Interactive video distribution systems – Operator interface – To facilitate tuning or selection of video signal
Reexamination Certificate
1998-08-20
2003-01-07
Faile, Andrew (Department: 2611)
Interactive video distribution systems
Operator interface
To facilitate tuning or selection of video signal
C725S050000
Reexamination Certificate
active
06505347
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates generally to a control information generating apparatus for broadcast systems, and more particularly to a control information generating apparatus for broadcast systems which are designed to transmit audio and video signals and/or teletext signals together with video control information and program information in multiplexed form.
2. Background of Related Art
Usually, when transmitting television programs, a broadcasting station prepares and transmits control information, i.e., EPG (Electronic Program Guide) information for transmission of audio and video signals.
FIG. 1
shows a typical example of such a broadcast system which includes a broadcast database
1
, an audio/video data transmitter
2
, a control information generator
3
, and a multiplexer
4
. The broadcast database
1
stores therein television program information. The audio/video data transmitter
2
reads a program schedule and audio/video data out of the broadcast database
1
periodically and transmits them in a data stream form to the multiplexer
4
. The control information generator
3
reads program schedule information out of the broadcast database
1
, produces control information for each program contained in the program schedule information, and transmits it in a data stream form to the multiplexer
4
. The multiplexer
4
multiplexes the audio/video data from the audio/video transmitter
2
and the control information from the control information generator
3
to output them on a broadcast wave.
The control information generator
3
includes, as shown in
FIG. 2
, a control data generating circuit
5
. The control data generating circuit
5
consists of a schedule database
7
, a sequential data generator
8
, and an output circuit
9
. The schedule database
7
stores therein the program schedule information read out of the broadcast database
1
. The sequential data generator
8
controls reception of the program schedule information from the broadcast database
1
in the schedule database
7
and processes the information stored in the schedule database
7
in sequence to produce control data components. The output circuit
9
transmits the control data components to the multiplexer
4
.
The output circuit
9
consists of a plurality of data output units (only three
9
a
,
9
b
, and
9
c
are shown in
FIG. 2
for the brevity of illustration).
FIG. 3
shows one of the data output units
9
a
to
9
b
which includes an input circuit
10
receiving the control data components coming from the sequential data generator
8
, a storage device
11
storing therein the received control data, an output circuit
12
outputting the control data components stored in the storage device
11
, and a scheduler
13
controlling reading of the control data components from the storage device
11
.
The data output units
9
a
to
9
c
receive the control data components from the sequential data generator
8
and output them in parallel to the multiplexer
4
. The storage device
11
of each of the data output units
9
a
to
9
c
stores the control data component as a plurality of tables (e.g., 400 tables: PAT, PMT
0
, PMT
1
, TMT
2
, PMT
3
, . . . ) and output the tables in response to a command from the scheduler
13
.
The above conventional broadcast system, however, encounters the following drawback.
The control information generator
3
must receive a large amount of the program schedule information and perform in a CPU a large number of operations to generate the control data components, which will result in a delay in output from the CPU and also make it difficult to increase the accuracy of transmission cycles of the control data components. For example, when the number of tables stored in the storage device
11
exceeds 1,000, it will cause an operational load of the output circuit
9
to be increased, thus resulting in delay in output from the output circuit
9
.
SUMMARY OF THE INVENTION
It is therefore a principal object of the present invention to avoid the disadvantages of the prior art.
It is another object of the present invention to provide a control information generating apparatus for broadcast systems which is capable of altering program control information without interrupting a system operation to output audio/video data.
It is a further object of the present invention to provide a control information generating apparatus for broadcast systems which is capable of altering a TV program schedule at regular intervals and taking measures to meet unexpected program change requirements.
According to one aspect of the present invention, there is provided a control information generating apparatus for use in a broadcast system including a broadcast database storing therein program information and an audio/video data transmitter. The control information generating apparatus receives a program schedule and audio/video data from the broadcast database and transmits a data signal thereof and a multiplexer and comprises: (a) a control information generating circuit which receives program schedule information on a program from the broadcast database to generate control information on a program of the program schedule information and outputs a signal of the control information; and (b) a control information outputting circuit which receives the signal of the control information from the control information generating circuit and outputs the control information to the multiplexer in which the control information and the data signal from the audio/video data transmitter are multiplexed.
In the preferred mode of the invention, the control information generating circuit includes an input circuit which receives the program schedule information from the broadcast database, a version generator which receives the program schedule information from the input circuit to generate table information and assigns a version number to the table information, a TS packetizing circuit which packetizes the table information outputted from the version generator, a bandwidth adjuster which determines a transmission cycle of the table information so that all the table information may be transmitted for adjusting a transmission bandwidth thereof, and an output circuit which outputs the table information to the control information outputting circuit.
The control information outputting circuit includes an input circuit which receives the control information outputted from the control information generating circuit, a storage device which stores the control information in grouped table forms, an output circuit which outputs the control information stored in the storage device, and a scheduler which controls timing where the control information is outputted from the storage device to the output circuit.
The program schedule information consists of a PSI element and an SI element which are transmitted independently from the broadcast database to the control information generating circuit.
The program schedule information is provided in units of a file containing programs for one day broadcasted through all services.
The version generator sections a schedule database prepared by the input circuit in units of a table to produce table information elements and assigns consecutive version numbers at least one to each of the table information elements. The version generator includes a version skip detecting circuit detecting a skip of the version numbers.
The control information outputting circuit may include a plurality of control information outputting units. The control information outputting units are controlled so that the control information being transmitted currently will be updated simultaneously at a switching time that is a current time plus a marginal time.
The bandwidth adjuster includes a bandwidth adjustment table for determining a bandwidth adjustable range and changing the degree of bandwidth adjustment according to a property of each table of the table information.
From some of the table information elements having the different vers
Ishibashi Hiroyoshi
Kaneko Shigeki
Kawaguchi Toru
Nagao Takeshi
Nakagawa Aki
Faile Andrew
Lonsberry Hunter
Lowe Hauptman & Gilman & Berner LLP
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