JPH1125600A - Recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently use a recording area of a recording medium on the side of a terminal device. SOLUTION: A packet identifier(PID) from a PID register 75 into which this PID fitted to a header of a program selected by a user in advance is loaded and a PID fitted to a header of each individual program of a transmitting channel detected by a packet header detecting circuit 73 are compared by a coincidence detecting circuit 76. Upon detection of coincidence of the above two PIDs, a packet data compressing part 72 is controlled by a control circuit 74 to output this packet without being compressed, and upon detection of noncoincidence of the two PIDs, a data main body (pay-load) is compressed and outputted without compressing the header. By recording a data from this compressing part 72 on a recording medium, unrequired program data other than program data selected by the user can be compressed and recorded leaving headers unchanged, so that the recording area of the recording medium can efficiently be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for transmitting and receiving signals between apparatuses and a technique for recording and reproducing the same, and more particularly to a movie or program transmitted by a transmission means such as a coaxial cable, an optical cable, a telephone line, and a satellite broadcast. The present invention relates to a recording / reproducing apparatus suitable for a digital video system or the like for receiving the digital information signal described above and transmitting / receiving the received digital information signal between apparatuses.

[0002]

2. Description of the Related Art In recent years, as a form of broadcasting and communication, a digital system represented by international standards such as MPEG has been adopted. In this method, audio and video signals constituting a program are digitized, compression-encoded, packetized in a predetermined format, and multiplexed, and a plurality of programs are packetized in a conventional single transmission channel. Time division multiplexing and transmission are possible. The MPEG standard also specifies multiplex transmission with digital information signals such as program information.

Here, when decoding a signal compressed in this manner, if the decoding speed is higher than the transmission speed of the signal sending side, the data becomes insufficient and decoding becomes impossible. Therefore, it is necessary to synchronize between the transmission speed of the signal to be transmitted and the decoding speed of the signal.

For this reason, in the MPEG-2 standard standardized after the MPEG-1 standard, a time reference value called "PCR" is added to packet data.
At the time of decoding, a clock signal for decoding is restored based on the PCR. Therefore, the arrival time of the packet cannot move.

On the other hand, in the related art, Japanese Patent Laid-Open Publication No. Hei 8-297922 discloses a digital signal for recording and reproducing only a desired program by removing unnecessary programs and data from such digitally transmitted data. Recording and reproducing methods and apparatuses have been proposed.

In this method and apparatus, only packets of a desired program are sequentially taken out from a plurality of programs (bit streams) transmitted in a time-division multiplexed manner as described above, and the intervals between the packets are reduced to be recorded on a recording medium. At the time of this recording, packet arrival time information is added as a header to each packet and recorded so that the original packet can be reproduced while maintaining the time interval of the original packet. ing.

At the time of reproduction, a packet of a program recorded on a recording medium is reproduced by returning the interval on the time axis of a packet to be actually reproduced based on the packet arrival time. I have.

[0008]

However, in this method and apparatus for recording and reproducing digital signals, it is necessary to newly add a header including time information to all packets to be recorded in a bit stream. . Therefore, there is a problem that complicated circuits and processes such as timing control for adding a header and delay control of recording timing of a packet for the header are required. Similarly, at the time of reproduction, complicated circuits and processes are required to restore the clock signal for decoding based on the time information and to control the packet interval to be reproduced. Thus, there is a problem that the circuit scale of the device is large and expensive.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and can be realized at a low cost with a small circuit scale, eliminating unnecessary programs and data, and recording only desired programs efficiently and stably. It is an object of the present invention to provide a recording / reproducing apparatus capable of reproducing and improving the recording efficiency of a recording medium.

[0010]

According to the present invention, there is provided a recording / reproducing apparatus which performs recording from among data which is packetized and time-division multiplexed with header information and transmitted in order to solve the above-mentioned problem. Recording data selection means for selecting one or a plurality of desired data; and record matching detection for detecting a match between header information of each transmitted data and header information of data selected by the recording data selection means. Means for detecting the coincidence of each of the header information by the recording coincidence detecting means, and recording the corresponding data on a recording medium without compression, and detecting the inconsistency of each of the header information by the recording coincidence detecting means. And recording control means for compressing a portion of the corresponding data other than the header information and recording the compressed data on a recording medium.

Also, together with the recording means, reproduction data selecting means for selecting desired data to be reproduced from data recorded on the recording medium, and header information of each data reproduced from the recording medium. Reproduction match detection means for detecting a match between the header information of the data selected by the reproduction data selection means and the header information of the data selected by the reproduction data selection means, and expanding the corresponding data when the match of the respective header information is detected by the reproduction match detection means. And reproduction control means for decompressing and reproducing a part other than the header information of the corresponding data when the reproduction coincidence detection means detects a mismatch of the header information. .

The fact that the header information of each of the transmitted data matches the header information of the data selected by the recording data selecting means means that the data currently received is the data for which recording is specified. Indicates that For this reason, when the coincidence of the header information is detected by the recording coincidence detecting means, the recording control means records the corresponding data on the recording medium without compression.

The fact that the header information of the transmitted data does not match the header information of the data selected by the recording data selecting means means that the recording of the currently received data is specified. Indicates that the data is not present and is unnecessary data. For this reason, when the record matching detecting means detects the mismatch of the respective header information, the recording control means compresses a portion other than the header information of the corresponding data and records it on the recording medium.

Thus, unnecessary data can be compressed and recorded, so that the recording area of the recording medium occupied by the unnecessary data can be minimized.
The recording area of the recording medium can be used efficiently.

[0015] Even if the data is unnecessary to be compressed,
Because header information is recorded without compression,
Using the time information attached to the original header information, data of the original bit length can be reproduced. Therefore, it is not necessary to form header information to which new time information is added and to add the header information to each program data, and to form and record the header information to which this new time information is added and to record the data to which the header information is added. A complicated processing circuit or the like required for reproduction can be omitted, and the circuit size and cost of the recording / reproducing apparatus can be reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the recording / reproducing apparatus according to the present invention will be described below in detail with reference to the drawings.

First, a recording / reproducing apparatus according to the present invention will be described with reference to FIG.
It can be applied to a video distribution service system using a communication satellite as shown in FIG.

In the video distribution service system according to the first embodiment of the present invention, a center apparatus 1 for transmitting data such as a movie or a program in response to a user request or the like, and a subscription to the video distribution service system. It is composed of a terminal device 2 lent to a user and a communication satellite 3 that relays data transmitted from the center device 1 to the terminal device 2.

The center device 1 includes a software supply center 4 for transmitting data such as a movie and a program (hereinafter referred to as program data), and a terminal device 2 on the user side via a telephone line 14.
An operation center 5 for controlling transmission of program data in response to a request from a user; a program distribution center 6 for controlling distribution of program data from the software supply center 4 in accordance with control by the operation center 5; The transmission unit 7 transmits the program data whose distribution is controlled by the program distribution center 6 to the communication satellite 3.

FIG. 1 shows a software supply center 4.
However, there are actually a plurality of software supply centers, and the user receives program data from each of these centers.

The terminal device 2 provided on the user side includes a receiving unit 10 for receiving program data from the center device 1 distributed via the communication satellite 3, and a data processing of the program data received by the receiving unit 10. TV receiver 9
And a terminal main body 8 that supplies the power to the terminal.

The terminal body 8 includes a telephone / modem 11 which is a telephone and a communication modem connected to the operation center 5 of the center apparatus 1 via a telephone line 14, and a receiving unit 10
A receiver decoder 12 that decodes the program data received by the receiver and supplies it to the television receiver 9, and records the program data decoded by the receiver decoder 12 on a recording medium such as a hard disk or a magneto-optical disk, and reproduces the program data And a reproduction unit 13.

Although only one terminal device 2 is shown in FIG. 1, there are actually a plurality of subscriber terminal devices.

Next, the operation of the video distribution service system according to the embodiment having the above configuration will be described.

First, the program distribution center 6 provided in the center device 1 has a configuration as shown in FIG. 2 in detail, and program data from the software supply center 4 is input via the input terminal 20. The data is supplied to the reception processing circuit 22, and the control data from the operation center 5 is supplied to the program control circuit 23 via the input terminal 21.

The program data from the software supply center 4 is
It is supplied using communication means such as an optical fiber, a coaxial cable or a satellite. In some cases, storage media such as VTR cassettes, optical disks, and magnetic disks are transported.

When program data is supplied by the communication means, the reception processing circuit 22 applies demodulation processing, error correction processing, bit expansion processing to the program data supplied via the input terminal 20 as necessary. And the like, and this is processed, for example, by a digital video tape recorder (DVT).
R), an optical disk (including a magneto-optical disk, etc.), a magnetic disk or the like, and supplies it to a storage medium 24 having a recording / reproducing function, temporarily stores the same, and supplies it to a changeover switch 25.

The changeover switch 25 includes a reception processing circuit 22
When the program data is supplied by transporting the storage medium such as the VTR cassette, the program data read from the transported storage medium 26 is supplied. I have. The changeover switch 25 is connected to the reception processing circuit 2 according to each of the above cases.
2 or the program data read from the storage medium 26, and the selected
To supply.

The bit compression circuit 27 is, for example, an MPEG-
The program data is compression-encoded according to the two standards, and the supplied program data is reduced to a data amount necessary for transmission. Then, the compression-encoded program data is supplied to a storage medium 28 having a recording / reproducing function such as a digital video tape recorder (DVTR), an optical disk (including a magneto-optical disk or the like), a magnetic disk, or the like.

When data compressed and encoded in advance is supplied from the software supply center 4, the bit compression circuit 27 can be omitted.

On the other hand, when the control data from the operation center 5 is supplied to the program control circuit 23 via the input terminal 21, the program control circuit 23 transmits the control data to the storage media 24, 28 and the transmission processing circuit 29. To supply.

Specifically, if the control data indicates transmission of the program data supplied by the communication means, the program control circuit 23 controls reproduction of the storage medium 24. The program data reproduced by the reproduction control of the storage medium 24 is, for example, MP
The data is compression-coded based on the EG-2 standard, reduced to the data amount necessary for transmission, and supplied to the transmission processing circuit 29.

If the control data indicates transmission of the program data read from the transported storage medium 26, the program control circuit 23
Playback control. The program data reproduced by the reproduction control of the storage medium 28 is supplied to the transmission processing circuit 29.

The transmission processing circuit 29 has a configuration as shown in FIG. 3, and the compression-encoded program data is
The signals are supplied to the corresponding encryption circuits 36 via the respective input terminals 35. The encryption circuit 36 performs a predetermined encryption process on the supplied program data, and supplies this to the time-division multiplexing circuit 37.

When the program data is distributed to the user, additional information such as viewing right control information and program guide information is added, and the program data is distributed together with the program data. For this reason, the above-mentioned encryption processing may be applied to this additional information.

The time division multiplexing circuit 37 compresses each program data in the time axis direction by packetizing each program data into a predetermined format. Then, by selecting each of the compressed program data based on the selection data supplied from the program control circuit 23 via the input terminal 41, the respective program data is multiplexed and supplied to the error correction code adding circuit 38. .

The error correction code adding circuit 38 includes a satellite line,
An error correction code for correcting a transmission error caused by noise in a CATV line or the like is added and supplied to a modulation circuit 39. The modulation circuit 39 forms one transmission channel by modulating the program data of the predetermined channel with a single carrier, and transmits this through an output terminal 40 as shown in FIG.
Is supplied to the transmission unit 7 shown in FIG. The transmitting unit 7 transmits the program data to the user terminal 2 via the communication satellite 3 shown in FIG.
Deliver to the side.

When the program data supplied from the software supply center 4 is immediately transmitted, the storage medium 2
Instead of reproducing and outputting the program data once recorded in the storage medium 4, the program data to be supplied to the storage medium 24 while being recorded in the storage medium 24 as necessary may be supplied to the bit compression device circuit 30. .

By supplying program data pre-compressed and coded from the software supply center 4 to the program distribution center, the bit compression circuits 27 and 30 can be omitted.

FIG. 2 shows that there are two input paths for program data to the transmission processing circuit 29. However, this is because the storage media 24 and 28 and the bit compression circuits 27 and 30 are actually used. And a plurality of transmission units each including a transmission processing circuit 29, so that program data can be transmitted through a plurality of transmission channels.

Here, as the program distribution center 6, FIG.
In addition to the configuration shown in FIG. 4, the configuration shown in FIG. 4 can be provided.

That is, in the program distribution center 6 shown in FIG. 4, the program data from the software supply center 4 is supplied to the storage medium controller 47 via the input terminal 45, and the control data from the operation center 5 is supplied to the input terminal. 46
Is supplied to the program control circuit 48 via the.

The program control circuit 48 controls the storage medium control unit 47 so as to temporarily store the program data in one of the storage media 49 based on the supplied control data, and stores the program data in the storage medium 49. The read program data is read and controlled. The program data read from the storage medium 49 is supplied to a bit compression circuit 50 provided corresponding to each storage medium 49, and subjected to a compression encoding process based on the MPEG-2 standard as described above. It is supplied to the transmission processing circuit 51.

When the program data is supplied to the transmission processing circuit 51, the program control circuit 48 selects the transmission processing circuit 51 via the program information generation section 52 so as to select the program data which has been subjected to the compression encoding processing. Control. As a result, the program data selected by the transmission processing circuit 51 is supplied to the transmission unit 53 and distributed to the user's terminal device 2 via the communication satellite 3 as described above.

Next, the program data distributed via the communication satellite 3 as described above is received by the receiving unit 10 provided in the terminal device 2 shown in FIG. Supplied.

The receiver decoder 12 has the configuration shown in FIG. 5, and provides a request signal for requesting the operation center 5 to distribute a desired program via the telephone / modem 11, and a reception status of a pay broadcast. Has an input / output terminal 55 for exchanging a signal for knowing the information. The request signal is transmitted to the operation center 5 through the input / output terminal 55, so that the program data desired by the user is delivered as described above, and is received by the receiving unit 10 and is received by the tuner through the input terminal 56. 57.

The tuner 57 selects a transmission channel desired by the user by performing a tuning operation according to the control data from the control circuit 58.

More specifically, the selected transmission channel is formed by a total of four program data of programs A to D as shown in FIG. Generally, the transmission rates of the respective program data of the respective programs A to D are different from each other, and the data amount fluctuates when viewed instantaneously. In order to control this efficiently, programs A to D
Each of the program data is packetized with header information (packet identifier: PID) added to the head thereof and time-division multiplexed.

As described above, the program data in each packet is encrypted as necessary, and the program guide information and the information related to the viewing right are also time-division multiplexed in a packet format.

When such a transmission channel is selected, the tuner 57 performs a demodulation process corresponding to the modulation process applied to each program data, and supplies this to the error correction circuit 59. The error correction circuit 59 corrects an error such as a transmission error based on the error correction code added to each program data, and supplies this to the interface unit 61 and the selection switch 60.

The selection switch 60 is selectively controlled by control data from the control circuit 58. When restoring received program data, the error correction circuit 59 is used.
When the program data from the interface unit 61 is selected and the reproduction output from the recording / reproduction unit 13 is restored, the program data from the interface unit 61 is selected and supplied to the program division circuit 63.

The program dividing circuit 63 selects a control circuit 5 from a plurality of programs time-division multiplexed on one transmission channel by the transmission processing circuits 29 and 51 shown in FIG. 2 or FIG.
The program data of the program desired by the user is selected based on the control data from 8 and supplied to the encryption / decryption circuit 64.

The encryption / decryption circuit 64 includes a transmission processing circuit 29,
The program data encrypted by the encryption circuit 36 in FIG. 51 (FIG. 3) is decrypted and supplied to the decryption circuit 65. The decoding circuit 65 subjects the program data to bit expansion processing corresponding to the bit compression processing performed by the bit compression circuits 27, 30, 50 shown in FIGS. 2 and 4 or the software supply center 4 shown in FIG. The decoded data is supplied to the output processing circuit 66.

The output processing circuit 66 converts this program data into
For example, it is converted into a television format of the NTSC system and supplied to the television receiver 9 shown in FIG. Thereby, the video of the program distributed from the center apparatus 1 in response to the user's request can be displayed on the television receiver 9.

The receiver decoder 1 shown in FIG.
2, the encryption / decryption circuit 64 is provided at the subsequent stage of the program division circuit 63. This is because the encryption / decryption circuit 64 is provided at the front stage of the program division circuit 63 to perform encryption / decryption of program data. After that, the program may be divided.

On the other hand, the program data of the transmission channel supplied from the error correction circuit 59 to the interface unit 61 is supplied to the recording / reproducing unit 1 shown in FIG.
3 is supplied.

The recording section of the recording / reproducing section 13 has the configuration shown in FIG. 7, and the program data of the transmission channel output via the interface section 61 and the input / output terminal 62 is supplied to the input terminal 71. The packet data is supplied to the packet data compression section 72 and the packet header detection section 73 via the communication section.

The packet header detector 73 detects header information of each packet of each program data of the supplied transmission channel, and supplies a packet identifier (PID) included in the header information to the coincidence detecting circuit 76. The PID register 75 stores in advance PIDs such as program guide information and viewing right-related information of the program for which recording has been selected, and the coincidence detection circuit 76 stores the prestored PI.
D and the PI extracted by the packet header detection unit 73
D, and supplies the comparison output to the control circuit 74.

The control circuit 74 controls the packet data compression section 72 so as not to compress the program data when the comparison output indicating that the two coincide with each other is supplied. When a comparison output indicating that the two do not match is supplied, the control circuit 74 controls the packet data compression unit 72 so as to compress the program data.

More specifically, as shown in FIG. 6A, assuming that the user selects program B from programs A to D, the PID of this program B is loaded into the PID register 75. The coincidence detection circuit 76 compares the PID sequentially supplied from the packet header detection unit 73 with the PID loaded in the PID register 75. When the control circuit 74 detects a match of the PID of the program B based on the comparison output, the control circuit 74 controls the packet data compression unit 72 so as not to compress data (payload portion) other than the program header. When a comparison output indicating that the two do not match is detected, the packet data compression unit 72 is controlled so as to compress data other than the program guide information and the viewing right relation information among the program data.

As a result, as shown in FIG. 6B, in this case, the data portions (perloads) other than the header information of the programs A, C and D which are unnecessary programs other than the program B desired by the user are not included. In FIG. 13B, the data is compressed as shown by the diagonally left diagonal line, and only the program data of the program B is output without being compressed.

The compressed program data or uncompressed program data is supplied to a recording head (not shown) via an output terminal 77, and is recorded on a recording medium such as a hard disk, a magneto-optical disk, and a video tape. Thereby, unnecessary programs other than the program B desired by the user are compressed and recorded to the minimum data amount, and the program B desired by the user is stored.
Can be recorded on a recording medium without compression. Therefore, even when recording program data in which a plurality of programs are multiplexed, the recording area of the recording medium occupied by unnecessary programs can be minimized, and the recording efficiency of the recording medium can be improved. Can be planned.

Further, even for program data to be compressed, data necessary for reproduction such as program guide information and viewing right related information is not compressed, but other data is compressed. It is not necessary to form and add new header information including time information to the information, and a complicated circuit required for processing such as addition of this new header information, recording and reproduction can be eliminated, and the circuit can be omitted. The size can be reduced and the price can be reduced.

In this example, only one program to be recorded is specified, but a plurality of programs may be specified and recorded.

In the program data, data other than the data necessary for reproducing the program guide information and the viewing right related information is compressed. Alternatively, data indicating null data (all zero data) may be added in place of data other than the data necessary for the above. The data indicating the null data is added by, for example, setting a flag in a reserve area (spare area) provided in the header information. As a result, the amount of data to be recorded on the recording medium can be reduced in each step, as compared with the case where data other than the data necessary for reproduction of the program guide information, the viewing right related information, etc. are compressed. Only the data necessary for reproducing the related information and the flag) and the recording efficiency of the recording medium can be made more remarkable.

Next, the reproducing section of the recording / reproducing section 13 for reproducing the program data of the transmission channel recorded as described above has the configuration as shown in FIG. Program data of a transmission channel as shown in FIG. 2B is reproduced by a reproducing head (not shown) and supplied to a packet data decompression circuit 82 and a packet header detection circuit 83 via an input terminal 81.

The packet header detection circuit 83 detects header information of each supplied program data, and matches the packet identifier (PID) included in the header information with the coincidence detection circuit 8.
6 The PID register 85 stores PPG information such as program guide information and viewing right related information of the program selected for reproduction.
The ID is stored in advance, and the match detection circuit 86 compares the PID stored in advance with the packet header detector 8.
3 is compared with the extracted PID, and the comparison output is supplied to the control circuit 84.

As described above, the program data recorded by the user's designation is the data of the program B. Then, program data other than the program data of the program B is compressed. Therefore, when a comparison output indicating that the two match is supplied, the control circuit 84 controls the packet data decompression unit 82 so as not to decompress the program data (in this case, the program data of the program B). Control. When a comparison output indicating that the two do not match is supplied, the control circuit 84 sets the program data (in this case,
The packet data compression unit 82 is controlled so as to expand program data other than the program B).

As a result, as shown in FIG. 6C, all the program data of the transmission channel including the program data of the programs A to D can be reproduced. This program data is supplied to the input / output terminal 62 and the interface unit 6 shown in FIG.
1 and supplied to the program division circuit 63 via the selection switch. Then, as described above, the program division circuit 63 extracts the program data of the program specified by the user (in this case, the program data of the program B), and
4, decoding circuit 65, output processing circuit 66, and output terminal 67
Is supplied to the television receiver 9 shown in FIG. As a result, the recording / reproducing unit 1 is
3, the video of the program reproduced in this case (in this case, program B) can be displayed.

When a flag indicating null data is set in place of data other than data necessary for reproduction such as program guide information and viewing right related information instead of compressing the program data, the control circuit Numeral 84 forms null data (all 0 data) corresponding to the data amount of the program based on the flag, and makes up for the original data with the null data. Therefore, even if this flag is set, the bit stream length of the transmission channel before and after compression does not change. In this case, among the programs to be reproduced, programs other than the program B are null data and cannot be reproduced. However, since these are programs that the user did not desire to record, there is no problem.

As is clear from the above description, the first
In the video distribution service system according to the embodiment, when recording the program data in the terminal device 2 on the user side, the program data of the program specified by the user among the program data of the transmission channels is recorded as it is. In addition, by compressing and recording program data of programs other than the designated program, it is possible to minimize recording of unnecessary data among data constituting the transmission channel,
The recording efficiency of the recording medium can be improved.

Even for program data to be compressed, data necessary for reproduction such as program guide information and viewing right related information is not compressed, but other data is compressed. It is not necessary to form and add new header information including time information, and the configuration and complicated circuits required for the addition and processing of this new header information can be eliminated. The size and the price can be reduced.

Next, a video distribution service system according to a second embodiment of the present invention will be described.

In the video distribution service system of the first embodiment, the recording / reproducing section 13 of the terminal device 2 detects the coincidence of the PIDs of the respective program data during recording and reproduction, and compresses or uncompresses them. Although the recording and reproduction of compression are performed, the video distribution service system according to the second embodiment, when recording, combines program data recorded in a compressed state and program data recorded in an uncompressed state. By writing discrimination data for discrimination in a table and performing reproduction by referring to this table at the time of reproduction, the P
The ID register and the coincidence detection circuit can be omitted.

The video distribution service system according to the second embodiment differs from the video distribution service system according to the first embodiment only in this point. Only the operation of the unit will be referred to, and redundant description will be omitted. In addition, the same reference numerals are given to the portions showing the same operations as those of the recording / reproducing unit shown in FIGS. 7 and 8, and the duplicate description will be omitted.

That is, the recording unit of the recording / reproducing unit 13 of the video distribution service system according to the second embodiment has the structure shown in FIG.
As shown in FIG. 7, together with the packet data compression unit 72, the packet header detection unit 73, the control circuit 74, the PID register 75, and the match detection circuit 76, discrimination data indicating the match or mismatch of the program data selected by the user with the PID is recorded. Table 78 is provided.

In such a recording unit, the PID register 75 stores PIDs such as program guide information and viewing right related information corresponding to the program selected by the user. ), Each program data of the transmission channels of the programs A to D is supplied. The packet header detection circuit 73 detects the header information of each program data, and finds the PID contained in this header information.
Is extracted and supplied to the coincidence detection circuit 76. The coincidence detection circuit 76 outputs the extracted PID and the PID register 75
PID of the program selected by the user stored in
The comparison output is supplied to the control circuit 74.

If a comparison output indicating that the two do not match is supplied, the control circuit 74 determines that the program has not been selected by the user,
In addition, the recording control of the header information of the program data is performed in the corresponding area in the recording area 8, and the recording of the discrimination data (attribute value) of, for example, “0” is controlled. In addition, the packet data compression unit 72 is controlled so as not to output program data not selected by the user.

Conversely, if a comparison output indicating that the two match is supplied, the program is selected by the user, and the header of the program data is stored in the corresponding area in the table 78. The recording of the information is controlled, and the recording of the determination data of, for example, “1” is controlled. Also,
The packet data compression section 72 is driven and controlled so as to output the program data selected by the user.

As a result, as shown in FIG. 11, the table 78 records the header information of each program data, as well as the discrimination data indicating the attribute (whether the user has made a selection). Then, as shown in FIG. 12B, only the program data of the program selected by the user is compressed and output via the output terminal 77.

The program data output via the output terminal 77 is recorded on a recording medium.
The control circuit 74 reads the header information and the discrimination data of each program stored in the table 78, and controls the recording of the header information and the program data on a recording medium together with the program data.

More specifically, the control circuit 47
8, the header information and the discrimination data of each program stored in
The header information of each program is recorded and controlled at the subsequent stage of the compressed and recorded program data, and each discrimination data which is a flag of “1” or “0” is recorded and controlled in a spare area (reserved area) of each header information. I do. This makes it possible to control the recording in such a manner that the header information and the discrimination data of each program are superimposed on the program data selected by the user.

Alternatively, the header information and the discrimination data of each program may be controlled at the preceding stage of the program data instead of the latter stage of the compressed and recorded program data. In this case, after the recording of the compressed program data is completed, the control circuit 47 returns the recording position to the preceding stage of the compressed and recorded program data, and controls the recording of the header information and the like.

Alternatively, when the recording medium is a disk-shaped recording medium such as an optical disk or a magnetic disk, the recording may be controlled in the form of a file on a user TOC (table of contents) or the like.

Next, the program data, each piece of header information and each piece of discrimination data thus recorded on the recording medium are reproduced by the reproducing section of the recording and reproducing section 13 as shown in FIG.

In FIG. 10, program data reproduced from a recording medium by a reproducing head (not shown), respective header information and respective discrimination data are supplied via an input terminal 81, and these are supplied to a packet data decompression circuit 82 and a packet data expanding circuit. It is supplied to the header detection circuit 83.

The packet header detection circuit 83 detects each piece of header information and discrimination data of each program data from the supplied data, and supplies them to the control circuit 84. The control circuit 84 stores and controls the header information and the determination data in the table 88.

The packet header detection circuit 83 detects each piece of header information of each piece of program data from the supplied data, and supplies this to the control circuit 84. Control circuit 84
When each piece of header information is supplied, the reference table 88 refers to the table 88 and detects the discrimination data of the currently supplied header information. Then, when this discrimination data is “0”,
That is, the program data corresponding to the current header information is:
If the packet is not selected by the user, the packet data decompression circuit 82 is controlled so that dummy data such as null data is added to the subsequent stage of the header information and output.

Conversely, when the discrimination data is "1", that is, when the program data corresponding to the current header information is selected by the user, the header information and the program data are changed. The packet data decompression circuit 82 is controlled so as to output the packet data as it is.

Thus, the program data of the transmission channels of the programs A to D as shown in FIG. 12C can be reproduced and output via the output terminal 87 of the reproducing section.

As is clear from the above description, this second
In the video distribution service system according to the embodiment, in the recording unit of the recording / reproducing unit 13, the header information of each program and the determination data indicating the presence or absence of selection by the user are stored in the table 78, and these are selected by the user. It is recorded on a recording medium together with the program data, and based on the discrimination data read from the recording medium at the time of reproduction, it is determined whether or not the program data is selected by the user,
When the data is selected by the user, the data is reproduced as it is. When the data is not selected by the user, the data is reproduced by adding dummy data such as null data to the header information.

Thus, the PI required by the reproducing unit
The D register and the match detection circuit can be omitted as shown in FIG. 10 to simplify the circuit configuration, and the same effects as those of the video distribution service system of the first embodiment can be obtained. it can.

Next, a video distribution service system according to a third embodiment of the present invention will be described.

In the video distribution service system according to the first embodiment, the recording / reproducing section 13 of the terminal device 2 detects the coincidence of the PIDs of the respective program data during recording and reproduction, and compresses or uncompresses them. Although the recording and reproduction of compression are performed, the video distribution service system according to the third embodiment records program data selected by the user without performing run-length compression at the time of recording. For program data not selected by the user, program data other than header information is run-length compressed and recorded.
It is possible to omit the PID register and the coincidence detection circuit required for reproduction.

The video distribution service system according to the third embodiment differs from the video distribution service system according to the first embodiment only in this point. Only the operation of the unit will be referred to, and redundant description will be omitted. In addition, the same reference numerals are given to the portions showing the same operations as those of the recording / reproducing unit shown in FIGS. 7 and 8, and the duplicate description will be omitted.

That is, the recording unit of the recording / reproducing unit 13 of the video distribution service system according to the third embodiment has the structure shown in FIG.
As shown in FIG. 3, the packet header detector 73 and the control circuit 7
4, a null data generation circuit 90 for generating null data, a run length compression circuit 92 for performing run length compression, together with a PID register 75 and a match detection circuit 76;
Selection switch 9 for selecting the null data from the null data generation circuit 90 or the program data supplied via the input terminal 71 and supplying the program data to the run length compression circuit 92 in accordance with
And 1.

In such a recording section, FIG.
Among the transmission channels composed of the program data of the programs A to D shown in FIG.
In the following, assuming that is selected, first, each program data of the transmission channel supplied via the input terminal 71 is supplied to the selection switch 91 and the packet header detection circuit 73.

The packet header detection circuit 73 detects the header of each program data of the transmission channel and supplies it to the control circuit 74 and the coincidence detection circuit 76. In this case, when the program B is selected by the user, the PID of the program B is loaded in the PID register 75, and the match detection circuit 76 determines the PID loaded in the PID register 75 and the packet header. By comparing the header information of each program data detected by the detection circuit 73 with the PID,
This comparison output is supplied to the control circuit 74.

When the control circuit 74 receives a detection output indicating that the two data do not match from the match detection circuit 76, the control circuit 74 selects the header information of the program data and supplies it to the run-length compression circuit 92. The selection switch 91 is selectively controlled so that null data from the null data generation circuit 90 is selected as data other than the header information and supplied to the run length compression circuit 92.

On the contrary, when the control circuit 74 is supplied with a detection output indicating that the two coincide with each other from the coincidence detection circuit 76, the header information and the packet body (payload) are supplied.
Is selected and supplied to the run-length compression circuit 92. As a result, the run-length compression circuit 92 stores the program data of the program B selected by the user as shown in FIG. 15 (b) and the programs A, C and D in which data other than the header information is null data. , And the program data of the transmission channel composed of the respective program data is supplied.

The control circuit 74 controls the run-length compression circuit 92 so as to perform the run-length compression processing on the null data portion of the program data of this transmission channel whose data other than the header is null data.
As a result, each program data of the transmission channel in which only the null data as shown in FIG. 15C has been run-length compressed is output via the output terminal 77 and recorded on the recording medium.

The control circuit 74 sets a flag indicating that the run-length compression processing has been performed on the PID of the header information corresponding to the null data on which the run-length compression processing has been performed.

Next, each program data of the transmission channel recorded on the recording medium as described above is reproduced by a reproducing head (not shown), and run through an input terminal 81 of the reproducing unit of the recording and reproducing unit 13 shown in FIG. It is supplied to the length extension circuit 93 and the packet header detection circuit 83.

The packet header detection circuit 83 detects the header information of each program data of the transmission channel, and supplies the detection output to the control circuit 84. The control circuit 84
The PID in the header information is detected based on the detection output from the packet header detection circuit 83.

As described above, among the program data of the transmission channels, the data subjected to the run-length compression processing is only null data. Therefore, only when the PID in the header information indicates that the run-length compression processing has been performed, the control circuit 84 executes the run-length expansion processing at the timing when null data is supplied to the run-length expansion circuit 93. The run-length extension circuit 93 is controlled so as to perform the following.

As a result, as shown in FIG. 15D, the program data of the program B selected by the user and the program data of the programs A, C and D each having header information and payload of null data. Are reproduced and output via the output terminal 87.

As is clear from the above description, the third
The video distribution service system according to the embodiment, the payload of a program other than the program selected by the user is null data, and only the null data portion is run-length compressed, and the header information of the run-length compressed program data is The PID is flagged and recorded, and at the time of reproduction, only the data with the flag set in the PID is run-length expanded and reproduced, thereby omitting the PID register and the coincidence detection circuit required for reproduction. In addition to the above, the same effects as those of the video distribution service system according to the first embodiment can be obtained.

Next, a video distribution service system according to a fourth embodiment of the present invention will be described.

In the video distribution service system according to each of the above-described embodiments, the transmission channels are, for example, programs A to
Although the transmission channel is formed only from the program data of the program D, this transmission channel is actually used in addition to the program data of each program, as shown in FIG. Information) is also often superimposed as a packet. In many cases, the same content is repeatedly superimposed a plurality of times as the program guide information. If all of the program guide information is recorded together with the program data, the recording area of the recording medium cannot be efficiently used. Hereinafter, the additional information will be described as the program guide information.

In the video distribution service system according to the fourth embodiment, the recording of the program guide information is minimized, and the recording efficiency of the recording medium is improved.

In the video distribution service system according to the fourth embodiment, the configuration of the recording / reproducing section 13 is characteristic in order to minimize the recording of the program guide information. The configuration is the same as the video distribution service system according to the first embodiment. For this reason, in the following description, only the operation of the recording / reproducing unit, which is a different point, will be referred to, and redundant description will be omitted.

That is, the recording unit of the recording / reproducing unit 13 of the video distribution service system according to the fourth embodiment has the structure shown in FIG.
As shown in FIG. 6, in addition to the packet data compression section 72, the packet header detection circuit 73, the control circuit 74, the PID register 75, the coincidence detection circuit 76, a memory 95 for storing program guide information in a transmission channel is provided. .

In such a recording section, program guide information and program A as shown in FIG.
A transmission channel comprising packets 1 to 4 of the program data, program guide information, and program data of program B is supplied. Each piece of the program guide information has the same contents.

For example, if the user selects a program for recording both the program A and the program B from the transmission channel, the PIDs of the programs A and B are loaded into the PID register 75.

The packet header detection circuit 73 detects the program guide information of the transmission channel supplied via the input terminal 71 and the header information attached to the program data, and supplies the detection output to the coincidence detection circuit 76. I do. The match detection circuit 76 compares the header information detected by the packet header detection circuit 73 with the header information loaded in the PID register 75, and supplies the comparison output to the control circuit 74.

As described above, in this case, both the program A and the program B are selected by the user. Therefore, when a comparison output indicating that the two match is supplied, the control circuit 74 determines whether the data currently supplied via the input terminal 71 is the program A or the program B.
The packet data compression section 72 is controlled so as to output the program data without compression in order to indicate that it is the program data.

When the comparison circuit 74 first supplies the comparison output indicating that the two do not match,
To indicate that the data currently supplied via the input terminal 71 is the program guide information, the control circuit 74 stores and controls the program guide information in the memory 95,
The packet data compression circuit 72 is controlled so that the program guide information is output as it is without compression.

Here, when the program guide information is stored in the memory 95 as described above, the next time a comparison output indicating that the two do not match is supplied, the program guide information is already stored in the memory 95. Is stored. For this reason, if the program guide information has already been stored in the memory 95 the next time a comparison output indicating that the two do not match is supplied, the control circuit 74 does not change the content. It is determined whether or not. If there is no change in the contents, the packet data compression circuit 72 is controlled to compress the program guide information together with the header information.
When the contents are changed, the program guide information is stored and controlled in the memory 95 to update the contents of the memory 95 and to output the program guide information as it is without compression. Data compression circuit 72
Control.

As a result, as shown in FIG. 18B, one of the pieces of program guide information having the same contents (program guide information transmitted later in time) included in the transmission channel can be compressed. Each data of such a transmission channel is output via the output terminal 77 and recorded on a recording medium. The data recorded on the recording medium is obtained by compressing one of the program guide information having the same contents together with the header information. Therefore, as shown in FIG. 18 (c), the compressed recording area of the program guide information is omitted in a pseudo manner,
The inconvenience that the recording area of the recording medium is occupied by the duplicated program guide information can be prevented, and the recording area of the recording medium can be used efficiently.

Next, as shown in FIG. 17, the reproducing section of the recording / reproducing section 13 for reproducing the data recorded on the recording medium includes a packet data expanding section 82, a packet header detecting circuit 83, and a control circuit 84. , A PID register 85, a coincidence detection circuit 86, and a memory 95 for storing program guide information in a transmission channel.

In such a reproducing section, uncompressed program guide information, program data of program A, program guide information compressed together with header information as shown in FIG. A transmission channel including packets 1 to 4 of the program data of the program B is supplied.

The packet header detection circuit 83 detects each program guide information of the transmission channel supplied via the input terminal 81 and the header information attached to the program data, and supplies the detection output to the coincidence detection circuit 86. I do. The coincidence detection circuit 86 includes header information detected by the packet header detection circuit 83 and header information of program data selected by the user loaded in the PID register 85 (in this case, header information of the program A and the program B). Is supplied to the control circuit 84.

When a comparison output indicating that the two match is supplied, the control circuit 84 determines that the data currently supplied via the input terminal 81 is the program data of the program A or the program B. Therefore, the packet data decompression unit 82 is controlled so as to output the packet data without decompression.

If the comparison output indicating that the two do not match is supplied first, it indicates that the data currently supplied through the input terminal 81 is uncompressed program guide information. Therefore, the control circuit 84 controls the storage of the uncompressed program guide information in the memory 96, and also controls the packet data decompression circuit 82 so as to output the program guide information as it is without decompression processing.

After the inconsistency between the two is detected once, the control circuit 84 determines only the header information based on the program guide information stored in the memory 96 each time the inconsistency between the two is detected. The packet data expansion circuit 82 is controlled so as to expand the packet data.

As a result, as shown in FIG. 18D, the program guide information and its header information located as the first data of the transmission channel, the program data of Program A and its header information, and the compressed program The guide information and its header information, and the program data of program B and its header information can be reproduced.

Although the program guide information other than the first program guide information is not reproduced, the contents of the first program guide information and the subsequent program guide information are the same. Since the header information of the program guide information other than the above is reproduced, there is no problem.

As is clear from the above description, the fourth
In the video distribution service system according to the embodiment, among the additional information such as the program guide information multiplexed and transmitted with each program data, the same information is first (second or third).
Other than that, the program information is compressed and recorded together with the header information, and at the time of reproduction, only the header information of the compressed program guide information is expanded and reproduced. Thus, the inconvenience of duplicating recording of program guide information having duplicate contents can be prevented, so that the recording efficiency of the recording medium can be improved, and the video distribution of the first embodiment described above can be achieved. The same effect as the service system can be obtained.

The memory 95 for storing the program guide information described in the video distribution service system according to the fourth embodiment is a memory 98 as shown by a dotted line in FIG. It may be provided in the video distribution service system according to the third embodiment, or may be provided as the memory 99 in the video distribution service system according to the third embodiment described above, as indicated by a dotted block in FIG. As a result, as in the video distribution service system according to the fourth embodiment, it is possible to prevent redundant recording of additional information such as program guide information and to efficiently utilize the recording area of the recording medium.

Next, a video distribution service system according to a fifth embodiment of the present invention will be described.

In the data transmitted in a time-division multiplexed manner, time management information (PCR) necessary for reproduction is called an adaptation field (AF) of a packet of a specific program, as shown in FIG. Has been added to the field. This time management information has a small data amount itself, and is not always included in all the packets of the program. Of course, the time management information is not always added to the program selected to be recorded by the user.

For this reason, in the video distribution service system according to the fifth embodiment, the control circuit 74 of the recording unit of the recording / reproducing unit 13 does not add the time management information to the program designated to be recorded by the user. In this case, for a packet of a program which is not specified by the user but to which time management information is added, the packet header detection circuit 73, the PID register 75, and the coincidence detection circuit 76 of the recording unit in each of the above-described embodiments. It is determined whether or not time management information is added to each input packet. If the time management information is not added, the packet is regarded as an unnecessary packet, and if the time management information is added. In the packet data, the remaining portion excluding, for example, the adaptation field portion is regarded as unnecessary data.

Then, this packet is compressed by performing data compression processing or run-length compression processing as described in each of the above embodiments. As a result, FIG.
As shown in (b), a program other than the program selected by the user (in this case, program B) can be compressed while leaving the header information and the adaptation field, and the recording efficiency can be further improved.

Next, a video distribution service system according to a sixth embodiment of the present invention will be described.

Some program data transmitted in a time-division multiplexed manner is encrypted beforehand and transmitted. To view the encrypted program, the center device 1
It is necessary to perform decoding based on the program viewing permission management information transmitted in a time-division multiplexed manner. As information (key) for this decryption, different information is transmitted periodically depending on the terminal device 2 of each subscriber.

Therefore, the control circuit 74 of the recording / reproducing unit 13 of the video distribution service system according to the sixth embodiment.
Are the packet header detection circuit 73 and the PID register 7
5. The match detection circuit 76 detects a program viewing permission management information packet. Then, it is determined whether or not the packet is related to reception and recording / reproduction. Only when the packet is not related to reception / recording / reproduction, the packet is regarded as an unnecessary packet as described in each of the above embodiments. , Data compression or run-length compression. As a result, packets not related to reception and recording / reproduction can be compressed and recorded, and the recording efficiency can be further improved.

Finally, the description of each of the above embodiments is only an example of the present invention. For this reason, it goes without saying that various changes can be made in accordance with the design and the like without departing from the technical idea of the present invention.

[0138]

According to the recording / reproducing apparatus of the present invention, unnecessary data can be recorded by compressing it without header information, so that the recording area on the recording medium occupied by the unnecessary data is minimized. And the recording area on the recording medium can be used efficiently.

Further, even if the data is unnecessary data to be compressed,
Since the header information portion is recorded without being compressed, data of the original bit length can be reproduced using time information and the like attached to the original header information. Therefore, it is not necessary to form header information to which new time information is added and to add it to each data, and to form and record the header information to which this new time information is added, and to reproduce the data to which this header information is added. A complicated processing circuit and the like required in the above can be omitted, and the circuit size and cost of the recording / reproducing apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall block diagram of a video distribution service system according to a first embodiment to which a recording / reproducing device according to the present invention is applied.

FIG. 2 is a block diagram of a program distribution center provided on the center device side of the video distribution service system according to the first embodiment.

FIG. 3 is a block diagram of a transmission processing circuit provided in the program distribution center.

FIG. 4 is a block diagram of another program distribution center provided on the center device side of the video distribution service system according to the first embodiment.

FIG. 5 is a block diagram of a receiver decoder provided on the terminal device side of the video distribution service system according to the first embodiment.

FIG. 6 is a diagram showing program data on a transmission channel transmitted from the center device side and program data on a transmission channel recorded and reproduced on the terminal device side.

FIG. 7 is a block diagram of a recording unit provided in a recording / reproducing unit on a terminal device side that records program data of the transmission channel.

FIG. 8 is a block diagram of a reproducing unit for reproducing program data of a transmission channel recorded by the recording unit.

FIG. 9 is a block diagram of a recording unit provided in a recording / reproducing unit on a terminal device side of a video distribution service system according to a second embodiment to which the recording / reproducing device according to the present invention is applied.

FIG. 10 is a block diagram of a playback unit provided in a recording / playback unit on a terminal device side of the video distribution service system according to the second embodiment.

FIG. 11 is a packet identifier (PID) of each program data recorded in a table provided in a recording unit on the terminal device side of the video distribution service system according to the second embodiment.
FIG.

FIG. 12 is a diagram showing each program data recorded and reproduced by a recording and reproducing unit on the terminal device side of the video distribution service system according to the second embodiment.

FIG. 13 shows a third example to which the recording / reproducing apparatus according to the present invention is applied;
It is a block diagram of the recording part provided in the recording and reproducing part of the terminal device side of the video distribution service system of the embodiment.

FIG. 14 is a block diagram of a reproducing unit provided in a recording / reproducing unit on the terminal device side of the video distribution service system according to the third embodiment.

FIG. 15 is a diagram showing each program data recorded and reproduced by a recording and reproducing unit on the terminal device side of the video distribution service system according to the third embodiment.

FIG. 16 is a fourth diagram to which the recording / reproducing apparatus according to the present invention is applied;
It is a block diagram of the recording part provided in the recording and reproducing part of the terminal device side of the video distribution service system of the embodiment.

FIG. 17 is a block diagram of a playback unit provided in a recording / playback unit on the terminal device side of the video distribution service system according to the fourth embodiment.

FIG. 18 is a diagram showing program data recorded and reproduced by a recording and reproducing unit on a terminal device side of the video distribution service system according to the fourth embodiment.

FIG. 19 is a fifth embodiment to which the recording / reproducing apparatus according to the present invention is applied;
It is a figure which shows each program data recorded / reproduced by the recording / reproducing part of the terminal device side of the video distribution service system of Embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Center device, 2 ... Terminal device, 3 ... Communication satellite, 4 ... Software supply center 5 ... Operation center, 6 ... Program distribution center, 7 ...
Transmitting unit 8: Terminal body, 9: Television receiver, 10: Receiving unit 11: Telephone / modem, 12: Receiver decoder, 13 ...
Recording / reproducing unit 72 packet data compression circuit 73 packet header detection circuit 74 control circuit 75 PID register 76 coincidence detection circuit 82 packet data decompression circuit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Machida 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside Toshiba Multimedia Technology Research Laboratories Co., Ltd. (72) Shinichi Oi 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Inside Toshiba Multimedia Technology Research Laboratories (72) Inventor Osamu Yoshida 8 at Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside Toshiba Multimedia Technology Research Laboratories (72) Shoichi Koike Shin-Sugita, Isogo-ku, Yokohama-shi, Kanagawa Prefecture 8 Tochiba, Inc. Toshiba Multimedia Technology Research Laboratories (72) Inventor Isao Miyazaki 3-3-9, Shimbashi, Minato-ku, Tokyo Inside Toshiba AV EE Co., Ltd. (72) Inventor Keiko Ando Tokyo Metropolitan Port 3-3-9, Shimbashi, Ward Toshiba Abu E Co., Ltd.

Claims (7)

[Claims] 1. A recording data selecting means for selecting one or a plurality of desired data to be recorded from each data packetized and time-division multiplexed with header information and transmitted, and A record match detecting unit that detects a match between the header information of each data and the header information of the data selected by the record data selecting unit; and a case where the match of the header information is detected by the record match detecting unit. The corresponding data is recorded on the recording medium without compression, and when the recording match detecting means detects a mismatch between the respective header information, the portion other than the header information of the corresponding data is compressed and recorded on the recording medium. Recording means comprising: recording control means for recording; and reproduction data selection for selecting desired data to be reproduced from data recorded on the recording medium. Means, reproduction match detection means for detecting a match between header information of each data reproduced from the recording medium and header information of the data selected by the reproduction data selection means, and each of the headers by the reproduction coincidence detection means. When a match of information is detected, the corresponding data is reproduced without decompression. When a mismatch between the header information is detected by the reproduction match detection means, a portion other than the header information of the corresponding data is reproduced. A recording / reproducing apparatus, comprising: a reproducing unit including a reproduction control unit that performs decompression and reproduction. 2. The reproduction control means, when the reproduction coincidence detection means detects a mismatch of the header information, reproduces a part of the data other than the header information as null data which is all zero data. The recording / reproducing apparatus according to claim 1, wherein: 3. The recording control means, when a mismatch of each of the header information is detected by the recording coincidence detecting means, sets a portion of the corresponding data other than the header information as null data, and converts the null data into run-length data. 2. A compression processing for recording on a recording medium.
The recording / reproducing apparatus as described in the above. 4. The recording means has a recording table for recording, together with header information of each data, discrimination data indicating whether or not the data is compressed, wherein the recording control means comprises: While recording the header information and each determination data recorded in the recording table on a recording medium,
Only when the match of the respective header information is detected by the recording match detecting means, the corresponding data is recorded on the recording medium without compression, and the reproduction control means sets the respective data reproduced from the recording medium. Based on the header information and the discrimination data, the data recorded on the recording medium without compression is reproduced without expansion, and data other than the data recorded without compression is null data, which is all zero data. 2. The recording / reproducing apparatus according to claim 1, wherein the reproduction is performed by adding the corresponding header information reproduced from the recording medium to the null data. 5. The recording means has additional information storage means for storing additional information transmitted with header information attached thereto, and the recording control means stores the transmitted additional information in the additional information storage. Means for storing the additional information in the additional information stored in the additional information storage means and the newly transmitted additional information each time new additional information is transmitted. If the two match, the newly transmitted additional information is compressed and recorded. If the two do not match, the new additional information is stored and updated in the additional information storage means and updated. 5. The recording / reproducing apparatus according to claim 1, wherein the new additional information is recorded on a recording medium. 6. The header information is provided with time management information necessary for reproducing the data at predetermined intervals, and the recording control means includes a data control unit for storing data other than the data selected by the recording data selection means. Detects the header information attached to, and if the time management information is not added to the header information, compresses and records the corresponding data, and if the time management information is added to the header information, 6. The recording / reproducing apparatus according to claim 1, wherein data other than the time management information is compressed and recorded. 7. Each of the time-division multiplexed and transmitted data has been subjected to a predetermined encryption process, and decrypted data for decrypting the data subjected to the encryption process. Is transmitted as the data.If the transmitted decoded data corresponds to the data selected by the recording data selecting means, the recording control means records the decoded data without compressing it. ,
4. The method according to claim 1, wherein when the transmitted decoded data corresponds to data other than the data selected by the recording data selecting means, the decoded data is compressed and recorded. 7. The recording / reproducing apparatus according to any one of 6.