Pulse or digital communications – Bandwidth reduction or expansion – Television or motion video signal
Reexamination Certificate
1999-03-12
2004-05-18
Kelley, Chris (Department: 2613)
Pulse or digital communications
Bandwidth reduction or expansion
Television or motion video signal
C375S240190
Reexamination Certificate
active
06738421
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a digital data transmission method for transmitting digital data of differing resolution, a digital data transmission device suitable for implementing this transmission method, and a digital data reception device for receiving transmitted digital data.
BACKGROUND ART
Recently, image and sound compression methods based on MPEG (Moving Picture Experts Group) standards have come to be used, and the methods described in ISO/IEC13818-1, 1383818-2, 13818-3 are commonly known. Furthermore, with regard to broadcast methods, in Japan, CS digital broadcast systems and CATV digital transmission systems are stipulated by Finding No.74 of the Electrical Communications Technology Commission.
With regard to animated image encoding methods, the Main Profile/Main Level (MP@ML) method described in ISO/IEC13818-2 involves compression encoding of a signal running up to a maximum of 30 frames/second based on a sequential scanning system (progressive) or an interlaced scanning system, and this is suitable for conventional television broadcast.
FIG. 32
is a diagram showing the composition of transmission data in a conventional transmission method for image data.
In this example, image data for program number
1
and program number
3
in a band centred on a reception frequency of 12.568 GHz is superimposed with NIT (network information table), PMT (program maintenance table), and EIT (event information table), in packet units. The data structure in these packets and the standards for their multiplexing are stipulated in detail by ISO/IEC13818-1, 13818-2, 13818-3 and Finding No.74 of the Electrical Communications Technology Commission.
In this diagram, numeral
17
is a packet of image data for program number
1
, and by defining its leading packet identifier PID as 0x91, it is possible for this packet to be recognized as an image data packet for program number
1
. Numeral
18
is an image data packet for program number
3
, and by defining its leading packet identifier PID as 0x93, it is possible for this packet to be recognized as an image data packet for program number
3
.
Numeral
19
is an NIT (network information table) packet, which defines the frequency at which the image data relating to program number
1
and program number
3
is transmitted. In the present example, it indicates that the image data for program number
1
and program number
3
is superimposed in the 12.568 GHz band, as described above.
Numeral
20
is a PMT (program maintenance table) packet and in the present example, it indicates that the packet identifier for the program number
1
image data is contained in packet 0x91, and the packet identifier for the program number
3
image data is contained in packet 0x93.
Numeral
21
is an EIT (event information table) packet which is a table of the program contents. In the present example, it shows that program number
1
will be broadcasting baseball a between 19:00-20:00, a quiz between 20:00-21:00, and a foreign film from 21:00 onwards, whilst program number
3
will be broadcasting baseball a between 19:00-20:00, soccer between 20:00-21:00, baseball b between 21:00-22:00, and news from 22:00 onwards.
FIG. 33
is a compositional diagram of a conventional transmission device
45
and reception device
46
for image data. In the diagram, numeral
47
denotes compression encoding means, which compresses and encodes an input digital video signal, in this case, for example, an interlaced scanning signal or a sequential scanning signal running at 30 frames or less, in accordance with ISO/IEC138318-2. Numeral
48
denotes multiplexing means for multiplexing the image data for program number
1
and program number
3
, and numeral
49
denotes modulating means for performing modulation, such as QPSK, or the like.
Numeral
50
denotes demodulating means for demodulating information containing at the least image data multiplexed and transmitted in order to broadcast programs, and in
FIG. 32
, demodulating means
50
demodulates image data for program number
1
, image data for program number
3
, NIT, PMT and EIT. Numeral
51
denotes separating means for separating information containing image data demodulated by demodulating means
50
.
52
denotes program selecting means, which receives a program selection control made by the operator (user) and indicates the selected program to the demodulating means
50
and separating means
51
. Examples of program selecting means
52
include commonly and widely used devices, such as a remote control device for selecting television programs, or channel selection by television channel buttons or a PC mouse. Numeral
53
denotes image decoding means for decoding image data separated by separating means
51
, which in the present example involves a bit stream encoded by an MP@ML system, and outputting this data in the form of a video signal to image display means
54
.
In addition to these elements, a standard image data reception device also requires various components, such as a decoding section for decoding sound data, for example, but since these components do not relate directly to the present invention, a description thereof is omitted here.
Below, the operation of a conventional transmission and reception device constituted as described above is described.
Firstly, when program selecting means
52
receives a program selection control from the operator, it indicates the selected program to demodulating means
50
. Demodulating means
50
then demodulates the image data for the designated channel. Separating means
51
separates the image data in the information demodulated by demodulating means
50
on the basis of the instruction from program selecting means
52
.
In specific terms, if an instruction is given indicating that the data for program number
1
is to be reproduced, then the value of the packet identifier 0x91 of the image data in program number
1
is obtained from the PMT value, and the packet having packet identifier 0x91 is extracted and transferred to subsequent processing. Furthermore, if an instruction is given indicating that the data for program number
3
is to be reproduced, then the value of the packet identifier 0x93 of the image data in program number
3
is obtained from the PMT value, and the packet having packet identifier 0x93 is extracted and transferred to subsequent processing.
Image decoding means
53
decodes the image data separated by separating means
51
and outputs this data in the form of a video signal.
DISCLOSURE OF THE INVENTION
(Technical Problems to be Solved by the Invention)
Recently, attention has started to focus on animated images having higher resolution than interlaced scanning signals or sequential scanning signals operating at 30 frames or less and compression encoded by a conventional Main Profile/Main Level (MP@ML) method, as described above. In this case, the frame number may be, for example, 59.94 frames/seconds, namely, twice the NTSC frame rate, and systems conforming to main profile H14 (MP@H14) in ISO/IEC13818-2 have been envisaged.
Therefore, it is anticipated that, in the future, low-resolution image data and high-resolution image data will be multiplexed and broadcast simultaneously by hierarchical encoding, and moreover, hierarchical encoded data and non-hierarchical encoded data will be multiplexed and broadcast simultaneously. However, in a conventional composition as described above, it is not possible to identify between hierarchical encoding and non-hierarchical encoding, or between low-resolution image data and high-resolution image data, so if it is supposed that MP@ML image data is multiplexed and transmitted with image data relating to a sequential scanning signal of image size 704×480 and operating at a higher frame frequency than MP@ML, for example, 59.94 frames, then although the frame number will be 59.94 frames/seconds, which is twice the frame rate of NTSC, for example, and the signal will conform to Main Profile H14 (MP@H14), since the image size is
Bugg George A
Greenblum & Bernstein P.L.C.
Kelley Chris
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