Communication of VBI data in digital television data streams

• US 5,844,615 A
• Filed: 01/16/1997
• Issued: 12/01/1998
• Est. Priority Date: 01/16/1997
• Status: Expired due to Term

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Inventors: Walker, Kent, Nuber, Ray
• Primary Examiner(s): BRITTON, HOWARD W
• Application Number:
  US08/783,432
• Time in Patent Office: 684 Days
• Field of Search: 348/423, 348/571, 348/461, 348/468, 348/473, 348/478, 348/845.2
• US Class Current: 375/240.01
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/89 involving methods or arrangements for detection of transmission errors at the decoder

Abstract

A method and apparatus are provided for communicating VBI user information in digital television data streams via a generic syntax. The syntax allows the digital transport of virtually any type of user data that may be carried in the VBI portion of an analog television signal. A pixel generator is used to insert VBI lines into a digital video signal using information provided in the user portion of the digital data stream. The syntax provides the pixel generator with the start time of the first symbol, the number of pixels per symbol, the high and low levels to insert, the fraction of the symbol time that is transition time, the number of symbols to insert and the frame line number on which to insert the data.

Claims

1. A method for communicating, in a digital television data stream, information of a type conventionally carried as NRZ data in a vertical blanking interval (VBI) waveform of an analog television signal, said digital television data stream transporting data according to a convention that includes a user data syntax, said method comprising the steps of:

supplementing said user data syntax with a line indicator value specifying horizontal television line(s) relative to a base VBI frame line in which user information is carried as NRZ data in a counterpart television signal;

supplementing said user data syntax with at least one timing reference value that defines a relationship between a symbol rate of said NRZ data and a reference clock of said digital television data stream;

supplementing said user data syntax with at least one count value indicating an amount of user information carried in the digital television data stream; and

supplementing said user data syntax with at least one user information field sufficient to carry the amount of user information indicated by said at least one count value.

2. A method in accordance with claim 1 wherein:

said NRZ data is carried in a luminance (luma) portion of said VBI waveform; and

said timing reference value comprises a luma NRZ symbol clock increment value and a luma NRZ symbol clock modulus value, said symbol clock increment and modulus values being related to said NRZ symbol rate and said reference clock as follows;

##EQU2##

3. A method in accordance with claim 1 wherein:

said NRZ data is carried in a luminance (luma) portion of said VBI waveform; and

said count value comprises a word count indicating an integer number of luma NRZ words that follow and a remainder count indicating a number of luma NRZ bits totaling less than a full luma NRZ word that follow;

said syntax thereby providing an efficient use of bandwidth by enabling remainders of less than a full NRZ word to be communicated.

4. A method in accordance with claim 1 wherein:

said NRZ data is carried in a luminance (luma) portion of said VBI waveform;

said user information is carried according to said user data syntax as luma NRZ words and luma NRZ bits;

each luma NRZ word comprises a string of luma NRZ symbols with the first bit corresponding to a first luma NRZ symbol to be reconstructed on a video line as displayed from left to right; and

each luma NRZ bit represents a luma NRZ symbol to be reconstructed on said video line;

said luma NRZ bits being provided in the order in which their symbols are to be reconstructed on said video line subsequent to symbols reconstructed from any luma NRZ words, as displayed from left to right.

5. A method in accordance with claim 1 comprising the further step of:

supplementing said user data syntax with a start sample value indicative of a sample point at which a transition into a first luma NRZ symbol is to commence in a counterpart television signal reconstructed from said digital television data stream.

6. A method in accordance with claim 5 comprising the further step of:

supplementing said user data syntax with a first amplitude value indicative of an amplitude at which luma NRZ symbols are to appear in said counterpart television signal reconstructed from said digital television data stream.

7. A method in accordance with claim 6 comprising the further step of:

supplementing said user data syntax with a pulse shape value indicative of a pulse shape that is to be provided for said luma NRZ symbols in said counterpart television signal reconstructed from said digital television data stream.

8. A method in accordance with claim 7 comprising the further step of:

supplementing said user data syntax with a field number indicative of a television field in which corresponding VBI data is to be inserted in said counterpart television signal reconstructed from said digital television data stream.

9. A method in accordance with claim 8 wherein said user data syntax is capable of delivering a plurality of luma NRZ constructs, each carrying associated user information, comprising the further step of:

supplementing said user data syntax with a luma NRZ count value indicative of the number of said luma NRZ constructs following the luma NRZ count value.

10. A method in accordance with claim 9 comprising the further step of:

supplementing said user data syntax with a data type field specifying that luma NRZ data follows.

11. A method in accordance with claim 10 comprising the further step of:

supplementing said user data syntax with a second amplitude value indicative of a second amplitude level of said luma NRZ symbols.

12. A method in accordance with claim 11 comprising the further step of:

supplementing said user data syntax with a priority value designating a priority of said luma NRZ constructs for use in reconstructing said counterpart television signal from said digital television data stream.

13. A method in accordance with claim 12 wherein said timing reference value comprises a luma NRZ symbol clock increment value and a luma NRZ modulus value, said symbol clock increment and modulus values being related to said NRZ symbol rate and said reference clock as follows:

##EQU3##

14. A method in accordance with claim 12 wherein:

said user information is carried according to said user data syntax as luma NRZ words and luma NRZ bits;

each luma NRZ word comprises a string of luma NRZ symbols with the first bit corresponding to a first luma NRZ symbol to be reconstructed on a video line as displayed from left to right; and

each luma NRZ bit represents a luma NRZ symbol to be reconstructed on said video line;

said luma NRZ bits being provided in the order in which their symbols are to be reconstructed on said video line subsequent to symbols reconstructed from any luma NRZ words, as displayed from left to right.

15. A method in accordance with claim 12 wherein said count value comprises a word count indicating an integer number of luma NRZ words that follow and a remainder count indicating a number of luma NRZ bits totaling less than a full luma NRZ word that follow;

said syntax thereby providing an efficient use of bandwidth by enabling remainders of less than a full NRZ word to be communicated.

16. A method in accordance with claim 15 wherein said luma NRZ words are each 22 bits in length, said method comprising the further step of:

inserting a marker bit after each luma NRZ word to guard against a false MPEG start code.

17. Receiver apparatus for decoding, from a digital television data stream, user information of a type conventionally carried as NRZ data in a vertical blanking interval (VBI) waveform of an analog television signal, said digital television data stream transporting data according to a convention that includes a user data syntax, comprising:

a syntax processor for detecting information carried in accordance with said user data syntax, said information including;

a first value identifying horizontal television line(s) relative to a base VBI frame line in which particular user information is carried in a counterpart television signal,

a second value identifying a relationship between an NRZ symbol rate of said counterpart television signal and a digital television data reference clock,

a third value indicating an amount of user information carried in the digital television data stream, and

said user information;

a reconstruction processor responsive to said first, second and third values for formatting said user information into VBI NRZ data; and

a VBI inserter for inserting said VBI NRZ data into a television signal reconstructed from said digital television data stream.

18. Apparatus in accordance with claim 17 wherein:

said syntax processor detects a start sample value indicative of a sample point at which a transition into a first NRZ symbol is to commence in said reconstructed television signal; and

said VBI inserter is responsive to said start sample value for inserting said NRZ data into said reconstructed television signal.

19. Apparatus in accordance with claim 18 wherein:

said syntax processor detects a first amplitude value indicative of an amplitude at which NRZ symbols are to appear in said reconstructed television signal; and

said reconstruction processor is responsive to said first amplitude value to provide said VBI NRZ data at said amplitude.

20. Apparatus in accordance with claim 19 wherein:

said syntax processor detects a pulse shape value indicative of a pulse shape that is to be provided for said NRZ symbols in said reconstructed television signal; and

said reconstruction processor is responsive to said pulse shape value to provide said VBI NRZ data with said pulse shape.

21. Apparatus in accordance with claim 20 wherein:

said syntax processor detects a field number indicative of a television field in which corresponding VBI data is to be inserted in said reconstructed television signal; and

said VBI inserter is responsive to said field number for inserting said corresponding VBI data into a proper field.

22. Apparatus in accordance with claim 21 wherein:

said syntax processor detects and is responsive to an NRZ count value indicative of a number of NRZ constructs to be processed.

23. Apparatus in accordance with claim 22 wherein:

said syntax processor detects and is responsive to a data type field for locating NRZ data in said digital television data stream.

24. Apparatus in accordance with claim 23 wherein:

said syntax processor detects a second amplitude value indicative of a second amplitude at which NRZ symbols are to appear in said reconstructed television signal; and

said reconstruction processor is responsive to said first and second amplitude values to provide said VBI NRZ data at said first and second amplitudes.

25. Apparatus in accordance with claim 24 wherein:

said syntax processor detects a priority value designating a priority of said NRZ constructs; and

said reconstruction processor is responsive to said priority value for use in formatting said user information.