Pulse or digital communications – Bandwidth reduction or expansion
Reexamination Certificate
1999-06-01
2003-03-04
Kelley, Chris (Department: 2613)
Pulse or digital communications
Bandwidth reduction or expansion
C370S474000, C370S487000, C370S498000, C370S345000, C370S527000, C370S394000
Reexamination Certificate
active
06529550
ABSTRACT:
TECHNICAL FIELD
This invention relates to a coded stream splicing device, a coded stream splicing method, a coded stream generating device, and a coded stream generating method which are used in a digital broadcasting system. Particularly, it relates to a coded stream splicing device, a coded stream splicing method, a coded stream generating device, and a coded stream generating method which are adapted for generating a seamless spliced stream by splicing two coded streams at a stream level.
BACKGROUND OF THE INVENTION
FIG. 1
illustrates a current television broadcasting system. In the current television broadcasting system, broadcasting stations for distributing television programs to each household include a key station (or main station) S
K
for producing television programs on a nationwide scale, and a plurality of local stations (or branches) S
A
, S
B
and S
C
affiliated with the key station for producing unique local television programs. The key station S
K
is a broadcasting station for producing nationwide television programs and transmitting the produced television programs to the local stations. The local stations are broadcasting stations for distributing, to households within the local areas, the original television programs sent from the key station through inter-station transmission and television programs produced by editing a part of the original television programs into unique local versions. For example, as shown in
FIG. 1
, the local station S
A
is a station for producing television programs to be transmitted to households in a broadcasting area E
A
. The local station S
B
is a station for producing television programs to be transmitted to households in a broadcasting area E
B
. The local station S
C
is a station for producing television programs to be transmitted to households in a broadcasting area E
C
. Editing processing carried out at each local station is, for example, processing for inserting a unique local weather forecast program into a news program transmitted from the key station, or processing for inserting a local commercial into a program such as a movie or drama.
FIGS. 2A
to
2
C illustrate editing processing at each local station.
FIG. 2A
shows an original television program PG
OLD
produced at the key station.
FIG. 2B
shows a substitute television program PG
NEW
for local viewers produced at a local station.
FIG. 2C
shows a television program PG
EDIT
edited at a local station. The example of editing processing shown in
FIGS. 2A
to
2
C is an example of editing processing for replacing a commercial CM
1
, a program
3
and a commercial CM
3
of the original television programs transmitted from the key station with a commercial CM
1
′, a program
3
′ and a commercial CM
3
′ produced at the local station for local viewers. As a result of this editing processing at the local station, television programs for local viewers are produced in which the television programs produced at the key station (that is, a program
1
, a program
2
, a CM
2
and a program
4
) and the television programs produced at the local station (that is, the commercial CM
1
′, the program
3
′ and the CM
3
′) coexist.
The current television broadcasting system employs analog broadcasting for distributing analog base band television signals to each household. However, attempts have been recently made to replace the analog broadcasting system with a next-generation broadcasting system that uses a digital technique. The digital broadcasting system employs compression-coding of video data and audio data through a compression coding technique such as MPEG2 (Moving Picture Experts Group Phase 2), and transmits the coded streams to each household and other stations through land or satellite-based communication links. Particularly, from among broadcasting techniques proposed as the digital broadcasting system, the DVB (Digital Video Broadcasting) standard proposed as a next-generation broadcasting system in Europe is the most popular technique. This DVB standard is becoming the de facto standard.
With reference to
FIG. 3
, a typical digital transmission system for transmitting a program including video data and audio data from a transmitting side system to a receiving side system by using the MPEG standard will now be described.
In the typical digital transmission system, a transmission side system
10
has an MPEG video encoder
11
, an MPEG audio encoder
12
, and a multiplexer
13
. A receiving side system
20
has a demultiplexer
21
, an MPEG video decoder
22
, and an MPEG audio decoder
23
.
The MPEG video encoder
11
encodes base band source video data V on the basis of the MPEG standard, and outputs the coded stream as a video elementary stream ES. The MPEG audio encoder
12
encodes base band source audio data A on the basis of the MPEG standard, and outputs the coded stream as an audio elementary stream ES. The multiplexer
13
receives the video elementary stream from the MPEG video encoder
11
and the audio elementary stream from the MPEG audio encoder
12
. The multiplexer
13
then converts the streams into the form of transport stream packets, thus generating transport stream packets corresponding to the video elementary stream and transport stream packets corresponding to the audio elementary stream. The multiplexer
13
multiplexes the transport stream packets so that the transport stream packet including the video elementary stream and the transport stream packet including the audio elementary stream coexist, thus generating a transport stream to be transmitted to the receiving system
20
.
The demultiplexer
21
receives the transport stream transmitted through a transmission line, and demultiplexes the transport stream into the transport stream packets corresponding to the video elementary stream and the transport stream packets corresponding to the audio elementary stream. The demultiplexer
21
then generates the video elementary stream from the transport stream packets corresponding to the video elementary stream, and generates the audio elementary stream from the transport stream packets corresponding to the audio elementary stream. The MPEG video decoder
22
receives the video elementary stream from the demultiplexer
21
, and decodes this video elementary stream on the basis of the MPEG standard, thus generating the base band video data V. The MPEG audio decoder
23
receives the audio elementary stream from the demultiplexer
21
, and decodes this audio elementary stream on the basis of the MPEG standard, thus generating the base band audio data A.
In the case where the conventional analog broadcasting system is to be replaced with the digital broadcasting system using such a technique of digital transmission system, video data of television programs are transmitted to the local station from the key station in the form of a coded stream which is compression-coded on the basis of the MPEG2 standard. Therefore, to carry out editing processing at the local station for replacing a part of the original coded stream transmitted from the key station with a coded stream produced at the local station, the coded stream must be decoded once to restore the base band video data before the editing processing is carried out. That is, since the direction of prediction of each picture included in a coded stream in conformity to the MPEG standard is correlated with the direction of prediction of the preceding and subsequent pictures, an unrelated coded stream cannot be inserted at an arbitrary position on the stream. If such insertion is attempted, data at the seam of the coded streams become discontinuous and cannot be decoded accurately.
Therefore, to realize editing processing as described with reference to
FIGS. 2A
to
2
C, it is necessary to carry out decoding processing for once decoding both an original coded stream supplied from the key station and a coded stream produced for local viewers so as to restore base band video signals, editing processing for editing the two base band video data to generate vi
Negishi Shinji
Tahara Katsumi
Yasuda Mikita
An Shawn S.
Frommer William S.
Frommer & Lawrence & Haug LLP
Kelley Chris
Polito Bruno
LandOfFree
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