CN1144457C - Method and apparatus for reproducing/recording at variable speeds dependent upon the bit rate of the MPEG encoded signal - Google Patents
Method and apparatus for reproducing/recording at variable speeds dependent upon the bit rate of the MPEG encoded signal Download PDFInfo
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- CN1144457C CN1144457C CNB951203525A CN95120352A CN1144457C CN 1144457 C CN1144457 C CN 1144457C CN B951203525 A CNB951203525 A CN B951203525A CN 95120352 A CN95120352 A CN 95120352A CN 1144457 C CN1144457 C CN 1144457C
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Abstract
When a transport packet of the MPEG2 signal is recorded, a tape speed is reduced to +E,fra 1/2+EE or +E,fra 1/4+EE of that used to record standard data in accordance with the bit rate of the program. Two heads (A and B) having different azimuths are provided in close proximity with each other at the same height on a drum. If the +E,fra 1/2+EE tape speed mode is selected, the recording is performed by head A during the first scan of the tape and by head B during the next scan. Even when the tape speed is a fraction of an even number of the standard tape speed, the azimuth angles of adjacent tracks are different and azimuth recording is performed to reduce crosstalk.
Description
The present invention relates to a kind of data recording/reproducing device and method of numerical data, be used for according to the bit rate of coding stream with speed change to/from magnetic recording/reproduction MPEG2 signal bitstream.
The numeral VTR exploitation make progress, this VTR utilizes DCT (discrete cosine transform) and variable length code compressed digital video signals, and utilize rotating magnet head signal record on tape.In this digital VTR, can be provided with the record TSC-system or similarly the pattern (being called the SD pattern later on) and being used for of vision signal write down the pattern (being called the HD pattern later on) of the vision signal of HDTV system.Vision signal is recorded with the speed of 25Mbps in the SD pattern.Vision signal is with the speed record of 50Mbps in the HD pattern.The technology that writes down the bit stream of MPEG2 (Moving Picture Experts Group) with this digital VTR is studied.The transmission package of MPEG2 signal can be digital CATV or its similar signal.
In MPEG2, have the Polymera function, it can transmit a plurality of programs, and the data flow of own coding is carried out multiplexing by time-division ground being called on the short relatively unit basis of transmission package.Transmission package is set to the regular length of 188 bytes.Title division (header) contains the content identification information of transmission package.The transmission package of needs reproduction target program is selected and utilize these information to decipher.
Figure 23 A-D shows the structure of this transmission package.Shown in Figure 23 A, transmission package comprises title and payload (payload), latter's storing data information.Shown in Figure 23 B, title comprises: the synchrodata of 8 bytes; The transmission error designator that promptly whether has transmission error in the indication bag; The PU Payload Unit that the indication PU Payload Unit begins begins designator; The transmission priority indicator of the importance of indication bag; The bag recognition data (PID) of the private data stream of indication bag; Indication exists payload encryption or the non-existent transmission of indication payload encryption to encrypt control data and type; Indicate whether to exist the self adaptation field control data of self adaptation field (field); Be used for detecting the continuous counter whether part of bag has gone out of use; And the self adaptation field, it can be used to insert the additional information about private data stream and byte of padding (Stuffing byte).
Shown in Figure 23 C, the self adaptation field comprises: the self adaptation field length data of expression self adaptation field length; The expression system clock is reset and is obtaining the discontinuous designator of fresh content; The random access indicator of representing random-access inlet point; Be illustrated in and exist the prioritized data of pith to flow basic designator, mark (flag) in the payload; Select field and byte of padding.
Shown in Figure 23 D, select field to comprise: the PCR data; The OPCR data; Engage countdown; The exclusive data length of transmission; The exclusive data of transmission; The self adaptation field extension length; Mark (flag); And selection field.The PCR data are the time marks (stamp) that are used for setting and proofread and correct as time reference value in the MPEG decoding system.System clock (27MHz) is reproduced by PLL (phase-locked loop) circuit from PCR, and keeps the time basic information of transmission package, is used for regularly and then deciphering the system-timing reference of handling thereby set up.
As shown in figure 24, for the transmission package with digital VTR record MPEG2 signal, select a program from program A, B, C (for example program A), these programs send with the form of time-division multiplex transmission.Selected program is to wrap the similar pulse train form that the unit is the basis formation.If the data rate of a plurality of programs for example equals 30Mbps, and select the speed of program for example to equal 10Mbps, then data rate is converted to 10Mbps so that write down selected program from 30Mbps by the rate transition buffer.
Shown in Figure 25 A, the transmission package of selected program is sent to rate transition buffer 102 from input 101.Rate transition buffer 102 reduces 3 times to data rate.Like this, just, be reduced to 10Mbps from 30Mbps.Transmission package through rate transition is output to output 103, and by digital VTR record.In order to reproduce, also need the signal of rate transition numeral VTR to make its speed increase by three times, the speed during promptly with record reduces opposite.
When the signal that is reproduced by digital VTR is decoded by the top frame (topbox) of a setting, system clock (27Mhz) by PLL by PCR reconstruct.This system clock is used as the timing reference that decoding is handled.Therefore, need by the record of signal and the time basic information of reproduction reservation transmission package.Yet rate transition can change the time basic information of input signal during writing down.Therefore, when reproducing, the time base can not recover its reset condition.
In MPEG2, transmission I image, P image and B image, they are respectively inner picture coding, forward prediction coding and bi-directional predictive coding.At the speed change reproduction period, can not obtain the continuous images data, therefore, when speed change is reproduced, have only the data of I image to be used, because the data of P and B image can not be decoded.
Yet, when transmission package writes down with VTR, comprising that the transmission package of I image can not fully be read out when speed change is reproduced, this is because the position of the I image that is recorded is uncertain.Therefore, can not be read out in the correct time at the speed change reproduction period corresponding to the data of the I image of the specific part of a frame, thereby picture quality degenerates.
The method that provides according to the present inventor, before ingress rate translation buffer 102, will be from the temporal information (moment that the expression transmission package arrives) of a definite reference clock, each that is added to the selected program received at input 104 by temporal information adjunct circuit 105 wrapped, shown in Figure 25 B.When same reference clock is used for reproducing and during record, transmission package is transmitted according to the reference clock temporal information, thereby at the speed change reproduction period, with the recording period identical time state can be by reconstruct.The title sync byte of each transmission package (byte) is eliminated when bag arrives and uses the value of three bytes of the counter of reference clock (27MHz) to be latched at the bag due in.
Selected program is like this with digital VTR record, the bit rate of each program in Digital Transmission general according to program content and difference.As shown in figure 26, the bit rate of high image quality program for example the sports cast and so on of rapid movement be higher than slowly or the bit rate of the program of less physical activities, for example music program, movie program etc.The bit rate of 15Mbps is the highest bit rate of MPEG2.Therefore, if this program in the mode standard (SD mode) of digital VTR with the bit rate record of 25Mbps, will waste very much.
Preferably change writing speed, so that tracer signal more effectively according to the bit rate of program.There are three kinds of patterns to use: SD pattern, 1/2SD pattern and 1/4SD pattern.In the 1/2SD pattern, tape speed reduces twice than the SD pattern.In the 1/4SD pattern, tape speed reduces 4 times than the SD pattern.The recording rate of each pattern and writing time are as shown in figure 27.
With Figure 26 is example, select the 1/4SD pattern be used for recoding/reproduction for example its speed such as movie program, music program be equal to or less than the program of 6.25Mbps, select the 1/2SD pattern to be used to for example high image quality program of recoding/reproduction, its speed such as sports cast is equal to or less than the program of 12.5Mbps.Select the SD pattern to be used for the recoding/reproduction bit rate and surpass the program of 12.5Mbps.The bit rate of selected program is converted into recorded bit speed in each pattern by rate transition buffer 102 and empty data adjunct circuit.For example,, promptly equal the bit string of " 0 ", make the data volume equilibrium that under every kind of pattern, is recorded on its magnetic track by additional empty data.
Digital VTR according to shown in Figure 28 has magnetic head A and B on magnetic drum, they are separated by 180 °, and this magnetic drum rotates with 9000r.p.m, a tape (not shown) around the outer surface of magnetic drum be slightly larger than 180 ° around square ring around.The azimuth in the gap of magnetic head A and B is different.Thereby, when reproducing, can suppress interference, and just can carry out record without guard band from adjacent track.
When being set at the 1/2SD pattern, signal is recorded on the tape as shown in figure 28.In Figure 28 (and among other figure that will illustrate later on), for the sake of simplicity, oblique magnetic track is expressed as vertical magnetic track, and oblique line is represented the azimuth.In first scanning, magnetic head A record data and magnetic head B be record data not.The 3rd scanning also is same operation.Record data not on even-line interlace.Record is carried out in the odd number scanning of appointment by magnetic head A or B.Track pitch when the 1/2SD pattern and SD pattern identical.
Be appreciated that by Figure 28 record only finishes with the A magnetic head, thereby to suppress cross (talk) by azimuth loss be impossible.Record and similar problem also takes place when reproducing under the 1/4SD pattern.When tape running speed reduces odd-multiple, for example to compare with the belt speed under the SD pattern, the 1/3SD pattern can suppress to disturb by azimuth loss.Yet the velocity mode of one of use odd number of points has limited the optional scope of recording rate.
Therefore, the objective of the invention is to, the apparatus and method of a kind of digital data record/reproduction are provided, it can be with the adjacent magnetic track of head records/reproduction of different orientations under a kind of belt speed, and described belt speed reduces one of odd number of points than mode standard.
Another object of the present invention is, a kind of digital data record/transcriber and method are provided, even transmission package was carried out rate transition, the time base that it can correctly be kept for reproducing when record.
Another object of the present invention is, a kind of digital data record/transcriber and method are provided, even transmission package was carried out rate transition when record, it can not become bad in speed change reproduction period picture quality.
The numerical data of record is recorded on two magnetic tracks simultaneously by rotating magnet head A and B, and magnetic head A, B have the difference in height of a track pitch (track pitch), and has different azimuths and integrally constituted.For the belt speed of 1/N, carry out with the speed of every N sweep record 1 time.Like this, the azimuth of adjacent track is different.Magnetic head with different azimuth angle with different angles data record to magnetic track, these magnetic tracks are called the magnetic track with different orientations here.
When the SD pattern, record is finished in each scanning by rotating magnet head A and B.When the 1/2SD pattern, record is alternately finished in each scanning by magnetic head A and B.Like this, the data that are recorded on the adjacent track just have different azimuths, and the scanning of being skipped free of data under the 1/2SD pattern rewrites.
When writing down, the temporal information that transmission package arrives is added on each transmission package according to reference clock when the transmission package of the selected program of rate transition with by digital VTR.Like this, during the signal reproduction according to this temporal information and reference clock can reconstruct base state during original before record.
At the record of digital VTR with when reproducing, because the rotation of magnetic drum and reference clock are synchronous, thereby according to the bit rate select tape fast mode of transmission package.
Being provided for high speed change reproduction also is arranged on it on magnetic track with different azimuths respectively with special play-back district (trick playareas) TP1 that hangs down the speed change reproduction and TP2.In special play-back district TP1 and TP2, writing down the I view data.At the speed change reproduction period, read the data among special play-back district TP1 and the TP2.Like this, just, improved picture quality at the speed change reproduction period.By means of each special play-back district is only used an azimuthal magnetic track, reproduce and hang down special play-back district TP1 and the TP2 that speed change reproduces and be arranged on magnetic track with different orientations being used for high speed change.Therefore, the magnetic head structure of this device is unrestricted.
With reference to the accompanying drawings invention is elaborated so that understand the present invention better below in conjunction with embodiment, label identical in the accompanying drawing is represented identical part.
Brief Description Of Drawings
Fig. 1 is magnetic head structure and the azimuth magnetic track thereof of digital VTR of the present invention;
Fig. 2 is another kind of magnetic head structure and its azimuth magnetic track of digital VTR of the present invention;
Fig. 3 is the timing diagram of different magnetic head structure operations;
Fig. 4 is the register system of digital VTR of the present invention;
Fig. 5 A-B is the additional period information of transmission package;
Fig. 6 is the block diagram that is used for the circuit of transmission package additional period information;
Fig. 7 is the setting of transmission package in the synchronization blocks;
Fig. 8 is the additional header that adds in the synchronization blocks of Fig. 7;
Fig. 9 is the location in the special play-back district on magnetic track;
Figure 10 is the waveform schematic diagram that reproduces pulse train from the special play-back district;
Figure 11 is the layout plan of data on the magnetic track;
Figure 12 is the further division of magnetic track among Figure 11;
Figure 13 is the speed schematic diagram in the special play-back district of given various magnetic head instructions under speed or phase locking state;
Figure 14 is at the schematic diagram that tracks that is higher than the magnetic track under the usual speed;
Figure 15 A-B reads part according to the magnetic track of the track among Figure 14;
Figure 16 A-B is the arrangement of synchronization blocks on each magnetic track;
Figure 17 is used to reproduce in the speed locking mode/belt speed of the various patterns of recording of trick broadcast area 1;
Figure 18 is used to reproduce under the phase locking pattern/the various pattern belt speed of recording of trick broadcast area 1;
Figure 19 is used to reproduce under the phase locking pattern/belt speed of the different mode of recording of trick broadcast area 2;
Figure 20 is the detailed decomposition of canned data in Figure 11 magnetic track zone;
Figure 21 is the block diagram that is used to set the circuit system in special play-back district;
Figure 22 is the block diagram of circuit of the playback system of digital VTR of the present invention;
Figure 23 A-D is the structure chart of transmission package of the present invention;
Figure 24 A-B is a schematic diagram of selecting a program from a plurality of programs;
Figure 25 A-B is the circuit block diagram to additional timing information of the transmission package of MPEG2 signal and rate transition;
Figure 26 is according to the programme content of transmission package bit rate for example;
Figure 27 is recording rate and the graph of a relation between writing time in various logging modes;
Figure 28 is magnetic head structure and the operation chart thereof of existing digital VTR.
Embodiments of the invention are described now.As mentioned above, the transmission package of MPEG2 signal arrives by digital CATV or its analog, and several bit rate are arranged, and they are less than or equal to the highest MPEG speed of 15Mbps according to programme content.Use the corresponding three kinds of recoding/reproduction patterns of bit rate in the present embodiment with bag.
First kind of pattern is the SD pattern, is used for the recoding/reproduction of the digital video signal of bit rate from 12.5 to 25Mbps.Second kind of pattern is the 1/2SD pattern, is used for the digital video signal of the bit rate of recorded bit speed from 6.25 to 12.5Mbps.The third pattern is the 1/4SD pattern, is used for the digital video signal of its bit rate of recoding/reproduction less than 6.25Mbps.In the 1/2SD pattern, tape speed reduces 2 times than SD pattern tape speed.In the 1/4SD pattern, tape speed reduces 4 times than SD mode speed.Model selection is to realize by the rate information in the title of each transmission package that detects the MPEG2 signal.
The magnetic head structure of Fig. 1 and Fig. 2 be with the speed that reduces in different azimuth adjacent tracks or from the embodiment of adjacent track recoding/reproduction.An example of this magnetic head structure illustrates with reference to Fig. 1.The magnetic head of Fig. 1 has both sides' parallactic angle structure.Magnetic head A has different azimuths with B, and is overall structure, is positioned on the position with the close enough on the magnetic drum of 9000r.p.m rotation, and has the difference in height of a track pitch TP (=10 μ m).
Utilize this both sides' parallactic angle structure, under 1/2SD pattern situation,, and down do not carrying out record on the one scan at the enterprising line item of first scanning tape.Carry out record with per twice sweep record speed once.The tape (not shown) is looped around on the magnetic drum with the angle that is slightly larger than 180 °.When magnetic head will be at the tape identifying recording layer, supply with record current to magnetic head.Under the pattern situation of 1/4SD, per 4 scannings of magnetic head A and B are only to magnetic recording one secondary data.Under the SD pattern, each scanning is write down once by each magnetic head.
As shown in Figure 1, on adjacent magnetic tape track, the head records figure has different azimuths, and these magnetic tracks carry out record with the 1/2SD pattern, its track pitch (track pitch) and SD pattern identical.For the magnetic head structure that uses Fig. 1 carries out record with magnetic head A and B simultaneously, two systems must be provided, each system comprises an encoder and a record amplifier that is used for digital modulation.This duplex system is expensive, therefore preferably uses structure shown in Figure 2.
Figure 2 shows that another kind of magnetic head structure of the present invention.In this both sides' parallactic angle structure, magnetic head A has different azimuths with B, and is made into an integral body, but magnetic head A and B are positioned at sustained height, and and 180 ° at interval of magnetic head A, provide magnetic head B ' with SD mode record/reproduction.Magnetic head B has identical azimuth with B '.
In Fig. 2, show an example that carries out recording operation with the 1/2SD pattern.In this pattern, magnetic head A and B scanning tape and follow the tracks of same magnetic track during each rotation of magnetic drum.Magnetic head A and magnetic head B alternately carry out record, and the magnetic track that the result is adjacent has different azimuths.Also can rewrite greater than track pitch slightly by track (track) width of setting magnetic head.In Fig. 2, when scanning for the first time, carry out record by magnetic head A, when scanning next time by magnetic head B record.In the 1/4SD pattern because tape speed is reduced to 4 times than SD pattern, so when scanning for the first time by magnetic head A record when scanning for the third time by magnetic head B record; When the second and the 4th scanning, do not carry out record.
On tape, form magnetic track, and the azimuth between the adjacent track is different with predetermined track pitch.In the magnetic head structure of Fig. 2,, magnetic head A and B need not provide two channel coder systems the magnetic head structure of Fig. 1 because with 1/2SD pattern record data alternately on magnetic track, just need not resembling.Can reduce the volume and the cost of electrical equipment like this.
Fig. 3 is the sequential chart that carries out recording operation with above-mentioned magnetic head structure.The pulse signal of 150Hz and magnetic drum rotation are synchronous, and one-period is equivalent to the once rotation of magnetic drum.With 180 ° 2 magnetic heads (illustrating in background technology of the present invention) of being separated by during with SD mode record digital video signal, two magnetic heads alternately carry out recording operation.In the 1/2SD pattern, use this magnetic head structure, then only write down and do not carry out azimuth recording with magnetic head A.
In the 1/2SD pattern, use two head records vision signals simultaneously according to the magnetic head that Fig. 1 constitutes, shown in second sequential chart of the bottom of Fig. 3.Shown in the sequential chart of Fig. 3 bottom, when magnetic head A that constitutes according to Fig. 2 and B difference scanning tape, replace record, like this, data are recorded on the adjacent magnetic track with different orientations.
Though present embodiment relates to the tape speed example that a tape speed during from the SD pattern reduces even-multiple, when the tape speed minimizing odd-multiple of tape speed during, also can use the magnetic head structure of Fig. 1 and 2 from the SD pattern.
Fig. 4 represents the circuit block diagram of the register system of digital VTR of the present invention.In Fig. 4, input 1 receives the vision signal of television system, for example NTSC system etc.During recording operation, the vision signal of delivering to input 1 is sent to A/D converter 2.This vision signal converts digital signal to by A/D converter.DCT compressor circuit 3 is by DCT conversion compression digital signal and variable length code.Like this, be divided into piece, and shuffled (shuffled) and be carried out the DCT conversion from the digital signal of A/D converter.The output of DCT compressor circuit is set to equal lengths according to predetermined buffer cell (not shown).This system produces a quantization table, makes the length of total sign indicating number be equal to or less than predetermined length.Vision signal is quantized in this best quantization table, is carried out the coding of variable-length and is divided into frame.
When the transmission package of MPEG2 signal was recorded, switching circuit 4 was connected to terminal 4A, then was connected to terminal 4B when the vision signal from terminal 1 input is recorded.The conversion of transmission package through-rate and the format conversion unit 9 of MPEG2 signal are delivered on the terminal 4A of switching circuit.Vision signal from input 1 is delivered to terminal 4B from the DCT compressor circuit.
Rate transition and format conversion unit are selected program and the rate transition of selected program are become to be used for each the speed of being scheduled to of three kinds of modes from the transmission package of MPEG2 signal.The data in special play-back district are set, so that reproduce best image at the speed change reproduction period.
The output of switching circuit 4 is sent to frame and forms circuit 5.Frame forms circuit data is formed predetermined frame and carry out error correction code.The output of frame formation circuit is sent to channel coder 6 and carries out digital modulation.The output of channel coder, or the compression vision signal or the transmission package of MPEG2 signal be recorded on the tape.
The output of channel coder 6 selects the circuit (not shown) to be assigned to record amplifier 7A, 7B and 7B ' by magnetic head, when the magnetic head assembling constitutes by Fig. 2, is sent to rotating magnet head 8A, 8B and 8B ' respectively.According to or the validity of SD pattern, 1/2SD pattern or 1/4SD pattern, magnetic head selects circuit that tracer signal is distributed to record amplifier 7A, 7B and 7B '.Tape speed also changes according to selected pattern.Can change tape speed by the command signal that supplies a pattern to capstan motor servo circuit (not shown).
During the record of the transmission package of MPEG2 signal, switching circuit is connected to terminal 4A.The transmission package of the MPEG2 signal of through-rate conversion and format conversion unit 9 inputs forms circuit 5 by frame and is divided into frame, records on the tape by channel coder 6 modulation and by rotating magnet head 8A and 8B.
Be input at record during the vision signal of input 1, switching circuit 4 is connected to terminal 4B.Vision signal converts digital signal to by A/D converter 2, is compressed in DCT compressor circuit 3, forms 5 fens framing of circuit by frame, is modulated by channel coding 6, and by rotating magnet head 8A and 8B it is recorded on the tape.
As mentioned above, in order to write down the transmission package of MPEG2 signal, by the program that rate transition and format conversion unit 9 are selected in a plurality of programs, the bit rate of selected program is detected, thereby selects suitable pattern.For example, the speed of program can be converted to 12.5Mbps from 30Mbps by buffer and sky (dymmy) data adjunct circuit.Rate transition changes time base (time base) information during writing down, therefore, in order to make the same a period of time base of data before returning to record, rate transition and format conversion buffer 9 are added to the time base information of expression transmission package due on each transmission package of MPEG2 signal according to reference clock at reproduction period.By use identical reference clock and can be at reproduction period at record and reproduction period according to the reproduced transmission package of base message transmission when additional, basic state when reproducing identical before the record.
Shown in Fig. 5 A, the sync data of 8 bytes are added to the title (header) of transmission package.During the record of the transmission package of MPEG2 signal, a byte of sync data is cancelled, and adds the temporal information of three bytes, shown in Fig. 5 B.This time information can make when original base reproduced from the data that rate transition is crossed.
Fig. 6 is the block diagram that three byte time information shown in Fig. 5 B is appended to the circuit of transmission package before data rate is converted and is recorded.Circuit shown in Figure 6 is included in rate transition shown in Figure 4 and the format conversion circuit 9.In Fig. 6, transmission package was sent to input 31 before rate transition.Transmission package is sent to sync detection circuit 32.Synchrodata in the sync detection circuit detected transmission packet header.The detection output of sync detection circuit is sent to latch cicuit 33.Another output of sync detection circuit 32 is sent to synchronous cancellation circuit 37.When being detected synchronously, cancelling circuit 37 synchronously and just delete a byte in the synchrodata.The output of cancellation circuit 37 synchronously is sent to time mark (stamp) circuit 38.
Reference clock 34 produces for example reference clock of 27MHz.Reference clock is sent to PLL35 sum counter 36.According to the output of PLL35, magnetic drum is with the speed rotation of for example 150Hz (9000r.p.m.).The rotating speed of magnetic drum is that constant and pattern are irrelevant.
The output of reference clock 34 is by counter 36 countings.Temporal information obtains from the output of counter.Temporal information is delivered to latch 33 from counter.When being detected by sync detection circuit 32 synchronously of transmission package, temporal information is latched in the latch 33, and the synchronous quilt of a byte is cancelled circuit 37 deletions synchronously.The temporal information of three bytes is added on the transmission package by time mark circuit 38.The output of time mark circuit is from output 39 outputs.
As mentioned above, the output of reference clock 34 is added to PLL35, and magnetic drum is pressed the output rotation of PLL.At record and reproduction period, the rotation and the reference clock of magnetic drum are synchronous.Like this, base information when reproduction period is can reconstruct original.
Transmission package is made of 188 bytes.Deleted and when adding the temporal information of three bytes when the synchrodata of a byte, transmission package is made of 190 bytes, shown in Fig. 5 A, B.Two bags of 190 bytes are divided into the bag of 5 synchronization blocks, as shown in Figure 7.
When using digital VTR, a synchronization blocks is made of 90 bytes.5 bytes are added in represents synchronously and the title division of ID that each synchronization blocks is set the parity of a byte and the payload (payload) of 77 bytes.The additional header of a byte is added on each synchronization blocks, as shown in Figure 8.Sequence number of additional 5 synchronization blocks of title storage and so on.76 bytes of remaining payload are specified and are used for writing down transmission package.In 5 synchronization blocks, remaining 380 bytes:
Therefore 5 * 76=380 byte can store two bags in 5 synchronization blocks, each comprises 190 bytes, wherein is added with the temporal information of three bytes:
2 * 190=380 byte
According to an embodiment, when speed change is reproduced, set and to reproduce the district for the special play-back district, to improve picture quality.The transmission package that contains the I image is recorded in the special play-back district.The I image is a kind of image that carries out the image intraprediction encoding with the MPEG2 form.When speed change is reproduced, only use the I image to obtain reproduced image.Can reproduce on the magnetic track, the transmission package that contains the I image is recorded in (high speed change is reproduced as the TP1 district, and low speed change is reproduced as the TP2 district) in the special play-back district.
When in the SD pattern, the recording rate of digital VTR is 25Mbps, and transmission package is recorded with 10Mbps, and VTR has unnecessary recording rate.Therefore, the I image can be recorded the special play-back district by overlapping ground (overlappingly), thereby can reproduced image at the speed change reproduction period.
Figure 9 shows that the track of magnetic head when speed change is reproduced.As shown in Figure 9, when magnetic head is followed the tracks of magnetic track, but be reproduction regions by the part that TP represents.Can reproduce district TP and be used as the special play-back district, be used for writing down the transmission package that speed change is reproduced.In the VTR that uses helical scan and azimuth recording, the data of reproducing from TP have similar pulse train (burst-like) shape, as shown in figure 10.By means of the position that is fixed on the reproduced district on the magnetic track, can reproduce among the district TP by automatic following function (ATF) or similar operations and by the transmission package that comprises the I image is recorded in, can reproduce the data of I image at the speed change reproduction period.
According to the present invention, two class special play-back district TP1 and TP2 are provided.A special play-back district TP1 is used for high speed change and reproduces, and another special play-back district TP2 is used for low speed change and reproduces, and they are provided on the magnetic track with different azimuths.
As shown in figure 11, magnetic track is divided into ITI section district, audio section district, the video-frequency band district that is used for (after-recording) after record or the similar operations and is used to retrieve or the subcode section district of similar operations.Two magnetic heads or double azimuth head with 180 ° relative position settings can be used as the magnetic head structure of following the tracks of this magnetic track.Pilot signal is followed the tracks of thereby carry out ATF by multiplexing.
As shown in figure 12, specify the special play-back district TP1 that is used for high speed change reproduction.For example, pilot signal f
0Magnetic track be the zones that can reproduce with 18 times of speed.Data are repeatedly write down 18 times in special play-back district TP1.Be used for special play-back district TP2 that low speed change reproduces and be defined as the zones that to reproduce with 4 times of speed, for example remove and be used for pilot signal f
0Magnetic track.In special play-back district TP2, same data are repeatedly write down twice.
As mentioned above, special play-back district TP1 and TP2 are set in the magnetic track with different orientations.For among special play-back district TP1 and the TP2 each, by using an azimuthal magnetic track is only arranged, two magnetic heads that the restriction that the performance that variable-ratio reproduces is not subjected to magnetic head structure for example is provided with 180 ° relative position etc.
When carrying out phase locking, removing f
0Outside the magnetic track of pilot signal in trace information be subjected to the influence near error of magnetic head etc. easily because trace information is from f
0The magnetic track of pilot signal in obtain.Therefore, being used for the special play-back district TP2 that low speed change reproduces is set at except that f
0Outside the magnetic track of pilot signal in.The special play-back district TP1 that is used for high speed change reproduction is set at pilot signal f
0Magnetic track in.Distribute the special play-back district to be by this way because the surplus that is used for tracing deviation in 4 times of speed greater than the surplus of 18 times of speed, is respectively 25 synchronization blocks and 5 synchronization blocks.
Be used for the special play-back district TP1 that high speed change is reproduced, same data are repeated to write down 18 times.Be used for the special play-back district TP2 that low speed change is reproduced, same data are repeated to write down 2 times.
Therefore, the tape speed that can realize as shown in figure 13.
The tape speed of reproducing when speed change is set to (N+0.5) doubly speed, and when for example 1.5 times, 2.5 times or 3.5 times were fast, shown in Figure 14 and 15A-B, all parts with the magnetic track at same orientation angle can be reproduced in twice scanning.Figure 13 shows that maximum speed change reproduction speed to be set to 7 times of speed and speed change to reproduce be the situation of carrying out with 3.5 times of speed.Shown in Figure 15 A-B, reproduced by scanning for the first time in the two end portions of same azimuthal magnetic track, and the middle body of this azimuthal magnetic track is reproduced by scanning for the second time, therefore, whole magnetic head reproduces with twice scanning.By repeatedly write down same special play-back data in same azimuthal magnetic track, all data on the magnetic track in having same azimuth magnetic track can be reproduced with twice scanning.Therefore, by for same azimuthal magnetic track recording of trick played data repeatedly, the special play-back data with (N+0.5) doubly speed reproduce for example 1.5 times, 2.5 times or 3.5 times of speed.
Figure 16 A is illustrated in the setting of the synchronization blocks on each magnetic track.135 synchronization blocks are arranged on a magnetic track.Shown in Figure 16 A, normal play district and special play-back district TP1 are located on magnetic track T0 and the T2.Normal play district and special play-back district TP2 are located on the magnetic track T1.Have only the normal play district to be positioned on the magnetic track T3, magnetic track T3 does not contain special play-back district TP1 or TP2.
When special play-back district TP1 or TP2 are located on the magnetic track, use 25 synchronization blocks storage data.The normal play district uses 101 synchronization blocks.Self-correcting code ECC3 needs 9 synchronization blocks.Because two transmission package are stored in 5 synchronization blocks, preferably the quantity for each the used synchronization blocks among special play-back district TP1 and the TP2 is the integral multiple of 5 synchronization blocks.
Shown in Figure 16 B, in magnetic track T0 and T2,5 special play-back district TP1 are present on each magnetic track, and are writing down the data in 40 to 44,62 to 66,84 to 88,106 to 110 and 128 to 132 the synchronization blocks number therein.Special play-back district TP2 is positioned on the magnetic track T1, and is writing down the data of synchronization blocks numbers 38 to 62 therein.
Be used for the special play-back district TP1 that high speed change is reproduced, magnetic head is set at the position that two subcode section districts and ITI section district can be read out.Like this, at the high speed change reproduction period with 18 times of speed, subcode also can be by access.When speed is set to 18 times when fast, the length of pulse train is also short, and can not obtain enough tracking error signals and be used for ATF control.ATF control can be finished by the information of reading in the ITI section district, pilot signal for example, and it has and is higher than the obtainable S/N ratio in other data field.At 4 times when fast,, just can realize ATF control without ITI district data because pulse train is long.Therefore, being used for the special play-back district TP2 that low speed change is reproduced, magnetic head is arranged on the position of having only subcode to be read out.
The tape speed that Figure 17 explanation can be realized by special play-back district TP1 by the locking tape speed.The tape speed that Figure 18 explanation can be realized by special play-back district TP1 by locking tape phase place.The tape speed that Figure 19 explanation can be realized by special play-back district TP2 by locking tape phase place.
Under with SD mode record data conditions, the speed multiple (ie speed multiple) that the ratio of tape speed and usual speed reproduces corresponding to speed change.When with SD mode record data, tape speed is increased to 1.25 times, 1.5 times ..., the speed multiple in speed change is reproduced also is increased to 1.25 times, 1.5 times ....But, in 1/2SD pattern or 1/4SD pattern, the speed multiple during the ratio of tape speed and usual speed does not reproduce corresponding to speed change.For example, when with 1/2SD mode record data, if the tape speed of record is increased to 1.25 times, 1.5 times ..., it is 2.5 times that the speed multiple when speed change is reproduced is increased, 3 times ....Therefore, if in speed change is reproduced, be not thought of as SD pattern, 1/2SD pattern or 1/4SD pattern during the setting speed multiple, then can cause confusion, because record and reproduction speed extremely depend on selected pattern.For example, suppose that digital VTR is set to 18 times of speed, though reproduce with 18 times of speed with the tape of SD mode record, if data with the 1/2SD mode record, then tape must reproduce with 36 times of speed.
According to one embodiment of the present of invention, the speed multiple in speed change is reproduced is according to mode initialization.If speed setting is 8.5 times of speed, then checks, thereby determine to be to use SD pattern, 1/2SD pattern or 1/4SD pattern.As shown in figure 17, if the pattern of using is confirmed as the SD pattern, belt speed is set to 8.5 times of speed so; If it is the 1/2SD pattern that used pattern is confirmed as, then tape speed is set to 4.25 times of speed (or 4.5 times); If it is the 1/4SD pattern that pattern is confirmed as, belt speed is set to 2.25 times of speed (or 2.5 times of speed) so.
For example, suppose that now belt speed is set to-2 times of speed.In this case, as shown in figure 19, belt speed is set as-2 times of speed under the SD pattern.Belt speed is set as-1.0 times of speed under the 1/2SD pattern, is set at-1/2 times of speed under the 1/4SD pattern.
Magnetic tape format of the present invention is described now.Figure 20 represents to be recorded in a data array on the magnetic track.In Figure 20, magnetic head enters magnetic track in the left side, leaves magnetic track by the right side.Record data not in edge or interblock gap (IBG).
The details of the signal that writes down in each the magnetic track district among Figure 20 is described now.
(1) ITI district
The ITI district comprises: 1400 preceding mark (preamble); 1830 initial synchronization blocks district (SSA); 90 magnetic track information district (TIA); And 280 back mark (post-amble).Before mark function its be similar to insertion (run-in) or the similar operations of PLL at reproduction period, then mark provides an edge.
SSA and TIA comprise having the SYNC piece that every unit is 30 bit data length.In each SYNC piece, in 20 part of the back of 10 SYNC signals (ITI-SYNC), writing down data.In SSA, writing down synchronization blocks number (0 to 60).In TIA, writing down three APT information, the guiding frame of one logging mode (SP/LP) information and servo system.APT represents to stipulate the ID data of the data structure on the magnetic track.
Because each synchronization blocks in the ITI district is recorded in the fixed position on the tape, detect the 61st SYNC signal graph of SSA the position its be used as a reference position and be used for back record position on the regulation magnetic track.Therefore, finish record back behind record during (after-recording) in high precision and the definite position that will be rewritten of accuracy.
(2) audio zone
The audio zone that is used for writing down the pcm audio signal have lay respectively at before the voice data and after preceding mark (preamble) and back mark (postamble).Preceding mark comprises: starting (run-up) signal and the preamble that is used for the pre-detection of audio sync piece that are used for PLL traction (pull-in).Back mark comprises: be used for confirming the postamble that audio zone finishes and protect the guard plot of audio zone at video data recording between the later stage.
Preamble is made of two synchronization blocks.After constitute by a synchronization blocks synchronously.In the 6th byte of preamble, writing down the ID byte of SP/LP.The ID byte is represented the SP pattern when it is FFh, when it represents the LP pattern during for OOh.When the SP/LP mark (flag) in being recorded in the ITI district can not be read out, then use the ID byte of the SP/LP of preamble.FFh is recorded in the 6th the synchronous byte of back as empty data.The voice data that writes down between preceding mark and back mark is divided into frame and affix parity.
(3) video area
The transmission package of MPEG2 signal is recorded in video area.Video area has the preceding mark and the back mark of the audio zone of being similar to.But, the back mark of video area is bigger than audio zone, thereby forms bigger guard plot.
Before being recorded, vision signal forms in the circuit at frame and is handled by video auxiliary data (video AUX data) for each magnetic track.Add self-correcting code then.The video data of 77 bytes is formed the vertical stacks (pile) of the individual piece in 135 (5 * 27), and the video AUX data of three pieces are added to the upper and lower of vertical stacks.The data of 30 DCT pieces of supposition are included in 5 synchronization blocks that form buffer cell now.
77 bytes that are positioned at horizontal direction are encoded by (85,77) Read-Solomon (Reed Solo-mln) sign indicating number, and form the parity (C1 parity) of 8 bytes.138 bytes that are positioned at the formation foreign key of vertical direction are encoded by (249,138) Reed Solomon code, and form the parity (C2 parity) of 11 bytes.Coded data with parity bytes is that the basis is read out with the module unit, and adds the ID of three bytes and the synchronizing signal of two bytes in the title (header) of each piece.Resulting data are converted into a synchronization blocks of 90 bytes.
In one embodiment, remove and be used to write down outside the SD pattern of a video standard signal, also have the 1/2SD pattern, wherein tape speed is compared with the SD pattern and is reduced twice, and the 1/4SD pattern, and wherein tape speed is compared with the SD pattern and is reduced 4 times.The pattern of record data is with the mode instruction mark indication that is arranged in video AUX data, for using at reproduction period.
(4) subcode area
Subcode area is mainly used in the information of using in the retrieval at a high speed that is recorded in.Subcode area comprises 12 synchronization blocks, and each has the data length of 12 bytes.The preceding of sub-code data and after provide before mark and back mark.But, they do not resemble and comprise preamble (Pre-SYNC) and back (Post-SYNC) synchronously the Voice ﹠ Video district.Provide the data division of 5 bytes in 12 synchronization blocks each.Use (14,10) Reed Solomon code to produce parity, so that protect the subcode of 5 bytes, and thereby formation internal code parity C1.
Figure 21 is used for speed change is reproduced the circuit block diagram of record data in special play-back district TP1 and the TP2.In Figure 21, the transmission package of MPEG2 signal is sent to input 51.This transmission package is imported into rate transition buffer 52 and is used for rate transition, and is sent to TS/PES decoder 53.Rate transition buffer 52 is the data rate transition of input and the corresponding set rate of operator scheme.If several programs send by time-division ground multiplexing and as Polymera, then from these programs, select a program and offer rate transition buffer 52 and TS/PES decoder 53.
The TS/PES decoder is deciphered transmission package.The output of TS/PES decoder is sent to initial code analysis circuit 54, and this initial code analysis circuit need to determine whether speed change to reproduce from title (header) information of transmission package.The initial code analysis circuit determines from the information of transmission prior information of being stored in the transmission package title and so on whether this transmission package is necessary, and promptly whether it contains the I image.Thereby identify the transmission that contains the I image in speed change is reproduced, using.The output of initial code analysis circuit is sent to TP treatment circuit 55.The output of TP treatment circuit 55 is sent to the TS/PES bag and forms circuit 56.The TS/PES bag forms circuit 56 and forms the bag that will be recorded among special play-back district TP1 and the TP2, for using in speed change is reproduced.High frequency coefficient (Highfrequency coefficients) can be eliminated from the data being recorded in special play-back district TP1 and TP2.The output that the TS/PES bag forms circuit is sent to TP1/TP2 buffer 57.The output of rate transition buffer 52 and TP1/TP2 buffer 57 is sent to multiplexer 58.The output of multiplexer multiplexing rate transition buffer 52 and TP1/TP2 buffer 57, thus respectively the output of rate transition buffer 52 is recorded in the normal play district, the output of TP1/TP2 buffer 52 is recorded in special play-back district TP1/TP2.
Figure 22 is the block diagram of playback system of the present invention.In Figure 22, the tracer signal of tape is by rotating magnet head 60A, 60B and 60B ' reproduction, and delivered to channel coder 62 respectively by reproducing amplifier 61A, 61B and 61B '.Between reproduction amplifier 61A, 61B and 61B ' and channel coder 62, provide head switching circuit (not shown), be used for according to the reproducing signal of operator scheme selection from suitable rotating magnet head.Channel coder is carried out demodulation with the modulation system that the channel coder 6 corresponding to the register system of Fig. 4 realizes to reproducing signal.
The output of channel coder 62 is provided for time base corrector (TBC) 63.The moving composition of first-harmonic when TBC is used to eliminate reproducing signal any.Be fed to TBC according to the clock of reproducing signal with based on the clock of reference signal.
The output of TBC is provided for separates frame circuit 64.It is corresponding and carry out the processing of error correction and so on that the frame of separating frame circuit and the register system of Fig. 4 forms circuit 5.In separating the frame circuit, represent that the information of the pattern in the video AUX data that is stored in is separated, and according to the mode initialization tape speed, and be chosen in the magnetic head that will use when reproducing.
The output of separating frame circuit 64 is sent to switching circuit 65.When reproducing signal is the transmission package of MPEG2 signal, switching circuit splicing ear 65A.When reproducing signal is component signal, switching circuit splicing ear 65B.
The output of the terminal 65B of switching circuit 65 is provided for DCT expanded circuit 66 and is exported by output 67.DCT expanded circuit 66 is operated in the mode corresponding to the DCT compressor circuit 3 of the register system of Fig. 4.The DCT expanded circuit is deciphered variable length code, and carries out the DCT inverse transformation, thereby produces original input signal in the self-compressed vision signal.
The terminal 65A of switching circuit 65 is connected to bag treatment circuit 68.The bag treatment circuit comprises the rate transition buffer, and the transmission package of for example reproducing with the speed of 10Mbps is converted to its original speed, for example 30Mbps.The bag treatment circuit also detects three bytes of the time base information that is added on the transmission package title, and determines suitable time base according to this temporal information and reference clock.Magnetic drum to be rotated in reproduction period synchronous with its same and reference clock during writing down.Therefore, the time base state before record can be by complete reconstruct at reproduction period.
At the speed change reproduction period, need determine whether that the bag that reproduces contains the I image, be output because only contain the bag of I image.The output of bag treatment circuit 68 is from output 70 outputs.
Controller 71 conversion between common reproduction and speed change reproduction.From input unit 72 to the controller setting signal that supplies a pattern.According to the mode initialization signal servo circuit 73 and bag treatment circuit 68 are set.Use ATF control and carry out phase control and speed control by servo circuit 73 at the speed change reproduction period from the data of transmission package.Like this, special play-back district TP1 and TP2 are reproduced.Be admitted to controller 71 by separating the mode instruction information that frame circuit 64 separates, thus by controller 71 with the belt speed of reproduction period be set at write down during identical value.
In above-mentioned example, though selected and write down for example program in a plurality of programs of 30Mbps, and when whole speed of a plurality of programs equal 25Mbps whole programs direct record of available digital VTR all.Speed change reproduction processes in this example is as follows.
Select program A, and therefrom extract the I view data it is recorded in the special play-back district.In case the I view data of program A is recorded, program B is just selected, and record I view data wherein.Then, program C is selected and be recorded.To be similar to above-mentioned mode, program is handled with the similar fashion of program A-program B-program C...... program A-program B-program C.
Can select a program reproducing then, for example select program A.Like this, have only the data of program A reproduced, and when reading the data of other program, transmit empty data.
The present invention also can be used for encrypting the speed change reproduction of bit stream.In being stored in 1 position the title division of transmission package, when coding be used to refer to whether comprise the I image in this bag.Title at the reproduction period bag is examined, so that determine whether this bag comprises whether I image and data encrypt.If remove outside the data of in title, storing encryptedly, then need high frequency coefficient in order to reproducing, and when record, be not cancelled.When reproducing, the data in special play-back district are directly transmitted so that by the decoder deciphering, thereby still can reproduce the generation high quality graphic by speed change.
According to the present invention,, carry out rate transition and when being recorded, selecting tape speed according to the bit rate of selected program, and do not waste the recording tape space to write down selected program when from transmission package, selecting program.Like this, according to the present invention, the azimuth that can realize adjacent track is different azimuth recording.
According to the present invention, when program is selected from transmission package, carry out rate transition and when being recorded, on the title of each bag, add the transmission package information time of advent based on reference clock.Like this, reproduction period can reconstruct base state in same a period of time before the record.Because the rotation of magnetic drum and reference clock are synchronous, so this temporal information can be used for record or reproduces.
According to the present invention, provide to be used for high speed change and to reproduce and hang down two types of special play-back district TP1 that speed change reproduces and TP2, and it has been arranged in the magnetic track of different orientations.The data of I image are recorded among special play-back district TP1 and the TP2.At the speed change reproduction period, use the data among special play-back district TP1 and the TP2, thereby improve picture quality.Reproduce and hang down the special play-back district TP1 of speed change reproduction and the magnetic track that TP2 has been placed in different orientations respectively because be used for high speed change, so the magnetic head structure of this device is unrestricted.
Above-mentioned is most preferred embodiment of the present invention, should be appreciated that the present invention is not only limited to these certain embodiments, in the design of the present invention or scope that those skilled in the art limits in not breaking away from claim of the present invention, can make various variations and remodeling.
Claims (23)
1, a kind of being used for the device of program data recording to the recording medium, wherein, described program data comprises some programs with the variable-digit speed transmission, and this device comprises:
Input unit is used for receiving described program data;
Clock circuit is used for producing reference clock;
The temporal information circuit, be used for eliminating the synchrodata in the program data that receives, and temporal information added to the synchrodata that is eliminated with replacement in the program data that receives, described temporal information is based on the reference clock that is produced, and represents that described program data arrives the time of described input unit;
Extraction element is used for extracting program from described program data;
Checkout gear is used for the bit rate of the program that Detection and Extraction go out;
Choice device is used for selecting comprising at least one standard recording speed and 1/N this standard recording speed doubly in the described data rate as one in several data rates of the function of the bit rate of detected described program, and wherein, N is a positive integer;
Drive unit is used for driving described recording medium with the transmission speed corresponding to the data rate of described selection; And
Control device is used for controlling described choice device and described drive unit, so as to make a plurality of write heads with different orientations described program data recording to the adjacent track of described recording medium, suppress to disturb with this.
2, tape deck as claimed in claim 1, wherein, described data rate comprises 1/2 and 1/4 speed of described normal data rates.
3, tape deck as claimed in claim 1, wherein, described recording medium is a tape.
4, tape deck as claimed in claim 1, wherein, described several magnetic heads comprise two adjacent magnetic heads that are installed in the assembling of double azimuth head on the magnetic drum, described adjacent magnetic head has different azimuths, and difference in height therebetween is a track pitch.
5, tape deck as claimed in claim 4, wherein, described control device is controlled described double azimuth head assembling, side by side writes down described program data when alternately scanning described recording medium, thereby makes the adjacent track of described program data have different azimuths.
6, tape deck as claimed in claim 1, wherein, described several magnetic head comprise two adjacent magnetic heads with different orientations and be positioned on the magnetic drum be separated by 180 ° the 3rd magnetic head of described adjacent magnetic head, described the 3rd magnetic head is positioned at sustained height, so that follow the tracks of same magnetic track in the scan period of described recording medium.
7, tape deck as claimed in claim 6, wherein, described control device is controlled described adjacent magnetic head, in the mixed sweep of described recording medium, carry out record with one in the described magnetic head, thereby make the adjacent track of described program data have different azimuths.
8. tape deck as claimed in claim 6, wherein, described two adjacent magnetic heads under non-standard pattern to be lower than the described program data of a kind of record of described normal data rates; And described the 3rd magnetic head writes down described program data with described normal data rates under mode standard.
9. tape deck as claimed in claim 1, wherein, described program data is as corresponding to a plurality of program transmission of different channel, wherein, each program is transmitted with one of described variable-digit speed.
10. tape deck as claimed in claim 1, wherein, described choice device reduces an odd number mark by the bit rate with described program data and selects selecteed data rate.
11. tape deck as claimed in claim 1, wherein, described choice device is selected one of a plurality of described data rates corresponding to trickplay modes.
12. tape deck as claimed in claim 1 wherein, also comprises code device, is used for before described program data recording is to the described recording medium, according to the mpeg standard described program data of encoding.
13, a kind of transcriber, be used for the playback of programs data, described program data comprises the temporal information of the synchrodata that replacement eliminates from program data, described temporal information is based on a reference clock, and expression receives the time of described program data, described program is transmitted, be used for the variable-digit speed record, and record on the recording medium with the data rate of from plurality of data speed, selecting as the function of the bit rate of the variable-digit speed of the program data of detected transmission, described plurality of data speed comprises at least one standard recording speed and 1/N this standard recording speed doubly, wherein, N is a positive integer, described program data is recorded on the adjacent track of different orientations, and this device comprises:
Drive unit is used for driving described recording medium with the transmission speed corresponding to the selected data rate that is used for writing down described program data; And
Control device is used to control described drive unit, reproduces described program data with described variable-digit speed from the adjacent track with different orientations of described recording medium.
14, transcriber as claimed in claim 13, wherein, described recording medium is a tape.
15. transcriber as claimed in claim 13, wherein, when selected data rate was doubly described standard recording speed of 1/N, described transmission speed was that 1/N is doubly corresponding to the standard transmission speed of described standard recording speed.
16. transcriber as claimed in claim 15, wherein, when N=2, described transmission speed is about 4.25 times to 4.5 times of described standard transmission speed.
17. transcriber as claimed in claim 15, wherein, when N=4, described transmission speed is about 2.25 times to 2.5 times of described standard transmission speed.
18. transcriber as claimed in claim 15, wherein, described standard transmission speed selectively is used for the normal play mode or the trickplay modes of described recording medium, and described program data is recorded on this recording medium with described standard recording speed.
19, a kind ofly be used to write down and the record and the transcriber of playback of programs data, described program data comprise some with variable-digit speed be transferred to/from the program of a recording medium, this device comprises:
Input unit is used for receiving described program data;
Clock circuit is used to produce reference clock;
The temporal information circuit, be used for eliminating the synchrodata in the program data that receives, and temporal information added to the synchrodata that is eliminated with replacement in the program data that receives, described temporal information is based on the reference clock that is produced, and represents that described program data arrives the time of described input unit;
Extraction element is used for extracting program from described program data;
Checkout gear is used for the bit rate of the program that Detection and Extraction go out;
Choice device is used for selecting comprising at least one standard recording speed and 1/N this standard recording speed doubly in the described data rate as one in several data rates of the function of the bit rate of detected described program, and wherein, N is a positive integer;
Drive unit is used for driving described recording medium with the transmission speed corresponding to selected data rate; And
Control device is used for controlling described choice device and described drive unit, so as to make a plurality of magnetic heads described program recording to the adjacent track with different orientations of described recording medium, be suppressed at interference on the described recording medium with this; Be used for obtaining the device of the data rate of described selection, be used for reproducing described program from described recording medium;
Be used for from described recording medium, reproducing the device of described program.
20. record as claimed in claim 19 and transcriber, wherein, when the data rate of described selection was doubly described standard recording speed of 1/N, described transmission speed was that 1/N is doubly corresponding to the standard transmission speed of described standard recording speed.
21. record as claimed in claim 20 and transcriber, wherein, when N=2, described transmission speed is about 4.25 times to 4.5 times of described standard transmission speed.
22. record as claimed in claim 20 and transcriber, wherein, when N=4, described transmission speed is about 2.25 times to 2.5 times of described standard transmission speed.
23. record as claimed in claim 20 and transcriber, wherein, described standard transmission speed selectively is used for the normal play mode or the trickplay modes of described recording medium, and described program data is recorded on this recording medium with described standard recording speed.
Applications Claiming Priority (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP332092/1994 | 1899-12-30 | ||
| JP304421/94 | 1994-11-14 | ||
| JP30442194 | 1994-11-14 | ||
| JP304421/1994 | 1994-11-14 | ||
| JP33209294 | 1994-12-12 | ||
| JP332092/94 | 1994-12-12 | ||
| JP031683/95 | 1995-01-27 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1131369A CN1131369A (en) | 1996-09-18 |
| CN1144457C true CN1144457C (en) | 2004-03-31 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB951203525A Expired - Fee Related CN1144457C (en) | 1899-12-30 | 1995-11-14 | Method and apparatus for reproducing/recording at variable speeds dependent upon the bit rate of the MPEG encoded signal |
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| CN (1) | CN1144457C (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6456782B1 (en) | 1997-12-27 | 2002-09-24 | Sony Corporation | Data processing device and method for the same |
| WO2002039737A1 (en) * | 2000-11-07 | 2002-05-16 | Matsushita Electric Industrial Co., Ltd. | Video signal producing system and video signal recording/reproducing device in that system |
| WO2004023803A1 (en) * | 2002-09-06 | 2004-03-18 | Sony Corporation | Information processing device and program |
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1995
- 1995-11-14 CN CNB951203525A patent/CN1144457C/en not_active Expired - Fee Related
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| CN1131369A (en) | 1996-09-18 |
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