JP2003230102A - Data stream recording equipment, data stream recording method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide data stream recording equipment or the like for securing sufficient protection of data. <P>SOLUTION: A receiving unit 3 sends a data stream obtained by receiving digital broadcast to a mother board 1 via a connection bus B. The mother board 1 stores packets in an internal memory 33 for contents preservation of the receiving unit 3, in accordance with control of a contents recording and reproducing program. The packets stored in the memory 33 contain a slice layer of a part of one picture in an MPEG (Moving Picture Expert Group) format, from among TS packets contained in the data stream. The other packets are stored in a storage 2 for the mother board. When the contents are reproduced, the TS packets containing the slice layer are read from the internal memory 33, in accordance with the control of the contents recording and reproducing program, and the other TS packets are read from the storage 2, thereby restoring and reproducing the original 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 device according to a first aspect of the present invention acquires a data stream including image data representing an image, and represents a predetermined part of the image among a plurality of packets forming the acquired data stream. A first storage having a thinning means for allocating packets containing data to a first group and allocating remaining packets to a second group, and a first storage area for substantially preventing access from other than the thinning means. Means and second storage means having a second storage area, wherein the thinning means stores packets belonging to the first group in the first storage area, and stores the packets in the second group. The packet belonging thereto is stored in the second storage area.

The image data is MPEG2 (Moving Pic).
ture Expert Group) format image data or MPEG2
It may be composed of image data having substantially the same data structure as the format image data. In this case, the partial data may be composed of, for example, a slice layer representing a predetermined slice of the I picture in the image data representing the I picture.

At least one of the plurality of packets may include partial identification data for identifying a range in which the partial data exists. In this case, the thinning-out means may specify a packet including the partial data based on the partial identification data, and allocate the specified packet to the first group.

The thinning means includes a synthesizing means for reading the packets distributed to the first or second group from the first and second storage areas and restoring the data stream based on the read packets. It may be one.

The thinning means generates information indicating a position occupied in the data stream by the packets distributed to the first or second group, and stores the information in the first or second storage area. It may be one.

The thinning means converts the acquired data stream into a replaced data stream in which the packets distributed to the first group are replaced with dummy packets, and the second storage area is converted. It may be stored in.

The thinning 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 a bus that enables data transmission by the processor executing a predetermined program.

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

Further, in the data stream recording method according to the second aspect of the present invention, a data stream including image data representing an image is acquired, and among the plurality of packets forming the acquired data stream, the predetermined image of the image is acquired. The packets including the partial data representing the part of 1 are allocated to the first group, the remaining packets are allocated to the second group, and the packets belonging to the first group are substantially accessed by a device other than a predetermined access device. First to stop
Is stored in the storage area and the packets belonging to the second group are stored in the second storage area.

The image data is MPEG2 (Moving Pic).
ture Expert Group) format image data or MPEG2
It may be composed of image data having substantially the same data structure as the format image data. In this case, the partial data may be composed of, for example, a slice layer representing a predetermined slice of the I picture in the image data representing the I picture.

A program according to a third aspect of the present invention causes a computer to acquire a data stream including image data representing an image, and to select a predetermined image of the image from a plurality of packets forming the acquired data stream. A decimation means for allocating a packet containing partial data representing the part of No. 1 to a first group and allocating the remaining packets to a second group, and a first storage area for substantially blocking access from other than the decimation means. A program for causing the first storage means to have the function and the second storage means having the second storage area to function, wherein the thinning means includes the packets belonging to the first group as the first storage means.
In the storage area, and the packets belonging to the second group are stored in the second storage area.

[0018]

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 the broadcast recording / reproducing program stored in the mother board storage 2 and performs the processing described later according to the 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, audio or other content 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 these, the B picture and the P picture represent the difference from the I picture, and the B picture alone or the P picture alone does not represent a completed image.

As shown in FIG. 3, the PES packet includes a PES header including information for identifying the PES packet, a picture layer and k pieces (k is based on a vertical size of an image represented by the PES packet). PES data including a slice layer of a positive number determined by the above.

Of these, the picture layer is data (I) indicating the attribute of the screen represented by the PES packet including the picture layer.
Picture, B picture or P picture).

The j-th (j is an arbitrary positive number less than or equal to k)
The slice layer includes data indicating the attribute of the j-th slice when the screen represented by the PES packet including the slice layer is divided into k small screens (slices).

The PES data including the I picture includes a sequence header code having a predetermined value,
Further, the PES data including an I picture further includes a video sequence layer and a GOP (Group Of Picture) layer.

Also, as shown in FIG. 3, a PE representing an image
A PSC (Picture Start Code) having a predetermined value is included at the beginning of the picture layer of the S packet. PSC
Is data for identifying a range in which data belonging to the picture layer exists. Therefore, an apparatus that attempts to reproduce a moving image from a data stream including data in the MPEG2 format cannot correctly reproduce the moving image unless it can acquire a TS packet including a PSC of a PES packet including an I picture.

Also, as shown in FIG. 3, a PE representing an image
An SSC (Slice Start Code) having a predetermined value is included at the beginning of each slice layer of the S packet. The SSC included in the jth slice layer is data for identifying the range in which the data belonging to the jth slice layer exists. Therefore, if a device that tries to reproduce a moving image from a data stream including data in the MPEG2 format cannot acquire the TS packet including the SSC in the jth slice layer of the PES packet including the I picture, the device of the jth position of the moving image is not acquired. The slice cannot be played correctly.

As shown in FIG. 2, the TS packet header has 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, in the data stream, immediately after the TS packet including the payload unit start indicator whose value is “1” and immediately before the next TS packet including the payload unit start indicator whose value is “1”. It is generated by connecting the payload parts of consecutive TS packets up to the TS 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 or sound is represented).

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 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 non-volatile 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 flowchart showing the processing of the stream thinning block. FIG. 6 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 according to 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 TS packets are shown in FIG. 4 under the control of the demultiplexer 1A. 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 has 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 this 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 mother board 1 performs the processing shown in FIG. 5 under the control of the stream thinning block 1B.

That is, when the TS packet is delivered to the stream thinning block 1B (step S1 in FIG. 5), the mother board 1 determines whether or not the PID included in this TS packet indicates the content to be accumulated. (Step S2). When it is determined that the PID does not indicate the content to be accumulated, the PI
The TS packet including D is discarded, and the process of the stream thinning block 1B is returned to step S1. It should be noted that the content to be accumulated may be designated by, for example, data supplied from the outside according to the operation of the operator.

On the other hand, when it is determined that the content to be stored is indicated, the value of the payload unit start indicator included in the TS packet including this PID is PE.
It is determined whether or not the value indicates that the beginning of the S packet is included (step S3). When it is determined that the value does not include the beginning of the PES packet, the T
The S packet (non-sampling target slice packet) is delivered to the storage recording block 1D, and the process of the stream thinning block 1B is returned to step S1. (Note that in this specification and the drawings, the motherboard 1 to the receiving unit 3 are referred to.
The TS packet supplied to the storage device is called a sampling packet to be extracted, and the TS packet delivered from the stream thinning block 1B to the storage recording block 1D is called a non-extraction target slice packet. )

On the other hand, when it is determined that the value indicates that the PES packet includes the beginning, whether or not the TS packet includes the sequence header code (that is, the TS packet includes the I picture. Is included) (step S4). When it is determined that the sequence header code is not included, this TS packet (non-extraction target slice packet) is delivered to the storage recording block 1D,
The processing of the stream thinning block 1B is returned to step S1. On the other hand, when it is determined that the sequence header code is included, the processing of the stream thinning block 1B is performed in step S
Go to 5.

In step S5, the motherboard 1 determines that this TS packet, which is determined to include the sequence header code, has a predetermined slice layer to be stored in the internal memory 33 for content storage (hereinafter referred to as a sampling target slice layer). It is assumed that the number of target slice layers is one for each PES packet). When it is determined that the SSC is included, the process of the stream thinning block 1B is advanced to step S9 described below.

As a method for the mother board 1 to specify the extraction target slice layer, for example, the motherboard storage 2 may previously store data specifying the extraction target slice layer. Then, the motherboard 1 may read this data and specify the extraction target slice layer based on the read data.

On the other hand, when the motherboard 1 determines in step S5 that it does not include the SSC for identifying the slice layer to be extracted, the next TS packet is passed from the demultiplexer 1A to the stream thinning block 1B (step S6), and is delivered. PI included in Tako's TS packet
It is determined whether D indicates the content to be stored (step S7). When it is determined that the PID does not indicate the content to be accumulated, the TS packet including the PID is discarded and the process of the stream thinning block 1B is returned to step S6. On the other hand, if it is determined that the content to be stored is indicated, the process of the stream thinning block 1B proceeds to step S8.

In step S8, the mother board 1 indicates the contents to be stored, and the TS packet determined in step S7 identifies the SSC to be extracted from the TS packet.
It is determined whether or not When it is determined that the SSC is not included, the TS packet (non-extraction target slice packet) is delivered to the storage recording block 1D, and the process of the stream thinning block 1B is returned to step S6. On the other hand, if it is determined that the stream is included, the process of the stream thinning block 1B proceeds to step S9 described later.

In step S9, the motherboard 1 receives the TS packet (slice packet to be extracted) that is most recently delivered to the stream thinning block 1B in step S1, step S6, or step S10 described later.
Write to the internal memory 33 for content storage of the receiving unit 3.

The mother board 1 writes the extraction target slice packet in the internal content storage memory 33 by accessing the internal content storage memory 33 via the PCI bus bridge 32 and the IDE bus bridge 34. That is, when the mother board 1 accesses the content storage internal memory 33 and the extraction target slice packet is supplied to the reception unit 3, the PCI bus bridge 32 of the reception unit 3 transmits the extraction target slice packet to the IDE bus bridge 34. Then, the IDE bus bridge 34 accesses the internal content storage memory 33 and stores the extraction target slice packet in the storage area of the internal content storage memory 33.

After the processing of step S9 is finished, the mother board 1 delivers the next TS packet from the demultiplexer 1A to the stream thinning block 1B (step S10), and the PID contained in the delivered TS packet is accumulated. It is determined whether or not the target content is shown (step S11). When it is determined that the PID does not indicate the content to be accumulated, the PID
The TS packet including the ID is discarded, and the process of the stream thinning block 1B is returned to step S10. On the other hand, if it is determined that the content to be stored is indicated, the process of the stream thinning block 1B proceeds to step S12.

In step S12, the mother board 1 identifies the slice contents other than the extraction target slice layer (non-extraction target slice layer) in the TS packet determined in step S11 that indicates the content to be stored SSC (or Data other than the slice layer) is included. And if it is determined that it is not included,
The processing of the stream thinning block 1B is moved to step S9.

On the other hand, when it is determined in step S12 that the TS packet includes the SSC (or the data belonging to a layer other than the slice layer) for identifying the non-extraction target slice layer, the motherboard 1 detects the TSC in the received data stream.
It is determined that the TS packet located immediately before the S packet includes the end data of the extraction target slice layer, and the process of the stream thinning block 1B is performed in step S.
Return to 3.

On the other hand, while the processing shown in FIG. 5 is performed, the mother board 1 which performs the processing of the stream thinning block 1B receives the original data stream received by the receiving unit 3 when delivering the non-extraction target slice packet to the storage recording block 1D. The slice packet to be extracted is delivered to the storage recording block 1D in the form of a replaced data stream in which a dummy packet has been replaced. The dummy packet may be, for example, a packet in which the value of the predetermined portion of the TS packet is different from the value of the portion of the TS packet included in the original data stream.

Note that the contents of the payload part of the dummy packet are different from the contents of the payload part of the extraction target slice 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 extraction target slice packet located at the position of the dummy packet.

When the non-extraction target slice packet 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 this non-extraction target slice packet in the storage area of the motherboard storage 2, as shown in FIG.

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 extraction target slice packet in the original data stream, and this position information table is also stored in the storage recording block. Hand it over to 1D. The motherboard 1 also stores this position information table in the storage area of the motherboard storage 2 under the control of the storage recording block 1D. In order to identify which content the extraction target slice packet whose position is represented by the position information table represents, the motherboard 1 may display the position information table by the position information table, for example. It may be stored in association with a non-extraction target slice packet obtained from a common data stream with the extraction target slice packet.

(Reproduction of Recorded Content) When reproducing the recorded content, the motherboard 1 responds to a content reproduction instruction supplied from the outside in accordance with an operation of an operator, and executes the broadcast recording / reproduction program for the motherboard. It is read from the storage 2 and executed.

Then, the motherboard 1 accesses the internal memory 33 for content storage via the PCI bus bridge 32 and the IDE bus bridge 34, and reads the slice packet to be extracted. The read out extraction target slice packet is supplied to the IDE bus bridge 34, and
The E bus bridge 34 transfers this extraction target slice packet to the PCI bus bridge 32, and the PCI bus bridge 32 supplies this extraction target slice packet to the motherboard 1 via the connection bus B. The extraction target slice packet to be read is, for example, read from the motherboard storage 2 by referring to the position information table associated with the non-extraction target slice packet representing the content to be reproduced according to the control of the storage read block 1F. It can be specified by doing.

As shown in FIG. 6, the motherboard 1 delivers the extraction target slice packet read from the receiving unit 3 to the stream synthesizing block 1C.

On the other hand, when the sampling target slice packet is delivered to the stream synthesizing block 1C, the motherboard 1 sends the non-extraction target slice packet (replaced data stream) whose contents are common to this sampling target slice packet to the motherboard. Storage 2
Read more.

Specifically, the mother board 1 has, for example, information indicating a non-extraction target slice packet associated with the previously referred position information table (for example,
The file name, the address of the storage area in which the file is stored, etc.) is passed from the stream synthesis block 1C to the storage read block 1F. Then, the motherboard storage 2 is accessed under the control of the storage read block 1F, the non-extraction target slice 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 table indicating the position of the slice packet to be extracted in the original data stream from the mother board storage 2 under the control of the stream synthesizing block 1C and the storage reading block 1F.

Next, the mother board 1 controls the stream synthesizing block 1C under the control of the stream synthesizing block 1C.
The arrangement order of the extraction target slice packet and the non-extraction target slice packet delivered to C is restored to the state before thinning according to the contents of the read position information table. Specifically, the stream synthesis block 1C
The replaced data stream (ie,
The original data stream is restored by replacing the dummy packet included in the set of non-extraction target slice packets) with the extraction target slice packet that is identified as being in the position of the dummy packet according to the read position information table. To do. Then, the order in which the order was restored was T
The S packet is delivered to the MPEG decoding block 1E as shown in FIG.

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 it as content data as shown in FIG. To do.

This digital broadcast recorder performing the operation described above is a TS packet including data constituting a PES packet including an I picture in a payload portion and including an SSC of an extraction target slice layer (extraction target slice packet). The contents are stored in the internal memory 33 for storing contents. Then, even if an attempt is made to read the extraction target slice packet without following the control of the broadcast recording / playback program, access is substantially blocked. Therefore, for example, even if the storage 2 for the motherboard is separated and an external computer or the like is used to reproduce the content based on the stored content of the storage 2 for the mother board, the range of the slice layer to be extracted cannot be specified, and the extraction target of the video The slice corresponding to the slice layer cannot be played correctly. As a result, the content is protected.

The sampling packet to be extracted which the digital broadcast recorder stores in the internal memory 33 for content storage is a very small part of the TS packet including the I picture. Therefore, the storage capacity of the content storage internal memory 33 can be much smaller than the storage capacity required in the configuration in which all TS packets including I pictures are stored in the content storage internal memory 33, for example. .

The structure of this digital broadcast recorder is not limited to the above. For example, the image data included in the TS packet does not necessarily have to be the MPEG2 format data, and may include, for example, the MPEG4 format data. Further, the reception unit 3 may include a plurality of internal memories 33 for storing contents, and the data stream may be distributed to three or more groups. Further, the non-sampling target slice packet does not necessarily need to be stored in the motherboard storage 2 in the form of the replaced data stream. That is, the dummy packet is not necessary.

Further, the mother board 1 has a B picture and a P picture.
An internal memory 33 for content storage is a TS packet including data constituting a PES packet including a picture in a payload portion and including an SSC of a slice layer to be extracted.
You may make it memorize | store in. Furthermore, I picture,
Of the PES packets containing arbitrary image data not limited to B pictures and P pictures, a packet containing data representing a predetermined portion of the image represented by this image data may be stored in the internal memory 33 for content storage. Good.

Further, this digital broadcast recorder may 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 according to 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 extraction target slice packet in the internal memory 33 for content storage in association with the extraction target slice packet, and when reproducing the recorded content, The position information table may be read from the internal memory 33 for content storage and used.

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-extraction target slice packet and then stores it in the motherboard storage 2, and when reproducing the recorded content, the encrypted non-extraction target slice packet. The packet may be read and decoded before the data stream is restored. Similarly, when recording the content, the extraction target slice packet is encrypted and then written to the internal memory 33 for content storage. When reproducing the recorded content, the encrypted extraction target slice packet is read and decrypted. The data stream may be restored from the.

The number of slice layers to be extracted is PES.
There may be a plurality of packets per packet. When there are a plurality of slice layers to be extracted per PES packet, the motherboard 1 uses the stream thinning block 1B.
For example, the processing shown in FIGS. 7 and 8 may be performed as the processing.

As shown in the figure, the processing of steps S101 to S111 in the processing of FIG. 7 is substantially the same as the processing of steps S1 to S11 shown in FIG.

At step S112, the motherboard 1 is
When the content to be stored is indicated, it is determined whether or not the TS packet determined in step S111 includes SSC (or data belonging to a layer other than the slice layer) for identifying the non-extraction target slice layer. If it is determined that the stream is not included, the process of the stream thinning block 1B is moved to step S109.

On the other hand, when it is determined in step S112 that the TS packet includes SSC (or data belonging to a layer other than the slice layer) for identifying the non-extraction target slice layer,
The motherboard 1 determines whether or not the value of the payload unit start indicator included in this TS packet is a value indicating that the beginning of the PES packet is included (FIG. 8, step S113). Then, when it is determined that the value includes the beginning of the PES packet, the process of the stream thinning block 1B is returned to step S104.

On the other hand, when it is determined in step S113 that the value of the payload unit start indicator is a value indicating that the head of the PES packet is not included, the motherboard 1 delivers the TS packet to the storage recording block 1D and The TS packet of 1 is delivered from the demultiplexer 1A to the stream thinning block 1B (step S114).

Then, it is determined whether or not the PID included in this TS packet newly delivered in step S114 indicates the content to be stored (step S).
15). When it is determined that the PID does not indicate the content to be stored, the TS packet including the PID is discarded, and the process of the stream thinning block 1B is returned to step S114. On the other hand, if it is determined that the content to be stored is indicated, the process of the stream thinning block 1B proceeds to step S116.

At step S116, the motherboard 1 is
When indicating the content to be stored, it is determined whether or not the TS packet determined in step S115 includes the SSC identifying the extraction target slice layer. Then, if it is determined that it is not included, the processing of the stream thinning block 1B is returned to step S113, and if it is determined that it is included, the processing of the stream thinning block 1B is returned to step S109.

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.

If 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.

[0089]

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 flowchart showing processing of a stream thinning block.

FIG. 6 is a diagram showing a flow of processing for reproducing recorded content.

FIG. 7 is a flowchart illustrating a modified example of processing of a stream thinning block.

FIG. 8 is a flowchart showing a continuation of the processing of FIG.

[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

Continuation of front page (51) Int.Cl. ⁷ identification code FI theme code (reference) H04N 7/32 H04N 7/137 Z (72) Inventor Yasushi Yamagami 1-14-6 Dogenzaka, Shibuya-ku, Tokyo Kenwood Co., Ltd. Inner F-term (reference) 5C053 FA20 FA23 GA11 GB11 GB30 GB37 GB38 JA05 LA06 5C059 KK43 MA00 MA04 MA05 MA14 PP05 PP06 PP07 SS02 SS11 UA02 UA05 5D044 AB07 BC01 BC04 CC04 DE03 DE24 EF05

Claims (12)

[Claims] 1. A data stream including image data representing an image is acquired, and among a plurality of packets forming the acquired data stream, a packet including partial data representing a predetermined portion of the image is assigned to a first group. It has decimation means for allocating and allocating the remaining packets to the second group, first memory means having a first memory area that substantially blocks access from other than said decimating means, and second memory area. Second storage means, wherein the thinning means stores packets belonging to the first group in the first storage area and stores packets belonging to the second group in the second storage area. A data stream recording device characterized by: 2. The image data is MPEG2 (Moving Pic).
ture Expert Group) format image data or MPEG2
The partial data is composed of a slice layer that represents a predetermined slice of the I picture of the image data that represents an I picture. The data stream recording device according to claim 1, wherein 3. At least one of the plurality of packets includes partial identification data for identifying a range in which the partial data exists, and the thinning-out means converts a packet including the partial data into the partial identification data. 3. The data stream recording device according to claim 1, wherein the data stream recording device is specified based on the above, and the specified packet is distributed to the first group. 4. The synthesizing means for reading the packets allocated to the first or second group from the first and second storage areas, and restoring the data stream based on the read packets. The data stream recording apparatus according to claim 1, 2 or 3, further comprising: 5. The thinning means generates information indicating a position occupied by the packets assigned to the first or second group in the data stream, and stores the information in the first or second storage area. The data stream recording device according to any one of claims 1 to 4, wherein the data stream recording device stores the data. 6. The thinning means converts the acquired data stream into a replaced data stream in which the packets distributed to the first group are replaced with dummy packets, and the second data stream is converted into a replaced data stream. The data stream recording apparatus according to claim 1, wherein the data stream recording apparatus stores the data stream in a storage area. 7. The thinning means comprises a processor, and the processor accesses the first storage area by executing a predetermined program. The data stream recording device according to the paragraph. 8. 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 7. 9. The thinning means encrypts the packets distributed to the first and / or second groups and stores the encrypted packets in the first and / or second storage areas. Item 9. The data stream recording device according to any one of items 1 to 8. 10. A data stream including image data representing an image is acquired, and among a plurality of packets forming the acquired data stream, a packet including partial data representing a predetermined part of the image is assigned to a first group. Distribution,
The remaining packets are distributed to the second group, the packets belonging to the first group are stored in the first storage area that substantially blocks access from other than the predetermined access device, and belong to the second group. A data stream recording method, characterized in that the packet is stored in a second storage area. 11. The image data is MPEG2 (Moving P
icture Expert Group) format image data or MPEG
The partial data is composed of image data having substantially the same data structure as the image data of the two formats, and the partial data is composed of a slice layer representing a predetermined slice of the I picture of the image data representing the I picture. The data stream recording method according to claim 10, wherein: 12. A computer obtains a data stream including image data representing an image, and selects a first packet among a plurality of packets forming the obtained data stream, the packet including partial data representing a predetermined portion of the image. Thinning means for allocating the remaining packets to the second group, first storage means having a first storage area for substantially preventing access from other than the thinning means, and second storage A program for functioning as a second storage unit having an area, wherein the thinning unit stores packets belonging to the first group in the first storage area, and stores the packets in the second group. Storing a packet belonging to the second storage area in the second storage area.