U.S. patent application number 11/633027 was filed with the patent office on 2007-06-07 for recording medium and method and apparatus for decoding text subtitle streams.
Invention is credited to Byung Jin Kim, Seung Hoon Lee, Sung Wan Park, Kang Soo Seo, Young Sun Shim, Jea Yong Yoo.
Application Number | 20070127886 11/633027 |
Document ID | / |
Family ID | 34841856 |
Filed Date | 2007-06-07 |
United States Patent
Application |
20070127886 |
Kind Code |
A1 |
Seo; Kang Soo ; et
al. |
June 7, 2007 |
Recording medium and method and apparatus for decoding text
subtitle streams
Abstract
At least one text subtitle stream is recorded on a recording
medium. Each text subtitle stream includes a dialog style segment
defining a set of region styles and at least one dialog
presentation segment. Each dialog presentation segment contains at
least one region of dialog text and being linked to at least one of
the set of region styles. The dialog style segment further defines
a set of user control styles for each region style. Each user
control style is selectable by a user and is configured to change
at least one of region presentation properties specified by a
corresponding region style.
Inventors: |
Seo; Kang Soo; (Anyang-si,
KR) ; Yoo; Jea Yong; (Seoul, KR) ; Park; Sung
Wan; (Suwon-si, KR) ; Shim; Young Sun; (Seoul,
KR) ; Kim; Byung Jin; (Seongnam-si, KR) ; Lee;
Seung Hoon; (Seongnam-si, KR) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 8910
RESTON
VA
20195
US
|
Family ID: |
34841856 |
Appl. No.: |
11/633027 |
Filed: |
December 4, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11033494 |
Jan 12, 2005 |
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11633027 |
Dec 4, 2006 |
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60542850 |
Feb 10, 2004 |
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60542852 |
Feb 10, 2004 |
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60543328 |
Feb 11, 2004 |
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Current U.S.
Class: |
386/244 ;
386/353 |
Current CPC
Class: |
G11B 27/105 20130101;
H04N 21/434 20130101; H04N 21/426 20130101; H04N 21/42646 20130101;
H04N 5/781 20130101; H04N 21/4884 20130101; H04N 21/4325 20130101;
H04N 21/4316 20130101; G11B 2220/2541 20130101; H04N 9/8233
20130101; H04N 9/8042 20130101 |
Class at
Publication: |
386/095 |
International
Class: |
H04N 7/00 20060101
H04N007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 17, 2004 |
KR |
10-2004-0017935 |
Claims
1. A method for reproducing at least one text subtitle stream, the
method comprising: receiving the text subtitle stream from external
source, each text subtitle stream including a style segment
defining region style to be applied to at least one region, the
style segment further defining at least one set of user control
style for each region style, each set of user control style being
selectable and configured to change at least one of region
presentation properties specified by a corresponding region style;
and decoding the text subtitle stream using the style segment
defining the region style and the at least one set of user control
style.
2. The method of claim 1, wherein the style segment includes a data
field indicating a number of the region styles.
3. The method of claim 2, wherein the number of region styles is
less than or equal to 60.
4. The method of claim 1, wherein the style segment includes a data
field indicating a number of the set of user control styles defined
in the style segment for each region style.
5. The method of claim 4, wherein the number of the set of user
control styles defined for each region style is less than or equal
to 25.
6. The method of claim 1, wherein each user control style specifies
a direction and a magnitude of a change in the at least one of
region presentation properties specified by the corresponding
region style.
7. The method of claim 1, wherein the region presentation
properties include at least one of a region horizontal position, a
region vertical position, a text horizontal position, a text
vertical position, a line space, and a font size.
8. The method of claim 1, wherein each user control style specifies
a direction and a magnitude of a change in at least one of a region
horizontal position, a region vertical position, a text horizontal
position, a text vertical position, a line space, and a font size,
which are specified in the corresponding region style.
9. A method for reproducing at least one text subtitle stream, the
method comprising: receiving the text subtitle stream from external
source, the text subtitle stream including a style segment defining
region styles and at least one presentation segment, each
presentation segment containing at least one region and being
linked to at least one of the region styles, the style segment
further defining at least one set of user control styles for each
region style, each user control style configured to change at least
one of region presentation properties specified by a corresponding
region style; and decoding the presentation segment using the
linked region style and the user control styles.
10. A method for reproducing at least one text subtitle stream, the
method comprising: selecting the text subtitle stream from external
source or a recording medium, each text subtitle stream including a
style segment defining region style to be applied to at least one
region, the style segment further defining at least one set of user
control style for each region style, each set of user control style
being selectable and configured to change at least one of region
presentation properties specified by a corresponding region style;
and decoding the text subtitle stream using the style segment
defining the region style and the at least one set of user control
style.
11. A method for reproducing at least one text subtitle stream, the
method comprising: selecting the text subtitle stream from an
external source or a recording medium, the text subtitle stream
including a style segment defining region styles and at least one
presentation segment, each presentation segment containing at least
one region and being linked to at least one of the region styles,
the style segment further defining at least one set of user control
styles for each region style, each user control style configured to
change at least one region presentation property specified by a
corresponding region style; and decoding the presentation segment
using the linked region style and the user control styles.
12. An apparatus for reproducing at least one text subtitle stream,
the method comprising: decoder configured to decode the text
subtitle stream received from an external source, wherein the text
subtitle stream including a style segment defining region style to
be applied to at least one region, the style segment further
defining at least one set of user control style for each region
style, each set of user control style being selectable and
configured to change at least one of region presentation properties
specified by a corresponding region style; and controller
configured to control operation of the decoder to receive the text
subtitle stream from the receiver and decode the text subtitle
stream using the style segment defining the region style and the at
least one set of user control style.
13. The apparatus of claim 12, wherein each user control style
specifies a direction and a magnitude of a change in the at least
one of region presentation properties specified by the
corresponding region style.
14. The apparatus of claim 12, wherein the region presentation
properties include at least one of a region horizontal position, a
region vertical position, a text horizontal position, a text
vertical position, a line space, and a font size.
15. The apparatus of claim 12, wherein each user control style
specifies a direction and a magnitude of a change in at least one
of a region horizontal position, a region vertical position, a text
horizontal position, a text vertical position, a line space, and a
font size, which are specified in the corresponding region
style.
16. An apparatus for reproducing at least one text subtitle stream,
the method comprising: decoder configured to decode the text
subtitle stream received from an external source, wherein the text
subtitle stream including a style segment defining region styles
and at least one presentation segment, each presentation segment
containing at least one region and being linked to at least one of
the region styles, the style segment further defining user control
styles for each region style, each user control style being
selectable and configured to change at least one of region
presentation properties specified by a corresponding region style;
and controller configured to control operation of the decoder to
receive the text subtitle stream from the receiver and decode each
dialog presentation segment using the linked region style and one
of user control styles in the text subtitle.
17. An apparatus for reproducing at least one text subtitle stream,
the method comprising: decoder configured to decode the text
subtitle stream selected from an external source, wherein the text
subtitle stream including a style segment defining region style to
be applied to at least one region, the style segment further
defining at least one set of user control style for each region
style, each set of user control style being selectable and
configured to change at least one of region presentation properties
specified by a corresponding region style; and controller
configured to control operation of the decoder to decode the text
subtitle stream using the style segment defining the region style
and the at least one set of user control style.
18. The apparatus of claim 17, wherein each user control style
specifies a direction and a magnitude of a change in the at least
one of region presentation properties specified by the
corresponding region style.
19. The apparatus of claim 17, wherein the region presentation
properties include at least one of a region horizontal position, a
region vertical position, a text horizontal position, a text
vertical position, a line space, and a font size.
20. The apparatus of claim 17, wherein each user control style
specifies a direction and a magnitude of a change in at least one
of a region horizontal position, a region vertical position, a text
horizontal position, a text vertical position, a line space, and a
font size, which are specified in the corresponding region
style.
21. An apparatus for decoding at least one text subtitle stream
recorded on a recording medium or received from an external source,
the apparatus comprising: decoder configured to decode the text
subtitle stream selected from an external source, wherein the text
subtitle stream including a style segment defining region styles
and at least one presentation segment, each presentation segment
containing at least one region and being linked to at least one of
the region styles, the style segment further defining at least one
set of user control styles for each region style, each a set o user
control style configured to change at least one of region
presentation properties specified by a corresponding region style;
and controller configured to control operation of the decoder to
decode each presentation segment using the linked region style and
one of the set of user control styles.
Description
PRIORITY INFORMATION
[0001] This is a continuation application of application Ser. No.
11/033,494 filed Jan. 12, 2005, the entire contents of which are
hereby incorporated by reference.
[0002] This application claims the benefit of U.S. Provisional
Application No. 60/542,850, filed on Feb. 10, 2004; U.S.
Provisional Application No. 60/542,852, filed on Feb. 10, 2004; and
U.S. Provisional Application No. 60/543,328, filed on Feb. 11,
2004, the entire contents of which are hereby incorporated by
reference. This application also claims the benefit of Korean
Patent Application No. 10-2004-0017935, filed on Mar. 17, 2004,
which is hereby incorporated by reference as if fully set forth
herein.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to a recording medium and a
method and apparatus for decoding a text subtitle stream recorded
on a recording medium.
[0005] 2. Discussion of the Related Art
[0006] Optical discs are widely used as an optical recording medium
for recording mass data. Presently, among a wide range of optical
discs, a new high-density digital video disc (hereinafter referred
to as "HD-DVD"), such as a Blu-ray Disc (hereafter referred to as
"BD"), is under development for recording high definition video and
audio data. Currently, global standard technical specifications of
BDs, which are known to be the next generation HD-DVD technology,
are under establishment as a next generation optical recording
solution that is able to have data significantly surpassing the
conventional DVD, along with many other digital apparatuses.
[0007] Accordingly, optical reproducing apparatuses having the
Blu-ray Disc (BD) standards applied thereto are also being
developed. However, since the Blu-ray Disc (BD) standards are yet
to be completed, there have been many difficulties in developing a
complete optical reproducing apparatus. Particularly, in order to
effectively reproduce the data from the Blu-ray Disc (BD), not only
should the main AV data as well as various data required for a
user's convenience, such as subtitle information as the
supplementary data related to the main AV data, be provided, but
also managing information for reproducing the main data and the
subtitle data recorded in the optical disc should be systemized and
provided.
[0008] However, in the present Blu-ray Disc (BD) standards, since
the standards of the supplementary data, particularly the subtitle
information, are not completely consolidated, there are many
restrictions in the full-scale development of a Blu-ray Disc (BD)
basis optical reproducing apparatus. And, such restrictions cause
problems in providing the supplementary data such as subtitles to
the user.
SUMMARY OF THE INVENTION
[0009] Accordingly, the present invention is directed to a text
subtitle decoder and a method for decoding text subtitle streams
recorded on a recording medium that substantially obviates one or
more problems due to limitations and disadvantages of the related
art.
[0010] An object of the present invention is to provide a recording
medium including a dialog style segment defining a set of user
control styles, each of which is able to change at least one of
region presentation properties specified by a region style.
[0011] Another object of the present invention is to provide a
method and an apparatus for decoding a text subtitle stream by
using a user control style which changes at least one of the region
presentation properties specified by a region style.
[0012] Additional advantages, objects, and features of the
invention will be set forth in part in the description which
follows and in part will become apparent to those having ordinary
skill in the art upon examination of the following or may be
learned from practice of the invention. The objectives and other
advantages of the invention may be realized and attained by the
structure particularly pointed out in the written description and
claims hereof as well as the appended drawings.
[0013] To achieve these objects and other advantages and in
accordance with the purpose of the invention, as embodied and
broadly described herein, a recording medium includes a data area
storing at least one text subtitle stream, each of which includes a
dialog style segment defining a set of region styles to be applied
to at least one region of dialog text. Each text subtitle stream
may further include at least one dialog presentation segment, each
of which contains at least one region of dialog text and is linked
to at least one of the set of region styles. The dialog style
segment further defines a set of user control styles for each
region style, where each user control style is selectable and is
configured to change at least one of region presentation properties
specified by a corresponding region style. For example, each user
control style may specify a direction and a magnitude of a change
in at least one of a region horizontal position, a region vertical
position, a text horizontal position, a text vertical position, a
line space, and a font size, all which are specified in the
corresponding region style.
[0014] In another aspect of the present invention, a method and an
apparatus for decoding a text subtitle stream recorded on a
recording medium are provided. A subtitle loading buffer loads the
text subtitle stream, which includes a dialog style segment
defining a set of region styles and at least on dialog presentation
segment. Each dialog presentation contains at least one region of
dialog text and is linked to at least one of the set of region
styles. The dialog style segment further defines a set of user
control styles for each region, where each user control style is
selectable and is configured to change at least one of region
presentation properties specified by a corresponding region style.
A text subtitle decoder is able to decode each dialog presentation
segment using the linked region style and one of the set of user
control styles defined in the dialog presentation segment.
[0015] Each user control style may specify a direction and a
magnitude of a change in the region presentation properties
specified by the corresponding region style. The region
presentation properties include at least one of a region horizontal
position, a region vertical position, a text horizontal position, a
text vertical position, a line space, and a font size, which are
specified in the corresponding region style.
[0016] It is to be understood that both the foregoing general
description and the following detailed description of the present
invention are exemplary and explanatory and are intended to provide
further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] 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 principle of the invention. In the drawings;
[0018] FIG. 1 illustrates a file structure of data files recorded
on an optical disc according to an example of the present
invention;
[0019] FIG. 2 illustrates data storage areas of an optical disc
according to an example of the present invention;
[0020] FIG. 3 illustrates a text subtitle and a main image
presented on a display screen when a text subtitle stream and a
main AV stream are reproduced;
[0021] FIG. 4 is a schematic diagram illustrating reproduction
control of a main AV clip and text subtitle clips by a
PlayList;
[0022] FIG. 5A illustrates a dialog presented on a display screen
according to an example of the present invention;
[0023] FIG. 5B illustrates regions of a dialog according to an
example of the present invention;
[0024] FIG. 5C illustrates region and inline styles for regions of
a dialog according to an example of the present invention;
[0025] FIG. 6A illustrates presentations of text subtitle dialogs
on a display screen in presentation time stamp (PTS) intervals;
[0026] FIG. 6B illustrates continuities between text subtitle
dialogs presented on a display screen in PTS intervals;
[0027] FIG. 7A illustrates a text subtitle stream file according to
an example of the present invention;
[0028] FIG. 7B illustrates specific information contained within a
DPU and a DSU included in a text subtitle stream according to an
example of the present invention;
[0029] FIG. 8 illustrates a syntax for a text subtitle stream
according to an example of the present invention;
[0030] FIG. 9A illustrates a syntax for a dialog style unit
according to an example of the present invention;
[0031] FIG. 9B illustrates a syntax for a dialog style set included
in a dialog style unit according to an example of the present
invention;
[0032] FIG. 9C illustrates a syntax for a user changeable style set
included in a dialog style set according to an example of the
present invention;
[0033] FIG. 10 illustrates an example of the apparatus for decoding
main AV streams and text subtitle streams according to the present
invention; and
[0034] FIG. 11 illustrates an example of the method for decoding a
text subtitle stream recorded on an optical disc according to the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0035] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of 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.
[0036] In this detailed description, main data represent
audio/video (AV) data that belong to a title (e.g., a movie title)
recorded in an optical disc by an author. In general, the AV data
are recorded in MPEG2 format and are often referred to as AV
streams or main AV streams. In addition, supplementary data
represent all other data required for reproducing the main data,
examples of which are text subtitle streams, interactive graphic
streams, presentation graphic streams, and supplementary audio
streams (e.g., for a browsable slideshow). Theses supplementary
data streams may be recorded in MPEG2 format or in any other data
format. They could be multiplexed with the AV streams or could
exist as independent data files within the optical disc.
[0037] A subtitle represents caption information corresponding to
video (image) data being reproduced, and it may be represented in a
predetermined language. For example, when a user selects an option
for viewing one of a plurality of subtitles represented in various
languages while viewing images on a display screen, the caption
information corresponding to the selected subtitle is displayed on
a predetermined portion of the display screen. If the displayed
caption information is text data (e.g., characters), the selected
subtitle is often called a text subtitle. According to one aspect
of the present invention, a plurality of text subtitle streams in
MPEG2 format may be recorded in an optical disc, and they may exist
as a plurality of independent stream files. Each text subtitle
stream file includes text data for a text subtitle and reproduction
control data required for reproduction of the text data. According
to another aspect of the present invention, only a single text
subtitle stream in MPEG2 format may be recorded in an optical
disc.
[0038] FIG. 1 illustrates a file structure of data files recorded
on an optical disc, an example of which is a Blu-ray disc
(hereinafter "BD"), according to the present invention. Referring
to FIG. 1, at least one BD directory (BDMV) is included in a root
directory (root). Each BD directory includes an index file
(index.bdmv) and an object file (MovieObject.bdmv), which are used
for interacting with one or more users. For example, the index file
may contain data representing an index table having a plurality of
selectable menus and movie titles. Each BD directory further
includes four file directories that include audio/video (AV) data
to be reproduced and various data required for reproduction of the
AV data.
[0039] The file directories included in each BD directory are a
stream directory (STREAM), a clip information directory (CLIPINF),
a playlist directory (PLAYLIST), and an auxiliary data directory
(AUX DATA). First of all, the stream directory (STREAM) includes
audio/video (AV) stream files having a particular data format. For
example, the AV stream files may be in the form of MPEG2 transport
packets and be named as "*.m2ts", as shown in FIG. 1. The stream
directory may further include one or more text subtitle stream
files, where each text subtitle stream file includes text (e.g.,
characters) data for a text subtitle represented in a particular
language and reproduction control information of the text data. The
text subtitle stream files exist as independent stream files within
the stream directory and may be named as "*.m2ts" or "*.txtst", as
shown in FIG. 1. An AV stream file or text subtitle stream file
included in the stream directory is often called a clip stream
file.
[0040] Next, the clip information directory (CLPINF) includes clip
information files that correspond to the stream files (AV or text
subtitle) included in the stream directory, respectively. Each clip
information file contains property and reproduction timing
information of a corresponding stream file. For example, A clip
information file may includes mapping information, in which
presentation time stamps (PTS) and source packet numbers (SPN) are
one-to-one mapped by an entry point map (EPM). Using the mapping
information, a particular location of a stream file may be
determined from timing information (In-Time and Out-Time) provided
by a PlayItem or SubPlayItem, which will be discussed later in more
details. In the industry standard, each pair of a stream file and
its corresponding clip information file is designated as a clip.
For example, 01000.clpi included in CLIPINF includes property and
reproduction timing information of 01000.m2ts included in STREAM,
and 01000.clpi and 01000.m2ts form a clip.
[0041] Referring back to FIG. 1, the playlist directory (PLAYLIST)
includes one or more PlayList files (*.mpls), where each PlayList
file includes at least one PlayItem which designates at least one
main AV clip and the reproduction time of the main AV clip. More
specifically, a PlayItem contains information designating In-Time
and Out-Time, which represent reproduction begin and end times for
a main AV clip designated by Clip_Information_File_Name within the
PlayItem. Therefore, a PlayList file represents the basic
reproduction control information for one or more main AV clips. In
addition, the PlayList file may further include a SubPlayItem,
which represents the basic reproduction control information for a
text subtitle stream file. When a SubPlayItem is included in a
PlayList file to reproduce one or more text subtitle stream files,
the SubPlayItem is synchronized with the PlayItem(s). On the other
hand, when the SubPlayItem is used to reproduce a browsable
slideshow, it may not be synchronized with the PlayItem(s).
According to the present invention, the main function of a
SubPlayItem is to control reproduction of one or more text subtitle
stream files.
[0042] Lastly, the auxiliary data directory (AUX DATA) may include
supplementary data stream files, examples of which are font files
(e.g., *.font or *.otf), pop-up menu files (not illustrated), and
sound files (e.g., Sound.bdmv) for generating click sound. The text
subtitle stream files mentioned earlier may be included in the
auxiliary data directory instead of the stream directory.
[0043] FIG. 2 illustrates data storage areas of an optical disc
according to the present invention. Referring to FIG. 2, the
optical disc includes a file system information area occupying the
inmost portion of the disc volume, a stream area occupying the
outmost portion of the disc volume, and a database area occupied
between the file system information area and the stream area. In
the file system information area, system information for managing
the entire data files shown in FIG. 1 is stored. Next, AV streams
and one or more text subtitle streams are stored in the stream
area. The general files, PlayList files, and clip information files
shown in FIG. 1 are stored in the database area of the disc volume.
As discussed above, the general files include an index file and an
object file, and the PlayList files and clip information files
include information required to reproduce the AV streams and the
text subtitle streams stored in the stream area. Using the
information stored in the database area and/or stream area, a user
is able to select a specific playback mode and to reproduce the
main AV and text subtitle streams in the selected playback
mode.
[0044] FIG. 3 illustrates a text subtitle and a main image
presented on a display screen when a text subtitle stream and a
main AV stream are reproduced. The main image and the text subtitle
are simultaneously displayed on the display screen when a main AV
stream and a corresponding text subtitle stream are reproduced in
synchronization.
[0045] FIG. 4 is a schematic diagram illustrating reproduction
control of a main AV clip and text subtitle clips by a PlayList.
Referring to FIG. 4, a PlayList file includes at least one PlayItem
controlling reproduction of at least one main AV clip and a
SubPlayItem controlling reproduction of a plurality of text
subtitle clips. One of text subtitle clip 1 and text subtitle clip
2 shown in FIG. 4 for English and Korean text subtitles may be
synchronized with the main AV clip such that a main image and a
corresponding text subtitle are displayed on a display screen
simultaneously at a particular presentation time. In order to
display the text subtitle on the display screen, display control
information (e.g., position and size information) and presentation
time information, examples of which are illustrated in FIG. 5A to
FIG. 5C, are required.
[0046] FIG. 5A illustrates a dialog presented on a display screen
according to the present invention. A dialog represents entire text
subtitle data displayed on a display screen during a given
presentation time. In general, presentation times of the dialog may
be represented in presentation time stamps (PTS). For example,
presentation of the dialog shown in FIG. 5A starts at PTS (k) and
ends at PTS (k+1). Therefore, the dialog shown in FIG. 5A
represents an entire unit of text subtitle data which are displayed
on the display screen between PTS (k) and PTS (k+1). A dialog
includes at least one line of subtitle text (characters). When
there are two or more lines of subtitle text in a dialog, entire
text data may be displayed according to a style defined for the
dialog. The maximum number of the characters included in a dialog
may be limited to about 100.
[0047] In addition, FIG. 5B illustrates regions of a dialog
according to the present invention. A region represents a divided
portion of text subtitle data (dialog) displayed on a display
screen during a given presentation time. In other words, a dialog
includes at least one region, and each region may include at least
one line of subtitle text. The entire text subtitle data
representing a region may be displayed on the display screen
according to a region style (global style) assigned to the region.
The maximum number of regions included in a dialog should be
determined based on a desired decoding rate of the subtitle data
because the greater number of regions generally results a lower
decoding ratio. For example, the maximum number of regions for a
dialog may be limited to two in order to achieve a reasonably high
decoding rate. However, the maximum number could be greater than
two for other purposes.
[0048] FIG. 5C illustrates style information for regions of a
dialog according to the present invention. Style information
represents information defining properties required for displaying
at least a portion of a region included in a dialog. Some of the
examples of the style information are position, region size,
background color, text alignment, text flow information, and many
others. The style information may be classified into region style
information (global style information) and inline style information
(local style information).
[0049] Region style information defines a region style (global
style) which is applied to an entire region of a dialog. For
example, the region style information may contain at least one of a
region position, region size, font color, background color, text
flow, text alignment, line space, font name, font style, and font
size of the region. For example, two different region styles are
applied to region 1 and region 2, as shown in FIG. 5C. A region
style with position 1, size 1, and blue background color is applied
to Region 1, and a different region style with position 2, size 2,
and red background color is applied to Region 2.
[0050] On the other hand, inline style information defines an
inline style (local style) which is applied to a particular portion
of text strings included in a region. For example, the inline style
information may contain at least one of a font type, font size,
font style, and font color. The particular portion of text strings
may be an entire text line within a region or a particular portion
of the text line. Referring to FIG. 5C, a particular inline style
is applied to the text portion "mountain" included in Region 1. In
other words, at least one of the font type, font size, font style,
and font color of the particular portion of text strings is
different from the remaining portion of the text strings within
Region 1.
[0051] FIG. 6A illustrates presentations of text subtitle dialogs
on a display screen in presentation time stamp (PTS) intervals.
There are four dialogs to be displayed between PTS1 to PTS6. More
specifically, Dialog #1 has only one region and Text #1 is
displayed within this region between PTS1 to PTS2. Next, Dialog #2
has Region 1 and Region 2 and Text #1 and Text #2 are displayed
within Region 1 and Region 2, respectively, between PTS2 to PTS3.
Thereafter, Dialog #3 also has only one region and Text #2 is
displayed within this region between PTS3 and PTS4. There is no
dialog to be presented between PTS4 to PTS5, and Text #3 is
displayed within a region of Dialog #4 between PTS5 to PTS6.
Information defining a dialog includes dialog presentation time
information and dialog text data including style information and
text strings to be displayed within each region of the dialog. An
example of the presentation time information is a set of start PTS
start and PTS end, and the style information includes region
(global) style information and inline (local) style information
described above. It is shown in FIG. 6A that different style
information sets may be applied to the dialogs.
[0052] FIG. 6B illustrates continuities between text subtitle
dialogs being presented on a display screen in PTS intervals.
Referring to FIG. 6B, the presentation end time of Dialog #1 is
identical to the presentation start time of Dialog #2. Therefore, a
continuity exists between Dialog #1 and Dialog #2. Display of Text
#1 in a region of Dialog #1 is continuous with display of Text #1
in Region 1 of Dialog #2. In other words, PTS intervals of both
dialogs are continuous and same style information (region and
inline) is used when presenting Text #1 in both regions. Similarly,
another continuity exists between Dialog #2 and Dialog #3 because
display of Text #2 in Region 2 of Dialog #2 is continuous with
display of Text #2 in a region of Dialog #3. In order to ensure a
continuity between two consecutive dialogs displaying same subtitle
text, presentation times (PTS intervals) of the dialogs must be
continuous. In addition, same region and inline style information
must be used when presenting the same text in the regions,
respectively. Referring back to FIG. 6B, there is no continuity
between Dialog #3 and Dialog #4 because their PTS intervals are not
continuous. An indicator (e.g., continuous_presentation_flag) may
be included in presentation information of a current dialog to
indicate whether the dialog is continuous with a previous
dialog.
[0053] FIG. 7A illustrates a text subtitle stream file (e.g.,
10001.m2ts shown in FIG. 1) according to the present invention. It
may be formed of an MPEG2 transport stream including a plurality of
transport packets (TP), all of which have a same packet identifier
(e.g., PID=0x18xx). When a disc player receives many input streams
including a particular text subtitle stream, it finds all the
transport packets that belong to the text subtitle stream using
their PIDs. Referring to FIG. 7A, each sub-set of transport packets
form a packet elementary stream (PES) packet. One of the PES
packets shown in FIG. 7A corresponds to a dialog style unit (DSU)
defining a group of region styles. A DSU is also often referred as
a dialog style segment (DSS). All the remaining PES packets
correspond to dialog presentation units (DPUs), each of which
includes presentation information for a dialog having at least one
region, and dialog text data including a region style indicator,
inline style information, and text strings for each region.
Similarly, a DPU sis also often referred as a dialog presentation
segment (DPS).
[0054] FIG. 7B illustrates specific information contained within a
DPU and a DSU included in a text subtitle stream according to the
present invention. A DSU contains information sets defining a group
of region styles, each of which is applied to a corresponding
region of a dialog. In addition, a DPU contains dialog text data
and dialog presentation information for a dialog. The dialog text
data includes text strings to be included in each region of the
dialog, inline style information to be applied to a particular
portion of the text strings, and a region style identifier
indicating a region style to be applied to each dialog region. The
region style identifier identifies one of the group of region
styles defined in the DSU. On the other hand, the dialog
presentation information includes presentation time information and
palette (color) update information for a dialog. The presentation
time information may include presentation start time (e.g.,
PTS_start) and presentation end time (e.g., PTS_end) for presenting
the dialog on a display screen, and the palette update information
may include an indicator (e.g., palette_update_flag) indicating
whether to update display colors of the dialog and palette
information (e.g., Palette for update) to be applied when updating
the display colors.
[0055] All the data included in a text subtitle stream may be
classified into three types of data based on their basic functions.
For example, the data could be classified into dialog text data,
composition information, and rendering information, as shown in
FIG. 7B. The dialog text data include text string(s), inline style
information, and a region style identifier for each region of a
dialog. The composition information includes presentation time
information, examples of which are presentation start and end
times, position information for a dialog region, and palette update
information for a dialog. Lastly, the rendering information
includes information required for rendering the text strings to
graphic data for presentation. Referring to FIG. 7B, the horizontal
and vertical positions of each region included in the DSU is a part
of the composition information, and the region width, region
height, font color, background color, text flow, text alignment,
line space, font name, font style, and font size included in the
DSU represent the rendering information.
[0056] A DSU includes a set of region style information (dialog
style set) defining a limited number of author-defined region
styles, respectively. For example, the maximum number of the region
styles defined in a DSU may be limited to 60, and the region styles
may be identified by their region style identifications
(region_style_id). Therefore, an author stores a DSU defining only
a limited number of region styles in an optical disc. The region
styles are used by a disc player when reproducing text subtitle
streams recorded on the optical disc. Alternatively, the disc
player may use other region styles defined by an additional set of
style information, which may be provided from other source. An
example of the source is a local data storage included in the disc
player. As a result, the subtitle regions reproduced from the text
subtitle streams recorded on the optical disc can have a variety of
region styles.
[0057] FIG. 8 illustrates a syntax for a text subtitle stream
(Text_subtitle_stream ( )) according to an example of the present
invention. As mentioned earlier, the text subtitle stream syntax
includes a syntax for a dialog style unit (dialog_style_unit ( ))
including a set of information defining a set of region styles,
respectively, and syntaxes for a plurality of dialog presentation
units (dialog_presentation_unit ( )), where each DPU syntax
includes dialog presentation information and at least one region of
dialog text. Each region of dialog text includes a region style
identifier, one or more text strings, and inline style information,
and the region style identifier identifies one of the set of region
styles defined in the DSU syntax.
[0058] FIG. 9A illustrates the syntax for a dialog style unit
(dialog_style_unit ( )) included in the text subtitle stream syntax
shown in FIG. 8. The dialog style unit syntax includes a syntax for
a dialog style set (dialog_styleset ( )) in which a set of
author-defined region styles are defined. FIG. 9B illustrates the
syntax for a dialog style set (dialog_styleset ( )) included in the
dialog style unit syntax shown in FIG. 9A. The dialog style set
syntax includes a set of region style information defining a set of
region styles (region_style ( )), respectively, and a data field or
a flag (player_style_flag) indicating whether the author permitted
a player to generate its own set of styles (player styles) for a
text subtitle in addition to the set of author-defined style
defined in region_style ( ). The dialog style set syntax further
includes a syntax for a user-changeable style set
(user_changeable_styleset ( )) defining a set of user control
styles.
[0059] Referring to FIG. 9B, region style identifications
(region_style_id) are assigned to the set of region styles
(region_style ( )), respectively, and each region style information
represents global style information to be applied to an entire
portion of a region of dialog text. The region style identifier
included in a DPU for each region includes one of the region style
identifications. Therefore, a region style corresponding to the
region style identifier is applied when reproducing at least one
region of dialog text contained in each DPU.
[0060] Reference will now be made in detail to specific region
presentation properties defined in each region style (region_style
( )). A region horizontal position (region_horizontal_position)
specifies the horizontal address of the top left pixel of a region
in a graphics plane, and a region vertical position
(region_vertical_position) specifies the vertical address of the
top left pixel of the region in the graphics plane. In addition, a
region width (region_width) specifies the horizontal length of the
region rectangle from the region horizontal position, and a region
height (region_height) specifies the vertical length of the region
rectangle from the region vertical position. A region background
color index (region_bg_color_index) specifies an index value
indicating the background color of the region.
[0061] In addition, a text horizontal position
(text_horizontal_position) specifies the horizontal address of an
origin of text in the region, and a text vertical position
(text_vertical_position) specifies the vertical address of the text
origin in the region. A text flow (text_flow) specifies at least
one of character progression (left-to-right or right-to-left) and
line progression (top-to-bottom or bottom-to-top) in the region. A
text alignment (text_alignment) specifies alignment (left, center,
or right) of rendered text in the region. When a dialog has more
than one regions, the same text flow must be applied to all the
regions in order to prevent the viewers' confusion. Referring back
to FIG. 9B, a line space (line_space) specifies the distance
between two adjacent lines of text in the region. A font
identification (font_id) indicates the font identification
specified in a clip information file. A font style (font_style)
specifies the style of font for the text in the region, examples of
which are normal, bold, italic, and bold and italic. A font size
(font_size) specifies the size of font for the text in the region,
an example of which is the vertical size of a character in unit of
pixels. Lastly, a font color index (font_color_index) specifies an
index value indicating the color of the text in the region.
[0062] The player style flag (player_style_flag) shown in FIG. 9B
indicates whether au author permitted a disc player to generate
and/or use its own set of styles (player styles), which may be
pre-stored in a local data storage of the disc player, for a text
subtitle in addition to the author-defined region styles defined in
an optical disc. For example, if the value of the player style flag
is set to 1b, the author permits the player to generate and/or use
its own set of player styles. On the other hand, if the value of
the player style flag is set to 0b, the author prohibits the player
from generating and/or using the set of player styles.
[0063] FIG. 9C illustrates a syntax for a user changeable style set
(user_changeable_styleset ( )) included in the dialog style set
syntax shown in FIG. 9B. user_changeable_styleset ( ) includes a
set of user control style information defining a set of user
control styles (user_control_style( )), where each user control
style is configure to change at least one of the region
presentation properties specified by a corresponding region style.
By selecting one of the set of user control styles, a user is able
to change the region style of each region in a very simple manner.
However, if all the properties specified by the region style are
changeable by a user, the display control of a dialog by the user
may be very difficult. For this reason, the region presentation
properties that are changeable by a user control style may be
limited to at least one of the region horizontal position, region
vertical position, font size, text horizontal position, text
vertical position, and line space.
[0064] According to FIG. 9B and FIG. 9C, a set of user control
styles are defined for each region style having a region style ID,
and user style IDs (user_style_id) are assigned to the set of user
control styles, respectively. The maximum number of the user
control styles defined for each region style may be limited to 25.
Since the maximum number of the region styles defined in a dialog
style set is limited to 60, the total number of the user changeable
styles defined for a DPU must be less than or equal to 1500.
[0065] Referring to FIG. 9C, in order to change the region
horizontal position, a user control style may include a region
horizontal position direction
(region_horizontal_position_direction) specifying the direction of
the region horizontal position's horizontal movement and a region
horizontal position delta (region_horizontal_position_delta)
specifying the number of the horizontal movement in the unit of
pixels. For example, the horizontal movement may be in a right
direction if the horizontal position direction is set to 0 and may
be in a left direction if it is set to 1. In order to change the
region vertical position, a user control style may include a region
vertical position direction (region_vertical_position_direction)
specifying the direction of the region horizontal position's
vertical movement and a region vertical position delta
(region_vertical_position_delta) specifying the number of the
vertical movement in the unit of pixels. For example, the vertical
movement may be in a downward direction if the vertical position
direction is set to 0 and may be in a upward direction if it is set
to 1. Furthermore, in order to change the font size defined by a
region style with a region style ID, a user control style may
include a font size change direction (font_size_inc_dec) specifying
the direction of the font size change, and a font size delta
(font_size_delta) specifying the number of the font size change in
unit of pixels. For example, the font size may be increased if
font_size_inc_dec is set to 0 and may be decreased if it is set to
1.
[0066] Some of the characteristic features of the user changeable
style set according to the present invention are as follows. First,
a set of user control styles are defined for each of a set of
region styles defined in a dialog style unit, and the number of the
set of control styles are fixed. Therefore, the numbers of the user
control styles defined for two different region styles,
respectively, are identical. The number of the set of user control
styles to be used when reproducing each region of dialog text is
fixed. Next, the set of user control. styles are identified by
different user style IDs, respectively. Third, all the changes in
the region presentation properties are defined in combination by a
single user control style. For example, the region horizontal
position and font size are not changed separately by two distinct
user control styles. They are changed in combination by a single
user control style. Fourth, a change of a certain property is
represented with its direction and magnitude rather than with an
actual property value. The actual property value may be obtained by
applying the magnitude (delta) and direction of the change to the
original property value defined in a region style.
[0067] In conclusion, when an author records main AV streams in an
optical disc, the author also records at least one text subtitle
stream. Each text subtitle stream includes a DSU defining a set of
dialog styles and a plurality of DPUs. The set of region styles
have different region style IDs. The DSU further defines a set of
user control styles for each region style, where the user control
styles have different user style IDs. Each user control style is
configured to change at least one of the author-defined region
presentation properties which are specified by a corresponding
region style. In addition, the dialog style set includes a player
style flag indicating whether the author permitted a player to
generate and/or use its own set of player styles for a text
subtitle in additional to the author-defined style set.
[0068] Reference will now be made in detail to an apparatus for
decoding man AV streams and text subtitle streams according to the
present invention, an example of which is illustrated in FIG. 10.
The apparatus includes a packet identifier (PID) filter 5 for
separating input streams into video streams, audio streams, graphic
streams, and text subtitle streams based on their packet
identifiers, a video decoding part 20 for decoding the video
streams, an audio decoding part 10 for decoding the audio streams,
a graphic decoding part 30 for decoding the graphic streams, and a
text subtitle decoding part 40 for decoding the text subtitle
streams.
[0069] The text subtitle streams may be extracted from an optical
disc or from an additional external source, as shown in FIG. 10.
For this reason, the apparatus additionally includes a switch 6
which selects an input data source. Therefore, if the text subtitle
streams are extracted from the optical disc, the switch 6 selects
data line A connected to the PID filter 5. On the other hand, if
they are inputted from the external source, the switch 6 selects
line B connected to the external source.
[0070] Referring back to FIG. 10, the audio decoding part 10, video
decoding part 20, and graphic decoding part 30 include transport
buffers 11, 21, and 31, respectively, for storing stream data to be
decoded. A video plane (VP) 23 and a graphic plane 33 are included
in the video decoding part 20 and the graphic decoding part 30,
respectively, for converting decoded signals into displayable video
and graphic images. The graphic decoding part 30 includes a color
look up table (CLUT) 34 for controlling color and transparency
levels of the displayable graphic images.
[0071] When the text subtitle decoding part 40 receives a text
subtitle stream supporting a single language from the switch 6, an
entire portion of the text subtitle stream may be preloaded into a
subtitle preloading buffer (SPB) 41 at once. Alternatively, when
there are more than one text subtitle streams for supporting
multi-languages, all the text subtitle streams may be preloaded
into the SPB 41 at once. Therefore, the size of the SPB 41 should
be determined based on a total number of text subtitle stream files
received from the switch 6. For example, the size of the SPB 41
should be greater than or equal to 0.5 megabytes for preloading a
0.5 megabyte text subtitle stream file. In addition, in order to
ensure seamless presentation of a text subtitle when a user
switches among two 0.5 megabyte text subtitle stream files, the
size of the SPB 41 should be greater than or equal to 1 megabytes.
The size of the SPB 41 should be large enough to preload all the
required text subtitle stream files at once.
[0072] The text subtitle decoding part 40 shown in FIG. 10 further
includes a font preloading buffer (FPB) 410 for storing all the
associated font files which may be included in the auxiliary data
directory shown in FIG. 1. Similarly, the size of the FPB 410
should be large enough to preload all the required font files at
once in order to ensure seamless presentation of a text subtitle
supporting one or more languages. Since all the available text
subtitle stream files and related font files are preloaded,
extraction and use of the preloaded data can be done in a simple
manner. Also the control of the SPB 41 and the FPB 410 could be
quite simple due to the this reason. The text subtitle decoding
part 40 further includes a text subtitle decoder 42 which decodes
each text subtitle stream stored in the SPB 41, a graphic plane 43
in which the decoded subtitle data are composed as displayable
subtitle images, and a color look up table (CLUT) 44 controlling at
least one of color and transparency levels of the converted
subtitle images.
[0073] The text subtitle decoding part 40 further includes a local
data storage 45 which stores a player style set defining a set of
player styles to be selectively used when reproducing a text
subtitle stream preloaded in the SPB 41. In addition, the local
data storage 45 may further store a user changeable set specifying
a set of user control styles to be selectively used when
reproducing the text subtitle stream. This user changeable set may
be similar to the user changeable set included in a DSU, an example
of which is shown in FIG. 9C.
[0074] In first aspect of the present invention, each player style
represents a region style specifying a complete set of region
presentation properties for a region of dialog text, examples of
which are a region horizontal position, region vertical position,
region width, region height, region background color index, text
horizontal position, text vertical position, text flow, text
alignment, line space, font identification, font style, font size,
and font color index. In this case, the set of player styles stored
in the local data storage 45 is used independent of a set of region
styles defined in a DSU.
[0075] In second aspect of the present invention, each player style
is configured to redefine at least one of region presentation
properties which are initially defined by a region style defined in
a DSU. For example, if a region style defined in the DSU defines a
complete set of region presentation properties including font
identification and a player style redefines the font
identification, then the redefined font identification and all
other properties specified by the region style are used in
combination.
[0076] In third aspect of the present invention, each player style
may be configured to change at least one of region presentation
properties which are initially defined by a region style defined in
a DSU. For example, a player style may specify a direction and a
magnitude of a change in a region horizontal position defined in
the region style. In this case, the player style set is similar to
the user changeable set, an example of which is illustrated in FIG.
9C.
[0077] FIG. 11 illustrates a method of decoding a text subtitle
stream recorded on an optical disc according to an example of the
present invention. After the text subtitle decoder 42 starts
reproducing a text subtitle stream preloaded into the SPB 41, it
initially reads player_style_flag included in a DSU to determine
whether the use of a player style set stored in the local data
storage 45 is permitted (S110). For example, if player_style_flag
is set to 0b, use of the player style set is not permitted. In this
case, the text subtitle decoder 42 must use the author-defined
region styles recorded on the optical disc (S111). On the other
hand, if player_style_flag is set to 1b, the text subtitle decoder
42 is permitted to use the player style set stored in the local
data storage 45. Then the text subtitle decoder 42 independently
determines whether to use any one of a set of player styles defined
in the player style set (S112). For example, the text subtitle
decoder 42 may compare the set of player styles with the region
styles defined in the text subtitle stream and use a result of this
comparison for the determination of step S112. If the set of player
styles are not determined to be used in step S112, the region
styles recorded on the optical disc are used (S111). On other hand,
if the set of player styles are determined to be used in step S112,
the text subtitle decoder 42 may use them independently or in
combination with the set of region styles recorded on the disc.
[0078] In addition, when the text subtitle decoder 42 decodes a
DPU, it may use a region style identified by a region style
identifier included in the DPU. If a user wises to change this
region style, he or she may input a command for changing the region
style. By selecting one of a set of user control styles, which are
defined by a user-changeable style set defined in a DSU, at least
one of the region horizontal position, region vertical position,
and font size may be changed.
[0079] The apparatus shown in FIG. 10 further includes an image
superimposition part 50 which superimposes the images outputted
from the video decoding part 20, the graphic decoding part 30, and
the text subtitle decoding part 40. These combined images are
displayed on a display screen, as shown in FIG. 3. In general, the
video images outputted from the VP 23 of the video decoding part 20
may be displayed as a background of the display screen, and the
images outputted from the graphic decoding part 30 and/or text
subtitle decoding part 40 may be superimposed over the video images
in a predetermined order. For example, if the output images of the
graphic decoding part 30 are presentation graphic images, these
images may be initially superimposed over the video images by a
first adder 52, and subsequently, the text subtitle images from the
text subtitle decoding part 40 may be superimposed over the video
images by a second adder 53. However, if the output images of the
graphic decoding part 30 are interactive graphic images, the text
subtitle images from the text subtitle decoding part 40 may be
initially superimposed over the video images by the first adder 52.
Thereafter, the interactive graphic images may be further
superimposed over the subtitle-superimposed images by the second
adder 53.
[0080] Lastly, the apparatus shown in FIG. 10 further includes a
system decoder 4 for decoding input transport streams (e.g., MPEG
transport streams), and a microprocessor 3 for controlling
operations of all the components of the apparatus mentioned
above.
[0081] 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 provided they come within the
scope of the appended claims and their equivalents.
[0082] According to the present invention, a plurality of user
control styles are defined for each region style defined in a
dialog style segment. Each user control style is selectable by a
user and is configured to change the region presentation properties
specified by a corresponding region style. Therefore, a user can
have options of selecting one of a variety of user control
styles.
* * * * *