Apparatus for generating sub-picture units for subtitles and storage medium storing sub-picture unit generation program

• US 6,046,778 A
• Filed: 10/28/1998
• Issued: 04/04/2000
• Est. Priority Date: 10/29/1997
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Uesaka, Yasushi, Kozuka, Masayuki, Inoue, Mitsuhiro, Nonomura, Tomoyuki
• Primary Examiner(s): HSIA, SHERRIE Y
• Application Number:
  US09/181,408
• Time in Patent Office: 524 Days
• Field of Search: 348/563, 348/564, 348/565, 348/569, 348/589, 348/600
• US Class Current: 348/565
• CPC Class Codes: H04N 21/4312 involving specific graphical features, e.g. screen layout, special fonts or colors, blinking icons, highlights or animations
• CPC Class Codes: H04N 21/434 Disassembling of a multiplex stream, e.g. demultiplexing audio and video streams, extraction of additional data from a video stream; Remultiplexing of multiplex streams; Extraction or processing of SI; Disassembling of packetised elementary stream demultiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00
• CPC Class Codes: H04N 21/4884 for displaying subtitles
• CPC Class Codes: H04N 5/44504 Circuit details of the additional information generator, e.g. details of the character or graphics signal generator, overlay mixing circuits

Abstract

To provide a sub-picture unit generation apparatus for generating a plurality of sub-picture units that compose a sub-picture stream which is interleaved with a video stream into a system stream, each sub-picture unit including a subtitle image that is to be superimposed on moving images reproduced from the video stream. The sub-picture unit generation apparatus includes an attribute storage unit for storing a display attribute that shows a base position for arranging each subtitle image, a character string storage unit for storing a plurality of subtitle character strings, a subtitle image generation unit for generating a subtitle image from one of the plurality of subtitle character strings stored in the character string storage unit, a display position determination unit for determining a display position of the subtitle image according to the display attribute, and a sub-picture unit generation unit for generating a sub-picture unit that includes the subtitle image and display position data showing the determined display position.

Claims

1. A sub-picture unit generation apparatus for generating a plurality of sub-picture units that compose a sub-picture stream which is interleaved with a video stream into a system stream, each sub-picture unit including a subtitle image that is to be superimposed on moving images reproduced from the video stream, the sub-picture unit generation apparatus comprising:

attribute storage means for storing a display attribute that shows a base position for arranging each subtitle image;

character string storage means for storing a plurality of subtitle character strings;

subtitle image generation means for generating a subtitle image from one of the plurality of subtitle character strings a stored in the character string storage means;

display position determination means for determining a display position of the subtitle image according to the display attribute; and

sub-picture unit generation means for generating a sub-picture unit that includes the subtitle image and display position data showing the determined display position.

2. The sub-picture unit generation apparatus of claim 1,

wherein the subtitle image generated by the subtitle image generation means is rectangular, and

wherein the display attribute shows a position at which one of a top end, a bottom end, a left end, and a right end of each subtitle image is to be aligned.

3. The sub-picture unit generation apparatus of claim 2,

wherein the subtitle image generation means generates the rectangular subtitle image in which one of the plurality of subtitle character strings is horizontally written,

wherein the attribute storage means stores one of a first horizontal attribute and a second horizontal attribute as the display attribute, the first horizontal attribute showing a position at which the top end of each subtitle image is to be aligned and indicating centering of each subtitle image, the second horizontal attribute showing a position at which the bottom end of each subtitle image is to be aligned and indicating centering of each subtitle image, and

wherein the display position determination means calculates coordinates (X_-- tl, Y_-- tl) at which a top left point of the subtitle image is to be placed, according to the display attribute, a height and a width of the subtitle image expressed in pixels, and a height and a width of a display screen expressed in pixels.

4. The sub-picture unit generation apparatus of claim 3,

wherein the display position determination means uses a formula set to calculate the coordinates (X_-- tl, Y_-- tl) at which the top left point of the subtitle image is to be placed, when the display attribute is the first horizontal attribute,

the formula set being

5. The sub-picture unit generation apparatus of claim 3,

wherein the display position determination means uses a formula set to calculate the coordinates (X_-- tl, Y_-- tl) at which the top left point of the subtitle image is to be placed, when the display attribute is the second horizontal attribute,

the formula set being

6. The sub-picture unit generation apparatus of claim 3,

wherein the subtitle image generation means includes:

an outline font storage unit for storing outline fonts;

a read unit for reading one of the plurality of subtitle character strings from the character string storage means; and

a rasterization unit for performing gray-scale rasterization based on outline fonts corresponding to the read subtitle character string to generate the subtitle image.

7. The sub-picture unit generation apparatus of claim 2,

wherein the subtitle image generation means generates the rectangular subtitle image in which one of the plurality of subtitle character strings is vertically written,

wherein the attribute storage means stores one of a first vertical attribute and a second vertical attribute as the display attribute, the first vertical attribute showing a position at which the top end of each subtitle image is to be aligned and a position at which the left end of each subtitle image is to be aligned, the second vertical attribute showing a position at which the top end of each subtitle image is to be aligned and a position at which the right end of each subtitle image is to be aligned, and

wherein the display position determination means calculates coordinates (X_-- tl, Y_-- tl) at which a top left point of the subtitle image is to be placed, according to the display attribute, a height and a width of the subtitle image expressed in pixels, and a height and a width of a display screen expressed in pixels.

8. The sub-picture unit generation apparatus of claim 7,

wherein the display position determination means uses a formula set to calculate the coordinates (X_-- tl, Y_-- tl) at which the top left point of the subtitle image is to be placed, when the display attribute is the first vertical attribute,

the formula set being

9. The sub-picture unit generation apparatus of claim 7,

wherein the display position determination means uses a formula set to calculate the coordinates (X_-- tl, Y_-- tl) at which the top left point of the subtitle image is to be placed, when the display attribute is the second vertical attribute,

the formula set being

10. The sub-picture unit generation apparatus of claim 7,

wherein the subtitle image generation means includes:

an outline font storage unit for storing outline fonts;

a read unit for reading one of the plurality of subtitle character strings from the character string storage means; and

a rasterization unit for performing gray-scale rasterization based on outline fonts corresponding to the read subtitle character string to generate the subtitle image.

11. A sub-picture unit generation apparatus for generating a plurality of sub-picture units that compose a sub-picture stream which is interleaved with a video stream into a system stream, each sub-picture unit including a subtitle image that is to be superimposed on moving images reproduced from the video stream, the sub-picture unit generation apparatus comprising:

attribute storage means for storing at least two out of a first horizontal attribute, a second horizontal attribute, a first vertical attribute, and a second vertical attribute that each show a base position for arranging a subtitle image,

the first horizontal attribute showing a position at which a top end of a subtitle image is to be aligned and indicating centering of the subtitle image,

the second horizontal attribute showing a position at which a bottom end of a subtitle image is to be aligned and indicating centering of the subtitle image,

the first vertical attribute showing a position at which a left end of a subtitle image is to be aligned and a position at which a top end of the subtitle image is to be aligned, and

the second vertical attribute showing a position at which a right end of a subtitle image is to be aligned and a position at which a top end of the subtitle image is to be aligned;

text storage means for storing a text that includes a plurality of subtitle character strings which are each accompanied with a display attribute indication;

subtitle image generation means for generating a subtitle image from one of the plurality of subtitle character strings stored in the text storage means;

display position determination means for determining a display position of the subtitle image according to a display attribute corresponding to a display attribute indication for the subtitle character string; and

sub-picture unit generation means for generating a sub-picture unit that includes the subtitle image and display position data showing the determined display position.

12. The sub-picture unit generation apparatus of claim 11,

wherein when one of the first horizontal attribute and the second horizontal attribute is indicated for the subtitle character string, the subtitle image generation means generates the subtitle image in which the subtitle character string is horizontally written, and when one of the first vertical attribute and the second vertical attribute is indicated for the subtitle character string, the subtitle image generation means generates the subtitle image in which the subtitle character string is vertically written.

13. The sub-picture unit generation apparatus of claim 12, wherein when the first horizontal attribute is indicated, the display position determination means uses a first formula set to calculate coordinates (X_-- tl, Y_-- tl) at which a top left point of the subtitle image is to be placed,

the first formula set being

14. The sub-picture unit generation apparatus of claim 12,

wherein the subtitle image generation means includes:

an outline font storage unit for storing outline fonts;

a read unit for reading one of the plurality of subtitle character strings and the display attribute indication accompanied with the subtitle character string from the text storage means;

a judgement unit for judging whether one of the first horizontal attribute and the second horizontal attribute is indicated for the subtitle character string in order to determine that the subtitle character string is to be horizontally written, and for judging whether one of the first vertical attribute and the second vertical attribute is indicated for the subtitle character string in order to determine that the subtitle character string is to be vertically written; and

a rasterization unit for generating the subtitle image by performing gray-scale rasterization based on outline fonts corresponding to the subtitle character string that is written in accordance with a judgement result by the judgement unit.

15. A computer-readable storage medium storing a sub-picture unit generation program for generating a plurality of sub-picture units that compose a sub-picture stream which is interleaved with a video stream into a system stream, each sub-picture unit including a subtitle image that is to be superimposed on moving images reproduced from the video stream, the sub-picture unit generation program comprising:

a subtitle image generation step for reading each of a plurality of subtitle character strings from a character string file and generating a subtitle image from a read subtitle character string;

a display position determination step for reading a display attribute showing a base position for arranging each subtitle image from an attribute file, and for determining a display position of the generated subtitle image according to the read display attribute; and

a sub-picture unit generation step for generating a sub-picture unit that includes the subtitle image and display position data showing the determined display position.

16. The computer-readable storage medium of claim 15,

wherein the subtitle image generated by the subtitle image generation step is rectangular, and

wherein the display attribute shows a position at which one of a top end, a bottom end, a left end, and a right end of each subtitle image is to be aligned.

17. The computer-readable storage medium of claim 16,

wherein the subtitle image generation step generates the rectangular subtitle image in which the subtitle character string is horizontally written,

wherein the display attribute is one of a first horizontal attribute and a second horizontal attribute, the first horizontal attribute showing a position at which the top end of each subtitle image is to be aligned and indicating centering of each subtitle image, the second horizontal attribute showing a position at which the bottom end of each subtitle image is to be aligned and indicating centering of each subtitle image, and

wherein the display position determination step calculates coordinates at which a top left point of the subtitle image is to be placed, according to the display attribute, a height and a width of the subtitle image expressed in pixels, and a height and a width of a display screen expressed in pixels.

18. The computer-readable storage medium of claim 16,

wherein the subtitle image generation step generates the rectangular subtitle image in which the subtitle character string is vertically written,

wherein the display attribute is one of a first vertical attribute and a second vertical attribute, the first vertical attribute showing a position at which the top end of each subtitle image is to be aligned and a position at which the left end of each subtitle image is to be aligned, the second vertical attribute showing a position at which the top end of each subtitle image is to be aligned and a position at which the right end of each subtitle image is to be aligned, and

wherein the display position determination step calculates coordinates at which a top left point of the subtitle image is to be placed, according to the display attribute, a height and a width of the subtitle image expressed in pixels, and a height and a width of a display screen expressed in pixels.

19. A computer-readable storage medium storing a sub-picture unit generation program for generating a plurality of sub-picture units that compose a sub-picture stream which is interleaved with a video stream into a system stream, each sub-picture unit including a subtitle image that is to be superimposed on moving images reproduced from the video stream, the sub-picture unit generation program comprising:

a subtitle image generation step for reading each of a plurality of subtitle character strings which are each accompanied with a display attribute indication from a character string file and for generating a subtitle image from a read subtitle character string;

a display position determination step for reading a display attribute indicated for the subtitle character string from an attribute file and determining a display position of the generated subtitle image according to the read display attribute,

wherein the attribute file stores at least two out of a first horizontal attribute, a second horizontal attribute, a first vertical attribute, and a second vertical attribute that each show a base position for arranging a subtitle image,

the first horizontal attribute showing a position at which a top end of a subtitle image is to be aligned and indicating centering of the subtitle image,

the second horizontal attribute showing a position at which a bottom end of a subtitle image is to be aligned and indicating centering of the subtitle image,

the first vertical attribute showing a position at which a left end of a subtitle image is to be aligned and a position at which a top end of the subtitle image is to be aligned, and

the second vertical attribute showing a position at which a right end of a subtitle image is to be aligned and a position at which a top end of the subtitle image is to be aligned; and

a sub-picture unit generation step for generating a sub-picture unit that includes the generated subtitle image and display position data showing the determined display position.

20. The computer-readable storage medium of claim 19,

wherein when one of the first horizontal attribute and the second horizontal attribute is indicated for the subtitle character string, the subtitle image generation step generates the subtitle image in which the subtitle character string is horizontally written, and when one of the first vertical attribute and the second vertical attribute is indicated for the subtitle character string, the subtitle image generation step generates the subtitle image in which the subtitle character string is vertically written.