JP3125786B2 - Electronic equipment and signal processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device and a signal processing method, and more particularly, to an electronic device and a method for inputting and decoding undecoded video data and audio data from an external recording / reproducing device. The present invention relates to a signal processing method.

[0002]

2. Description of the Related Art In recent years, in the United States and European countries, MPE
A system in which a video signal and an audio signal are encoded by applying a high-efficiency encoding technology such as G (Moving Picture Image Coding Experts Group), transmitted via a communication satellite or the like, and demodulated on the receiving side. Is spreading.

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

In this system, a receiving / demodulating device is required to receive the above-mentioned transport stream of a desired channel and to separate video data and audio data of a desired program.
PSI (Pr) is included in the multiplexed transport stream.
ogram Spesific Information: EPG (Electronic Program Guide)
Or SI (Service Information)
Is added.

[0005]

A video tape recorder (hereinafter referred to as DVTR) for encoding and recording / reproducing a video signal and an audio signal has been proposed. It has been considered that such a DVTR is recorded / reproduced without decoding the above-described digital broadcast video data and audio data (Yukio Kubota, “Illustrated Digital Video Reader”, pp.140-152, (Ohm Co., Ltd., August 25, 1995).

According to the present invention, when a DVTR as described above continuously reproduces a plurality of digital broadcasting programs and inputs the programs to the above-mentioned receiving / demodulating device, the DVTR receives and demodulates even if the program changes or is discontinuous. It is an object of the present invention to provide an electronic device and a signal processing method that can quickly perform a decoding operation of video data and audio data in a device and that does not interrupt decoding output.

[0007]

According to another aspect of the present invention, there is provided an electronic apparatus capable of receiving a transport stream from another apparatus via a digital interface. Detecting means for detecting whether or not discontinuous information is included in the additional information in the transport stream received via the interface; and detecting the additional information in the transport stream when the discontinuous information is detected. information,
Control means for controlling so as to write the data in a memory attached to the separation means for separating the transport stream.

A signal processing method according to the present invention is a signal processing method for an electronic device capable of receiving a transport stream from another device via a digital interface, wherein the signal is received via the digital interface. It is detected whether or not the discontinuous information is included in the additional information in the transport stream to be transmitted. When the discontinuous information is detected, the additional information in the transport stream is separated from the transport stream. The present invention is characterized in that control is performed so as to write data into a memory attached to the separating means.

According to the present invention, when information indicating discontinuity of a program is detected, additional information in a transport stream is captured.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an electronic apparatus and a signal processing method according to the present invention will be described 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 processing device is called an IRD (Integrated Receiver Decoder).

This digital signal processing apparatus receives a RF signal sent from a down converter (not shown), and selects a transport stream of a desired channel from 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 is provided, and a buffer memory 3 for temporarily storing data input / output through the demultiplexer 2.

The digital signal processing device decodes the video data separated by the demultiplexer 2.
A PEG video decoder 4; an MPEG audio decoder 5 for decoding audio data separated by the demultiplexer 2; and an NT for converting a video signal decoded by the MPEG video decoder 4 into an NTSC video signal.
It comprises an SC encoder 6, a D / A converter 7 for converting the output of the NTSC encoder 6 into an analog signal, and a D / A converter 8 for converting the output of the MPEG audio decoder 5 into an analog signal. 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, MPEG video data separated by the 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 includes a tuner and a QPSK.
It comprises a demodulator and an error correction circuit, and selects a transport stream of a desired channel specified by the user on the front panel 10 from the multiplexed transport streams of a plurality of channels, and
SK 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 multiplexed) are multiplexed in a transport stream of one channel. Here, the program is a virtual broadcasting channel, which is, for example, a broadcasting service of NHK satellite No. 1, NHK satellite No. 2, etc. in the current broadcasting in Japan.

The data of each program has a predetermined length (18
8 bytes) and has a header at the beginning. The header includes a PID (Packet Identification) for identifying data.
Is given.

The transport stream of the desired channel selected by the front end 1 is temporarily written to the buffer memory 3 through the demultiplexer 2. Then, the MPEG video data and the MPEG audio data of the desired program are read and separated therefrom, 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, video data and audio data of the program 2 are separated.

At the time of this separation, the PID (packet ID) assigned to the packet is checked. Then, 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.
In, the PID assigned to the video data of the program 2 is “xx”, and the PID assigned 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 a buffer memory 4a, and is read and decoded as appropriate. The decoded video data is N
After being converted into an NTSC video signal by the TSC encoder 6 and converted into an analog video signal by the D / A converter 7, it is supplied to an external monitor device (not shown). The audio data sent to the MPEG audio decoder 5 is stored in the buffer memory 5a, and is appropriately read 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 digital broadcast video signal and audio signal can be received, decoded, and displayed on the monitor device.

Next, the additional information will be described. As described above, PSI is included in the multiplexed bit stream.
(Program use information), EPG (electronic program guide) or SI (service information). Here, a description will be given of PSI specified by MPEG and SI specified by DVB (Digital Video Broadcasting) system which is a digital broadcast in Europe.

: PAT (Programme Association Tabl)
e) This table is specified by MPEG, and the PID (packet ID) is 0. The main contents are the description of the PID of the NIT and the PID of the PMT, which will be described later.

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

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

: NIT (Network Information Tabl)
e) The PID is 0010. The main contents are a description of a network name (satellite name, terrestrial transmission station, etc.) and a description of a modulation method and a frequency for each transport stream (physical channel).

The following table is defined in DVB.

: BAT (Bouquet Association Tabl)
e) The PID is 0011. The main contents are the name of Bouquet (program supplier) and a description of the destination country, the contents of services related to transport streams (physical channels), and CASS (Conditional Access Server).
ce System) method.

: SDT (Service Description Tabl)
e) The PID is 0011. The main content is a description of a transport stream (physical channel) such as a service ID included therein and a name of a bouquet thereof. Here, the service ID is NHK satellite first, NH
It is a broadcasting channel such as the K satellite second. That is, it is the same as the program number specified in MPEG.

: EIT (Event Information Table) The PID is 0012. The main contents are the description of the event ID, its start time, broadcast time, program contents, 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 (Dec.
Day broadcast)).

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

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

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

First, in the digital signal processing device,
Settings such as constants are made according to the method of each network. Since this information is described in the NIT, a modulation method, a frequency, a bit rate, an error correction method, and the like can be obtained for each transport stream. After the setting, the information is stored in an EEPROM (not shown) of the microcomputer 9.

Next, an event is searched using the EIT. Each broadcast event is provided with a unique event ID, and the name and contents of the broadcast program are described in the EIT together with the start time.
D and a service ID are described. Therefore, the transport stream ID is determined from the EIT, the digital signal processing device is set using the transport stream constant obtained in the NIT, and the transport stream of the desired channel is selected.

The processing for selecting a transport stream of a 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 the video data to the video decoder 4 and the MPEG audio decoder 5 will be described.

FIG. 3 shows an example of a transport stream input to the demultiplexer 2 and PAT and P in the transport stream.
Shows the contents of MT. 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, description will be made assuming that the broadcast of program number 1 is selected.

First, as shown in step S 1 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 FIG.

Next, as shown in step S2, a PAT is searched for from the additional information written in the additional information area 3C of the buffer memory 3. In this process, a packet having a PID of 0 may be searched for. As shown in FIG. 3 (2), the PAT contains the PID of the PMT for each program (here, the PMT of the PMT1).
(ID is “cc” and PMT2 PID is “dd”)
Is described.

Then, a packet whose PID is "cc" is searched. Thus, the PMT corresponding to program number 1
1 can be detected. As shown in FIG.
PMT1 describes MPEG video data, MPEG audio data of program number 1, and PID of ECM.

Therefore, when watching the broadcast of program number 1, the packet whose PID is "aa" is read from the MPEG video data area 3A of the buffer memory 3, sent to the MPEG video decoder 4 through the demultiplexer 2, and the MPEG audio data The packet with the PID “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. Further, the scramble is decoded using the ECM information described in the packet with the PID “xx”.

If a broadcast of program number 2 is to be watched, a packet having a PID of "dd" is similarly searched. As shown in FIG. 3D, the packet includes video data, audio data, and ECM of program number 2.
Is described. Therefore, a packet whose PID is "ba" is read from the MPEG video data area 3A and sent to the MPEG video decoder 4, and a packet whose PID is "bb" is read from the MPEG audio data area 3B and sent to the MPEG audio decoder 5.
Also, the E described in the packet whose PID is “zz”
The scramble is decoded 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 shown in FIG. 1 further includes MPEG video data M
PEG audio data and additional information are transferred to an external recording / reproducing device,
It can be output to a VTR. Also, MPEG video data, MPEG audio data, and additional information output from an external recording / reproducing device are transferred to the digital interface 1.
1 and sent to the demultiplexer 2. Next, these processes will be described.

First, the microcomputer 9 transmits 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 above-described normal processing, only different points will be described.

The MPEG video data and the 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 9 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 program number 1 is selected, only the PID of PMT1 (“cc” in the case of FIG. 3) is left, and the others are removed.

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

Next, the case where the data recorded on the DVTR as described above is reproduced and input to the digital signal processing device will be described. The external DVTR outputs the reproduced data in an isochronous packet. This isochronous packet is input to the digital interface 11, where the original MPEG video data, MPE
G video data and additional information are extracted and written to the buffer memory 3 through the demultiplexer 2.

MPEG written in buffer memory 3
Processing video data and MPEG audio data
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 microcomputer 9 processes PSI and SI written in the buffer memory 3 as follows.

The PAT and PMT are used as they are. As described above, an external DVTR is output from the digital signal processing device.
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, so the PAT in the data input from the external DVTR is Only the PID designating the PMT of the program number is described. Therefore, P
By looking at the AT, a PMT is searched, and by looking at the PMT, MPEG video data and MPEG audio data of the program being input can be read. MPEG read out
The video data and the MPEG audio data are passed through a demultiplexer 2 to the MPEG video decoders 4 and M
The data is sent to the PEG audio decoder 5 and thereafter processed similarly to these data from the front end 1.

With respect to the EIT, only the actual and present information of the program described in the PAT is decoded, and the other information is ignored. Here, “actual” means that it is a transport stream of the selected channel, and “present” means that the selected program is currently being broadcast.

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

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

Regarding the TDT, when a reproduction signal from an external DVTR is input, the TDT in the reproduction signal indicates the time at the time of recording and does not indicate the current time. ignore. As a result, it is possible to avoid a situation where the internal clock is set to an incorrect time when setting the time.

Further, a case where a plurality of programs are continuously input from an external DVTR will be described. As described above, the microcomputer 9 searches the PAT for the PMT, and reads the MPEG video data and the MPEG audio data of the program being input from the external DVTR by looking at the PMT. However, when the external DVTR is continuously outputting a plurality of programs, the microcomputer 9
When the program is switched, the PAT is searched for a new PAT, and the MPEG of the switched program is searched.
Video data and MPEG audio data cannot be read. Further, in the MPEG video decoder 4 and the MPEG audio decoder 5, since the past data is used for the decoding process, when the program is switched, the data of the program before switching remaining in the buffer memories 4a and 5a is replaced. If it is not cleared, correct decoding cannot be performed.

Similarly, when the SI is switched to a program with a different transport stream, it is necessary to rewrite the SI in the buffer memory 3.

Therefore, in the present embodiment, when the program being reproduced by the DVTR changes, a flag is provided in the header of the isochronous packet to identify the change. FIG. 6 is a diagram showing a format of an isochronous packet. 2 bits of the tag (tag) field are 0
When 1 _2, common isochronous packet header of 2 Kuadoretto the head of the data field (hereinafter CI
P header). For the purpose of dealing with real time data in a digital audio video signal, such as digital video equipment and digital audio equipment, the value of the tag 01 _2.

[0058] CI if 7 takes a value tag = 01 ₂
Indicates a P header. FIG. 8 shows an example of allocation of FMT (format type) in the CIP header.
As shown in FIG. 6, DVT at FMT = 0000000 ₂
In R, 100001 ₂ specifies the format of the MPEG signal transmission. In this embodiment, the FDF
A discontinuity flag is provided in bit b0 of (format dependent field).

The discontinuity flag is set to the “H (high)” level for a predetermined time (for example, one second) when the transport stream becomes discontinuous in the DVTR reproduction signal. Specifically, when recording video data in a DVTR, the recording start position (REC STAR
T) and video ancillary data (VA) indicating the end position (REC END)
UX data), the discontinuity flag is set to “H (high)” when these auxiliary data are detected during playback.
To level.

In the present embodiment, when the mode of the DVTR changes from stop (STOP) to playback (PB),
The aforementioned discontinuity flag is set to “H (high)” level.
Thereby, even when the program is reproduced from the middle of the program, the data in the buffer memories 4a and 5a can be cleared and the SI in the buffer memory 3 can be rewritten.

Further, in this embodiment, a variable speed reproduction flag is provided at bit b1 of the FDF. This is DVT
This flag is set to the “H (high)” level when the operation mode of R is slow and cue / review. At the time of such variable speed playback, only the MPEG I picture becomes valid data, so that the buffer memory 4a underflows, and as a result, the output of the MPEG video decoder 4 is interrupted until the next I picture is decoded. Would. Therefore, the digital signal processing device is configured such that, when this flag is detected, the last decoded I picture is output from the MPEG video decoder 4 until the next I picture is input.

FIG. 9 is a flowchart showing the processing of the microcomputer 9 at the time of external input. First, the microcomputer 9 determines whether the input is an external input (step S11). Whether the input is an external input is determined based on the output of the front panel 10.

Next, it is determined whether or not a discontinuity flag has been detected (step S12). This determination is made based on whether the digital interface 11 has detected the discontinuity flag shown in FIG. If the discontinuity flag is detected, the PAT, PMT, and SI in the buffer memory 3 are rewritten, and an instruction to clear the data in the buffer memories 4a and 5a is issued to the MPEG video decoder 4.
And to the MPEG audio decoder 5 (step S13). That is, when a discontinuity flag is detected, PA, which is additional information in the transport stream,
T, PMT, and SI are fetched and buffer memory 3
Has been rewritten.

Next, it is determined whether or not the variable speed reproduction flag has been detected (step S14). This determination is made based on whether or not the digital interface 11 has detected the variable speed reproduction flag shown in FIG. 7, as in step S12.
If the variable speed reproduction flag has been detected, the MPEG video decoder 4 is instructed to continue outputting the last decoded I picture.

[0065]

As described above in detail, according to the present invention, discontinuity information is included in additional information in a transport stream received from another device via a digital interface. If the discontinuous information is detected, additional information in the transport stream is fetched to decode video data and audio data when an externally input program changes. The decoding can be performed quickly, and the decoded output is not interrupted.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating an example of a transport stream for one channel.

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

FIG. 4 is a diagram showing an example of the internal configuration of a buffer memory 3 in FIG. 1;

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.

FIG. 6 is a diagram showing a format of an isochronous packet.

7 is a diagram showing a CIP header when taking tag = 01 ₂ values.

FIG. 8 is a diagram showing an example of allocation of FMT (format type) in a CIP header.

FIG. 9 is a flowchart showing a process of the microcomputer at the time of external input.

[Explanation of symbols]

1 front end, 2 demultiplexer, 4
MPEG video decoder, 5 MPEG audio decoder, 9 microcomputer, 11 digital interface

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-132916 (JP, A) JP-A-58-85685 (JP, A) JP-A-7-162832 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H04N 5/44 H04N 5/91-5/956 H04N 7 / 08,7 / 801 H04N 7/24 H04L 29/06

Claims (2)

(57) [Claims] An electronic device capable of receiving a transport stream from another device via a digital interface, wherein discontinuous information is included in additional information in the transport stream received via the digital interface. Detecting means for detecting whether or not the information is included; and detecting the additional information in the transport stream when the discontinuous information is detected.
Write to the memory associated with the separation means that separates the
An electronic device comprising: a control unit that performs control as described above. 2. A signal processing method for an electronic device capable of receiving a transport stream from another device via a digital interface, wherein the additional information in the transport stream received via the digital interface is provided. To detect whether or not discontinuous information is included in the transport stream. If the discontinuous information is detected, additional information in the transport stream is transmitted to the transport stream.
Write to the memory associated with the separation means that separates the
A signal processing method characterized by performing control as described above.