JP2003228912A - Device and method for data stream recording, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data stream recording device for sufficiently protecting data. <P>SOLUTION: A reception unit 3 sends a data stream obtained by receiving a digital broadcast, to a motherboard 1. The motherboard 1 divides TS packets included in the data stream into two and stores one in an internal memory 33 for contents storage. Further, the motherboard 1 stores a data stream, obtained by substituting dummy packets for the TS packets of the data stream stored in the internal memory 33 for contents storage, in a storage 2 for the motherboard. The value of PID of the dummy packets is a value that the PID of the TS packets of the source data stream never possibly has. In reproduction, the data stream is restored by substituting packets to be thinned out for packets having values that the PID of the TS packets of the source data stream never possibly have in the substituted data stream. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data stream recording device, a data stream recording method and a program.

[0002]

2. Description of the Related Art Digital broadcasting is used in which contents such as images and sounds are broadcast in the form of a data stream consisting of a series of packets containing data representing the contents.

Digitally broadcast contents can be stored in a storage device as digital format data,
It is very unlikely that data will be deteriorated during storage. For this reason, a technique is used to protect the rights such as the copyright of the digitally broadcast content. Specifically, there is a method of encrypting data representing content and storing the data.

[0004]

However, if the encryption method is not sufficiently strong against an attack, the encrypted data can be easily decrypted by a person who does not know the decryption key. , Data cannot be protected enough.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a data stream recording device and a data stream recording method for sufficiently protecting data.

[0006]

[Means for Solving the Problems] In order to achieve the above object,
A data stream recording apparatus according to a first aspect of the present invention includes a thinning means for acquiring a data stream and distributing a plurality of packets constituting the acquired data stream into a plurality of groups according to a predetermined rule, and a means other than the thinning means. A first storage unit having a first storage area that substantially blocks access to the second storage unit and a second storage unit having a second storage area, and the thinning-out unit belongs to some groups. A packet is stored in the first storage area, the acquired data stream is converted into a replaced data stream in which the packets distributed to the partial groups are replaced with dummy packets, and the second data stream is converted into the replaced data stream. The data content of the predetermined data in the dummy packet is stored in the memory area of the dummy packet. It is different from the content of the predetermined data in the packet that constitutes the stream, and wherein the.

The packets forming the data stream acquired by the thinning means are, for example, TS (Transport St
ream) packet. In this case, the predetermined data in the packet forming the data stream acquired by the thinning-out means may be, for example, data including the PID (Program IDentifier) of the TS packet.

The thinning means comprises a synthesizing means for reading the packets distributed to the plurality of groups from the first and second storage areas and restoring the data stream based on the read packets. Good.

The thinning means is for generating information indicating a position occupied in the data stream by the packets distributed to the partial group and storing the information in the first or second storage area. May be.

The thinning-out means may include, for example, a processor, and the processor may access the first storage area by executing a predetermined program.

The first storage means and the thinning means may be connected to each other via, for example, a bus that enables data transmission by the processor executing a predetermined program.

The thinning means may encrypt the packets distributed to the partial group and / or other groups and store the encrypted packets in the first and / or second storage areas.

A data stream recording method according to a second aspect of the present invention acquires a data stream,
A plurality of packets forming the acquired data stream are distributed to a plurality of groups according to a predetermined rule, and packets belonging to a part of the groups are stored in a first storage area that substantially blocks access from other than a predetermined access device. A data stream recording method for storing and acquiring the obtained data stream, converting it into a replaced data stream in which the packets distributed to the partial groups are replaced with dummy packets and storing the converted data stream in a second storage area. The content of the predetermined data in the dummy packet is different from the content of the predetermined data in the packet forming the data stream acquired by the thinning means.

The packets forming the data stream to be acquired may be TS (Transport Stream) packets, for example. In this case, the predetermined data in the packet forming the data stream to be acquired may be data including the PID (Program IDentifier) of the TS packet, for example.

The program according to the third aspect of the present invention includes a thinning means for causing a computer to acquire a data stream and distribute a plurality of packets constituting the acquired data stream into a plurality of groups according to a predetermined rule. A program for functioning as first storage means having a first storage area that substantially blocks access from other than the thinning means and second storage means having a second storage area. The thinning means stores packets belonging to some groups in the first storage area, and replaces the acquired data stream with the packets distributed to the some groups with dummy packets. Is converted into a replaced data stream and stored in the second storage area, and is stored in the dummy packet. The contents of the data, the thinning means is different from the content of the predetermined data in the packet that constitutes the data stream to be acquired, it is characterized.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
A description will be given with reference to the drawings. FIG. 1 is a diagram showing a configuration of a digital broadcast recorder according to an embodiment of the present invention.
As shown in the figure, this digital broadcast recorder comprises a motherboard 1, a motherboard storage 2, and a receiving unit 3. The motherboard storage 2 is connected to the motherboard 1, and the receiving unit 3 is connected to the motherboard 1 via the connection bus B.

The motherboard 1 is, for example, a CPU (Ce
ntral Processing Unit) and R
A memory including an AM (Random Access Memory) and the like and a bus controller are provided. The connection bus B is P
It consists of a CI (Peripheral Component Interface) bus. The memory of the motherboard 1 has a storage area that serves as a work area for the processor of the motherboard 1. The bus controller of the motherboard 1 is composed of a control circuit for controlling data exchange between the processor of the motherboard 1 and a device external to the motherboard 1 via the connection bus B.

The mother board 1 reads out the broadcast recording / reproducing program stored in the mother board storage 2 and performs the processing described later according to this broadcast recording / reproducing program. The process controlled by the broadcast recording / playback program is
Functionally, it includes a plurality of processing blocks. Specifically, the demultiplexer 1 described later with reference to FIG. 4 and FIG.
A, stream thinning block 1B, stream composition block 1C, storage recording block 1D, MPEG
(Moving Picture Expert Group) Decode block 1
Each processing block of E and the storage read block 1F is included.

The motherboard storage 2 is composed of a hard disk device or the like, and stores the above-mentioned broadcast recording / playback program in advance. Then, according to the access from the mother board 1, the data supplied by the mother board 1 is stored, or the data stored in itself is read and supplied to the mother board 1.

The receiving unit 3 is a digital broadcast receiving section 3
1, a PCI bus bridge 32, an internal memory 33 for storing contents, an IDE (Intelligent Drive Electron)
ics) bus bridge 34.

The digital broadcast receiving section 31 comprises a demodulation circuit and is connected to the PCI bus bridge 32 via an internal bus. The digital broadcast receiving unit 31 restores TS (Transport Stream) packets forming a data stream by inputting and demodulating a modulated wave representing a data stream, which is digitally broadcast from the outside. Then, the restored TS packet is supplied to the motherboard 1 via the PCI bus bridge 32 and the connection bus B. The data stream represented by the modulated wave received by the digital broadcast receiving unit 31 represents an image, audio, or other content, and is composed of a plurality of continuous TS packets as shown in FIG.

The TS packet is a packet representing an image, a sound or other contents, and has a data structure shown in FIG. That is, the TS packet is TS
It is composed of a packet header and a payload part (adaptation / payload part) following the TS packet header.

The payload part is a part including data representing the content. As shown in FIG. 3, each TS packet including data representing the image of the same frame has a PES (Packetiziz) by connecting the respective payload parts in the order in which these TS packets were arranged.
ed Elementary Stream) packets can be formed.

If the data stream represents MPEG2 format image data (or image data having substantially the same data structure as MPEG2 format image data), PE
The S packet is one of three types of I picture, B picture, or P picture that is data representing an image forming a moving image.
Contains more than one seed. Among them, the B picture and the P picture represent the difference from the I picture.

Then, as shown in FIG. 3, the PES packet includes a PES header containing information for identifying the PES packet and a picture layer containing any of an I picture, a B picture and a P picture. .

A PES packet including an I picture includes a sequence header code having a predetermined value, and a PES packet including an I picture includes a PE.
In addition to the S header and picture layer, a video sequence layer and a GOP (Group Of Picture) layer are included.

As shown in FIG. 2, the TS packet header includes a synchronization byte, TS error data, payload unit start indicator, transport priority data, PID (Program IDentifier), transport scramble control data, and adaptation in order from the beginning. Contains field control data and continuity index.

Of these, the payload unit start indicator indicates whether or not the payload part of the TS packet including the payload unit start indicator itself includes the head data of the PES packet. Specifically, for example, when the value of the payload unit start indicator is “1”, the T including the payload unit start indicator itself is included.
It indicates that the payload part of the S packet includes the head data of the PES packet, and if it is "0", it indicates that the payload part does not include the head data of the PES packet.

Therefore, one PES packet is, for example, a TS packet including a payload unit start indicator having a value of "1" in the data stream and the next TS including a payload unit start indicator having a value of "1". It is generated by connecting the payload parts of consecutive TS packets up to the TS packet immediately before the packet.

The PID is data for identifying which content is represented by the payload part of the TS packet including the PID itself (for example, which image, voice or other data is represented).

The PID included in the TS packet that constitutes the data stream broadcast as digital broadcast
The range of values that cannot be taken is predetermined. Specifically, for example, a data stream including a TS packet having a PID value of “0x002F” indicates that the data stream broadcast from a broadcasting satellite is redistributed using a cable television. Therefore, in this case, the PID included in the TS packet forming the data stream broadcast as digital broadcast does not take the value “0x002F”. The PID value “0x002F” used when redistributing using a cable television represents a packet in which multiplex frame header information is stored. The multiplex frame header information is used, for example, for TMCC (Transmission and Multiplexing Configurator) in digital broadcasting.
ation Control) information (specifically, information for specifying the modulation format, error correction method, etc.). Therefore, the multiplex frame header information is data that is unnecessary for reproducing the content.

The PCI bus bridge 32 is composed of a bus controller and the like, is connected to the mother board 1 via a connection bus B, and is I via an internal bus.
It is connected to the DE bus bridge 34 and the digital broadcast receiver 31. The PCI bus bridge 32 mediates access to the internal memory 33 for content storage, which is performed by the motherboard 1 under the control of the broadcast recording / reproducing program. It also mediates the supply of data from the digital broadcast receiving unit 31 to the internal memory 33 for content storage.

The internal memory 33 for storing contents includes a nonvolatile memory such as a compact flash memory and an IDE.
It is composed of an interface circuit for transmitting data via the bus.

The IDE bus bridge 34 is composed of a bus controller and the like, and is connected to the PCI bus bridge 32 via an internal bus, while being connected to the internal memory 33 for content storage via the IDE bus. I
The DE bus bridge 34 mediates access to the internal memory 33 for content storage, which is performed by the motherboard 1 under the control of the broadcast recording / reproducing program. It should be noted that the PCI bus bridge 32 and the IDE bus bridge 34 substantially block this access even if the motherboard 1 accesses the content storage internal memory 33 without following the control of the broadcast recording / playback program.

(Operation) Next, the operation of the digital broadcast recorder will be described. FIG. 4 is a diagram showing a flow of processing for recording content. FIG. 5 is a diagram showing a flow of processing for reproducing the recorded content.

(Recording of Content) When the modulated wave representing the data stream is supplied to the digital broadcast receiving section 31 of the receiving unit 3, the digital broadcast receiving section 31 restores the data stream by demodulating the modulated wave. Then, the restored data stream is supplied to the mother board 1 via the PCI bus bridge and the connection bus B.

On the other hand, the mother board 1 reads the broadcast recording / reproducing program from the mother board storage 2 and executes it in response to a recording instruction supplied from the outside in accordance with an operation of the operator.

When the mother board 1 which executes the broadcast recording / reproducing program is supplied with the data stream (that is, when the TS packets are sequentially supplied), the PID included in the supplied TS packet according to the control of the demultiplexer 1A. And determines whether or not the specified PID indicates the content to be accumulated. The content to be accumulated may be designated by, for example, data supplied from the outside according to the operation of the operator.

When the motherboard 1 determines that the PID does not indicate the content to be stored, it discards the TS packet including this PID, and when it determines that it indicates, the TS packet including this PID is shown in FIG. As described above, the data is delivered to each processing block of the stream synthesis block 1C and the stream thinning block 1B.

When the TS packet is delivered from the demultiplexer 1A to the stream synthesizing block 1C (that is, when this digital broadcast recorder receives a digital broadcast), the mother board 1 uses the stream synthesizing block 1
Under the control of C, this TS packet is delivered to the MPEG decoding block 1E without any particular processing.

When the TS packet is delivered to the MPEG decoding block 1E, the mother board 1 decodes the image and audio represented by the TS packet under the control of the MPEG decoding block 1E, and as shown in FIG. It is output as content data including a video signal, an audio signal, etc.

On the other hand, the motherboard 1 passes the TS packets successively delivered from the demultiplexer 1A to the stream thinning block 1B to the stream thinning block 1B.
According to the control of, thinning out to meet a certain rule. That is, according to this rule, the TS packets are sorted into two groups, and the TS packets belonging to one group are stored in the content storage internal memory 33 of the receiving unit 3.
And write TS packets belonging to the other group to
It is delivered to the storage recording block 1D. The specific content of the rule is arbitrary.

The mother board 1 writes the packet to be thinned out to the internal memory 33 for storing contents by the PC.
This is performed by accessing the internal memory 33 for content storage via the I bus bridge 32 and the IDE bus bridge 34. That is, when the motherboard 1 accesses the content storage internal memory 33 and the thinning-out target packet is supplied to the receiving unit 3, the PCI bus bridge 32 of the receiving unit 3 transfers the thinning-out target packet to the IDE bus bridge 34. Then, the IDE bus bridge 34 accesses the internal content storage memory 33 and stores the thinning target packet in the storage area of the internal content storage memory 33. (In this specification and the drawings, the TS packets supplied from the mother board 1 to the receiving unit 3 are called thinning target packets, and the TS packets delivered from the stream thinning block 1B to the storage recording block 1D are non-thinning target packets. Called.)

On the other hand, the mother board 1 which performs the processing of the stream thinning block 1B has the storage recording block 1
The non-thinning target packet delivered to D is received by the receiving unit 3
Of the original data stream received by the above, it is delivered to the storage recording block 1D in the form of a replaced data stream in which the thinning-out target packet is replaced with a dummy packet.

The dummy packet is a packet in which the value of the PID included in the TS packet header is different from the value of the PID of the TS packet included in the original data stream. Therefore, the TS of the dummy packet
The value of the PID included in the packet header may be, for example, a value that cannot be taken by the PID included in the TS packet forming the data stream broadcast as digital broadcasting. Specifically, for example, the value “0x002F” described above may be used.

The contents of the payload part of the dummy packet are different from the contents of the payload part of the thinning-out target packet replaced by the dummy packet. It is desirable that there is substantially no correlation between the content of the payload part of the dummy packet and the content of the payload part of the thinning-out target packet located at the position of the dummy packet.

When the replaced data stream is delivered to the storage recording block 1D, the motherboard 1
Accesses the motherboard storage 2 under the control of the storage recording block 1D and stores the replaced data stream in the storage area of the motherboard storage 2.

Further, the mother board 1 which executes the processing of the stream thinning block 1B creates a position information table showing the position of each packet to be thinned in the original data stream, and this position information table is also stored in the storage recording block 1D. Hand over to. Motherboard 1
This position information table is also the storage recording block 1D.
It is stored in the storage area of the motherboard storage 2 under the control of.

In order to identify what content the thinning-out target packet whose position is represented by the position information table represents, the motherboard 1 uses this position information table to identify the position. The packet to be thinned out may be stored in association with the non-thinning target packet obtained from the data stream common to the represented thinning target packet.

(Playback of Recorded Content) When playing back the recorded content, the motherboard 1 responds to a content playback instruction supplied from the outside according to an operation of the operator, for example, and executes the broadcast recording / playback program for the motherboard. It is read from the storage 2 and executed.

Then, the mother board 1 accesses the internal memory 33 for content storage via the PCI bus bridge 32 and the IDE bus bridge 34, and reads out the packets to be thinned out. The read-out thinning-out target packet is supplied to the IDE bus bridge 34, the IDE bus bridge 34 transfers this thinning-out target packet to the PCI bus bridge 32, and the PCI bus bridge 32 transmits this thinning-out target packet via the connection bus B. Supply to the motherboard 1. The packet to be thinned out to be read is
For example, the position information table associated with the non-thinning-out target packet representing the content to be reproduced may be specified from the motherboard storage 2 under the control of the storage read block 1F and referred to.

As shown in FIG. 5, the mother board 1 delivers the thinning target packet read from the receiving unit 3 to the stream synthesizing block 1C.

On the other hand, when the packet to be thinned out is delivered to the stream synthesizing block 1C, the motherboard 1
A non-thinning-out target packet (replaced data stream) having the same content as this thinning-out target packet is read from the motherboard storage 2.

More specifically, the motherboard 1 is, for example, information indicating a non-thinning target packet associated with the position information table referred to above (for example, a file name, an address of a storage area in which the packet is stored, etc.). ),
The stream synthesis block 1C is delivered to the storage read block 1F. Then, according to the control of the storage reading block 1F, the motherboard storage 2
Is accessed, the non-thinning-out target packet indicated by this information is read from the motherboard storage 2, and is delivered to the stream synthesis block 1C.

The mother board 1 also reads the position information table indicating the positions of the packets to be thinned out in the original data stream from the mother board storage 2 under the control of the stream combining block 1C and the storage reading block 1F.

Next, the mother board 1 under the control of the stream synthesizing block 1C, the stream synthesizing block 1
The arrangement order of the thinning-out target packet and the non-thinning-out target packet delivered to C is restored to the state before thinning out according to the contents of the read position information table.
Specifically, a dummy packet included in the replaced data stream (that is, a set of non-thinning target packets) delivered to the stream synthesizing block 1C is identified, and the identified dummy packet is read by the read position information table. The original data stream is restored by replacing it with the thinning-out target packet that is identified as being at the position of the dummy packet. Then, as shown in FIG.
It is delivered to the EG decode block 1E.

It should be noted that the mother board 1 has a PID value of each packet included in the replaced data stream that is different from the PID value of the TS packet included in the original data stream. , For example, the dummy packet is identified by identifying the packet having the above-mentioned value “0x002F”).

When the TS packet is delivered to the MPEG decoding block 1E, the mother board 1 decodes the image and audio represented by the TS packet under the control of the MPEG decoding block 1E, and outputs the contents data as shown in FIG. To do.

This digital broadcasting recorder that performs the above-described operation stores some TS packets that meet a certain rule in the internal memory 33 for content storage. Then, the I-picture head packet is substantially blocked from being accessed even if the I-picture head packet is read out without being controlled by the broadcast recording / reproducing program. Therefore, for example, even if the motherboard storage 2 is separated and an external computer or the like is used to reproduce the content based on the storage content of the motherboard storage 2, the data included in some TS packets cannot be obtained. Therefore, the content cannot be played correctly. As a result, the content is protected. And which part of the replaced data stream should be replaced with the packet to be thinned out is
The data stream can be easily restored because it can be easily specified by verifying the PID value.

The configuration of this digital broadcast recorder is not limited to the above. For example, the data structure of the TS packet does not have to be as described above, and may have any data structure as long as it includes a portion corresponding to the PID. Further, the image data included in the TS packet does not necessarily have to be the data in the MPEG2 format.
It may be G4 or any other type of data.
Further, the receiving unit 3 has an internal memory 3 for storing contents.
3 may be provided in plural, and the data stream may be distributed to three or more groups.

The digital broadcast recorder may also include a video circuit for controlling the display of the image represented by the content data generated by the mother board 1, and a display device such as a liquid crystal panel for displaying the image in accordance with this control. Further, an amplifier circuit for reproducing the sound represented by the content data, a speaker, and the like may be provided. A video circuit and an amplifier circuit may be mounted on the motherboard 1.

Further, the mother board 1 stores the position information table indicating the position of the packet to be thinned out in the internal memory 33 for content storage in association with the packet to be thinned out, and when reproducing the recorded content, the position information table is reproduced. Internal memory 33 for storing table contents
It is also possible to read from and use. Further, the receiving unit 3 may include a processor such as a CPU, and the processor of the receiving unit 3 performs the processing of the demultiplexer 1A and the stream thinning block 1B to generate a position information table and store the contents internally. It may be stored in the memory 33 or the replaced data stream may be supplied to the motherboard 1.

The connection bus B is not necessarily limited to the PCI bus and may be a bus complying with any standard. Therefore, the connection bus B may be, for example, a bus conforming to the PC Card Standard, or may be an ISA (Industry Sta.
ndard Architecture) It may consist of a bus. However, when the connection bus B is not the PCI bus, the reception unit 3 is provided with a bus controller or the like that mediates data exchange conforming to the standard with which the connection bus B complies, instead of the PCI bus bridge 32.

The bus connecting the internal memory 33 for content storage and the IDE bus bridge 34 is not necessarily I.
The bus is not limited to the DE bus and may be a bus complying with any standard. Therefore, this bus may comprise, for example, a memory-only bus. However, if this bus is not an IDE bus, the receiving unit 3 will use the IDE bus bridge 34.
Instead of this, a bus controller that mediates data exchange conforming to the standard that this bus complies with is provided, and the interface circuit that the internal memory 33 for storing contents also composes data that conforms to the standard that this bus complies with. Shall mediate exchange.

When recording the content, the motherboard 1 encrypts the non-thinning-out target packet and stores it in the motherboard storage 2, and when reproducing the recorded content, the encrypted non-thinning-out target packet is encrypted. The data stream may be restored after being read and decoded. Similarly, when recording the content, the thinning-out target packet is encrypted and then written to the internal memory 33 for content storage, and when playing back the recorded content, the encrypted thinning-out target packet is read and decrypted before the data. The stream may be restored.

Although the embodiments of the present invention have been described above, the data stream apparatus according to the present invention can be realized by using a normal computer system instead of a dedicated system. For example, by installing the program from a medium (CD-ROM, MO, flexible disk, or the like) storing a program for causing the personal computer to execute the operations of the motherboard 1, the motherboard storage 2, and the receiving unit 3 described above, A digital broadcast recorder that executes the above processing can be configured.

Further, for example, a bulletin board (BB of a communication line)
The program may be posted in S) and distributed via a communication line. Alternatively, a carrier wave is modulated by a signal representing the program, the obtained modulated wave is transmitted, and the modulated wave is received. The device may demodulate the modulated wave to restore the program. Then, the above process can be executed by activating the program and executing it under the control of the OS in the same manner as other application programs.

When the OS shares a part of the processing,
Alternatively, when the OS constitutes a part of one component of the present invention, the recording medium may store the program excluding the part. Also in this case, in the present invention, it is assumed that the recording medium stores a program for executing each function or step executed by the computer.

[0069]

As described above, according to the present invention, the data stream recording device and the data stream recording method for sufficiently protecting the data are realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a digital broadcast recorder according to an embodiment of the present invention.

FIG. 2 is a diagram showing a data structure of a data stream and a TS packet.

FIG. 3 is a diagram showing a data structure of a PES packet.

FIG. 4 is a diagram showing a flow of processing for recording content.

FIG. 5 is a diagram showing a flow of processing for reproducing recorded content.

[Explanation of symbols]

1 Motherboard 2 Motherboard storage 3 receiving unit 31 Digital Broadcast Receiver 32 PCI bus bridge 33 Internal memory for storing contents 34 IDE Bus Bridge B connection bus

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshiaki Sakate             1-14-6 Dogenzaka, Shibuya-ku, Tokyo Stocks             Company Kenwood F-term (reference) 5C053 FA13 FA20 FA23 FA27 GB06                       GB08 GB11 GB38 JA01 JA30                 5D044 AB05 AB07 DE03 DE22 DE50                       GK11 GK17

Claims (10)

[Claims] 1. A thinning-out means for acquiring a data stream and distributing a plurality of packets constituting the acquired data stream into a plurality of groups according to a predetermined rule; and a first means for substantially preventing access from other than the thinning-out means. And a second storage means having a second storage area, wherein the thinning means stores packets belonging to some groups in the first storage area. Then, the acquired data stream is converted into a replaced data stream in which the packets distributed to the part of the groups are replaced with dummy packets and stored in the second storage area, The content of the predetermined data in the dummy packet is the predetermined data in the packet forming the data stream acquired by the thinning means. A data stream recording device, which is different from the contents of the data. 2. A packet forming a data stream acquired by the thinning-out means is a TS (Transport Stream) packet, and the predetermined data in the packet forming a data stream acquired by the thinning-out means is a TS. Packet PI
The data stream recording apparatus according to claim 1, wherein the data stream recording apparatus comprises data including D (Program IDentifier). 3. The decimating means comprises a synthesizing means for reading the packets assigned to the plurality of groups from the first and second storage areas and restoring the data stream based on the read packets. The data stream recording device according to claim 1 or 2. 4. The thinning-out means generates information indicating a position occupied in the data stream by the packets distributed to the partial group, and stores the information in the first or second storage area. The data stream recording apparatus according to claim 1, 2, or 3. 5. The thinning means includes a processor, and the processor executes the predetermined program to access the first storage area. The data stream recording device according to the paragraph. 6. The first storage means and the thinning-out means are connected to each other via a bus which enables data transmission by the processor executing a predetermined program. The data stream recording device according to claim 5. 7. The thinning means encrypts the packets distributed to the partial group and / or other groups and stores the encrypted packets in the first and / or second storage areas. The data stream recording device according to any one of claims 1 to 6. 8. A data stream is acquired, a plurality of packets constituting the acquired data stream are distributed to a plurality of groups according to a predetermined rule, and packets belonging to a part of the groups are accessed by a device other than a predetermined access device. The data stream obtained by storing the data stream in the first storage area that is substantially blocked is converted into a replaced data stream in which the packets distributed to the partial group are replaced by dummy packets. 2 is a data stream recording method for storing in a storage area of 2, wherein the content of the predetermined data in the dummy packet is different from the content of the predetermined data in the packet forming the data stream acquired by the thinning means. The data stream recording method is characterized by the following. 9. A packet forming a data stream to be acquired is a TS (Transport Stream) packet, and the predetermined data in the packet forming the data stream to be acquired is a PID (Program IDen) of a TS packet.
The data stream recording method according to claim 8, wherein the data stream recording method comprises data including a tifier). 10. A thinning-out means for acquiring a data stream by a computer, and allocating a plurality of packets constituting the acquired data stream into a plurality of groups according to a predetermined rule, and substantially preventing access from other than the thinning-out means. A program for causing the first storage means having a first storage area and the second storage means having a second storage area to function, wherein the thinning means is a part of a group. The belonging packet is stored in the first storage area, the acquired data stream is converted into a replaced data stream in which the packets distributed to the partial group are replaced with dummy packets, and the converted data stream is converted into the replaced data stream. The content of the predetermined data in the dummy packet is acquired by the thinning means. Is different from the content of the predetermined data in the packet configuring the data stream, program characterized by.