JPH11313300A - Digital broadcast receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital broadcast receiver where reception of a limited broadcast is secured even in the case that a transport stream of a broadcast signal is viewed after viewing a transport stream from a digital storage media(DSM) without failing to receive essential information from the broadcast signal. SOLUTION: In the case of viewing a transport stream TS-c from a DSM, a memory 8 stores essential information such as limited reception information extracted by a packet identifier filter 6. In the case of viewing a transport stream TS-a received from a broadcast signal, the essential information stored in the memory 8 is fed to a demultiplexer 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital broadcast receiver for receiving a digital broadcast, and more particularly, to a digital storage medium such as a digital VCR capable of storing a digital stream based on a digital broadcast signal. The present invention relates to a digital broadcast receiver having a data input / output interface.

[0002]

2. Description of the Related Art In digital broadcasting currently performed in CS broadcasting, video and audio digital data of a plurality of programs compressed by the MPEG2 system are multiplexed together with program information, limited reception information and the like in the form of a transport stream (TS). And transmitted.

A digital storage medium (hereinafter referred to as DSM) capable of recording the compressed video / audio digital data as it is in a digital stream such as a digital VTR.
(Abbreviated as “.”), It is possible to record more efficiently and without deteriorating the image quality than when recording the decoded signal using an analog VTR. Also, since additional information such as program information can be recorded at the same time, the information can be used at the time of reproduction.

The data rate of a digital stream that can be recorded on a DSM is often smaller than the rate of data (TS) transmitted by one transponder of digital broadcasting. Therefore, a digital broadcast receiver having a digital interface for outputting a digital stream to the DSM has a function of selecting and outputting information related to a specific program in order to reduce the transmission rate of the output digital stream. May have. FIG. 2 shows a configuration of a conventional digital broadcast receiver having a function of selecting and outputting information related to such a specific program.

In FIG. 2, a network interface module (NIM) 1 performs signal processing of a transmission system such as a tuner, digital demodulation, and error correction, and the output of the NIM 1 is a transport stream. The descrambler 2 descrambles a specific transport packet in the input transport stream according to an instruction from the host controller 5.

A transport stream TS-a of a broadcast signal output from the descrambler 2 includes compressed video and audio signals of a plurality of programs and additional information such as program names in FIG.
As shown in (A), the data is multiplexed in units of 188-byte transport packets. More specifically, packets (Vn, Vn, Vn) generated from video and audio elementary streams (ES) of a certain program n (n = 1, 2,...)
An) and a program association table (PA)
Program specific information (PSI: Program Specific Information) such as T: Program Associaion Table, program map table (PMT: Program Map Table), and program arrangement information (SI: Service Information) are time-division multiplexed.

[0007] The transport stream TS-a output from the descrambler 2 is input to an MPEG demultiplexer (hereinafter, demultiplexer) 3 via a PID filter 6 and a stream selector 7. The operation of the PID filter 6 will be described later. The transport stream TS-c input from the external DSM is also input to the demultiplexer 3 via the stream selector 7. The stream selector 7 is for selecting the transport stream TS-a output from the descrambler 2 and the transport stream TS-c input from the DSM and inputting them to the demultiplexer 3.

[0008] The demultiplexer 3 extracts PAT, PMT, and the like included in the input transport stream TS, and in accordance with an instruction from the host controller 5 on the basis of the information, converts a video / audio stream related to a predetermined program. The port packet is specified and input to the MPEG decoder 4. The MPEG decoder 4 decodes the input video / audio stream, and outputs a video signal and an audio signal.

FIG. 4 is a block diagram showing an example of a specific configuration of the demultiplexer 3 in FIG. A 13-bit packet identifier (PID:
Packet Identification), which allows the attributes of the packet to be specified. Also, PSI,
The SI and the like have a data structure called a section, and are stored in a payload portion of a transport packet.

In FIG. 4, a PID filter 31
A desired packet is selected using the ID and input to the section filter 32. The section filter 32 extracts a section of program identification information such as PAT or program arrangement information from the input packet, and inputs the section to the memory 33 in a form that the host controller 5 can refer to. The memory 33 is composed of a plurality of buffers, and stores information on video packets and audio packets output from the PID filter 31 and information on sections output from the section filter 32. Note that signal lines indicated by broken lines from the PID filter 31 and the section filter 32 indicate signal lines when a plurality of video packets and audio packets are output and other information is output. Therefore, the number of buffers in the memory 33 is appropriately increased or decreased according to the presence or absence of such data.

The host controller 5 reads information stored in the memory 33 via the memory controller 34 and performs appropriate processing such as physical channel selection, program selection, and presentation of service information. The packet including the video and audio elementary streams is specified by the information in the above section, and its transport packet (or ES packet) is specified.
Alternatively, only the stream called PES generated from the ES) is input to the MPEG decoder 4. This operation allows the user to select one desired program from the transport stream TS in which a plurality of programs are multiplexed.

Returning to FIG. 2, when outputting the transport stream TS to the DSM, the PID filter 6 uses the program identification information obtained from the demultiplexer 3 together with the program selection information from the user. According to an instruction from the host controller 5, a transport packet of a video / audio stream related to one or a plurality of programs is selected, and the transport stream TS-b is selected.
Output as This processing can be considered as a part of the function of the demultiplexer 3. Therefore, it is also possible to use a function of the demultiplexer 3 to output the transport stream TS-b to the DSM.

In this transport stream TS-b, not only one program is selected, but also auxiliary information such as PSI is output at the same time. FIG. 3B shows an example of the transport stream TS-b. When only a specific program is selected from the transport stream TS shown in FIG. 3A to obtain the transport stream TS-b shown in FIG. 3B, the form of the transport stream TS-b is as follows. PSI and the like are changed so as not to violate the rules of MPEG. SI is a selection information table (SIT: Selection Information Tabl).
e) Transmit only in a specific packet referred to as e). FIG.
A packet indicated by a broken line in (B) indicates a packet obtained by changing the packet illustrated in FIG.

In the example shown in FIG. 3, programs 1 and 2 (video packets V1 and V2 and audio packets A1 and
A2) selects a video / audio packet (V1, A1) of program 1 from the multiplexed transport stream TS, and deletes information about the unselected program from PAT and PMT1 accordingly. PMT1
Has changed. The SI outputs only information on the selected program in a SIT packet. In addition,
These change processes may be performed by the host controller 5.

With the above configuration, the digital broadcast receiver shown in FIG. 2 selects and decodes the transport stream TS-a obtained from the broadcast signal and the transport stream TS-c input from the DSM. And a transport stream TS-b of one or more programs can be output to the DSM.

[0016]

By the way, in a broadcast signal, in addition to a video and audio signal, for example, conditional access information for enabling a scrambled broadcast signal to be received only by a specific receiver, There is information that must be constantly received and monitored even when the user is not actually watching the broadcast, such as an emergency broadcast signal (hereinafter referred to as essential information).
However, in the above-described conventional digital broadcast receiver, the stream selector 7 selects the transport stream TS-c input from the DSM, and
When the decoder is decoding, the above essential information cannot be monitored.

Therefore, for example, when viewing of the transport stream TS-a input from the DSM is completed and the user intends to view the transport stream TS-a obtained from the broadcast signal, the essential information can be received. Otherwise, if the essential information is limited reception information, a problem may occur that the program cannot be viewed. Assuming that such essential information is transmitted at predetermined time intervals, it means that a conditional access broadcast (scramble broadcast) cannot be received until the essential information is received next time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and without failing to receive essential information from a broadcast signal, for example, after viewing a transport stream from a DSM, a transport stream from the broadcast signal is converted. It is an object of the present invention to provide a digital broadcast receiver which does not cause a problem that a conditional access broadcast cannot be received even when viewing.

[0019]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, the present invention provides a digital broadcast receiver for receiving a digital broadcast. A packet output unit (6) for partially extracting a packet constituting a first transport stream obtained from an output of the reception demodulation unit; and a second transport stream and a second externally input packet. A stream selector (7) for selecting a transport stream, a demultiplexer (3) for demultiplexing the first or second transport stream selected by the stream selector, and an output of the demultiplexer. Decoder to decode (4)
And a storage unit (8) for storing the essential information extracted by the packet output unit when the stream selector is selecting the second transport stream, and the essential unit stored in the storage unit. And a means for supplying information to the demultiplexer.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A digital broadcast receiver according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing one embodiment of a digital broadcast receiver according to the present invention. In FIG. 1, the same portions as those in FIG. 2 are denoted by the same reference numerals, and description of the common portions may be omitted as appropriate.

In FIG. 1, a network interface module (NIM) 1 performs signal processing of a transmission system such as a tuner, digital demodulation, and error correction, and the output of the NIM 1 is a transport stream. The descrambler 2 descrambles a specific transport packet in the input transport stream according to an instruction from the host controller 5.

The transport stream TS-a of the broadcast signal output from the descrambler 2 includes compressed video / audio signals of a plurality of programs and additional information such as program names in FIG.
As described in (A), they are multiplexed in units of 188-byte transport packets.

The transport stream TS-a output from the descrambler 2 is input to an MPEG demultiplexer (hereinafter, demultiplexer) 3 via a PID filter 6 and a stream selector 7. The operation of the PID filter 6 will be described later. The transport stream TS-c input from the external DSM is also input to the demultiplexer 3 via the stream selector 7. The stream selector 7 is for selecting the transport stream TS-a output from the descrambler 2 and the transport stream TS-c input from the DSM and inputting them to the demultiplexer 3.

The demultiplexer 3 extracts PAT, PMT and the like included in the input transport stream TS, and, based on the information, in accordance with an instruction from the host controller 5, converts a video / audio stream related to a predetermined program. The port packet is specified and input to the MPEG decoder 4. The MPEG decoder 4 decodes the input video / audio stream, and outputs a video signal and an audio signal.

The specific structure and operation of the demultiplexer 3 in FIG. 1 are as described with reference to FIG.

When outputting the transport stream TS to the DSM, the PID filter 6 uses the program identification information obtained from the demultiplexer 3 together with the program selection information from the user, and the host controller 5.
Selects a transport packet of a video / audio stream related to one or a plurality of programs and outputs the transport packet as a transport stream TS-b. This processing can be considered as a part of the function of the demultiplexer 3. Therefore, using the function of the demultiplexer 3, the transport stream T
A configuration for outputting Sb is also possible.

In the transport stream TS-b, not only one program is selected, but also auxiliary information such as PSI is output at the same time. An example of the transport stream TS-b is as described with reference to FIG.

Further, in the digital broadcast receiver of the present invention, a memory 8 is connected to the PID filter 6, and the memory 8 stores the essential information. The stream selector 7 receives not only the transport stream TS-a obtained from the broadcast signal and the transport stream TS-c input from the DSM but also the content stored in the memory 8 via the PID filter 6. It has become.

In order to view the transport stream TS-c input from the DSM, the host controller 5
When the stream selector 7 selects the transport stream TS-c according to the instruction from the PID filter 6, the PID filter 6 extracts the specific packet including the above essential information and stores it in the memory 8. In addition, as this memory 8,
Any memory that can write and read data may be used.

For example, when the viewing of the transport stream TS-c input from the DSM is completed and the user wants to view the transport stream TS-a obtained from the broadcast signal, the stream selector 7 first sets , P
The output of the ID filter 6 is selected. The essential information stored in the memory 8 is input to the demultiplexer 3 via the PID filter 6 and the stream selector 7. afterwards,
The stream selector 7 inputs the transport stream TS-a obtained from the broadcast signal to the demultiplexer 3.

Thus, even if the switched transport stream TS-a is a conditional access broadcast (scrambled broadcast), the demultiplexer 3 can obtain essential information for enabling the conditional access broadcast to be receivable. it can. This essential information is input to the host controller 5, and the descrambler 2 descrambles according to an instruction from the host controller 5. As a result, the above problem does not occur.

With the above configuration, the digital broadcast receiver of the present invention shown in FIG. 1 selects the transport stream TS-a obtained from the broadcast signal and the transport stream TS-c input from the DSM. It can decode, and can output one or more program transport streams TS-b to the DSM. In addition, when viewing the transport stream TS-c input from the DSM, essential information such as limited reception information or an emergency broadcast signal transmitted from a broadcast signal is not missed.

In the present embodiment, the stream selector 7 has a DS
A transport stream TS-a obtained from a broadcast signal from the transport stream TS-c input from M
When the stream selector 7 selects the output of the PID filter 6 immediately before switching to
The essential information stored in the memory 8 is supplied to the demultiplexer 3. The present invention is not limited to this. If the configuration is such that the essential information stored in the memory 8 is directly supplied to the demultiplexer 3, the stream selector 7 outputs the transport stream TS- Both before and after switching from c to the transport stream TS-a obtained from the broadcast signal is possible. Before the stream selector 7 switches from the transport stream TS-c input from the DSM to the transport stream TS-a obtained from the broadcast signal, the essential information stored in the memory 8 is supplied to the demultiplexer 3. Desirably, the point in time at which the essential information stored in the memory 8 is supplied to the demultiplexer 3 may be appropriately set.

[0034]

As described in detail above, the digital broadcast receiver according to the present invention receives and demodulates a digital broadcast, and a first demodulation unit (NIM) obtained from the output of the reception demodulation unit. A packet output unit (PID filter) for partially extracting a packet constituting a transport stream
A stream selector for selecting a first transport stream and a second transport stream input from the outside, and demultiplexing the first or second transport stream selected by the stream selector. A demultiplexer, a decoder for decoding the output of the demultiplexer, a storage unit for storing the essential information extracted by the packet output unit when the stream selector selects the second transport stream, Means for supplying essential information accumulated in the accumulation unit to the demultiplexer.
Never miss essential information from broadcast signals.
For example, when viewing a transport stream from a broadcast signal after viewing a transport stream from a digital storage medium such as a digital VTR,
There is no problem that the limited reception broadcast cannot be received.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional example.

FIG. 3 is a diagram illustrating a transport stream.

FIG. 4 is a block diagram showing an example of a specific configuration of a demultiplexer 3 in FIGS. 1 and 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Network interface module (reception demodulation part) 2 Descrambler 3 MPEG demultiplexer 4 MPEG decoder 5 Host controller 6 PID filter (packet output part) 7 Stream selector 8 Memory (storage part)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 7/20

Claims (2)

[Claims] 1. A digital broadcast receiver for receiving a digital broadcast, comprising: a receiving / demodulating unit for receiving and demodulating a digital broadcast; and a packet constituting a first transport stream obtained from an output of the receiving / demodulating unit. A packet output unit for selectively extracting, a stream selector for selecting the first transport stream and a second transport stream input from the outside, and a first or second selected by the stream selector. A demultiplexer for demultiplexing the transport stream; a decoder for decoding the output of the demultiplexer; and the packet output unit extracting when the stream selector is selecting the second transport stream. A storage unit for storing essential information; and a storage unit for storing the essential information. Means for supplying the essential information to the demultiplexer. 2. A descrambler for descrambling an output of the reception demodulation unit, wherein the essential information is limited reception information necessary for the descrambler to descramble the output of the reception demodulation unit. The digital broadcast receiver according to claim 1, wherein: