memory unit (e.g., PSRs) storing a

playback status of the secondary video and a playback

environment .

FIG. 5 is a block diagram of an overall configuration of an

optical record player according to an embodiment of the

present invention.

Referring to FIG. 5, an optical record player 10 according to

one embodiment of the present invention includes a pickup 11

for reproducing original data and reproduction management

information including file information recorded in an optical

disc, a servo 14 for controlling an action of the pickup 11,

and a signal processor 13 for restoring a reproduction signal received from the pickup 11 to a specific signal value. The

signal processor 13 also modulates a signal to be recorded

into a signal recordable on the optical disc. A

microprocessor 16 controls the overall operations of these

elements.

The pickup 11, the servo 14, the signal processor 13, and the

microprocessor 16 are also collectively referred to as a "recording/reproducing unit". In accordance with the present

invention, the recording/reproducing unit reads data from an optical disc 30 or storage 15 under the control of a

controller 12, and sends the read data to an AV decoder 17b.

The recording/reproducing unit also receives an encoded

signal from an AV encoder 18, and records the received signal

in the optical disc 30. Thus, the recording/reproducing unit

can record video and audio data in the optical disc 30.

The controller 12 downloads additional data present outside

the optical disc 30 in accordance with a user command, and

stores the additional data in the storage 15. The controller

12 also reproduces the additional data stored in the storage

15 and/or the original data in the optical disc 30 at the request of the user.

The optical recording/reproducing ^' apparatus 10 further

includes a playback system 17 for finally decoding data, and

providing the decoded data to the user under the control of

the controller 12.. The playback system 17 includes an AV decoder 17b for decoding an AV signal. The AV decoder 17b

may include a plurality of decoders. The playback system 17

also includes a player model 17a for analyzing an object

command or application associated with playback of a

particular title, for analyzing a user command input via the controller 12, and for determining a playback direction,

based on the results of the analysis. In an embodiment, the

player model 17a may be implemented as including the AV decoder 17a. In this case, the playback system 17 is the player model itself.

FIG. 6A and FIG. 6B are schematic block diagrams of a

playback system according to an embodiment of the present invention.

Referring to FIG. 6A, a decoder 17b according to one

embodiment of the present invention includes a primary video

decoder 610a decoding a primary video, a secondary video

decoder 610b decoding a secondary video, a PG decoder 630

decoding a presentation graphic stream and a text decoder 640

decoding a text subtitle stream. As shown, the various

streams are delivered from the optical disc 30 or storage 15

to the decoders via a switching structure.

The PG decoder 630 and the text decoder 640 do not

discriminate between the primary and secondary videos. In

particular, the PG decoder 630 is capable of decoding a

presentation graphic stream associated with the secondary video or the primary video and the text decoder 640 is

capable of decoding a text subtitle stream associated with

the secondary video or the primary video.

The primary and secondary videos are output via primary and

secondary video planes 620a and 620b to be provided to a user,

respectively. And, the decoded presentation graphic or text

subtitle is output via a PG plane 650. As shown, a combining

structure combines the output of the PG decoder 630 and the

text decoder 640 for application to the PG plane 650. The layering or sequence of the planes appearing on a screen

are as follows: the primary video plane 620a lies in the

lowest layer, the secondary video plane 620b lies on the

primary video plane 620a, and the PG plane 650 is displayed

on the secondary video plane 620b.

Referring to FIG. 6B, a decoder 17b according to another

embodiment of the present invention includes a primary video

decoder 610a decoding a primary video, a secondary video

decoder 610b decoding a secondary video, PG decoders 630a and

630b decoding presentation graphic streams and text decoders

640a and 640b decoding text subtitle streams. As shown, the

various streams are delivered from the optical disc 30 or

storage 15 to the decoders via a switching structure.

The PG decoder 630a is capable of decoding a presentation

graphic stream associated with the primary video, while the

PiP PG decoder 630b is capable of decoding a presentation graphic stream associated with the secondary video. The text

decoder 640a is capable of decoding a text subtitle stream

associated with the primary video, while the PiP text decoder

640b is capable of decoding a text subtitle stream associated

with the secondary video.

The decoded presentation graphic or text subtitle is

outputted via a PG plane 650. As shown, a combining structure

combines the output of the PG decoder 630a and the text decoder 630b for application to the PG plane 650. The PiP

presentation graphic or decoded text subtitle associated with

the secondary video is output via a PiP PG plane 660. As

shown, a combining structure combines the output of the PiP

PG decoder 640a and the PiP text decoder 640b for application

to the PiP PG plane 660.

The controller 12 checks reproduction management data of the

secondary video and controls the secondary video decoder 610b

so that the secondary video may be decoded for display at a

specific position and size and at a specific timing point

according to secondary video playback attribute information

included in the reproduction management data. Primary and/or

secondary video stream data may be recorded in a recording

medium 30 or may be downloaded to a storage 15 from outside

of the recording medium. In particular, the controller 12

controls the PG decoder 630 or 630b or the text decoder 640

or 640b to decode the presentation graphic or text subtitle associated with the secondary video included in the secondary

video reproduction management data.

An output signal decoded by the PG decoder 630 or 630b or the

text decoder 640 or 640b is synthesized by an image

synthesizing unit (not shown in the drawing) to be displayed on a display unit. In particular, the primary video output

via the primary video plane 620a after being decoded by the

primary video decoder 610a is displayed on the display unit as a background image. The secondary video decoded by the

secondary video decoder 620a is displayed on the background

image of the primary video by the secondary video plane 620b.

And, an image output via the PiP PG plane 660 after being

decoded by the PG decoder 630 or 630b or the text decoder 640

or 640b is overlapped with an image of the secondary video.

The optical record player 10 according to the present

invention includes an AV encoder 18. To perform a function of

recording a signal on an optical disc, the AV encoder 18

converts an input signal to a signal of a specific format,

e.g., an MPEG2 transport stream according to a control of the

controller 12 and then provides the converted signal to the

signal processing unit 13. Like the AV decoder 17b, the AV

encoder 18 can include a plurality of encoders. The

controller 12 is able to control the primary and secondary

video streams, primary and secondary audio streams,

reproduction management data, presentation graphic, text subtitle stream or the like to be recorded on the optical

disc.

FIG. 7 shows a data reproducing apparatus utilizing a playback system according to an embodiment of the present

invention, in which a secondary video is reproduced together

with a primary video by the data reproducing apparatus .

Referring to FIG. 7, a "playback system" includes collection

of reproduction processing means configured as programs

(software) and/or hardware provided within an optical record player and/or stored on the recording medium and downloaded

on the optical record player. The playback system plays a

recording medium loaded in the optical record player, and

simultaneously reproduces and manages the data that is associated with the recording medium such as that stored in a

storage (e.g., data downloaded from outside).

In particular, a playback system 17 includes "User Event

Manager (171)", "Module Manager (172) ", a "Metadata Manager

(173)", "HDMV Module (174) ", "BD-J Module (175) ", "Playback

control engine (176) ", "Presentation engine (177)" and "Virtual

File System(40)", which are explained in detail as follows.

As separate reproduction processing management means for

reproducing HDMV Title and BD-J Title, respectively, the

"HDMV Module (174)" for HDMV Titles and the "BD-J Module

(175)" for BD-J Titles are independently configured. Each of

the "HDMV Module (174)" and the "BD-J Module (175)" has a control function for receiving a command or program within

the aforesaid object (Movie Object or BD-J Object), and

processing the command or program. The "Metadata Manager

(173)" is able to perform a title selection and to provide a

recording medium and title metadata to a user at any time under a user's control. The "HDMV Module (174)" and "BD-J

Module (175)" enable a portability of a command or

application by separating the command or application from a hardware configuration of the playback system. As a means for

receiving to process the command, application or the like, a

"Command processor (174a) is provided within the "HDMV Module

(174), and a "Java VM (175a)" and an "Application manager

(175b)" are provided within the "BD-J Module (175).

The "Java VM (175)" is "Virtual Machine" (VM) executing an

application. The "Application manager (175b)" includes an

application management function of managing a lifecycle of an

application.

Moreover, the "Module Manager (172)" is provided to deliver a

user command to the "HDMV Module (174)" or the "BD-J Module

(175)" and to control an operation of the "HDMV Module (174)"

or the "BD-J Module (175)".

A "Playback control Engine (176)", which is also provided,

interprets PlayList file information recorded within a disc

according to a reproduction command of the "HDMV Module

(174)" or the "BD-J Module (175)" and performs a corresponding reproduction function. Moreover, a

"Presentation Engine {111)" for decoding a specific stream

reproduced and managed by the "Playback Control Engine (176)",

and for displaying the decoded stream on a screen is provided.

Specifically, the "Playback Control Engine (176)" includes

"Playback Control functions (176a)" actually managing

reproductions and "Player Registers (176b)" storing player

status registers (PSRs) and general purpose registers (GPRs) .

In some cases, "Playback Control functions (176a)" may mean "Playback Control Engine (176)".

In an embodiment of the present invention, the "Player

registers (176b)" becomes a memory unit indicating a playback

status of the secondary video. The memory unit will be

explained in detail with reference to FIGs. 8A and 8B later.

The HDMV title and BD-J title receive user commands in

separate types, respectively, and independently perform the

user commands. A means for receiving and delivering a user

command to either the "HDMV Module (174)" or "BD-J Module

(175)" is provided by the "user Event Manager (171)". So, if

a received command is a user command by "User Operation (UO) ",

the "User Event Manager (171)" transfers it to the "Module

Manager (172)" or "UO controller (171a)" to perform the user

command. If a received command is a user command by "Key

Event", the "User Event Manager (171)" transfers it to the

"Java VM (175a)" within the "BD-J Module (175)" to perform the user command.

And, the playback system 17 according to the present

invention may include the "Metadata Manager (173)" that

provides disc library and enhanced search metadata

applications to a user.

In the above-explained playback system of the present

invention, the "Module Manager (172)", the "HDMV Module

(174)", the "BD-J Module (175)" and the "Playback Control

Engine (176)" are enabled in software. Software processing tends to be more advantageous than a hardware configuration

in design. Yet, the "Presentation Engine (111)", the decoders

and the planes are normally designed by hardware. In

particular, the elements (e.g., reference numbers 172, 174,

175, 176) performed by software can be configured with a

portion of the controller 12. Hence, the configuration of the

present invention should be understood by its meaning but is

not limited to a hardware configuration or a software configuration .

FIG. 8A is an exemplary diagram of a status memory unit

provided in a reproducing apparatus according to an

embodiment of the present invention and FIG. 8B is an

exemplary diagram of PSR2 as a part of the status memory unit

shown in FIG. 8A. FIGs. 9A to 9C are exemplary diagrams for

explaining a reproduction of a subtitle according to an

embodiment of the present invention. One embodiment of the present invention is explained with reference to these

drawings as follows.

An optical record player 10 includes "Player Registers

(176b)" as sort of memory units storing information for

record playback status and environment of the player. The

"Player Registers (176b)" can be divided into "General

purpose Registers (GPRs)" and "Player Status Registers

(PSRs)".

The "Player Status Registers (PSRs)" can be divided into "Playback Status Registers" storing playback status

parameters (e.g., interactive graphics stream number' and ^Λprimary audio number' ) and "Player Setting registers"

storing optical record player configuration parameters.

In the embodiment of the present invention, "Player Status

Registers (PSRs)" storing a playback status of a secondary

video are provided to play back the secondary video as well

as a primary video. In particular, the present invention

relates to a PSR2 storing information for a secondary video

associated presentation graphic or text subtitle played over

the secondary video.

First of all, a PSR14 820 as one of the "Player Status

Registers (PSRs)" includes a "secondary video stream number"

field. A secondary video stream number is stored in the

"secondary video stream number" field. In this case, the

secondary video stream number is used in specifying the secondary video stream that should be presented from

secondary video stream entries within an STN table of a

current playitem.

A "disp_v_flag" is also stored in the PSR14 820. In this case,

"disp_v_flag" is a flag indicating whether the display of the

secondary video is enabled or disabled. For instance, if the

flag "disp_v_flag" is set to ^λdisable' (0_b) , the display is not executed although the secondary video may still be

decoded by the decoder 610b. Hence, a user is unable to view

the secondary video. On the other hand, if the flag

^λλdisp_v_flag" is set to ^λenable' (l_b) , the secondary video is decoded by the decoder 610b and displayed. Hence, a user is

able to view the secondary video via the secondary video plane 620b.

A value of the flag "disp_v_flag" can be changed by a command

generated from a user operation (UO) , playback system or

application programming interface (hereinafter abbreviated API) .

In the present invention, a secondary video can be reproduced

together with a presentation graphic or text subtitle

(hereinafter abbreviated ^ΛPG Text ST' ) . So, a memory unit

(e.g., PSR2 810 shown in FIG. 8B) is provided to store the

^ΛPG TextST' associated with the secondary video (hereinafter

called ^ΛPiP PG TextST').

The PSR2 810 includes a "PG TextST stream number" field, a "PiP PG TextST stream number" field, a ^λλdisp_s_flag" field

and a "PiP_PG_textST_valid_flag" field.

In the "PG TextST stream number" field, a PG or TextSt stream

number (hereinafter abbreviated ^ΛPG TextST stream number' )

associated with the primary video is stored.

The PG TextST stream number is information designating the PG

or TextST stream that shall be reproduced among PG TextST

stream entries within an STN table of a current playitem if

the secondary video is not displayed. In case that the secondary video is not displayed, the flag "disp_v_flag"

within the PSR14 820 is set to Misable' or a secondary video

stream is not displayed during a current playitem playback.

The PG TextST stream number is a value obtained by adding ^Λl'

to a PG TextST stream identifier defined in the STN table,

and will be explained later.

On the other hand, in the "PIP PG TextST stream number" field,

a PG or TextSt stream number (hereinafter abbreviated ^λPiP PG

TextST stream number' ) associated with the secondary video is stored.

The PiP PG TextST stream number is information designating

the PG or TextST stream that should be reproduced among PG

TextST stream entries within an STN table of a current

playitem if the secondary video is displayed. In case that

the secondary video is displayed, the flag "disp_v_flag"

within the PSR14 820 is set to 'enable' and a secondary video stream indicated by the PSR14 820 is displayed during a

current playitem playback.

In case that a value stored in the "PG TextST stream number"

field is "OxFFF', it means that a PG TextST stream entry is

not selected by the playback system or there exists no PG

TextST stream. And, in case that a value stored in the "PiP

PG TextST stream number" field is "OxFFF' , it means that PiP PG TextST stream entry is not selected by the playback system

or there exists no PG PiP TextST stream.

The PG TextST stream number is a value obtained by adding ^Λl'

to a PG TextST stream identifier defined in the STN table, and will be explained later.

The "disp_s_flag" is a flag indicating whether to display a subtitle stream (the PiP PG TextST stream or the PG TextST

stream) .

If the flag "disp_s_flag" is set to 'disable (0_b) ' , the PG

Text ST stream and PiP PG TextST stream are not displayed.

Yet, even if the flag "disp_s_flag" is set to Misable (0_b)',

a graphic or text may be displayed in part. For instance, a

composition object of a presentation graphic or a dialog

region of a text subtitle may be displayed according to a

value of an intrinsic flag ("forced_on_flag") , not shown.

On the other hand, if the flag "disp_s_flag" is set to

'enable (Ib)', a designated PG Text ST stream or PiP TG TextST

stream can be displayed to a user. Like the "disp v_flag" of W

32 the PSR14, the flag "disp_s_flag" can be changed by a user operation (UO) or application programming interface (API) .

The "PiP_PG_textST_valid_flag" indicates whether the "PiP PG

TextST stream number" field is valid or not.

The "PiP_PG_textST_valid_flag" is used in indicating what

kind of "PG TextST stream number" field is used in displaying

the secondary video stream.

For instance, if the "PiP_PG_textST_valid_flag" is set to "0_b", the "PG TextST stream number" field defined in the PSR2 is

used in displaying the secondary video stream.

On the other hand, if the "PiP_PG_textST_valid_flag" is set

to "Ib", the "PiP PG TextST stream number" field defined in

the PSR2 is used. The "PiP_PG_textST_valid_flag" has no

influence on the optical record player according to the

present invention if the secondary video stream is not

displayed. In this case, the PG TextST stream identifier

stored in the "PG TextST stream number" field defined in the

PSR2 may be used.

A value of the "PiP_PG_textST_valid_flag" can be changed by a

navigation command or application programming interface (API).

Herein, the navigation command or application programming

interface (API) may be used in making a menu for a user

interface (UI) . Therefore, if a secondary video stream is

displayed on a primary video stream, it is possible to

selectively reproduce PiP PG textST stream (a subtitle associated in the secondary video stream) or PG textST stream

(a subtitle associated in the primary video stream) according

to user's demand.

The PIP PG TextST stream identifier stored within the PSR2

810 is controlled by a selection model of the PiP PG TextST

stream.

If a secondary video stream is displayed, the

"PiP_PG_textST_valid_flag" within the PSR2 is set to ^Λable (^λl_b')', a value stored in the "PiP PG TextST stream number"

field is not "OxFFF' and the "disp_s_flag" within the PSR2 is

set to ^Λable ( ^Λl_b' ) ' , then a PiP PG Text stream decided by this selection model will be displayed.

This case is shown in FIG. 9A, where a graphic or text 940

associated with a secondary video can be displayed on the

secondary video 920 (but a graphic or text subtitle for the

primary video 910 is not displayed) . In some cases, as shown

in FIG. 9B, a graphic or text 930 associated with a primary

video is displayed on the primary video 910 and a graphic or

text 940 associated with a secondary video can be displayed

on the secondary video 920.

On the other hand, if a secondary video stream is displayed,

the "PiP_PG_textST_valid_flag" within the PSR2 is set to

'disable (^Λ0_b'), a value stored in the "PiP PG TextST stream

number" field is not "OxFFF" and the "disp_s_flag" within the

PSR2 is set to ^λable ( ^λl_b' ) ' , then a PG Text stream decided by this selection model will be displayed.

This case is shown in FIG. 9C, where a graphic or text 930

associated with a primary video may be displayed on the

primary video 910.

Referring to FIG. 8B, the PG textST stream number and the PiP

PG textST stream number are stored in the "PG TextST stream

number" field and the "PiP TextST stream number" field included in the PSR2, respectively. Meanwhile, the

"PiP_PG_textST_valid_flag" having 1-bit allocated thereto indicates whether PiP PG TextST is valid or not. And, the

"disp_s_flag" having 1-bit allocated thereto indicates whether PiP PG TextST stream and PG TextST stream is to be

displayed or not.

In the aforesaid PSR2, play status information for a subtitle

associated with a secondary video to be played according to reproduction management data is stored. The subtitle includes

a graphic or text subtitle. The controller 12 checks a

subtitle to be played according to the reproduction

management data and controls playback status information

associated with the checked subtitle to be stored in the PSR2.

The controller 12 is able to control the subtitle to be

played back by checking the playback status information

stored in the PSR2. In this case, the subtitle is output via

a PG plane and is displayed on a secondary video. In this

case, the secondary video is displayed on a primary video. FIG. 10 is an exemplary diagram of syntax of a table

including information for a presentation graphic or text

subtitle stream according to an embodiment of the present

invention.

The table (hereinafter called STN table) defines a list of

basic streams that can be selected by an optical record

player during a playback of a main path or sub path

associated with a current playitem. And, the STN table is provided in each playitem included in a playlist.

The optical record player 10 according to the present

invention possesses a function of processing a secondary video, a presentation graphic and a text subtitle. So, the

STN table according to the present invention stores entries

associated with secondary video, secondary audio, presentation graphic and text subtitle.

Referring to FIG. 10, a "number__of_PG__text_stream_entries"

field 1010, a "number_of_secondary_video_stream_entries"

field 1020, a "number_of_PiP_PG_textST_stream_entires_plus" field 1030, and fields 1110 and 1120 defining graphic/text

entries and secondary video entries, respectively, are

included in an STN table according to an embodiment of the

present invention.

The ^Nλnumber_of_PG__text_stream_entries" field 1010 indicates a

number of the recorded presentation graphics or text stream

entries ("PG textST stream entries") . The "number_of_secondary_yideo_stream_entries" field 1020

indicates a number of the recorded "secondary video stream

entries" .

The "number_of_PiP_PG_textST_stream_entires_plus" field 1030

indicates a number of presentation graphics or text stream

entries (PG TextST stream entries) for a PiP application.

In association with the PG textST streams, a PG textST stream

identifier ("PG textST stream id") is initialized to '0'

(1110) . The PG textST stream identifiers are generated by

adding 1 to the previous PG textST identifier as long as the

number of the ^λPG textST' stream entries ("PG and textST stream entries") plus the number of ^ΛPG textST stream entries

for PiP application ("PiP PG and textST stream entries") has not been reached (1110).

In association with the PG textST stream identifier, the "PG

textST stream number" explained in the PSR2 is equal to a

value resulting from adding 1 to the "PG textST stream id".

And, the "PG textST stream number" is equal to or smaller

than the number (1010) of the PG textST stream entries ("PG

textST stream entries") .

In association with the PiP PG textST stream identifier, the

"PiP PG textST stream id" is equal to the "PG textST stream

id". Hence, the "PiP PG textST stream number" explained in

the PSR2 is equal to a value resulting from adding 1 to the

"PG textST stream id". The "PiP PG textST stream number" is equal to or smaller than

a value resulting from adding the number of the "PiP PG

textST stream entries" and the "PiP PG textST stream entries"

together.

Meanwhile, a "stream entry ()" field 1112 indicates

information for a PG textST stream entry. For instance, this

field indicates information for length and type of a stream. And, depending on the type, this field 1112 can identify the

specific stream of a main clip or a sub clip, and may also identify a subpath, for the stream.

A "stream attribute ()" field 1114 indicates information for a stream attribute. For instance, this field indicates

information for a length and coding type of a stream. This

field can identify according to the stream coding type

whether a specific stream corresponds to a presentation

graphic stream, an interactive graphic stream or a text

subtitle (textST) stream. According to the identified type, a

language code may be defined if the specific stream is a

presentation graphic stream. A character code and a language

code are defined if the specific stream is a text subtitle stream.

In association with the secondary video stream, the secondary

video stream identifier ("secondary video stream id") is

initialized to ¹O'. The secondary video stream identifiers

are obtained by adding 1 to the previous secondary video stream identifier as long as the number of secondary video

stream entries ("secondary video stream entries") defined in

the STN table has not been reached (1120) .

A "stream entry ()" field 1122 indicates information for a

stream entry. For instance, this field indicates information for length and type of a stream. And, depending on the

indicated type, the stream entry identifies the specific

stream of a main clip or a sub clip, and may also identify a subpath, of the stream.

A "stream attribute ()" field 1124 indicates information for a

stream attribute. For instance, this field 1124 indicates

information for a video format and frame rate.

In reproducing the secondary video together with the primary

video, a PiP PG textST stream may be reproduced. In this case,

combination relations between PG textST streams and secondary

video streams are possible.

In association with the permitted combinations between the

secondary video streams and the PiP PG textST streams, the

STN table includes "combo__info_Secondary_video_PiP_PG_textST"

field 1126 for each secondary video stream identified in

field 1120. This field

("combo_info_Secondary_video_PiP_PG__textST") defines the

permitted combination between the corresponding secondary

video streams and ^ΛPiP PG textST' streams.

Below the field ("combo info Secondary video PiP PG textST") , the STN table includes a "number of

PiP_PG_textST_ref_entries" field and a

"PiP_PG_textST_stream_id_ref" field.

The "number of PiP_PG_textST_ref_entries" field indicates a

number of presentation graphic streams and text streams permitted in reproducing the secondary video stream.

For each of the a number of presentation graphic streams and

text streams, the "PiP_PG_textST_stream__id_ref" field indicates a presentation graphic stream and text stream

identifier (PiP__PG_textST_stream_id) permitted in reproducing

the secondary video stream. Namely, this field indicates

which PG textST stream will be reproduced in playing the

secondary video stream.

In addition, playback status information for the presentation

graphic stream and text stream identifier

(PiP_PG_textST_stream_id) is stored in the PSR 2.

Referring to FIG. 11, an optical record player 10 according

to the present invention reads and checks information

associated with secondary video streams and subtitle streams

included in data recorded in a recording medium (S1102) . In

this case, the data includes a primary video stream, at least

one secondary video stream, a primary video associated

subtitle stream, a secondary video associated subtitle stream and reproduction management data for managing reproduction of

these streams.

For instance, in case of a recording medium input or power-on,

the optical record player 10 reads a STN-table within the

recording medium and then checks information associated with the secondary video stream. In this case, the information

associated with the secondary video stream includes a number

of secondary video stream entries, a secondary video stream entry id and the like.

As another example, from the STN-table the player 10 checks

information for subtitle streams associated with the primary

and secondary video streams. In this case, the subtitle

includes a graphic or text subtitle associated with the

secondary video. The information associated with the subtitle

stream includes (number of PG textST stream entries + number

of PiP PG textST stream entries), PG textST stream entry id

and the like. In addition, the optical record player 10

checks a value of the "disp_s_flag" indicating whether or

display of subtitle3s is enabled. And the optical record

player 10 may check the secondary subtitle streams allowed

according to the ^Λλcombo_info_Secondary_video_PiP_PG__textST"

or not .

Subsequently, the optical record player 10 stores the

playback status information associated with the secondary

video stream in a memory unit (S1004) . The playback status information includes a secondary video stream number,

information for a secondary video playback size, enablement

of a secondary video screen display and the like. The

secondary video stream number can indicate one of the

secondary video stream entries of the STN table included in a

playlist and corresponds to the secondary video stream entry

identifier. The memory unit may include one or more of the player status registers (PSRs) included in the optical record player 10.

For instance, the optical record player 10 selects a

secondary video stream having a lowest number from among

secondary video stream numbers corresponding to the secondary

video stream entry identifiers read in the step S1104 and

then stores the corresponding secondary video stream number

in the PSR14. Alternatively, the secondary video stream number may be selected by user input.

Also in step S1104 the optical record player 10 stores

playback status information for the subtitle streams in the

memory unit. This playback status information includes PG

TextST stream number, PiP PG TextST stream number associated

with the secondary video, whether or not subtitles are to be

display, which of the PG TextST stream or PiP TextSt stream

is to be displayed and the like. The subtitle stream number

can indicate one of the subtitle stream entries of the STN

table included in a playlist and correspond to the graphic or text subtitle stream entry identifier. Herein the graphic or

text subtitle stream entry identifier is one of the

identifiers allowed in the

"combo_info_Secondary_video_PiP_PG_textST". The memory unit

may include one of the player status registers (PSRs)

included in the optical record player.

For instance, the optical record player 10 stores the secondary video stream associated graphic or text subtitle

stream corresponding to the lowest graphic or text subtitle stream entry identifier read out in the step S1102 among the

graphic or text subtitle stream numbers in a PSR2. Alternatively, this and other status information may be

selected by user input. Subsequently, the optical record player 10 reproduces

(including decodes) the video and subtitle streams indicated

in the PSRs (S1106) . For example, the optical record player

10 selects and reproduces the corresponding secondary video

associated graphic or text subtitle stream based on the

playback status information associated with the secondary

video associated graphic or text subtitle stream stored in

the memory unit .

Then the optical record player 10 plays the secondary video

on the primary video according to the reproduction management

data (S1108) . For instance, the secondary video is played

back according to a playback position and size of the secondary video according to metadata that manages a playback

of the secondary video included in the reproduction

management data.

The graphic or text subtitle stream associated with a

secondary video is output via the PG plane 650 (and/or PG plan 660) in step SlIlO. In this case, the selected graphic

or text subtitle stream associated with secondary video

should be a stream reproducible in the player. In case that there exists a secondary video stream previously

designated by a user operation (UO) , playback system or

application programming interface (hereinafter abbreviated

API) or the like, a number of the corresponding secondary

video stream shall be recorded in the memory unit (e.g., PSR

14). And, a priority of a playback sequence can be designated

according to a type of a secondary video stream as well.

Similarly, if there exists a subtitle stream previously

designated by a user operation (UO) , playback system or

application programming interface (hereinafter abbreviated

API) or the like, a number of the corresponding subtitle

stream shall be recorded in the memory unit (e.g., PSR 2) .

Furthermore, where multiple secondary video streams are

available or multiple subtitles for primary or secondary

video are available, it will be understood that selection may

be made by a user operation (UO) , playback system or

application programming interface (hereinafter abbreviated API) or the like - including commands reproduced from the

recording medium.

Accordingly, the present invention provides the advantage

that a secondary video can be played together with a primary

video and a graphic or text associated with each of the

videos can be provided. Also, a content provider may provide

various content and graphics or texts associated with the

content. Hence, a user can simultaneously view the various

content and visually obtain information associated with the content.

It will be apparent to those skilled in the art that various

modifications and variations can be made in the present

invention without departing from the spirit or scope of the

inventions. Thus, it is intended that the present invention

covers the modifications and variations of this invention.

Claims

[CLAIMS]

1. A method of managing reproduction of at least one picture-

in-picture presentation path, comprising:

determining which one of a primary subtitle associated with a primary video stream and a secondary subtitle

associated with a secondary video stream to display based on

management information stored in a memory, the secondary

video stream representing the picture-in-picture presentation path with respect to a primary presentation path represented

by the primary video stream, the primary video stream being recorded on a recording medium; and

selectively reproducing the determined subtitle based on the management information.

2. The method of claim 1, wherein the management information

includes a flag indicating which one of the primary subtitle

and the secondary subtitle to display.

3. The method of claim 2, wherein a state of the flag is set

based on an instruction.

4. The method of claim 3, wherein the instruction is received from a user.

5. The method of claim 3, wherein the instruction is received

from an application program interface.

6. The method of claim 1, wherein

the primary subtitle is one of a graphics subtitle and a text subtitle; and

the secondary subtitle is one of a graphics subtitle and

a text subtitle.

7. The method of claim 1, further comprising:

determining whether to display subtitles based on the management information; and wherein

the reproducing step displays the determined subtitle if

the determining whether to display a subtitle step determines

to display a subtitle.

8. The method of claim 7, wherein the management information

includes a flag indicating whether to display subtitles.

9. The method of claim 8, wherein a state of the flag is set

based on an instruction.

10. The method of claim 9, wherein the instruction is

received from a user.

11. The method of claim 9, wherein the instruction is

received from an application program interface.

12. The method of claim 1, further comprising:

reproducing a management table from the recording medium,

the management table indicating a number of secondary

subtitle entries; and

storing a secondary subtitle stream number identifying a selected one of the number of secondary subtitle entries as

the secondary subtitle in the memory as part of the

management information.

13. The method of claim 12, wherein

the management table includes a secondary subtitle

identifier for each of the number of secondary subtitle

entries; and

the storing step stores one plus the secondary subtitle

identifier of the selected secondary subtitle entry in the

memory as the secondary subtitle stream number.

14. The method of claim 12, wherein

the management table includes combination information, the

combination information indicating the secondary subtitles

that are combinable with the secondary video stream; and

the storing step stores the secondary subtitle stream number for one of the secondary subtitles indicated as combinable

with the secondary video stream.

15. The method of claim 12, wherein

the management table indicates a number of primary

subtitle entries; and further including,

storing a primary subtitle stream number identifying a selected one of the number of primary subtitle entries as the

primary subtitle in the memory as part of the management information.

16. The method of claim 12, wherein the management table is

included in at least one playitem of a playlist recorded on the recording medium, the playitem indicating a playing

interval of the primary video stream, and the playlist

indicating which playitems to reproduce.

17. The method of claim 1, wherein the reproducing step comprises :

decoding the determined subtitle.

18. The method of claim 1, wherein the determining step

determines which of the primary subtitle and the secondary

subtitle to display based on the management information when

the secondary video stream is to be displayed.

19. The method of claim 1, wherein the determining step

determines to display the primary subtitle when the secondary

video stream is not displayed.

20. A method of managing reproduction of at least one

picture-in-picture presentation path, comprising:

reproducing a management table from a recording medium,

the management table indicating a number of secondary subtitle entries; and

storing a secondary subtitle stream number identifying a

selected one of the number of secondary subtitle entries as

the secondary subtitle in a memory, a secondary subtitle identified by the stored secondary subtitle stream number

being associated with a secondary video stream, the secondary

video stream representing the picture-in-picture presentation

path with respect to a primary presentation path represented by a primary video stream; and

selectively reproducing the secondary subtitle based on

management information stored in the memory.

21. A reproduction apparatus, comprising:

a memory unit configured to store management information,

the management information indicating which one of a primary

subtitle associated with a primary video stream and a secondary subtitle associated with a secondary video stream

to display, the secondary video stream representing the

picture-in-picture presentation path with respect to a

primary presentation path represented by the primary video

stream, the primary video stream being recorded on a

recording medium; and

a controller configured to control reproduction of one

of the primary subtitle and the secondary subtitle based on

the management information.

22. The apparatus of claim 21, wherein the management information includes a flag indicating which one of the

primary subtitle and the secondary subtitle to display.

23. The apparatus of claim 22, wherein the controller is

configured to set a state of the flag based on an instruction,

24. The apparatus of claim 23, wherein the instruction is received from a user.

25. The apparatus of claim 23, wherein the instruction is

received from an application program interface.

26. The apparatus of claim 21, wherein

the primary subtitle is one of a graphics subtitle and a text subtitle; and

the secondary subtitle is one of a graphics subtitle and

a text subtitle.

27. The apparatus of claim 21, wherein the management

information further indicates whether to display subtitles.

28. The apparatus of claim 27, wherein the management

information includes a flag indicating whether to display subtitles.

29. The apparatus of claim 28, wherein the controller is

configured to set a state of the flag based on an instruction.

30. The apparatus of claim 29, wherein the instruction is

received from a user.

31. The apparatus of claim 29, wherein the instruction is

received from an application program interface.

32. The apparatus of claim 21, further comprising:

a driver configured to drive a reproducing device to

reproduce data from the recording medium; and wherein

the controller is configured to control the driver to

reproduce a management table from the recording medium, the management table indicating a number of secondary subtitle

entries; and

the controller configured to store a secondary subtitle

stream number identifying a selected one of the number of

secondary subtitle entries as the secondary subtitle in the

memory unit as part of the management information.

33. The apparatus of claim 32, wherein

the management table includes combination information, the combination information indicating the secondary subtitles

that are combinable with the secondary video stream; and

the controller is configured to store the secondary subtitle

stream number for one of the secondary subtitles indicated as

combinable with the secondary video stream.

34. The apparatus of claim 32, wherein

the management table indicates a number of primary

subtitle entries; and

the controller is configured to store a primary subtitle

stream number identifying a selected one of the number of

primary subtitle entries as the primary subtitle in the

memory as part of the management information.

35. The apparatus of claim 32, wherein the controller is

configured to control the driver to reproduce the management table from at least one playitem of a playlist recorded on

the recording medium, the playitem indicating a playing

interval of the primary video stream, and the playlist

indicating which playitems to reproduce.

36. The apparatus of claim 1, further comprising:

a decoder configured to decode the secondary subtitle.

37. A recording medium having a data structure for managing

reproduction of at least one picture-in-picture presentation path, comprising:

a primary video subtitle number area storing a number

identifying a primary subtitle associated with a primary video stream;

a secondary video subtitle number area storing a number

identifying a secondary subtitle associated with a secondary

video stream, the secondary video stream representing the

picture-in-picture presentation path with respect to a

primary presentation path represented by a primary video stream; and

a first flag area storing a first flag indicating which

of the primary subtitle and the secondary subtitle to display.

38. The recording medium of claim 37, further comprising:

a second flag area storing a second flag indicating whether to display subtitles.

39. An apparatus for recording a data structure for managing

reproduction of at least one picture-in-picture presentation

path, comprising:

a memory unit; and

a controller configured to store a primary video subtitle number identifying a primary subtitle associated

with a primary video stream in the memory unit;

the controller configured to store a secondary video

subtitle number identifying a secondary subtitle associated with a secondary video stream in the memory unit, the

secondary video stream representing the picture-in-picture presentation path with respect to a primary presentation path

represented by the primary video stream; and

the controller configured to store a first flag in the

memory unit, the first flag indicating which of the primary

subtitle and the secondary subtitle to display.

40. The apparatus of claim 39, wherein the controller is

configured to store a second flag in the memory unit, the

second flag indicating whether to display subtitles.

41. A method of recording a data structure for managing

reproduction of at least one picture-in-picture presentation path, comprising:

storing, in a memory unit, a primary video subtitle

number identifying a primary subtitle associated with a

primary video stream;

storing, in the memory unit, a secondary video subtitle number identifying a secondary subtitle associated with a

secondary video stream, the secondary video stream

representing the picture-in-picture presentation path with respect to a primary presentation path represented by the

primary video stream; and

storing, in the memory unit, a first flag indicating which of the primary subtitle and the secondary subtitle to display.

42. The method of claim 41, further comprising:

storing, in the memory unit, a second flag indicating whether to display subtitles.