Denomination of invention: digital signal processing appts and processing method thereof
Embodiment
Referring now to accompanying drawing, the present invention is described in more detail.
Fig. 1 is the block diagram that the structure of digital signal processor of the present invention has been used in expression.This digital signal processor is called as IRD (integrated receiver decoder).
This digital signal processor comprises that input is by low-converter (not shown) RF signal that transmits and the front end of selecting corresponding to the transmission stream of required channel 1, the demultiplexer 2 of MPEG video data, mpeg audio data and the auxiliary data of the required programs that separation is selected by front end 1, and the buffer storage 3 of temporary data through demultiplexer 2 input and output.
This digital signal processor also comprises the MPEG video decoder 4 of the video data that decoding is separated by demultiplexer 2, the mpeg audio decoder 5 of the voice data that decoding is separated by demultiplexer 2, the NTSC encoder 6 that is become the vision signal of NTSC form by the video signal conversion of MPEG video decoder 4 decodings, the output transform of NTSC encoder 6 is become the D/A converter 7 of analog format and the D/A converter 8 that the output transform of mpeg audio decoder 5 is become analog format.Provide the buffer storage 4a of temporary video data to MPEG video decoder 4, the buffer storage 5a of temporary voice data is provided to mpeg audio decoder 5.
This digital signal processor also comprises the microcomputer 9 of whole operations of controlling this processor, control panel 10, and digital interface 11,11 of this digital interfaces are sent to external equipment by demultiplexer 2 isolated M PEG video datas, mpeg audio data and auxiliary data, or the MPEG video data, mpeg audio data and the auxiliary data that receive from external equipment are sent to demultiplexer 2.
Front end 1 comprises tuner, qpsk demodulator and error correction circuit, and it is selected the user to utilize transmission stream, the execution QPSK of the required channel of control panel 10 appointments to separate to be in harmonious proportion from the transmission stream that comprises a plurality of multiplexer channels and carries out error detection/correction.
Fig. 2 represents the example corresponding to the transmission stream of a channel.As shown in the drawing, a plurality of programs (representing with program 1 to 3) at this in this transmission stream by multiplexed.At this, the term program refers to imaginary broadcast channel.In the broadcasting of current Japanese, this is for example corresponding to such as NHK satellite channel 1 and 2 such business.
The data of each program are according to the packet grouping of predetermined length (188 byte), and the beginning of each packet has title.PID (package identification) data are assigned to title, so that identification data.
By demultiplexer 2 packet that comprises from the auxiliary data that flows corresponding to the transmission of the required channel of being selected by front end 1 temporarily is written in the buffer storage 3.Identify and be separated in MPEG video data and mpeg audio data in the required programs then, video data is sent to MPEG video decoder 4, voice data is sent to mpeg audio decoder 5.In Fig. 2, video data and voice data in the program 2 are separated.
When carrying out this separation, the PID (packet ID) that distributes to packet is checked, when PID has identified the video data of required programs and voice data, just these data are sent to MPEG video decoder 4 and mpeg audio decoder 5 respectively.In Fig. 2, the PID that distributes to the video data of program 2 is " xx ", and the PID that distributes to the voice data of program 2 is " yy ".Below will be described in the method that is used for setting up the corresponding relation between program code and the PID in this digital signal processor.
The video data that sends MPEG video decoder 4 to is stored in the buffer storage 4a, and is read out at a convenient time with decoded.Decoded video data is for conversion into the NTSC signaling mode by NTSC converter 6, and after being for conversion into analog video data by D/A converter 7, it is provided for the external monitor (not shown).The voice data that sends mpeg audio decoder 5 to is stored in the buffer storage 5a, and is read out at a convenient time with decoded.After decoded voice data was for conversion into simulated audio signal by D/A converter 8, it was provided for the loudspeaker (not shown) of monitor.
So, just receive, decipher and on monitor, shown the vision signal and the audio signal of digital broadcasting.
Auxiliary data is below described.As mentioned above, add PSI (program specialized information), EPG (electronic program guides) or SI (information on services) for multiplexed bit stream.Explanation now adopt in Europe by the PSI of mpeg compliant with by the SI of DVB (digital video broadcasting) regulation.
(1) PAT (program correlation table)
This table is by mpeg compliant.PID (digital packets ID) is 0.The PID of the NIT of following explanation to the effect that of this table and the PID of PMT.
(2) PMT (Program Map Table)
This table is by mpeg compliant.PID is determined by above-mentioned PAT.This table provides the correspondence between program code and the PID, and the PID of ECM (additional scramble data to program).
(3) CAT (the access table of having ready conditions)
This table is by mpeg compliant.PID is 1.The EMM to the effect that of this table (user's scramble information)
(4) NIT (network information table)
PID is 0010.The network name to the effect that of this table (satellite name, ground wave launcher etc.) and with transmit stream (physical channel) relevant modulation scheme or frequency
Following table is stipulated by DVB.
(5) BAT (mannerism correlation table)
PID is 0011.The service details and CASS (Conditional Access service system) method of the title (program provider) of the mannerism to the effect that (bouquet) of this table and the title of destination country, transmission stream (physical channel).
(6) SDT (Service Description table)
PID is 0011.Main contents relate to and transmit stream (physical channel), transmit the service ID that comprises in the stream and the title of mannerism.In the present invention, service ID is such as the such broadcast channel of NHK satellite 1 and NHK satellite 2.Therefore, with identical by the program code of mpeg compliant.
(7) EIT (Event Information Table)
PID is 0012.To the effect that event id, their time started, airtime and program details.Each event id is specified transmission stream ID and service ID.An incident for example can refer to " 7 news in the morning (December 1) ".
(8) TDT (TDT Time and Date Table)
PID is 0010.The information of to the effect that relevant Greenwich mean time.The content clock (not shown) of processor utilizes this TDT to set.
(9) RST (Running Status Table)
PID is 0013.To the effect that about carrying out the information of incident, before promptly incident begins, its term of execution and information after it finishes.
To illustrate below how the microcomputer 9 in this digital information processor handles above-mentioned PSI and SI.
At first, in digital signal processor, set constant and other parameter in conjunction with variety of network systems.This information is written in the network information table goes, network information table has been determined modulation scheme, frequency, bit rate and error correction method for transmitting stream thus.After setting, this storage in the EEPROM of microcomputer 9 (not shown).
Search events from EIT then.In EIT, distribute unique event id for each broadcast event, programm name is written into content and their time started, writes for each incident and transmits stream ID and service ID.Distinguish transmission stream ID according to EIT, utilize the transmission stream constant that comprises in the NIT that digital signal processor is set, just selected transmission stream thus corresponding to required channel.
The above is the processing that is performed when the transmission of required channel stream is selected in front end 1.The processing that microcomputer is performed below is described when the output of demultiplexer 2 is transmitted to MPEG video decoder 4 and mpeg audio decoder 5.
Fig. 3 represents to input to an example and the PAT in this transmissions is flowed and the content of PMT of the transmission stream of demultiplexer 2.Fig. 4 represents the internal structure of buffer storage 3.Fig. 5 represents the flow process of this processing.Following description is at program 1 selecteed situation.
At first, in the step S1 of Fig. 5, by demultiplexer 2 output of front end 1 is written in the buffer storage 3 and goes.In buffer storage 3, the memory block 3A-3C that has been each data definition as illustrated in fig. 4, data of different types is written into these districts.
Then, in step S2, from the auxiliary data of the ancillary data area 3C that is written into buffer storage 3, search for PAT.In order to carry out this processing, can search for PID and be 0 packet.Shown in Fig. 3 (2), the PID of the PMT of each program (at this, the PID of PMT1 is " cc ", and the PID of PMT2 is " dd ") is write among the PAT and goes.
Search for the packet of PID then for " cc ".So just detect PMT1 corresponding to program 1.Shown in Fig. 3 (3), the PID of the ECM of MPEG video data, mpeg audio data and program 1 is written into PMT1.
Therefore, in order to watch program 1, just from the MPEG video data district 3A of buffering memory 3, read PID and it is sent to MPEG video decoder 4, from the 3B of mpeg audio data field, read PID and it is sent to mpeg audio decoder 5 for the packet of " ab " and by demultiplexer 2 for the packet of " aa " and by demultiplexer 2.In this course, send not data as illustrated in fig. 2 with title.Also utilize the ECM information that is written in the packet that PID is " xx " to decipher scramble.
In order to watch program 2, PID is the packet of " dd " according to the same manner search.In this packet, the PID of video data, voice data and ECM is written into shown in Fig. 3 (4).From the MPEG video data district 3A of buffering memory 3, read PID and send MPEG video decoder 4 to, from the 3B of mpeg audio data field, read PID and send mpeg audio decoder 5 to for the packet of " bb " and with it for the packet of " ba " and with it.Also utilize the ECM information that is written in the packet that PID is " zz " to decipher scramble.
Above description is flowed common process performed when decoded at the transmission of importing when front end 1.The digital signal processor of Fig. 1 can also be by digital interface 11 being exported to such record/playback device such as DVCR by demultiplexer 2 isolated M PEG video datas, mpeg audio data and auxiliary data.In addition, this processor can also utilize digital interface 11 to receive MPEG video data, mpeg audio data and the auxiliary data of being exported by external record/reproducing device.This processing is described now.
At first, the processing that the output of demultiplexer 2 is sent to the microcomputer 9 of external equipment from digital interface 11 is described.Because the major part of this processing is identical with above-mentioned common process, so at this difference will only be described.
MPEG video data and mpeg audio data are transmitted to digital interface 11 with packet header.In other words, when microcomputer 9 was read from buffering memory 3, it read each title data, and by demultiplexer 2 it is sent to digital interface 11.
PSI and SI also are transmitted to digital interface 11 with title.But PAT only stays the PID by the PMT regulation with selected program code, deletion remainder.For example, when program 1 is selected, have only the PID (being " cc " under the situation of Fig. 3) of PMT1 to stay, remainder is deleted.
The data that send digital interface 11 to are transmitted to external equipment.This digital interface is for example based on IEEE-1394, and in this case, data were inserted into before it is output in the asynchronous data packets that meets IEEE-1394.The asynchronous data packets of digital interface 11 outputs is transmitted to outside DVCR etc.From this asynchronous data packets, extract data then, in register system, increase error correction coding, after data have been carried out chnnel coding just with its record.
Below describing resets in the manner described above is recorded in the data among the DVCR and it is inputed to the situation of digital signal processor.Outside DVCR inputs to replay data the asynchronous data packets that is output.This asynchronous data packets is transfused to digital interface 11, extracts original MPEG video data, mpeg audio data and auxiliary data, and by demultiplexer 2 these data is written to buffer storage.
The processing that is written into the MPEG video data of buffer storage 3 and mpeg audio data is identical with the processing of above-mentioned data from the transmission stream of front end 1 input.On the contrary, microcomputer 9 is handled the PSI and the SI of write buffering memory 3 as described below.
Do not make to change ground and use PAT and PMT.As mentioned above, when data when digital signal processor exports outside DVCR to, have only the PID that has stipulated corresponding to the PMT of the program code of selecting according to PAT to be left, remainder data is deleted, therefore, having only the PID of the PMT that has stipulated the current program code that is being transfused to be written among the PAT in the data of outside DVCR input goes.Therefore, by checking this PAT search PMT, MPEG video data and the mpeg audio data that just can read the current program that is being transfused to.MPEG video data that is read out and mpeg audio data send MPEG video decoder 4 and mpeg audio decoder 5 to by demultiplexer 2, are carried out processing according to the mode identical with the mode that the data of being imported by front end 1 are handled then.
As for EIT, only reality in being written into the program of PAT or current data are decoded, and remainder data is left in the basket.Term herein " reality " refers to the transmission stream in selected channel, and " current " refers to that selected program is being broadcasted this fact.
As for RST, have only the element relevant decoded with the program that is written into PAT, remainder is left in the basket.As for SDT, only the actual element in being written into the program of PAT is decoded, and remainder is left in the basket.
Need NIT that front end 1 is set, still, owing in demultiplexer 2, do not need it, so it is ignored.BAT also is left in the basket.
As for TDT, when input during from the replay signal of external record/reproducing device, the TDT in this replay signal of this equipment represents the time that videograph was performed at that time, be not the current time, so TDT also is left in the basket.When the input signal from external equipment was not replay signal, TDT just represented the current time, to its decoding.In other words, whether represent the current time according to TDT, processing is inequality.Therefore, if whether represent that the data of current time will be easily for input signal increase expression TDT from external equipment.So just avoided when resetting internal clocking, setting the wrong time.
The situation of a plurality of programs is imported in explanation now continuously from outside DVCR.Microcomputer 9 checks that PAT searches for PMT, and by checking that PMT reads out in MPEG video data and the voice data in the program of being imported by outside DVCR.But when this outside DVCR exported a plurality of programs continuously and program changed, microcomputer 9 just checks PAT so that search PMT, and the MPEG video data and the mpeg audio data that are converted program can not be read out.Also owing in MPEG video decoder 4 and mpeg audio decoder 5, use past data, so, otherwise just can not carry out correct decoding unless the program data that is retained in before the conversion in buffer storage 4a and the 5a is eliminated.
Similarly, as for SI, when utilizing different transmission stream translation programs, the SI in the buffer storage 3 also must be updated.
Therefore, according to this embodiment, when the program of DVCR playback changed, the Q-character that identifies this variation just was attached to the title of asynchronous data packets.Fig. 6 is the diagram of the form of expression asynchronous data packets.When 2 positions of tag field are 01
2The time, just insert the public asynchronous data packet header (being called the CIP title later on) that 2 quadwords save (quadlet) in the beginning of data field.The value of mark is decided to be 01
2, so that processing is from the real-time video and the audio signal data of digital-video equipment or digital audio-frequency apparatus.
Fig. 7 expressive notation=01
2The time the CIP title.Fig. 8 is illustrated in an example of specifying FMT (Format Type) in the CIP title.As shown in Figure 8, DVCR FMT=000000
2Stipulate that the mpeg signal transformat is with 100001
2Stipulate.According to this embodiment, discontinuous Q-character is assigned to the position b0 of FDF (according to relevant field).
When the transmission in the DVCR replay signal is flowed when discontinuous, be connection features position not one section preset time of " H (height) " level (for example 1 second) just.Specifically, when video data was recorded in DVCR, the starting position (REC START) of expression record and the video auxiliary data (VAUX data) of end position (REC END) were recorded with this video data.Therefore, in case detect this auxiliary data, just discontinuous Q-character is set to " H (height) " level at playback duration.
According to this embodiment, in case the DVCR pattern is changed into playback (PB) from stopping (STOP), above-mentioned discontinuous Q-character just is changed to " H (height) " level.Therefore, even reset a program from the centre, also can remove the data in buffer storage 4a, the 5a and upgrade SI in the buffer storage 3.
In addition, according to this embodiment, the variable-speed replay Q-character is attached to the position b1 of FDF.When the DVCR operator scheme is at a slow speed or during prompting/checking mode, just be this feature locations " H (height) " level.During this variable-speed replay, having only the MPEGI image is valid data, so buffer storage 4 underflows, before next I image was decoded, the output of MPEG video decoder 4 ended.Therefore in a single day, digital signal processor has such structure, has promptly damaged this Q-character, just from the last decoded I image of MPEG video decoder 4 outputs, till next I image is output.
Fig. 9 is the flow chart of the expression processing that microcomputer 9 is carried out when the outside is imported.
At first, microcomputer 9 has judged whether outside input (step S11).Make the judgement whether outside input is arranged according to the output of front panel 10.
Then, judge whether to detect discontinuous Q-character (step S12).Whether this judgement detects discontinuous Q-character shown in Figure 7 based on digital interface 11.In case detect not connection features position, just upgrade PAT, PMT and SI in the buffer storage 3, and send the order (step S13) of removing the data in buffer storage 4a, the 5a to MPEG video decoder 4 and mpeg audio decoder 5.
Then, judge whether to detect variable-speed replay Q-character (step S14).Similar with the judgement of step S12, whether this judgement detects variable-speed replay Q-character shown in Figure 7 based on digital interface 11.In case detect the variable-speed replay Q-character, just order MPEG decoder 4 to continue the last decoded I image of output.
Fig. 6 is the diagram of the form of expression asynchronous data packets.When 2 positions of tag field are 01
2The time, the public asynchronous data packet header (being called the CIP title later on) of 2 quadword joints just is inserted into beginning place of data field.The value of mark is changed to 01
2, so that processing is from the real-time video and the audio signal data of digital-video equipment or digital audio-frequency apparatus.Fig. 7 expressive notation=01
2The time the CIP mark.Fig. 8 is illustrated in an example of specifying FMT (Format Type) in the CIP title.
According to this embodiment, FMT=100001
2And stipulated the form that mpeg signal transmits.Mpeg data is transfused to the data block after CIP title shown in Figure 6.
Figure 10 is the block diagram that the structure of DVCR of the present invention has been used in expression.This DVCR has the function of coding and recording/reproducing analog video signal, also has the function of recording/reproducing MPEG digital signal.
The recording/reproducing of analog video signal is at first described.
In order to write down analog video signal, this DVCR comprises the A/D converter 21 of digitized video, the output of A/D converter 21 is carried out the framer circuit 23 of the output of the data compression coding circuit 22 of DCT (discrete cosine transform) for example such data compression, quantification and variable-length encoding and framing data compression coding circuit 22.
In addition, this DVCR also comprises the output of making up framer circuit 23 and the multiplexer 24 of the video auxiliary data (VAUX data) that produced by signal processing microcomputer 28 described below, the error correcting code of increasing error correcting code for the output of multiplexer 24 increase the channel encoder 26 of the output of circuit 25 and record/modulation error correcting code circuitry 25.
This DVCR also comprises operating according to the user and produces vision signal TV channel and such as the mode treatment microcomputer 27 of such data-signal such as record date and time and the signal processing computer 28 that produces the VAUX data according to the output of mode treatment computer 27.VAUX data herein comprise recording start (REC START) position and record end (RECEND) position on TV channel, record date and time, the tape.
Figure 11 represents the form of the data of the magnetic track that error correcting code increase circuit 25 is exported.As shown in the figure, video data and VAUX data are organized according to the module unit of 90 bytes.These data are recorded in channel encoder 26/modulate, and are recorded the amplifier (not shown) and amplify, and be recorded on the tape by the magnetic head (not shown).In the DVCR of reality, video data, VAUX data, voice data and sub-code data are recorded in the magnetic track by the time-division mode.
Described above is the coding and the record of analog video input signal.Reproduction to the vision signal that is recorded is below described.
This DVCR comprises the playback circuitry 29 of the data of playback amplifier (not shown) amplification being carried out wave shape equalization and replay data clock, data to playback circuitry 29 outputs write down the channel decoder 30 of demodulation, the output of channel decoder 30 is carried out the error correction circuit 31 of error correction, separate the video data of error correction circuit 31 and the demultiplexer 32 of VAUX data, separate this video data frame separate framer circuit 33, the output execution of separating framer circuit 33 is deciphered such as variable length code, the data compression decoding circuit 34 of the processing that re-quantization and inverse DCT are such, and the output transform of data compression decoding circuit 34 become analog format and thus it is for conversion into the D/A converter 35 of analog video signal.The VAUX data of being separated by demultiplexer 32 send signal processor microcomputer 28 to, send schema processor microcomputer 27 to from this signal processor computer 28 again.
Recording/reproducing to the code signal of external equipment input is below described.This DVCR has digital interface 36.The structure of this digital interface 36 is identical with the structure of digital interface 11 in receiver/demodulator of Fig. 1.The IEEE-1394 packet sends the digital interface 11 of Fig. 1 to, and receives the IEEE-1394 packet from this interface.
Record to the mpeg data of digital interface 36 inputs is below described.The digital interface 11 of this mpeg data by receiver/demodulator of Fig. 1 is transfused in asynchronous data packets and is transmitted.
At first, separate to come the mpeg data of the asynchronous data packets in the comfortable digital interface 36, i.e. MPEG video data, mpeg audio data and auxiliary data.Separated data send multiplexer 24 to, carry out multiplexedly with the VAUX data of signal processor microcomputer 28 output by switch SW 1, and are increased the form that circuit 25 is for conversion into Figure 11 by error correcting code.In other words, MPEG video data, mpeg audio data and auxiliary data all are recorded in the video data recording district.The processing that error correcting code increases after the circuit 25 is identical with the record of above-mentioned analog video signal.
Below be described in the processing during the playback mpeg data.Up to replay data being inputed to demultiplexer 32, the processing during the processing of playback duration and the video frequency signal replay is identical.The replay signal that inputs to demultiplexer 32 is separated into mpeg data and VAUX data.Mpeg data sends digital interface 36 to by switch SW 2.The VAUX data send signal processing microcomputer 28 to.
In digital interface 36, Fig. 6 and title shown in Figure 7 are added to mpeg data, and export to external equipment as asynchronous data packets.This asynchronous data packets inputs to the digital interface 11 of receiver/demodulator, extracts original MPEG video data, mpeg audio data and auxiliary data, and writes to buffer storage 3 by demultiplexer 2.
Above-mentioned mark as shown in figure 12.NP wherein is the normal play data, and TP is the triple speed played data.NP1-NP2 represents that the normal play program changes.