JPH09182066A - Digital signal processor and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To input/output digital data as it is to the outside without decoding the reception signal of a digital broadcast. SOLUTION: A front end selects the transport stream of a desired channel from the RF signal transmitted from a down converter. A demultiplexer 2 separates the MPEG video data and MPEG audio data of a desired program and additional information from the transport stream. An MPEG video decoder 4 and an MPEG audio decoder 5 decodes the separated MPEG video data and MPEG audio data A digital interface 11 transmits and receives MPEG video data, MPEG audio data and additional information between the demultiplexer 2 and the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for receiving and decoding digital broadcasting, and more particularly to a process for inputting and outputting digital video signals and digital audio signals before decoding to an external recording / reproducing device or the like. It is a thing.

[0002]

2. Description of the Related Art In recent years, in the United States and European countries, MPE
G (Moving Picture Image Cod)
A system in which a video signal and an audio signal are encoded by applying a high efficiency encoding technique such as ing Experts Group), transmitted through a communication satellite or the like, and demodulated at the receiving side is becoming popular. .

These systems require a dedicated receiving / demodulating device on the receiving side. In this receiving / demodulating device, a portion for selecting a transport stream of a desired channel from a transport stream in which data of a plurality of channels are multiplexed, and video data and audio of a desired program from the transport stream of the desired channel. It has a part for separating the data and a part for decoding the separated video data and audio data.

Further, in this system, in order to enable the receiving / demodulating device to receive the transport stream of the desired channel and to separate the video data and the audio data of the desired program,
In the multiplexed transport stream, PSI (P
program Specific Information
on: Program specification information) and EPG (Electro)
ic Program Guide: Electronic Program Guide) or SI (Service Information)
(n: service information) is added.

[0005]

Video tape recorders (hereinafter referred to as DVCRs) for encoding and recording / reproducing video signals and audio signals have been commercialized. When recording / reproducing the received signal of the above-mentioned digital broadcast in such a DVCR, it is inefficient if the received video data and audio data are decoded and then encoded again in the DVCR and recorded. Decryption of /
The signal deteriorates during the encoding process.

The present invention has been made in view of the above circumstances, and a digital signal processing apparatus and a digital signal processing apparatus for inputting and outputting digital data as it is to the outside without decoding a received signal of a digital broadcast. The purpose is to provide a method.

[0007]

In order to solve the above-mentioned problems, a digital signal processing apparatus according to the present invention selects an arbitrary one-channel transport stream from multiplexed multiple-channel transport streams. 1 means, 2nd means for separating video data and audio data of an arbitrary program from this transport stream by referring to additional information in the selected transport stream, and 3rd means for decoding the separated data And a digital signal processing device comprising:
A fourth means for transmitting and receiving video data, audio data, and additional information between the second means and the outside is provided.

A digital signal processing method according to the present invention is the digital signal processing apparatus according to the present invention,
The processing of the additional information received from the fourth means is different from the processing of the additional information in the transport stream received from the first means.

According to the present invention, the video data before decoding and the audio data before decoding separated by the second means,
And the additional information in the transport stream can be transmitted to the outside via the fourth means. Further, these data and additional information inputted from the outside can be sent to the second means through the fourth means. Then, in the second means, processing different from the processing of the additional information input from the first means is performed on the additional information input from the outside.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a digital signal processing device to which the present invention is applied. This digital signal processor is an IRD (Integral)
This is called a "Rated Receiver Decoder".

This digital signal processing device receives an RF signal sent from a down converter (not shown) and selects a transport stream of a desired channel, and a front end 1 and a transformer selected by the front end 1. M of desired program from port stream
A demultiplexer 2 for separating PEG video data, MPEG audio data, and additional information, and a buffer memory 3 for temporarily storing data input / output through the demultiplexer 2 are provided.

Further, this digital signal processing device is an M which decodes the video data separated by the demultiplexer 2.
A PEG video decoder 4, an MPEG audio decoder 5 for decoding the audio data separated by the demultiplexer 2, and an NT for converting the video signal decoded by the MPEG video decoder 4 into an NTSC video signal.
The SC encoder 6, the D / A converter 7 that analogizes the output of the NTSC encoder 6, and the D / A converter 8 that analogizes the output of the MPEG audio decoder 5 are provided. The MPEG video decoder 4 is provided with a buffer memory 4a for temporarily storing video data, and the MPEG audio decoder 5 is provided with a buffer memory 5a for temporarily storing audio data.

Further, this digital signal processing apparatus has a microcomputer (hereinafter referred to as a microcomputer) 9 for controlling the operation of the entire apparatus, a front panel 10 and MPEG video data separated by a demultiplexer 2 and MPEG.
It has a digital interface 11 for transmitting audio data and additional information to the outside and for sending MPEG video data, MPEG audio data and additional information received from the outside to the demultiplexer 2.

The front end 1 is a tuner and QPSK
It is composed of a demodulator and an error correction circuit, and selects a transport stream of a desired channel designated by the user from the front panel 10 from the multiplexed transport streams of a plurality of channels, and Q is selected.
PSK demodulation and error detection / correction are performed.

FIG. 2 shows an example of a transport stream for one channel. As shown in this figure, a plurality of programs (here, program numbers 1 to 3 are shown) are multiplexed in the transport stream of one channel. Here, the program is a virtual broadcasting channel, and in the case of current broadcasting in Japan, for example, a broadcasting service such as NHK satellite No. 1 and NHK satellite No. 2 etc.

The data of each program has a predetermined length (18
It is packetized with 8 bytes) and has a header at the beginning. Then, in the header, a PID (Packet Identifier) for identifying the data
on: packet ID) is assigned.

From the transport stream of the desired channel selected by the front end 1, a packet containing additional information is temporarily written in the buffer memory 3 through the demultiplexer 2. Then, MPEG video data and MPEG audio data of a desired program are recognized and separated from this, and the video data is sent to the MPEG video decoder 4 and the audio data is sent to the MPEG audio decoder 5. In FIG. 2, program 2
The video data and audio data of are separated.

At the time of this separation, the PID (packet ID) given to the packet is checked. If it is a PID for identifying video data and audio data of a desired program, it is sent to the MPEG video decoder 4 and the MPEG audio decoder 5, respectively. FIG.
, The PID given to the video data of program number 2 is “xx”, and the PID given to the audio data is “yy”. A method of knowing the correspondence between the program number and the PID in the digital signal processing device will be described later.

The video data sent to the MPEG video decoder 4 is stored in the buffer memory 4a, appropriately read and decoded. Decoded video data is N
The video signal is converted into an NTSC video signal by the TSC encoder 6, converted into an analog video signal by the D / A converter 7, and then supplied to an external monitor device (not shown). Further, the audio data sent to the MPEG audio decoder 5 is stored in the buffer memory 5a, read out as appropriate, and decoded. The decoded audio data is converted into an analog audio signal by the D / A converter 8 and then supplied to a speaker (not shown) such as a monitor device.

As described above, the video signal and audio signal of the digital broadcast can be received, decoded and displayed on the monitor device.

Next, the additional information will be described. As described above, PSI may be included in the multiplexed bitstream.
(Program use information), EPG (electronic program guide) or SI (service information) is added. Here, PSI defined by MPEG and DVB (Digital Video Br), which is a digital broadcast in Europe, are used.
SI prescribed by the Oadcasting system
Will be described.

: PAT (Programmable Ass)
acquisition Table) This table is MPE
It is defined by G, and PID (packet ID) is 0. And the main contents are the PID of NIT, which will be described later,
This is a description of the PMT PID.

: PMT (Program Map
Table) This table is also defined by MPEG, and the PID is determined by the PAT described above. The main contents are a description of the correspondence between the program number and PID,
PID of ECM (scrambled data attached to the program)
Is a description of.

： CAT (Conditional A
access table) This table is also defined by MPEG, and the PID is 1. The main content is a description of EMM (scramble information for customers).

[0025]: NIT (Network Info)
mation table) PID is 0010. The main contents are a description of the network name (satellite name, terrestrial transmission station, etc.) and a description of the modulation method and frequency for each transport stream (physical channel).

The following table is specified by DVB. : BAT (Bouquet Association)
Table) PID is 0011. The main contents are the description of the bouquet (Bouquet: program supplier) and the destination country, and the transport stream (physical channel).
Content of services and CASS (Condition)
nal Access Service System
m) A description of the method.

[0027]: SDT (Service Descr)
Iption Table) PID is 0011. The main content of the transport stream (physical channel) is a description of the service ID and the name of the bouquet included in the service stream. Here, the service ID is NHK satellite 1st, NH
It is a broadcasting channel such as the second satellite of K satellite. That is, it is the same as the program number specified by MPEG.

[0028]: EIT (Event Information)
Tion Table) PID is 0012. The main content is a description of the event ID, its start time, broadcast time, program content, and the like. Then, a transport stream ID and a service ID are described for each event ID. Here, the event is, for example, “7 o'clock news (December 1
It is a program such as "broadcast for daily broadcast".

: TDT (Time and Data)
Table) PID is 0010. And the main content is the description of the information of the world standard time. Using this TDT, the time of a clock (not shown) in the apparatus can be adjusted.

RST (Running Status)
s Table) PID is 0013. The main content is a description of the execution status of the event. That is, the description such as before the start of a certain event, during the execution, and the end is described.

Next, how the microcomputer 9 in the digital signal processing device processes the PSI and SI described above will be described.

First, in the digital signal processing device,
Set the constants etc. according to the method of each network. Since this information is described in NIT, the modulation method, frequency, bit rate, error correction method, etc. can be obtained for each transport stream. After setting, these pieces of information are stored in the EEPROM (not shown) of the microcomputer 9.

Next, an event is searched using the EIT. A unique event ID is given to each broadcast event, the name and contents of the broadcast program are described in the EIT together with the start time, and the transport stream I for each event is recorded.
D and the service ID are described. Therefore, the transport stream ID is determined from the EIT, the digital signal processing device is set using the constant of the transport stream obtained by NIT, and the transport stream of the desired channel is selected.

The processing for selecting the transport stream of the desired channel in the front end 1 has been described above. Next, the output of the demultiplexer 2 is MPEG
The processing of the microcomputer 9 when sending to the video decoder 4 and the MPEG audio decoder 5 will be described.

FIG. 3 shows an example of the transport stream input to the demultiplexer 2 and PAT and P therein.
The contents of MT are shown. Further, FIG. 4 shows an example of the internal configuration of the buffer memory 3. FIG. 5 is a diagram showing the flow of this processing. Here, it is assumed that the program number 1 broadcast is selected.

First, as shown in step S1 of FIG. 5, the output of the front end 1 is written into the buffer memory 3 through the demultiplexer 2. The buffer memory 3 is shown in FIG.
Since the storage areas 3A to 3C are defined for each data as shown in, the data is written in each area.

Next, as shown in step S2, the PAT is searched from the additional information written in the additional information area 3C of the buffer memory 3. This processing may be performed by searching for a packet whose PID is 0. As shown in FIG. 3B, the PAT has a PID of the PMT for each program (here, PID of the PMT1).
(ID is "cc", PMT2 PID is "dd")
Is described.

Then, a packet with a PID of "cc" is searched for next. As a result, the PMT corresponding to program number 1
1 can be detected. As shown in FIG. 3 (3),
The PMT 1 describes the MPEG video data, MPEG audio data, and ECM PID of program number 1.

Therefore, when watching the program number 1, the packet with PID "aa" is read from the MPEG video data area 3A of the buffer memory 3 and sent to the MPEG video decoder 4 through the demultiplexer 2 to receive the MPEG audio data. A packet having a PID of "ab" is read from the area 3B and sent to the MPEG audio decoder 5 through the demultiplexer 2.
As shown in FIG. 2, at this time, only the data excluding the header is sent. Also, the scramble is decoded using the ECM information described in the packet with the PID of "xx".

If the program number 2 is to be viewed, the packet with PID "dd" is searched for in the same manner. In this packet, as shown in FIG. 3 (4), video data, audio data, and ECM of program number 2
PID is described. Therefore, the packet with the PID "ba" is read from the MPEG video data area 3A and sent to the MPEG video decoder 4, and the packet with the PID "bb" is read from the MPEG audio data area 3B and sent to the MPEG audio decoder 5.
In addition, E described in the packet whose PID is "zz"
Decode the scramble using the CM information.

The normal processing for decoding the transport stream input from the front end 1 has been described above. The digital signal processing device of FIG. 1 further includes MPEG video data M and M separated by the demultiplexer 2.
The PEG audio data and the additional information are transmitted via the digital interface 11 to an external recording / reproducing device such as D
It can be output to a VCR. In addition, the MPEG video data, the MPEG audio data, and the additional information output from the external recording / reproducing apparatus are transferred to the digital interface 1.
It can be received via 1 and sent to the demultiplexer 2. Next, these processes will be described.

First, the processing for sending the output of the demultiplexer 2 from the digital interface 11 to the outside will be described. Since most of this processing is the same as the normal processing described above, only different points will be described.

The MPEG video data and MPEG audio data are sent to the digital interface 11 with the packet header attached. That is, when the microcomputer 9 reads from the buffer memory 3, the header is read and the digital interface 11 is read through the demultiplexer 2.
Send to

The PSI and SI are also sent to the digital interface 11 with the header attached. However, the PAT leaves only the PID designating the PMT of the selected program number and removes the others. For example, when the program number 1 is selected, only the PID of PMT 1 (“cc” in the case of FIG. 3) is left and the others are removed.

In this way, the digital interface 1
The data sent to 1 is sent out from here. The digital interface 11 is, for example, IEEE-139.
4 is compliant. In this case, the data is IEEE
-Output in a 1394 isochronous packet. The isochronous packet output from the digital interface 11 is sent to an external DVCR or the like. Then, here, data is extracted from the isochronous packet, added with an error correction code in the recording system, subjected to channel coding processing, and then recorded.

Next, the processing for sending an external input from the digital interface 11 to the demultiplexer 2 will be described. The isochronous packet input to the digital interface 11 from the outside is the original MPE
The G video data, the MPEG audio data, and the additional information are extracted and written into the buffer memory 3 through the demultiplexer 2.

MPEG written in the buffer memory 3
The processing of video data and MPEG audio data is
This is the same as the processing of these data in the transport stream input from the front end 1 described above. On the other hand, the PSI and SI written in the buffer memory 3 are processed as follows.

The PAT and PMT are used as they are. As described above, the digital signal processor is connected to the external DVCR.
When outputting data to the PAT, only the PID designating the PMT of the program number selected from the PAT is left and the others are removed. Therefore, the PAT in the data input from the external DVCR is being input to the PAT. Only the PID designating the PMT of the program number is described. Therefore, P
It is possible to look for the PMT by looking at the AT, and read the PMT to read the MPEG video data and the MPEG audio data of the program being input. Read MPEG
The video data and the MPEG audio data pass through the demultiplexer 2 and the MPEG video decoder 4 and M
The data is sent to the PEG audio decoder 5 and thereafter processed in the same manner as these data from the front end 1.

Regarding EIT, only the information of the actual and present of the program described in PAT is decoded,
Ignore the others. Here, “actual” means a transport stream of the selected channel, and “present” means that the selected program is currently being broadcast.

Regarding RST, only those relating to the program described in PAT are decoded, and the others are ignored. Regarding SDT, only the actual one of the program described in PAT is decoded, and the others are ignored.

The NIT is necessary for the setting in the front end 1, but is not necessary in the demultiplexer 2 and is ignored. Similarly, BAT is ignored.

Regarding the TDT, when the reproduction signal of the external recording / reproducing apparatus is input, the TDT in the reproduction signal of the recording / reproducing apparatus indicates the time at the time of recording and indicates the current time. Therefore, this TDT is ignored.
When the input signal from the outside is not the reproduction signal of the recording / reproducing apparatus and the TDT indicates the present time, the TDT is decoded. That is, the process is changed depending on whether or not it indicates the current time. Therefore, it is preferable to add information indicating whether or not the time of TDT is the present time to the input signal from the outside.
As a result, it is possible to avoid a situation where the internal clock is set to the wrong time when the time is set.

In the above description, the demultiplexer 2
The description has been made assuming that one program transmits MPEG video data and MPEG audio data to the outside. However, if the external DVCR has a recording rate capable of recording a plurality of programs, a plurality of programs are transmitted. It may be configured as follows.

[0054]

As described above in detail, according to the present invention, video data before decoding, audio data before decoding, and additional information can be transmitted / received to / from the outside. Therefore, the external recording / reproducing apparatus can efficiently record / reproduce these data and additional information without deterioration.

Further, with respect to the additional information input from the outside, a process different from the process of the additional information in the received transport stream can be performed. For example, additional information unrelated to the video data and audio data of the program input from the outside is ignored. As a result, it is possible to avoid a situation in which the program guide regarding a program that is not input from the outside is erroneously displayed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a digital signal processing device to which the present invention has been applied.

[Fig. 2] Fig. 2 is a diagram illustrating an example of a transport stream for one channel.

FIG. 3 is a diagram showing an example of a transport stream input to a demultiplexer and the contents of PAT and PMT therein.

FIG. 4 is a diagram showing an internal configuration example of a buffer memory 3 in FIG.

FIG. 5 is a diagram showing a processing flow of a microcomputer when sending an output of a demultiplexer to an MPEG video decoder and an MPEG audio decoder.

[Explanation of symbols]

1 ... Front end, 2 ... Demultiplexer, 4 ... MP
EG video decoder, 5 ... MPEG audio decoder, 9 ... Microcomputer, 11 ... Digital interface

Claims (2)

[Claims] 1. A first means for selecting a transport stream of any one channel from a multiplexed transport stream of a plurality of channels, and the transport with reference to additional information in the selected transport stream. A digital signal processing device comprising: a second means for separating video data and audio data of an arbitrary program from a stream; and a third means for decoding the separated video data and audio data. 2. A digital signal processing device, characterized by comprising: a fourth means for transmitting / receiving video data, audio data, and additional information between the second means and the outside. 2. A first means for selecting a transport stream of any one channel from a multiplexed transport stream of a plurality of channels, and the transport with reference to additional information in the selected transport stream. Second means for separating video data and audio data of an arbitrary program from a stream, third means for decoding the separated data, and video data and audio data between the second means and the outside. ,
And a fourth means for transmitting and receiving additional information, wherein the second means receives the processing of the additional information received from the fourth means from the first means. A digital signal processing method characterized by being different from information processing.