Data decorder and data decoding method

• US 6,067,653 A
• Filed: 12/12/1997
• Issued: 05/23/2000
• Est. Priority Date: 04/12/1996
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Tsukagoshi, Ikuo
• Primary Examiner(s): Tu, Trinh L.
• Application Number:
  US08/983,067
• Time in Patent Office: 893 Days
• Field of Search: 714/48, 714/49, 714/54, 714/57, 714/704, 714/746, 714/748, 714/819, 714/700, 364/265, 364/265.1, 364/265.2, 364/943.9, 364/944.5, 360/77.04, 360/53, 377/33, 341/94
• US Class Current: 714/746
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers
• CPC Class Codes: G11B 2220/218 Write-once discs
• CPC Class Codes: G11B 2220/2525 Magneto-optical [MO] discs
• CPC Class Codes: G11B 2220/2545 CDs
• CPC Class Codes: G11B 27/034 on discs G11B27/036, G11B27/038 take precedence
• CPC Class Codes: H04N 19/00 Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/50 using predictive coding H04N19/61 takes precedence
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/895 in combination with error concealment
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/4348 Demultiplexing of additional data and video streams
• CPC Class Codes: H04N 21/44209 Monitoring of downstream path of the transmission network originating from a server, e.g. bandwidth variations of a wireless network arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896
• CPC Class Codes: H04N 21/4884 for displaying subtitles
• CPC Class Codes: H04N 21/8547 involving timestamps for synchronizing content
• CPC Class Codes: H04N 5/04 Synchronising for television systems using pulse code modulation H04N7/56
• CPC Class Codes: H04N 5/06 Generation of synchronising signals
• CPC Class Codes: H04N 5/445 for displaying additional information H04N5/50 takes precedence
• CPC Class Codes: H04N 5/46 for receiving on more than one standard at will deflecting circuits of multi-standard receivers H04N3/27
• CPC Class Codes: H04N 5/783 Adaptations for reproducing at a rate different from the recording rate
• CPC Class Codes: H04N 5/85 : on discs or drums
• CPC Class Codes: H04N 7/0122 : the input and the output signals having different aspect ratios
• CPC Class Codes: H04N 9/8042 : involving data reduction
• CPC Class Codes: H04N 9/8063 : using time division multiplex of the PCM audio and PCM video signals
• CPC Class Codes: H04N 9/8244 : involving the use of subcodes

Abstract

Bit stream data that contains a digital video signal and character data is input to a decoding apparatus. Bit map character data is extracted by a demultiplexer 1 and supplied to a data decoder 7. A word detecting portion 20 of the data decoder 7 detects a line that has error data. A line processor 40 detects a line that has error data and stores an address of the end of the line to a register. Thus, when data is displayed, while it is being read from a buffer memory 22 and decoded, the buffer memory is randomly accessed. Consequently, a particular line can be displayed a plurality of times. Alternatively, a particular line can be skipped. Instead of reading data of a line that has an error, by accessing lines that immediately precede or immediately follow the line that has the error in the memory, character data can be interpolated for each line.

Claims

1. A data decoding apparatus for receiving bit stream data including at least a digital video signal and graphic data, comprising:

extracting means for extracting said graphic data from the received bit stream data;

error detecting means for detecting an error in the extracted graphic data; and

substituting means for substituting the graphic data that has the error with graphic data that does not have an error.

2. The data decoding apparatus as set forth in claim 1,

wherein said graphic data is comprised of a plurality of lines of bit map data,

wherein said error detecting means detects a line that has an error, and

wherein said substituting means substitutes the line that has an error with a line that does not have an error.

3. A data decoding apparatus for receiving bit stream data including at least a digital video signal and graphic data, comprising:

extracting means for extracting said graphic data from the received bit stream data, said graphic data being comprised of a plurality of lines of bit map data;

error detecting means for detecting a line of the extracted graphic data that has an error; and

substituting means for substituting the line that has an error with a line that does not have an error;

said substituting means having a buffer memory for storing the extracted graphic data and instead of reading a line that has an error, the buffer memory is randomly accessed so as to read the stored lines that immediately precede or immediately follow the line that has an error.

4. The data decoding apparatus as set forth in claim 3, wherein said graphic data includes character data.

5. The data decoding apparatus as set forth in claim 4,

wherein said error detecting means has:

counter means that counts up whenever line end identification code contained in the character data is detected; and

a register for storing the count value of said counter means as a line number when the error is detected,

wherein said substituting means has;

line number generating means for generating a line number that precedes the line number of a line that is read from said buffer memory so as to actually display character data;

line number comparing means for comparing the generated line number with the line number of a line that has an error and that is stored in said register; and

data reading means for reading data of a line that immediately precedes or immediately follows the generated line number from said buffer memory when the line numbers match as the compared result of said line number comparing means.

6. The data decoding apparatus as set forth in claim 5, further comprising:

reproducing means for reproducing information stored in a record medium and outputting the bit stream data.

7. The data decoding apparatus as set forth in claim 6,

wherein the character data is data of a subtitle.

8. The data decoding apparatus as set forth in claim 5, further comprising:

receiving means for receiving a digital television broadcast signal, demodulating the received signal, and outputting the bit stream data.

9. The data decoding apparatus as set forth in claim 8,

wherein the character data is data of a subtitle.

10. The data decoding apparatus as set forth in claim 8,

wherein the character data is data of a program guide.

11. A data decoding method for receiving bit stream data including at least a digital video signal and graphic data, comprising the steps of:

extracting said graphic data from the received bit stream data;

detecting an error in the extracted graphic data; and

substituting the graphic data that has the error with graphic data that does not have an error.

12. The data decoding method as set forth in claim 11,

wherein said graphic data is comprised of a plurality of lines of bit map data,

wherein said error detecting step is performed by detecting a line that has an error, and

wherein the substituting step is performed by substituting the line that has an error with a line that does not have an error.

13. A data decoding method for receiving bit stream data including at least a digital video signal and graphic data, comprising the steps of:

extracting said graphic data from the received bit stream data, said graphic data being comprised of a plurality of lines of bit map data;

detecting a line of the extracted graphic data that has an error; and

substituting the line that has an error with a line that does not have an error by storing the extracted graphic data in a buffer memory and instead of reading a line that has an error, the buffer memory is randomly accessed so as to read the stored lines that immediately precede or immediately follow the line that has an error.

14. The data decoding apparatus as set forth in claim 13, wherein said graphic data includes character data.

15. The data decoding method as set forth in claim 14,

wherein the error detecting step has the steps of:

counting up a counter whenever line end identification code contained in the character data is detected; and

storing the count value of the counter step as a line number when the error is detected,

wherein the substituting step has the steps of;

generating a line number that precedes the line number of a line that is read from the buffer memory so as to actually display character data;

comparing the generated line number with the line number of a line that has an error and that is stored in the register; and

reading data of a line that immediately precedes or immediately follows the generated line number from the buffer memory when the line numbers match as the compared result of the line number comparing step.

16. The data decoding method as set forth in claim 15, further comprising the steps of:

reproducing information stored in a record medium and outputting the bit stream data.

17. The data decoding method as set forth in claim 16,

wherein the character data is data of a subtitle.

18. The data decoding method as set forth in claim 15, further comprising the steps of:

receiving a digital television broadcast signal, demodulating the received signal, and outputting the bit stream data.

19. The data decoding method as set forth in claim 18,

wherein the character data is data of a subtitle.

20. The data decoding method as set forth in claim 18,

wherein the character data is data of a program guide.