Interactive video distribution systems – Satellite video distribution system – Receiver
Reexamination Certificate
1998-04-10
2003-08-19
Srivastava, Vivek (Department: 2611)
Interactive video distribution systems
Satellite video distribution system
Receiver
C725S063000, C725S098000, C725S148000, C348S558000
Reexamination Certificate
active
06609251
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a digital broadcasting transmitting method, a digital broadcasting transmitting apparatus, and a digital broadcasting reproducing apparatus and, more particularly to a digital broadcasting transmitting method, a digital broadcasting transmitting apparatus, and a digital broadcasting reproducing apparatus in a digital broadcasting system wherein a transport stream in which plural packets comprising packets of video data of digitized video and packets of service information about broadcasting of the video have been multiplexed is transmitted over a network.
BACKGROUND OF THE INVENTION
Conventionally, in TV broadcasting or the like, analog signals were transmitted and received. Recently, much attention has been focused on digital broadcasting in which video, audio, character or other data are handled in the same manner.
Advantages of the digital broadcasting are as follows. i) Since various types of data can be handled collectedly, integration of services can be provided. ii) A compression technique is employed to transmit/receive data, thereby a great deal of broadcasting of high quality can be performed with a limited transmission bandwidth. iii) Uniform services are offered to users by employing an error correcting technique. iv) High techniques may be employed with ease as an encryption technique for limited receiving.
In a case where the various types of data, especially moving pictures of large volumes of data are recorded, transmitted or received as digital data, analog information of the moving pictures is generally subjected to analog-to-digital conversion, and the resulting digital data is compressively coded. There has been proposed an MPEG standard (Moving Picture Experts Group) of a moving picture compression technique, which is widely available, and described in “LATEST MPEG TEXTBOOK” published by ASCII Corp. Aug. 1, 1994, and “PRACTICAL MPEG TEXTBOOK” published by ASCII Corp. Nov. 1, 1995, a video data transmitting/receiving method or a digital broadcasting reproducing apparatus according to MPEG described in these text books is well-known.
Generally, the digital data or compressively coded data is transmitted/received in packeted form. A packet is a unit of data in which entire data is divided into given size data. Transmitting/receiving data in packeted form allows higher efficiency and precision in data communication. For example, in a case where packet switching is performed over a computer network, since packets are respectively sent to transfer destination at different timings, where they are restructured to be original data, information about the transfer destination, transmitting end, or order of packets is added to respective packets.
Thus, in communication systems such as the digital communication system, by employing a packeting technique, various data such as video, audio and additional information are packeted and combined to create multiplexed data, to be transmitted/received.
FIGS.
57
(
a
) and
57
(
b
) show a prior art digital broadcasting system. As shown in FIG.
57
(
a
), in a transmitting end, various types of data is packeted and then multiplexed, resulting in a transport stream to-be-transmitted.
As shown in FIG.
57
(
b
), one or a plurality of transport streams are transmitted over a network. In general, each transport stream includes plural services, namely, “PROGRAM” which correspond to channels in conventional analog TV broadcasting, and each of the services includes one or a plurality of events which correspond to programs. Thus, in the digital TV broadcasting service, audio, video, and additional information of plural channels can be transmitted as multiplexed data. Viewers can utilize the digital broadcasting by the use of receivers adapted to the corresponding networks. Specifically, networks
1
and
2
in FIG.
57
(
b
) are supposed to be used by receivers for them, respectively.
FIG. 58
shows an NIT (Network Information Table), an SDT (Service Description Table), and an EIT (Event Information Table), which are used in the digital broadcasting system. The NIT is information for each network, and contains various types of information about each network or information about a transport stream which belongs to each network. The SDT is information for each transport stream, and contains various types of information about each transport stream and information about a service which belongs to each transport stream. The EIT is information for each service, and contains various types of information about each service and information about events which belong to each service.
In a case where digital broadcasting is performed over plural networks, if failures should occur in lines or a satellite in satellite broadcasting, a transport stream which belongs to a network (original network) may be broadcast over another network. In this case, information about the network to which the transport stream belongs is held by an original network identifier (hereinafter referred to as “ID”) contained in service information such as the NIT. Information about a network through which the transport stream has been broadcast is held by a network ID of the NIT
Note that it is not necessarily to specify the original network. In the prior art digital broadcasting system,
A. In a receiving end, normal receiving and processing is carried out only when an original network ID is recognized, and is identical to a network ID, and
B. In a receiving end, normal receiving and processing is carried out even if the original network ID is not recognized or it is different from the network ID. On the other hand, in TV broadcasting using conventional analog signals, video i.e., a moving picture is converted into TV signals, which are transmitted, and received by a receiver, in which the TV signals are reproduced, resulting in the moving picture, to be displayed. In case of audio signals in which the relationship between time and sound pressure may be handled as one-dimensional information, instantaneous (short time) sound pressure can be directly converted into electric signals, while in case of a moving picture comprising still pictures, since the still picture is two-dimensional information as d plane, the plane must be scanned so that it can be handled as one-dimensional information, i.e., plural scan lines, prior to conversion into signals. In this case, a non-interlace method and an interlace method are employed to make an image plural lines. In the former method, all scan lines are sequentially scanned for each frame (screen) from the top, and in the latter method, scan lines are scanned every other line.
In a display having a relatively low level of performance, since there is a large time difference between first and last lines in the non-interlace method, “flicker” occurs. Therefore, in the conventional TV broadcasting, the interlace method has been mainly employed. In general NTSC system, assuming that one frame (screen) has 525 scan lines, odd-numbered lines and even-numbered lines are scanned separately, that is, scanning is performed twice for two fields.
On the other hand, in a display having a relatively high level of performance, the non-interlace method can reduce “flicker”. In general displays for computers, number of displays per second of a non-interlace type display is about twice as many as that of an interlace type display. Accordingly, in TV of high quality image, attention has been paid to the non-interlace method in which high quality image is obtained and which is suited for CG (computer graphics).
As described above, the interlace method has been employed in TV broadcasting using analog signals to transmit/receive data of the digital TV broadcasting in the prior art digital broadcasting system, and accordingly techniques have been developed for video data according to the interlace method. Also, where a system uses video data according to the non-interlace method, the system has been developed as such.
Hereinafter, a description is given of the prior art digital broadcasting in which the v
Parkhurst & Wendel L.L.P.
Salce Jason
Srivastava Vivek
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