JP3106937B2 - Packet data recording method, reproducing method, recording / reproducing apparatus, and recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet data recording method, a packet data reproducing method, a recording / reproducing apparatus, and a recording medium.
In particular, the present invention relates to a recording method, a reproducing method, a recording / reproducing apparatus, and a recording medium for recording or reproducing packet data on or from a tape-shaped recording medium.

[0002]

2. Description of the Related Art At present, not only existing analog television broadcasting but also digital television broadcasting has been put into practical use with the advancement and development of digital technology and integrated circuit technology. In this digital television broadcasting, for example, DSS (Digital Satellite Syst
em) has its own packet, D
In VB (Digital Video Broadcasting), a plurality of programs (programs) are time-division multiplexed and transmitted using an MPEG2 transport packet, which is a color moving image encoding system.

At this time, a broadcast station (encoder) receives a (transport) packet of an arbitrary program from among (transport) packets of a plurality of programs (multi-programs), and receives a (transport) packet of a receiver. (Transport) of each program at a time interval such that overflow and underflow of
Send a packet. Therefore, when only a specific program among the multi-programs of the digital television broadcast is recorded in the bit stream, the packet interval (generally called an arrival interval or an arrival time) can be accurately reproduced together with the packet contents. Must be recorded.

At this time, a continuous packet is recorded in whole in real time (for example, a multi-program transmitted without wasting capacity is entirely recorded by a device having a recording rate of substantially the same capacity) or an intermittent packet is recorded. Even in the case of recording, in the case where dummy data or the like is recorded and the time interval is filled and recorded, the packet arrival time interval is easily reproduced together with the packet content.

Further, like a hard disk or a memory,
In an apparatus capable of recording and reproducing data at random and at high speed as compared with recording on a magnetic tape, it is sufficient to simply record and reproduce packet contents and packet intervals.

[0006]

However, as described above, when recording only one arbitrary program of digital television broadcasting, that is, when a packet arriving intermittently is recorded in a bit stream on a magnetic tape, it is necessary to input the program at the time of reproduction. To reproduce the same signal as the bit stream that was reproduced, to reproduce the original packet arrival time interval, to respond to instantaneous data rate fluctuations due to variations in packets arriving per unit time, buffer memory capacity, etc. It is necessary to take into consideration the simplification of the above-mentioned apparatus and the waste of the recording capacity of the continuously running magnetic tape.

[0007] The present invention has been made in view of the above points,
In view of the above, it is an object of the present invention to provide a recording method, a reproducing method, a recording / reproducing apparatus, and a recording medium of packet data which can efficiently record and reproduce a packet of a high data rate and can correspond to many data formats. .

[0008]

In order to achieve the above object, a recording method according to the present invention provides an arrival time identification time stamp whose value changes in synchronization with an arrival time management clock of packet data to be recorded. Is generated and added to the packet data, or an arrival time management clock synchronized with a change in the value of the arrival time identification time stamp previously added to the packet data to be recorded is generated, and the arrival time management clock is generated. A track sequentially formed on a recording medium based on a reference control signal synchronized with the reference position within a range between a reference position on the track corresponding to the arrival time of the packet data and a predetermined position behind the reference position. The time stamp and the packet data are recorded in the order of arrival of the packet data.

Thus, according to the present invention, the time stamp and the packet data can be recorded by synchronizing the change of the time stamp value with the track position on the recording medium. Further, the recording position of the packet data can be freely set to move within a certain range around the reference position.

Further, in order to achieve the above object, the reproducing method of the present invention uses a recording medium in which a time stamp for identifying the arrival time of the packet data is added to the packet data and is recorded in a sequential track. While reproducing the packet data and the time stamp, an output time management clock synchronized with the recording position of the track and delayed by a predetermined time is generated, or the output time management clock is set with the reproduced time stamp as an initial value. It is characterized in that packet data generated and reproduced with reference to the output time management clock and at the timing indicated by the time stamp are output.

According to the reproduction method of the present invention, the output time management clock is generated in synchronization with the recording position of the track, the packet is output, and the capacity of the memory for temporarily storing the reproduction packet data and the time stamp is small. Can be used.

Further, a recording apparatus and a reproducing apparatus according to the present invention are apparatuses utilizing the above recording method and reproducing method, and achieve the above objects. The recording / reproducing apparatus according to the present invention is a magnetic recording / reproducing apparatus of a helical scan system, wherein the recording method and the reproducing method described above are combined. Rotation control means for synchronously controlling the rotation of the rotary drum, time stamp adding means for generating a time stamp in synchronization with the arrival time management clock and adding the packet to the packet data, packet data and time from the time stamp adding means The stamp is a reference position of the track on the magnetic tape corresponding to the arrival time of the packet data,
Start recording of a track within a track between a predetermined position behind the reference position, within two tracks between a predetermined position before and after the reference position, and a track having the reference position. 1 between the position and the given position behind
A recording processing unit for supplying a time stamp and packet data to a plurality of rotary heads within a range larger than the track range and in the order of arrival of the packet data, a clock generation unit for generating a clock of a predetermined frequency, and a magnetic tape. Track control means for controlling the running speed of the rotating drum and the magnetic tape for each of the six reproduction tracks based on the reproduction signals and the clock reproduced by the plurality of rotary heads; And a value which changes in synchronization with the output management clock and a time stamp reproduced by a plurality of rotary heads. Output means for outputting the reproduction packet data to which the symbol is added, and reproduction data output from the output means. From those having a structure in which a time stamp removing circuit for outputting and removing the time stamp.

Alternatively, in the recording / reproducing apparatus according to the present invention, in the above-mentioned recording / reproducing apparatus, the arrival time management clock is synchronized with a change in a value of an arrival time management time stamp previously added to packet data to be recorded. And generate
In this configuration, the time stamp removing circuit is removed.

Further, the recording medium of the present invention includes a plurality of packets.
Packet data and each packet in multiple packet data.
To reproduce the arrival time interval between
Timestamp added to each packet data
Recording arranged on multiple tracks sequentially formed
A medium, a plurality of packet data, and the reference position on the track corresponding to the arrival time of the packetized <br/> Ttodeta respectively, behind than the reference position, 1 track from a reference position
A first position between the first position after a period corresponding to
Within a range or ahead of the reference position, one ton from the reference position
The second position before the period corresponding to the rack and the first position
Between the recording start position of the track where the reference position exists and the first position between the recording start position and the first position.
Record and place within any of the ranges
A buffer means in the playback device for storing a plurality of packet data
, And are recorded and arranged in the order of arrival of a plurality of packet data so that the packets are reproduced in the order of arrival.

[0015]

Next, an embodiment of the present invention will be described. FIG. 1 shows a block diagram of a first embodiment of a packet data recording method and a recording system of a recording / reproducing apparatus according to the present invention. In the figure, multi-program packet data received and demodulated by a digital television broadcast receiver (set top box) is passed through a digital interface (I / F) circuit 1 to a time stamp / PCR extraction circuit 2 and recorded. It is supplied to the time stamp adding circuit 3 respectively. Here, there are two types of the set top box, one is to add a time stamp indicating the arrival time of the packet in the header of the received packet and the other is to output it without adding it. The embodiments can be applied to both types.

The time stamp / PCR extraction circuit 2 stores the time stamp added to the header of the packet data and the program time reference value of the input MPEG-2 transport stream (TS). A PCR (program clock reference) is extracted and input to a phase locked loop (PLL) 4 having an oscillation frequency of 27 MHz, and the output oscillation frequency is synchronized with a change in time stamp or PCR. In addition,
The time stamp / PCR extraction circuit 2 may not be necessarily provided.

The 27 MHz clock output from the PLL 4 as an arrival time management clock is supplied to a mod N counter 5 where it is divided by 1 / N. here,
Since the value of the dividing ratio N is set to “225000” when the system frequency of the apparatus is 30 Hz, the counter 5 outputs a signal of 120 Hz. When the system frequency is 29.97 Hz, the value of the dividing ratio N is “22522”.
5 ", and a signal of 119.88 Hz is output from the counter 5.

The output signal of the counter 5 is a recording time stamp adding circuit 3, a mod 12 × k counter 6, a frequency divider 7
And 8 respectively. The recording time stamp adding circuit 3 is a digital interface (I / F) circuit 1
A 32-bit time stamp indicating the arrival time of the packet data from the digital I / F circuit 1 is added to the header of the packet data from the digital I / F circuit 1. In addition, digital I /
Even when a time stamp is added to the header of the packet data from the F circuit 1, a new time stamp is added instead.

The 32-bit time stamp uses the 18-bit count value from the counter 5 as the lower bit and the 8-bit count value of, for example, 10 Hz (when k = 1) from the counter 6 as the upper bit ( However,
The upper 4 bits are 26 bits, which are always 0), and the upper 6 bits are added as a reserve, for a total of 32 bits. It is assumed that packet data to the digital I / F circuit 1 arrives with the arrival time interval to the set top box maintained.

The frequency divider 7 divides the output signal of the counter 5 by a frequency division ratio corresponding to the recording / reproducing mode to generate a reset signal having a 6-track cycle. 5, 6 and 1/4 are input as reset signals to the frequency divider 8, respectively. Here, as the above recording / reproducing mode, the recording rate is 19 Mbps ×
STD mode of 1 (ch), recording rate of 19 Mb
There is an HD mode which is ps × 2 (ch).

Here, two tracks are scanned by one rotation of the rotary drum 10 to be described later, and one track scanning is 1/6.
Since the time is 0 second, in the STD mode in which recording and reproduction are performed at half the speed of the tape running speed in the existing VHS standard mode, the frequency division ratio of the frequency divider 7 is set to 1/12 and 6 times. 10 Hz is output so that six tracks can be recorded and reproduced by ((1/60) × 6 = 1/10) track scanning. In the HD mode in which two rotating heads simultaneously record and reproduce two tracks in parallel at 1/60 second at the same speed as the tape running speed in the existing VHS standard mode, the frequency divider 7 is used.
Is 1/6, and 3 times ((1/60) × 3 =
The frequency is set to 20 Hz so that six tracks can be recorded and reproduced by (1/20) track scanning. It should be noted that k of 1 / (12 × k) of the frequency division ratio of the counter 6 indicates the magnification of the recording rate with respect to the STD mode.

The frequency of the 1/4 frequency divider 8 is 30 Hz or 2
The output signal of 9.97 Hz is input as a rotation reference signal of the rotating drum 10 to a drum rotation control circuit including a motor (not shown) and a drive control circuit thereof. Thus, the rotating drum 10 is synchronously rotated at 30 rps or 29.97 rps by a motor (not shown). This rotating drum 10
A magnetic tape (not shown) running at a constant speed has two rotating heads (or two double azimuth rotating heads), not shown, which are mounted on the rotating surface thereof facing each other. It is wound obliquely over an angle range slightly greater than 180 °.

Here, the two rotary heads are supplied with the packet data having the time stamp in the header extracted from the processor 9 having the memory,
As a result, recording by the known helical scan method is performed on the magnetic tape.

In this embodiment and the recording apparatus of FIG. 8 described later, a track number indicating the order of recording tracks is also generated in the recording apparatus and recorded on a magnetic tape.
That is, the processor 9 generates a track number synchronized with the six-track reference signal from the frequency divider and records the track number on the track on the magnetic tape. Therefore, the change of the time stamp and the recording track number are recorded in correspondence. In addition, similar to the existing helical scan VTR,
A control pulse of a track cycle is recorded on a magnetic tape by a control head (not shown).

In this embodiment, the change of the time stamp value and the recording track position are synchronized, and recording is performed in a synchronous manner which will be described later in detail with reference to FIG. That is, the rotating drum 10 rotates in synchronization with the change of the time stamp which is the count value of the counters 5 and 6, the recording tracks are sequentially formed, and the recording track is synchronized with the change of the time stamp.
The processor 9 specifies the position of the recording track at the repetition period of six tracks based on the track reference signal, and records the packet data having the time stamp.

Also, in this embodiment, a time stamp synchronized with the rotation control of the rotary drum 10 and the repetition position of six tracks is newly generated in the recording apparatus, and the time stamp is newly added to the packet data and recorded. There is a feature.

Next, the recording format on the magnetic tape will be described. As shown in FIG. 2, each track includes a margin area 21, a preamble area 22, a subcode area 23, a postamble area 24, an IBG area 25, a preamble area 26, a main data area 28, a postamble area 28, and a margin area 29. Consists of

Here, the main data area 28 is composed of a total of 336 sync blocks from sync block numbers 0 to 335, which are composed of a data area and an error correction code area.
Of which, the data area is 306 which is a multiple of 6 sync blocks.
The error correction code area is set in a sync block, and an error correction code area is an area in which an outer code (C3 code) for error correction is recorded, and includes 30 sync blocks.

Here, the first transmission method, MPEG2
(Moving PictureExperts Gr
The digital signal having a packet size of 188 bytes in the transport packet (TP) transmission system of up 2) and the digital signal having a packet size of 140 bytes are interchangeably recorded and reproduced on the assumption of the packet transmission system which is the second transmission system. Things.

The track format includes a recording wavelength, a required recording capacity of main data, a required recording capacity for other information, a lock area of a phase locked loop (PLL circuit),
The determination is made in consideration of the relationship with the margin area for editing and the like. Among these, when determining the required recording capacity of the main data, 6 is a least common multiple of 2 sync blocks which are recording and reproducing units of the first transmission method and 3 sync blocks which are recording and reproducing units of the second transmission method. The condition is that the data block is composed of multiples of the data sync block in units of a sync block.

The above-mentioned sync block is constituted by arranging a plurality of data areas of a fixed amount corresponding to data blocks in accordance with the scanning of the rotary head. FIG. 3 shows an example format of this sync block. As shown in the figure, a sync block includes a 2-byte synchronization signal (Sync) area 31 for reproducing the sync block,
A 3-byte address information (ID) area 32, a 99-byte substantial data storage area 33 including a header,
The 8-byte parity area 34 for error correction of the information of the sync block is combined in a time-series manner to form a total of 112 bytes.

Here, when the set top box records the digital signal of the MPEG2-TS system of the first transmission system of the type in which the time stamp indicating the arrival time of the packet is not added to the header of the received packet, FIG. 4 shows SB # n and SB
These are sync blocks indicated by # n + 1, respectively.
A digital signal is repeatedly recorded in units of two sync blocks SB # n and SB # n + 1, and reproduced.

Here, in FIG. 4, the sync block S
B # n is the 99-byte data storage area 3 shown in FIG.
Area 3 is a 4-byte additional information storage area 40 in which additional information (eg, packet arrival time and other information) of one packet (188 bytes) is recorded and reproduced;
It comprises a data storage area 41 for recording and reproducing 92 bytes of data from the beginning of one 188-byte packet. Also, the adjacent sync block S
B # n + 1 is the remaining 9 of the one packet.
Data storage area 4 for recording and reproducing 6-byte data
2. The time stamp is recorded in the additional information storage area 40.

Further, the set top box is
A second transmission system of a type in which a time stamp indicating the arrival time of a packet is added to the header of a received packet is one of the U.S. digital broadcast television standards, and has a packet size of 130 bytes and 10 bytes of data. (Dummy or additional information) and transmit it in a size of 140 bytes (for convenience of explanation, this 14
0 byte is also called a packet). At the time of digital signal recording of this system, the sync blocks shown in FIG. 3 are changed to sync blocks indicated by SB # n, SB # n + 1 and SB # n + 2 in FIG. 5, respectively, and these three sync blocks SB # n and SB # n + 1 And a digital signal is repeatedly recorded in units of SB # n + 2 and reproduced.

Here, in FIG. 5, the sync block S
B # n indicates that the data storage area 33 shown in FIG.
Of the 4-byte additional information (for example, packet arrival time and other information) for each of two packets (2 × 140 = 280 bytes), 4-byte additional information for the first packet is recorded and reproduced. It comprises an additional information storage area 45 and a data storage area 46 for recording and reproducing 92 bytes of packet data from the beginning of the first packet.

The adjacent sync block SB # n +
1 indicates that the area of the data storage area 33 shown in FIG. 3 has the remaining 38-byte packet data of the first packet of the above two packets and the 10-byte data added thereto (dummy data or Data storage areas 47 and 48 in which additional information is recorded and reproduced, an additional information storage area 49 in which 4-byte additional information for the second packet is recorded and reproduced, and 44 bytes of data from the beginning of the second packet And a data storage area 50 for recording and reproduction.

Further, in the sync block SB # n + 2, the area of the data storage area 33 shown in FIG. 3 is added to the remaining 86-byte packet data of the second packet of the above two packets. 10 bytes of data (dummy data or additional information) are formed of data storage areas 51 and 52, respectively. The time stamp is recorded in the additional information storage areas 45 and 49.

As a result, since one packet of the digital signal of the first transmission method is recorded in units of two sync blocks, 153 (= 306/2 ×)
1) The packet is recorded and reproduced. In the digital signal of the second transmission method, two packets are recorded in units of three sync blocks.
(= 306/3 × 2) packets are recorded and reproduced.

Next, the relationship between the packet data and the time stamp and the recording track position on the magnetic tape will be described. In this embodiment, the change of the time stamp is synchronized with the recording track position, that is, a so-called synchronous system in which the value of the time stamp and the track position are related.

That is, changes in the time stamps (000,..., 500,...) Shown in FIG.
A counter 5 based on the reference clock of the recording device shown in FIG.
The positions (0-00,..., 5-00,...) On the track shown in FIG. The signal is recorded by the processor 9 in a repetition cycle of six tracks by the reference signal, and the time stamp change and the track position are synchronized. For example, time 000 of the time stamp corresponds to position 0-00 on the track (the head position of the track number).

Now, the digital I / F circuit 1 is shown in FIG.
As schematically shown in (A), 100 packet data from the 000th to the 099th arrives continuously in 1/60 second, and after that, the 200th packet data after 1/60 second and further every 1/120 second It is assumed that the 250th and 300th packet data have arrived intermittently.

In this case, of the tracks sequentially recorded on the magnetic tape every 1/60 second, as shown in FIGS. 6B and 6D, from the 000th to the 099th which arrived continuously. Are recorded in two consecutive tracks (more precisely, in a data area as described later). This is because the 100th packet data from the 000th to the 099th arrives continuously, so that the data rate instantaneously becomes higher than the recording rate on the magnetic tape and cannot be recorded on one track. The packet data is time-expanded and recorded on the two tracks using the memory in the processor 9.

On the other hand, the 200th and 250th packet data intermittently arriving and their time stamps are recorded on the next track in accordance with the arriving time.
Further, the 300th packet data and its time stamp are recorded on the next track corresponding to the arrival time.

In the above recording method, the packet data input intermittently is recorded together with the time stamp in accordance with the arrival time. On the other hand, FIG.
If there is no packet data between the 200th packet data and the 250th packet data as indicated by I between (B) and (B), the 250th packet data and its time stamp are recorded on the same track. 20 to be done
The recording may be performed following the 0th packet data and its time stamp. In this specification, this recording method is referred to as a left-justified method.

In both the pseudo real-time system and the justified system, the packet arrival order is recorded in order while observing the order. This is because the time stamp is repeated at a time interval of six tracks, and before and after the counter reset, the magnitude of the time stamp does not match the order of arrival time.

Next, the pseudo real-time method and the justification method will be described in detail with reference to FIG. As shown in FIG. 7A, when a packet P is input within one track period (= 1/60 s), as shown in FIG.
Of the tracks recorded in the track cycle of the book, as shown by the solid arrow R in the pseudo real-time method, they are recorded in the section between the tracks T0 and T1 corresponding to the packet P. As shown, it is recorded in the section between tracks T0 and T1.

That is, as described above, as shown in FIG. 7B, packet data is recorded in the area Y of 306 sync blocks from sync block numbers 0 to 305, which are data areas in one track. As shown in FIG. 7 (C), the packet P arriving near the center position of the packet P in the pseudo real-time system is located within the data area R within one track behind the track position (reference position M) corresponding to the arrival position. The data is recorded in the data area F within one track from the position SB0 of the first sync block number 0 of the track corresponding to the arrival position to the track position corresponding to the arrival position (reference position M) in the justified format. Recorded with MSB justified.

In FIGS. 7 (C), 6 (B) and 6 (D) and FIGS. 11 (B) and 11 (D) to be described later, black triangles indicate track boundaries, and black circles indicate track data. It indicates the boundary of the area.

For this reason, a buffer memory for one track is required for the recording of the pseudo real time system, and a buffer memory for two tracks is required for the recording of the justified system. In either method, the position of the actually recorded packet data on the track can be freely set within the above range, so that even when a high data rate packet arrives instantaneously, the recording is extended and recorded. Therefore, the recording capacity of the magnetic tape can be efficiently used without waste, and a specific position on the track can be fixedly recorded for special data (for high-speed reproduction data, for example). Can respond to.

Further, in the justified method, since the packet data only needs to be left-justified from the data recording start position on the track and recorded continuously at one time, the design of the recording apparatus is easier than in the pseudo real-time method. .

In a recording apparatus that uses both the pseudo real-time recording method and the justified recording method, a minimum of 2
A buffer memory for the track is required. Therefore, in such a case, the pseudo real-time recording range may be extended to two tracks. That is, as shown in FIG. 7C, the packet P arriving near the center position is 2
In the pseudo real-time method using a buffer memory for a track, data is recorded in a data area 2R for a total of two tracks in front of and behind a track position (reference position M) corresponding to the arrival position. In the recording of the pseudo real-time system for two tracks, the recording position can be moved and set over a wider range, and the degree of freedom increases.

FIG. 8 is a block diagram showing a second embodiment of the packet data recording method and the recording system of the recording / reproducing apparatus according to the present invention. In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals. The embodiment shown in FIG. 8 is a type in which a time stamp indicating the arrival time of a packet is added to the header of a received packet by the set-top box, and a synchronized drum control pulse and a six-track reference signal are used. It is applied only to those that can be generated with the time stamp added in advance.

In FIG. 8, a received packet having a time stamp indicating the arrival time of the packet added to the header is extracted by the time stamp extracting circuit 11, and the PLL 4 and the mod N counter 12
And the counter 13 of the mod 12 are supplied as reference values.

The output signal of the PLL 4 is divided by the mod N counter 12 into 1 / N (N = 225000 in this case) to 120 Hz, and further divided by the mod 13 counter 13 into 1/12 to 10 Hz. And 1/4
It is supplied to the frequency divider 8 and the frequency divider 14. The counter 12 generates a clock synchronized with the time stamp in the packet data from the digital I / F circuit 1 and
The rotation of the rotary drum 10 is controlled via the frequency divider 8.

It is to be noted that both output signals of the counters 12 and 13 are input to the 1/4 frequency divider 8 as reset signals, respectively, so that the values of both output signals of the counters 12 and 13 become predetermined values. The 1/4 frequency divider 8 is reset every second. This is because the output of the counter 12 is used in addition to the output of the counter 13 to reset it with higher accuracy. May reset the 1/4 frequency divider 8 only with the output signal of the counter 13.

The frequency divider 14 divides the input signal by 1/12 and supplies a 10 Hz signal to the processor 15 as a reference signal for every six tracks. Processor 15 is a digital I / O
Receiving the packet data from the F circuit 1 as an input signal,
This is processed together with a track number synchronized with a reference signal for every six tracks and supplied to a recording head (not shown).

In this embodiment, packet data is recorded by a so-called synchronous method in which the change of the time stamp value and the recording track position are synchronized. This embodiment generates a clock synchronized with a time stamp added in advance in the packet data from the digital I / F circuit 1 to control the rotation of the rotary drum 10 and to record a track with a track number. There is a feature.

FIG. 9 is a block diagram showing a first embodiment of the packet data reproducing method and the reproducing system of the recording / reproducing apparatus according to the present invention. This embodiment is similar to that of FIGS.
This is a reproducing apparatus of the magnetic tape recorded by the synchronous recording apparatus shown in FIG. In the figure, a recorded digital signal on a magnetic tape is reproduced by a rotating head (not shown),
The reproduced signal is supplied to the processor 68.

On the other hand, the oscillation output signal (clock) of 27 MHz output from the crystal oscillator 61 is mod N
After the 1 / N frequency division by the counter 62 of
3, a mod 12 × k counter 64 and a ４ frequency divider 65, respectively. The output signal of the １ ／ frequency divider 65 is output as a rotation control signal of the rotary drum 10. The output signal of the frequency divider 66 is output to the processor 68
Is input as a reference signal having a 6-track cycle,
The signals are input as reset signals to the counters 62 and 64 via the ４ frequency divider 65 and the one-track delay circuit 67, respectively.

Here, the frequency divider 66 has a frequency division ratio of 1/12 in the STD mode and 1/6 in the HD mode. It should be noted that the frequency division ratio of the counter 64 is 1 / (12 ×
k in k) indicates a magnification of the recording rate with respect to the STD mode.

The processor 68 discriminates the track number from the reproduced signal, compares the track number with the reference signal from the frequency divider 66, and generates a capstan control signal so that the two are synchronized with each other to drive the capstan 71. The rotation of a motor (not shown) is controlled to control the running phase of the magnetic tape. Note that a reproduction control pulse is also used to control the rotation of the capstan 71, as in the existing helical scan type VTR. Further, the processor 68 separates the time stamp from the reproduction signal and supplies the time stamp to the comparison circuit 63.

The output signal of the frequency divider 66 is
This signal is input as a reset signal of the 1/4 frequency divider 65, and after being delayed (offset) by one track period by the one-track delay circuit 67, the signals are sent to the counters 62 and 64. Each is input as an output time management reset signal.

Therefore, the count values of the counters 62 and 64 are offset-synchronized with the position on the track to be reproduced, and the 18-bit count value from the counter 62 and the 8-bit count value from the counter 64 (output clock) ) Are compared in the comparison circuit 63 to determine whether they match the lower 18 bits and the upper 8 bits of the 26-bit time stamp in the reproduced signal from the processor 68, and when they match, an output instruction is generated by the comparison circuit 63. .

When this output command is input, the processor 68 reads the reproduced signal stored in the internal memory thereof and supplies it to the time stamp removing circuit 69, where the time stamp is removed and the reproduced packet is removed. The data is obtained and output to a circuit subsequent to the set top box via the digital I / F circuit 70. Set Top
In the box, the reproduction packet data is expanded and demodulated and output as, for example, video and audio.

In this embodiment, when playback is performed from the 000th packet data recording position indicated by a in FIG. 6B, the playback signal is delayed by one track as shown in FIG. 6C. After that, the data is reproduced in 1/60 seconds, and the original arrival interval is reproduced to reproduce the recorded packet data. In FIG. 6, S indicates the capacity of the buffer memory in the processor 68 required at the time of reproduction.

The output clocks shown in FIGS. 6C and 6E (the count values of the counters 62 and 64 in FIG. 9) are recorded in synchronization with the change of the time stamp and the position on the track. For example, when the position on the track is “0-00”, the value offset by one track period is “5”.
An output clock value of “00” is uniquely generated, and a packet having a corresponding time stamp is output based on the output clock.

The 000-th packet is the first packet that has been time-expanded, and in order to reproduce the time interval with the 099-th packet that is the last packet that has been time-expanded, the 000-th packet has one track. It is necessary to output with a delay of a minute.

When the data is reproduced from the recording position of the 099th packet data indicated by b in FIG. 6D, the reproduced signal becomes one track after the reproduction of the 099th packet data as shown in FIG. 6E. After being delayed by the minute, the next 200th packet data is reproduced.

In the embodiment of the reproducing system corresponding to the synchronous recording, the change of the position on the track and the output clock change correspondingly, and a fixed offset value between them, that is, In the pseudo real time method for one track, there is an offset value for one track period,
The output clock is uniquely generated as an offset value for one track period. In this embodiment, the capacity of the buffer memory in the processor 68 can be as small as the capacity at the time of recording. An extra buffer memory such as an asynchronous type described later with reference to FIGS. 11D and 11E is not required.

Next, a description will be given of a second embodiment of the packet data reproducing method and the reproducing system of the recording / reproducing apparatus according to the present invention. FIG. 10 is a block diagram showing a second embodiment of the packet data reproducing method and the reproducing system of the recording / reproducing apparatus according to the present invention. 9, the same components as those of FIG. 9 are denoted by the same reference numerals, and the description thereof will be omitted. This embodiment is a playback apparatus connected to a type for adding a time stamp to a packet received by the set top box.

This reproducing apparatus has a configuration in which the time stamp removing circuit 69 provided in the reproducing apparatus of FIG. 9 is deleted.
In this reproducing apparatus, packet data with a time stamp added to the header reproduced from the recorded magnetic tape is input to the processor 68, and when the output time management clock matches the time stamp from the comparison circuit 63. The data is read out and output to the digital I / F circuit 70 as it is.

In the embodiment shown in FIGS. 9 and 10, if there is a buffer amount capable of reproducing the packet data recorded in the left-justified format (double the capacity of the pseudo real-time format), the packet recorded in the pseudo real-time format is used. Can play data.

Although the above is the embodiment of the synchronous system, the present invention can also be applied to an asynchronous system in which the reference change of the time stamp and the track position are asynchronous. This asynchronous recording / reproducing method will be described with reference to FIG.
Now, as schematically shown in FIGS. 11A and 11D, it is assumed that the packet data and the time stamp are recorded in a pseudo real-time manner regardless of the track position.

Here, “00” shown by a in FIG.
When playing from the 0th packet data recording position,
As schematically shown in FIG. 11C, after the reproduction signal is delayed by one track, the time stamp of the reproduction signal is set with the time stamp of 000 added to the reproduced 000th packet data as an initial value. Independently generates a timing clock for output from the
-Th to the 099th packet data are reproduced.
After the delay of the track, the 200th and subsequent packet data are reproduced. That is, the original arrival interval is reproduced, and the recorded packet data is reproduced. In FIG. 11 , S indicates the capacity of the buffer memory in the processor 68 .

When the data is reproduced from the recording position of the 099th packet data indicated by b in FIG. 11 (D), the reproduced signal is represented by the 099th packet data as schematically shown in FIG. 11 (E). After playing one track delayed,
The next 200th packet data is reproduced with a delay of one track.

This is because the 099th packet is not the first packet that has been time-expanded like the 000th packet, but it cannot be determined whether or not it is a time-expanded packet during reproduction. This is because it is necessary to uniformly delay the output by one track. Furthermore,
Since the 099th packet and the 200th packet separated by one track in the arrival time interval may be continuously recorded on the track, the 200th packet is reproduced in order to reproduce this interval. Is required to be output with a delay of one track.

Therefore, in order to reproduce packet data recorded in the asynchronous system and in the pseudo real-time system, a buffer memory having a capacity twice as large as that of the buffer memory at the time of recording is required.

In order to record / reproduce packet data recorded in the asynchronous system and in the justified system, a buffer memory having a capacity twice as large as that of the synchronous pseudo real-time system is required at the time of recording. Sometimes, a buffer memory having a capacity three times or four times as large as that of the synchronous pseudo-real-time system is required. However, the asynchronous system has a simpler configuration than the synchronous system shown in FIGS.

In either case of the synchronous type or the asynchronous type, if the packet data to which the time stamp is added is recorded by the pseudo-real method or the justified method described with reference to FIG. Position can be moved freely within a certain range, so that even when a high data rate packet arrives instantaneously, it is possible to record the data by expanding the time and efficiently using the recording capacity of the magnetic tape without waste. Further, a specific position on the track can be fixedly recorded as special data (for example, for high-speed reproduction data), and it can correspond to many data formats.

[0080]

As described above, according to the present invention,
Since the time stamp value and the packet data can be recorded and reproduced by synchronizing the change of the time stamp value with the track position on the recording medium, even when a high data rate packet is time-expanded and recorded, With the small-capacity buffer memory, the same data as the input bit stream can be reproduced from the packet data at the original packet arrival intervals. When packet data can be recorded within a predetermined range around the reference position (pseudo real-time, left-justified), the data recording area of the track can be used freely, so that it can support many data formats.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of a packet data recording method and a recording system of a recording / reproducing apparatus according to the present invention.

FIG. 2 is a diagram illustrating an example of a track format.

FIG. 3 is a diagram showing a format of an example of a sync block.

FIG. 4 is a diagram showing a configuration of a sync block when recording a digital signal of a first transmission method.

FIG. 5 is a diagram illustrating a configuration of a sync block when recording a digital signal of a second transmission method.

FIG. 6 is a diagram showing an example (synchronous type) of a relationship between packet data recorded and reproduced according to the present invention, a time stamp, and a recording track position on a magnetic tape.

FIG. 7 is a diagram illustrating a recording method of the pseudo real-time method and the justified method according to the present invention.

FIG. 8 is a block diagram of a second embodiment of a packet data recording method and a recording system of a recording / reproducing apparatus according to the present invention.

FIG. 9 is a block diagram of a first embodiment of a packet data reproducing method and a reproducing system of a recording / reproducing apparatus according to the present invention.

FIG. 10 is a block diagram of a second embodiment of a packet data reproducing method and a reproducing system of a recording / reproducing apparatus according to the present invention.

FIG. 11 is a diagram showing another example (asynchronous type) of a relationship between packet data recorded and reproduced according to the present invention, a time stamp, and a recording track position on a magnetic tape.

[Explanation of symbols]

 1, 70 Digital interface (I / F) circuit 2 Time stamp / PCR extraction circuit 3 Recording time stamp addition circuit 4 27 MHz phase locked loop (PLL) 5, 12, 62 mod N counter 6, 13, 64 mod 12 × k Counters 7, 14, 66 Frequency divider 8, 65 Quarter frequency divider 9, 15, 68 Processor 10 Rotating drum 11 Time stamp extraction circuit 40, 45, 49 Additional information storage area 61 27 MHz crystal oscillator 63 Comparison circuit 67 1 Track delay circuit 69 Time stamp removal circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/91-5/956 G11B 20/10-20/12 H04N 5/782-5/783 H04N 7 / 24-7/68

Claims (16)

(57) [Claims] 1. A time stamp for identifying an arrival time, the value of which changes in synchronization with an arrival time management clock of packet data to be recorded, is generated and added to the packet data. Tracks sequentially generated on a recording medium based on a reference control signal synchronized with a change in the value of the added time stamp for arrival time identification, which is synchronized with a change in the value of the arrival time identification time stamp. The time stamp and the packet data within a range between a reference position on the track corresponding to the arrival time of the packet data and a predetermined position behind the reference position, and in the order of arrival of the packet data. Recording method for recording packet data. 2. A time stamp for identifying an arrival time, the value of which changes in synchronization with a clock for managing the arrival time of packet data to be recorded, is generated and added to the packet data. Tracks sequentially generated on a recording medium based on a reference control signal synchronized with a change in the value of the added time stamp for arrival time identification, which is synchronized with a change in the value of the arrival time identification time stamp. Recording the time stamp and the packet data within a range between a predetermined position in front of and behind a reference position on the track corresponding to the arrival time of the packet data, and in the order of arrival of the packet data. A recording method of packet data, characterized in that: 3. A time stamp for arriving time identification, whose value changes in synchronization with a clock for arriving time management of packet data to be recorded, is generated and added to the packet data, or is added to the packet data to be recorded in advance. Tracks sequentially generated on a recording medium based on a reference control signal synchronized with a change in the value of the added time stamp for arrival time identification, which is synchronized with a change in the value of the arrival time identification time stamp. In a range between the data recording start position of the track where the reference position on the track corresponding to the arrival time of the packet data is present and a predetermined position behind the reference position, and A packet data recording method, wherein the time stamp and the packet data are recorded with the data recording head position shifted in the order of arrival. Data recording method. 4. A packet is sequentially formed on a recording medium based on a reference control signal which is newly added to packet data to be recorded or which is asynchronous with a change in a time stamp value for arrival time identification added in advance. A track, a position on the track corresponding to the arrival time of the packet data,
A method for recording packet data, comprising recording the time stamp and the packet data within a range between a predetermined position behind the position and the arrival order of the packet data. 5. A packet is sequentially formed on a recording medium based on a reference control signal which is newly added to packet data to be recorded or which is asynchronous with a change in a time stamp value for arrival time identification added in advance. The track has a reference position on the track corresponding to the arrival time of the packet data, within a range from a data recording start position of the track where the reference position is located to a predetermined position behind the reference position, and Recording the time stamp and the packet data in the order of arrival. 6. A packet is sequentially formed on a recording medium based on a reference control signal which is newly added to packet data to be recorded or which is asynchronous with a change in a time stamp value for arrival time identification added in advance. Recording the time stamp and the packet data on a track within a range between a predetermined position in front of and behind a position on the track corresponding to the arrival time of the packet data, and in the order of arrival of the packet data. Characteristic packet data recording method. 7. The packet data recording method according to claim 1, wherein the packet data to which the time stamp is added is recorded after being expanded in time. 8. Reproducing the packet data and the time stamp from a recording medium in which a time stamp for identifying the arrival time of the packet data is added to the packet data and sequentially recording the data on the track, and recording the track on the track. Synchronizing with the position, generating an output time management clock delayed by a predetermined time, and outputting the reproduced packet data based on the output time management clock and at the timing indicated by the time stamp. Characteristic packet data playback method. 9. The packet data and the time stamp are reproduced from a recording medium in which a time stamp for identifying the arrival time of the packet data is added to the packet data and recorded in a sequential track, and the reproduced time stamp is reproduced. Is used as an initial value to generate an output time management clock, based on this output time management clock, and
Outputting the reproduced packet data at the timing indicated by the time stamp. 10. A means for generating an arrival time management clock, and a time stamp for identifying an arrival time of packet data to be recorded is generated in synchronization with the arrival time management clock and added to the packet data. A time stamp adding means, and the packet data and the time stamp from the time stamp adding means are used as a reference position of a track on a recording medium corresponding to an arrival time of the packet data, or a recording start position of a track where the reference position exists. Or a recording unit that records the time stamp and the packet data in a range between a predetermined position before the reference position and a predetermined position after the reference position, and in the order of arrival of the packet data, The position of a track recorded on the recording medium by the recording means is used for the arrival time management. A packet data recording device, comprising: control means for controlling in synchronization with a clock. 11. A means for generating an arrival time management clock synchronized with a change in the value of an arrival time identification time stamp added to packet data to be recorded in advance, and adding an arrival time identification time stamp. The packet data to be recorded is recorded at a track position on the recording medium corresponding to the arrival time of the packet data, a recording start position of a track where the track position exists, or a predetermined position ahead of the track position. And within a range between a predetermined position behind the position of the track, and
Recording means for recording the time stamp and packet data in the order of arrival of the packet data; and control means for controlling the position of a track recorded and formed on the recording medium by the recording means in synchronization with the arrival time management clock. And a packet data recording device. 12. A reproducing means for reproducing the packet data and the time stamp from a recording medium in which a time stamp for identifying the arrival time of the packet data is added to the packet data and recorded in a sequential track; Clock generating means for generating a clock of the following; track control means for controlling a track reproducing position of the recording medium by the reproducing means in synchronization with the clock; and generating an output management clock by delaying the clock for a predetermined time. Output management clock generation means, comparing a value that changes in synchronization with the output management clock, and a time stamp reproduced by the reproduction means,
Output means for outputting the reproduced packet data to which the coincident time stamp is added each time the two coincide with each other. 13. The apparatus according to claim 1, further comprising a time stamp removing circuit for removing the time stamp from the reproduction data output from the output means and outputting the data.
3. The packet data reproducing device according to 2. 14. A packet data and a time stamp for identifying the arrival time of the packet data, respectively, on a magnetic tape that is wound around the rotary drum over a predetermined angle range by a plurality of rotary heads mounted on the rotary drum. What is claimed is: 1. A recording / reproducing apparatus for forming and recording a sequential track and reproducing said packet data and time stamp from said track using said rotary head, comprising: means for generating an arrival time management clock; The track 6 based on the clock for
Rotation control means for synchronously controlling the rotation of the rotary drum for each book; time stamp adding means for generating the time stamp in synchronization with the arrival time management clock and adding the time stamp to the packet data; The packet data and the time stamp from the means, the reference position of the track on the magnetic tape corresponding to the arrival time of the packet data,
Recording within one track between a predetermined position behind the reference position, within two tracks between each of a predetermined position before and after the reference position, or a track where the reference position exists Recording processing means for supplying the time stamp and the packet data to the plurality of rotary heads within a range larger than one track range between the start position and the rear predetermined position and in the order of arrival of the packet data; A clock generating means for generating a clock having a predetermined frequency; and a reproduction signal reproduced from the magnetic tape by the plurality of rotary heads and the clock, wherein the rotation drum and the magnetic tape are provided for every six reproduction tracks. A track control means for controlling a running speed; and an output management clock for generating an output management clock by delaying the clock for a predetermined time. And a value which changes in synchronization with the output management clock, and a time stamp reproduced by the plurality of rotary heads. Each time they match, the matching time stamp is added. A recording / reproducing apparatus comprising: an output unit for outputting the reproduced packet data; and a time stamp removing circuit for removing the time stamp from the reproduced data output from the output unit and outputting the data. 15. A packet data and a time stamp for identifying the arrival time of the packet data, respectively, on a magnetic tape that is inclined over the rotary drum and wound around a predetermined angle range by a plurality of rotary heads mounted on the rotary drum. What is claimed is: 1. A recording / reproducing apparatus which forms and records a sequential track and reproduces said packet data and time stamp from said track using said rotary head, wherein said apparatus is used for managing an arrival time previously added to packet data to be recorded. Means for generating an arrival time management clock synchronized with a change in the value of the time stamp, and the track 6 based on the arrival time management clock.
Rotation control means for synchronously controlling the rotation of the rotary drum for each book; the packet data to be recorded and a time stamp added in advance to the track data on a track on the magnetic tape corresponding to the arrival time of the packet data; The reference position exists within one track between a reference position and a predetermined position behind the reference position, or within two tracks between each predetermined position before and after the reference position, or the reference position exists The time stamp and the packet data are supplied to the plurality of rotary heads within a range larger than one track between the recording start position of the track to be recorded and the rear predetermined position and in the order of arrival of the packet data. Recording processing means; clock generation means for generating a clock of a predetermined frequency; and reproduction from the magnetic tape by the plurality of rotary heads Track control means for controlling the running speed of the rotary drum and the magnetic tape for every six reproduction tracks based on the reproduced signal and the clock, and generating an output management clock by delaying the clock for a predetermined time. An output management clock generating unit that compares a value that changes in synchronization with the output management clock with a time stamp reproduced by the plurality of rotary heads. And an output unit for outputting the reproduced packet data to which is added. 16. A plurality of packet data and a plurality of said plurality of packet data.
Arrival time between packet data in packet data
To reproduce the interval during playback, the multiple packet data
Time stamps added to each
A recording medium recorded and arranged on a plurality of tracks, wherein the plurality of packet data are respectively stored in a reference position on the track corresponding to an arrival time of the packet data, and the reference position behind the reference position. From 1 to
The first position after the period corresponding to the rack
1 or in front of the reference position,
The second position before a period corresponding to one track from the position
And a recording start position of a track within a second range between the first position and the track where the reference position exists .
Within any of the third ranges between the first position
While arranging the recording, the recording
Data arrives via buffer means in the playback device
To be sequentially reproduced, the recording medium characterized by recording disposed in the order of arrival of said plurality of packet data.