Differentiated PSIP table update interval technology

Abstract

An apparatus, method and data structure for generating at least one table in a broadcast environment, are provided. The apparatus includes a generator to generate an event information table (EIT) and an extended text table (ETT). The ETT has program guide information for an n-hour span and has a transmission interval. The ETT has a transmission interval and program description information according to the EIT. The transmission interval of the EIT is shorter than the transmission interval of the ETT.

Claims

1. A method to set repetition intervals for tables to be transmitted as part of a digital television (DTV) transport stream, the method comprising: setting repetition intervals for a sequence of event information tables EIT0, EIT1, EIT2, and EIT3 containing program information covering different time spans, wherein the repetition interval of the EIT0 is less than the repetition interval of the EIT1; setting repetition intervals for a sequence of extended text tables ETT0, ETT1, ETT2, and ETT3 containing program description information associated with the EIT0, EIT1, EIT2, and EIT3, respectively, wherein the repetition interval of the ETT3 is greater than a sum of the repetition interval of the EIT0 and the repetition interval of the EIT1; wherein the repetition interval of the ETT1 is equal to the repetition interval of the EIT2, and wherein the repetition interval of the ETT1 is equal to the repetition interval of the EIT3; and broadcasting the DTV transport stream having the EITs and the ETTs therein to receiving devices.

2. The method of claim 1, wherein each of the different time spans is a 3 hour time span.

3. The method of claim 1, wherein the program information includes program guide information having at least program duration time information and program start time information.

4. The method of claim 1, wherein the repetition intervals of the EIT0 is 0.5 seconds.

5. A method of processing a digital television (DTV) stream in a DTV receiver, the method comprising: receiving in a DTV transport stream a sequence of event information tables EIT0, EIT1, EIT2, and EIT3 containing program information covering different time spans, wherein a repetition interval of the EIT0 is less than a repetition interval of the EIT1; and parsing at least one of the EIT0, EIT1, EIT2, and EIT3 from the DTV transport stream, wherein the DTV transport stream has a sequence of extended text tables ETT0, ETT1, ETT2, and ETT3 containing program description information associated with the EIT0, EIT1, EIT2, and EIT3, respectively, wherein a repetition interval of the ETT3 is greater than a sum of the repetition interval of the EIT0 and the repetition interval of the EIT1, wherein the repetition interval of the ETT1 is equal to the repetition interval of the EIT2, and wherein the repetition interval of the ETT1 is equal to the repetition interval of the EIT3.

6. The method of claim 5, wherein each of the different time spans is a 3 hour time span.

7. The method of claim 5, wherein the program information includes program guide information having at least program duration time information and program start time information.

8. The method of claim 5, wherein the repetition intervals of the EIT0 is 0.5 seconds.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus do not limit the present invention.

(2) FIG. 1 is a block diagram of a PSIP generator according to the invention in the context of typical inputs to it and outputs from it.

(3) FIG. 2 is an image of a dialog window within a screen of a graphical user interface (GUI) generated by the PSIP data generator according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(4) FIG. 1 is a block diagram of a program and system information protocol (PSIP) data generator according to the invention in the context of system 100 that can produce an Advanced Television Standards Committee (ATSC), standard A/65, compliant digital television (DTV) signal. The system 100 of FIG. 1 includes: a PSIP generator 102 according to the invention; sources of data upon which the PSIP generator operates, such as a source 108 of listing service data, a source 110 of traffic system data and a source 112 of other data; a multiplexer 114 to incorporate the PSIP data from the PSIP generator 102 into an A/65-compliant DTV signal; and a source 116 of audio data, video data, etc.

(5) In FIG. 1, the PSIP generator 102 includes an interface unit 104 and a non-uniform interval calculation unit 106.

(6) The PSIP generator 102 according to the invention can be implemented by adapting a well known PSIP generator according to the discussion herein. An example of a known PSIP generator is the PSIP BUILDER PRO brand of PSIP generator manufactured and sold by TRIVENI DIGITAL INC. The PSIP BUILDER PRO itself is based upon a programmed PC having a Pentium type of processor using the MICROSOFT WINDOWS NT4.0 operating system. The software can be written in the Java language. The other blocks of FIG. 1 correspond to known technology.

(7) In FIG. 1, the invention has been depicted in the context of a digital television broadcast such as a terrestrial broadcast, and more particularly one that is compliant with the Advanced Television Standards Committee (ATSC), where each event is a program, and the schedule data is PSIP data. However, the invention is readily applicable to any television format, e.g., analog terrestrial, analog cable, digital cable, satellite, etc., for which an electronic schedule is maintained and corresponding data is sent to a receiver for the purpose of presenting an electronic program guide (EPG) to a viewer.

(8) The units 104 and 106 within the PSIP generator 102 do not necessarily correspond to discrete hardware units. Rather, the units 102 and 104 can represent functional units corresponding to program segments of the software that can embody the invention.

(9) The interface unit 104 can generate a graphical user interface (GUI) that operates to receive at least one issuance parameter for like PSIP tables (e.g., ETTs or EITs) that do not all have an issue interval assigned by the A/65 standard. Such an interface will be described in more detail below with regard to FIG. 2. The non-uniform interval calculation unit 106 is operable to determine non-uniform issuance intervals for ones of the like PSIP tables that do not have an assigned interval, based upon the issuance parameter(s) received via the interface unit 104.

(10) FIG. 2 is an example image of a dialog window 200 (a GUI) that can be generated by the interface unit 104 according to the invention. In FIG. 2, the dialog window 200 can include: a Cycle Time Settings tab 202; a Miscellaneous Settings tab 204; a FTP Periodic Update Controls tab 206; an “Apply Settings” button 226; a “Defaults” button 228; a “Refresh” button 230; and a “Close” button 232. The position of the cursor can be indicated via the reverse highlighting 234. The Cycle Time Settings tab 202 can include a “Cycle Times (in seconds) for EITs:” region 208, a “Cycle Times (in seconds) for PSIP Tables:” region 210, a “Cycle Times (in seconds) for PSI Tables:” region 212 and a “Cycle Times (in seconds) for ETTs:” region 214.

(11) It is well known that EITs carry program schedule information including program title information and program start information. Each EIT covers a three-hour time span. ETTs carry text messages associated with the EITs, e.g., program description information for an EIT.

(12) In FIG. 2, the “Cycle Times (in seconds) for EITs:” region 208 of the dialog window 200 can include: a box 216 in which a user can enter a fixed interval for the EIT.sub.0 table; a box 218 in which a user can enter an increment for the EIT.sub.k table; and a box 220 in which a user can enter a maximum number of EIT tables that are to be sent. Usually, the number entered in box 220 will be far smaller than the maximum number of EIT tables permitted by the A/65 standard.

(13) Also, in FIG. 2, the “Cycle Times (in seconds) for ETTs:” region 214 can include: a box 222 in which a user can enter a fixed interval for the ETT.sub.0 table; and a box 224 in which a user can enter an increment for the ETT.sub.k table.

(14) The non-uniform interval calculation unit 106 can receive the values in the boxes 216, 218, 220, 222 and 224 from the regions 208 and 214, respectively, and use them to determine the non-uniform issuance intervals of, e.g., the EIT and ETT tables. Further discussion of the operation of the unit 106 is couched in a particular non-limiting example, for simplicity.

(15) The A/65 standard recommends a time interval for outputting the zeroith Event Information Table (EIT), i.e., EIT.sub.0, but provides no guidelines regarding EIT.sub.1 through EIT.sub.128. For the Rating Region Table (RRT), the A/65 standard recommends a value only for the output frequency of RRT.sub.1. And no recommendation is made regarding the output frequencies of any of the Extended Text Tables (ETTs).

(16) Under the A/65 standard, it is left to the discretion of the operator of a PSIP data generation system to select the frequency of table output for the unmentioned tables. The operator could specify an entry for each group of tables, but that would be burdensome because it would require a total of over 500 entries. A simple solution to the problem of unspecified output frequencies would be to set each type of table to the same output frequency, but that creates a problem in that the guidelines for bandwidth specified by the A/65 standard would be exceeded.

(17) A further consideration to solve the problem, namely of how to insert the least amount possible of meta data into the DTV signal and yet still achieve an A/65 compliant DTV signal, is: How closely in time to the present moment does each table relate? That is, table types such as the EIT describe event information up to two weeks into the future. A user of an electronic program guide that receives such table types will typically want to view event information concerning only the next 24-48 hours. Users typically do not look farther into the future than this because (at least in part) the event schedule information two weeks into the future is much more likely to change than is event schedule information concerning the next 24-48 hours, i.e., the farther into the future, the less reliable the event information becomes.

(18) Care must be exercised so as not to set the intervals to be too infrequent. This is because the DTV receiver can become stalled waiting for a table to arrive. If the DTV receiver is stalled for 0.5 seconds, a user might not notice or object if she did. But such a delay of, e.g., 4-5 seconds probably would be noticed by, and probably would annoy, the user. This reinforces the need to set short intervals for near term events because users are likely to want to display EPG information about them.

(19) Again, the invention, in part, provides an interface unit 104 that defines parameters that the non-uniform interval calculation unit 106 then can use to generate the time intervals between tables of the same type. Typically (but not necessarily) the function performed by the unit 106 will be linear, e.g., with a defined start interval (the root_time) and an increment interval (increment_time). For example, if the user desires EIT.sub.0 to be output every half second (root_time) with each succeeding EIT.sub.1 to be output 0.25 seconds less frequently than the preceding EIT, namely EIT.sub.i-1, the user would enter 0.5 seconds as the root_time in box 216 and 0.25 seconds as the increment_time in box 218. The function for each table EIT-i interval would then be:

(20) $\mathrm{Time}\mathrm{between}\mathrm{any}\mathrm{two}\mathrm{instances}\mathrm{of}{\mathrm{table}}_i=\mathrm{root\_time}+\left(\mathrm{increment\_time}*i\right)=0.5\sec +\left(0.25\sec *i\right)$
For example, EIT.sub.12 can be output every 0.5 sec+(0.25 sec*12)=3.5 seconds, which is less frequent than EIT.sub.0. Obviously, other examples are possible, e.g., the increment_time for each of different groups of like tables can be set.

(21) A similar calculation for ETTs can be performed by the unit 106.

(22) The invention has at least the following advantages: 1) it provides an easy way of entering the interval times for the tables: 2) it defines the interval times for like tables that are not all fixed to a constant interval; and 3) it provides an interval function that increases the interval for tables that represent information further out in time.

(23) The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.