JP3865374B2 - Data stream recording apparatus, data stream recording method and program - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data stream recording apparatus, a data stream recording method, and a program.
[0002]
[Prior art]
Digital broadcasting that broadcasts content such as images and sounds in the form of a data stream composed of continuous packets including data representing the content is used.
[0003]
Digitally broadcast content can be stored in a storage device as data in digital format, and data deterioration is unlikely to occur during storage.
For this reason, a technique for protecting rights such as copyrights relating to digitally broadcast content is used. Specifically, there is a method of encrypting and storing data representing content.
[0004]
[Problems to be solved by the invention]
However, if the encryption method is not strong enough to attack, the encrypted data can be easily decrypted by a person who does not know the decryption key, and the data cannot be sufficiently protected. .
[0005]
The present invention has been made in view of the above circumstances, and an object thereof is to provide a data stream recording apparatus 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 the first aspect of the present invention provides:
  MPEG2 ( Moving Picture Expert Group 2 ) Format image data or image data having substantially the same data structure as MPEG2 format image dataAmong the plurality of packets that acquire the data stream and make up the acquired data stream,PSC (identifying the range of the picture layer of the image data including the I picture ( Picture Start Code )Thinning means for distributing at least a part of the packets including the identification data to the first group and distributing the remaining packets to the second group;
  First storage means having a first storage area that substantially prevents access from other than the thinning means;
  Second storage means having a second storage area,
  The thinning-out means stores packets belonging to the first group in the first storage area,The acquired data stream is converted into a replaced data stream in which the packet allocated to the first group is replaced with a dummy packet, and the replaced data stream is converted into the replaced data stream.Packets belonging to the second groupAsStore in the second storage area,
  It is characterized by that.
[0008]
The thinning-out means may distribute packets that satisfy a predetermined condition among packets including the identification data to a first group, and distribute packets that do not satisfy the condition to a second group.
[0009]
The thinning-out means includes combining means for reading out 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. May be.
[0010]
The thinning-out means generates information indicating the position occupied by the packet allocated to the first or second group in the data stream, and stores the information in the first or second storage area. May be.
[0012]
The thinning unit may include a processor, for example, and the processor may access the first storage area by executing a predetermined program.
[0013]
The first storage unit and the thinning-out unit may be connected to each other via a bus that enables data transmission when the processor executes a predetermined program.
[0014]
The thinning-out means may encrypt the packet distributed to the first and / or second group and store it in the first and / or second storage area.
[0015]
  A data stream recording method according to the second aspect of the present invention includes:
  MPEG2 ( Moving Picture Expert Group 2 ) Format image data or image data having substantially the same data structure as MPEG2 format image dataAmong the plurality of packets that acquire the data stream and make up the acquired data stream,PSC (identifying the range of the picture layer of the image data including the I picture ( Picture Start Code )Distributing at least a part of the packets including the identification data to the first group, distributing the remaining packets to the second group,
  Storing packets belonging to some groups in a first storage area that substantially prevents access from other than a predetermined access device;
  The acquired data stream is converted into a replaced data stream in which a packet distributed to the first group is replaced with a dummy packet, and the replaced data stream is converted into the replaced data stream.Packets belonging to the second groupAsStore in the second storage area,
  It is characterized by that.
[0017]
  A program according to the third aspect of the present invention is:
  Computer
  MPEG2 ( Moving Picture Expert Group 2 ) Format image data or image data having substantially the same data structure as MPEG2 format image dataAmong the plurality of packets that acquire the data stream and make up the acquired data stream,PSC (identifying the range of the picture layer of the image data including the I picture ( Picture Start Code )Thinning means for distributing at least a part of the packets including the identification data to the first group and distributing the remaining packets to the second group;
  First storage means having a first storage area that substantially prevents access from other than the thinning means;
  A program for functioning as a second storage means having a second storage area,
  The thinning-out means stores packets belonging to the first group in the first storage area,The acquired data stream is converted into a replaced data stream in which the packet allocated to the first group is replaced with a dummy packet, and the replaced data stream is converted into the replaced data stream.Packets belonging to the second groupAsStore in the second storage area,
  It is characterized by that.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below 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 includes 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.
[0019]
The motherboard 1 includes, for example, a processor composed of a CPU (Central Processing Unit), a memory composed of a RAM (Random Access Memory), and a bus controller. The connection bus B is a PCI (Peripheral Component Interface) bus.
The memory of the motherboard 1 has a storage area that becomes a work area of the processor of the motherboard 1. The bus controller of the motherboard 1 includes 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.
[0020]
The mother board 1 reads out the broadcast recording / reproducing program stored in the motherboard storage 2 and performs the processing described later according to this broadcast recording / reproducing program.
The process controlled by the broadcast recording / reproducing program functionally includes a plurality of processing blocks. Specifically, a demultiplexer 1A, a stream decimation block 1B, a stream synthesis block 1C, a storage recording block 1D, an MPEG (Moving Picture Expert Group) decoding block 1E, and a storage reading block 1F, which will be described later with reference to FIGS. , Each processing block is included.
[0021]
The motherboard storage 2 is composed of a hard disk device or the like, and stores the above-described broadcast recording / reproducing program in advance. Then, in accordance with an access from the mother board 1, data supplied by the mother board 1 is stored, or data stored by itself is read out and supplied to the mother board 1.
[0022]
The receiving unit 3 includes a digital broadcast receiving unit 31, a PCI bus bridge 32, a content storage internal memory 33, and an IDE (Intelligent Drive Electronics) bus bridge 34.
[0023]
The digital broadcast receiving unit 31 includes 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 constituting the data stream by inputting and demodulating a modulated wave representing the data stream digitally broadcast from the outside. Then, the restored TS packet is supplied to the mother board 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, sound, or other content, and is composed of a plurality of continuous TS packets as shown in FIG.
[0024]
A TS packet is a packet representing an image, sound, or other content, and has a data structure shown in FIG. That is, the TS packet includes a TS packet header and a payload portion (adaptation / payload portion) following the TS packet header.
[0025]
The payload portion is a portion including data representing content. As shown in FIG. 3, each TS packet including data representing an image of the same frame is connected to each other in the order in which the TS packets are arranged, so that PES (Packetized Elementary Stream) ) Packets can be formed.
[0026]
When the data stream represents MPEG2 format image data (or image data having substantially the same data structure as the MPEG2 format image data), the PES packet is an I picture, B that is data representing an image constituting a moving image. One or more of three types of pictures or P pictures are included. Among these, the B picture and the P picture represent differences from the I picture, and the B picture alone or the P picture alone does not represent a completed image.
[0027]
As shown in FIG. 3, the PES packet includes a PES header including information for identifying the PES packet and PES data including a picture layer including any one of an I picture, a B picture, and a P picture. Yes.
[0028]
The PES data including the I picture includes a sequence header code having a predetermined value. The PES data including the I picture further includes a video sequence layer and a GOP (Group Of Picture) layer. include.
[0029]
Also, as shown in FIG. 3, a PSC (Picture Start Code) having a predetermined value is included at the head of the picture layer of the PES packet representing an image.
PSC is data for identifying a range in which data belonging to a picture layer exists. Therefore, an apparatus that attempts to reproduce a moving image from a data stream that includes MPEG2 format data cannot correctly reproduce the moving image unless it can obtain a TS packet that includes a PES packet including an I picture.
[0030]
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 field control data in order from the top. And continuity indicators.
[0031]
Among these, the payload unit start indicator indicates whether or not the payload portion of the TS packet including the payload unit start indicator itself includes the top data of the PES packet. Specifically, for example, when the value of the payload unit start indicator is “1”, it indicates that the payload portion of the TS packet including the payload unit start indicator itself includes the head data of the PES packet, When 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 immediately before a next TS packet including a payload unit start indicator having a value of “1”. It is generated by concatenating the payload portions of successive TS packets up to TS packets.
[0032]
The PID is data for identifying which content (for example, which image or sound represents) the payload part of the TS packet including the PID itself represents.
[0033]
The PCI bus bridge 32 is configured by a bus controller or the like, is connected to the motherboard 1 via the connection bus B, and is connected to the IDE bus bridge 34 and the digital broadcast receiver 31 via an internal bus. Yes.
The PCI bus bridge 32 mediates access to the content storage internal memory 33 which is performed by the mother board 1 according to the control of the broadcast recording / reproducing program. It also mediates the supply of data from the digital broadcast receiver 31 to the content storage internal memory 33.
[0034]
The content storage internal memory 33 includes a nonvolatile memory such as a compact flash memory and an interface circuit for transmitting data via the IDE bus.
[0035]
The IDE bus bridge 34 is composed of a bus controller or the like, and is connected to the PCI bus bridge 32 via an internal bus, while being connected to the content storage internal memory 33 via the IDE bus. The IDE bus bridge 34 mediates access to the content storage internal memory 33 that the motherboard 1 performs according to the control of the broadcast recording / playback program.
The PCI bus bridge 32 and the IDE bus bridge 34 substantially prevent this access even if the motherboard 1 accesses the content storage internal memory 33 without following the control of the broadcast recording / reproducing program.
[0036]
(Operation)
Next, the operation of this 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 processing of the stream thinning block.
FIG. 6 is a diagram showing a flow of processing for reproducing the recorded content.
[0037]
(Recording content)
When a modulated wave representing a data stream is supplied to the digital broadcast receiver 31 of the receiving unit 3, the digital broadcast receiver 31 restores the data stream by demodulating the modulated wave, and the restored data stream Are supplied to the mother board 1 via the PCI bus bridge and the connection bus B.
[0038]
On the other hand, the mother board 1 reads out and executes a broadcast recording / reproducing program from the mother board storage 2 in response to a recording instruction supplied from the outside in accordance with the operation of the operator.
[0039]
When the mother board 1 executing the broadcast recording / reproducing program is supplied with the data stream (that is, when TS packets are sequentially supplied), the TS packet is converted into the TS packet according to the control of the demultiplexer 1A as shown in FIG. The data is delivered to each processing block of the stream synthesis block 1C and the stream decimation block 1B.
[0040]
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 motherboard 1 specifically processes this TS packet according to the control of the stream synthesizing block 1C. The TS packet is delivered to the MPEG decode block 1E without being added.
[0041]
When the TS packet is delivered to the MPEG decoding block 1E, the mother board 1 decodes the image and sound represented by the TS packet according to the control of the MPEG decoding block 1E, and a video signal such as a composite signal, as shown in FIG. And output as content data consisting of audio signals.
[0042]
On the other hand, the mother board 1 performs the processing shown in FIG. 5 according to the control of the stream thinning block 1B.
[0043]
That is, when the TS packet is delivered to the stream decimation block 1B (FIG. 5, step S1), the mother board 1 determines whether or not the PID included in this TS packet indicates the content to be accumulated (step S2). ). If it is determined that the PID does not indicate the content to be accumulated, the TS packet including this PID is discarded, and the process of the stream thinning block 1B is returned to step S1. The content to be accumulated may be specified by data supplied from the outside according to the operation of the operator, for example.
[0044]
On the other hand, if it is determined that the content to be accumulated is indicated, it is determined whether or not the value of the payload unit start indicator included in the TS packet including the PID is a value indicating that the head of the PES packet is included (step S1). S3). If it is determined that the value does not include the head of the PES packet, the TS packet (non-I picture head packet) is transferred to the storage recording block 1D, and the process of the stream thinning block 1B is returned to step S1. (In this specification and drawings, the TS packet supplied from the mother board 1 to the receiving unit 3 is called an I picture head packet, and the TS packet delivered from the stream thinning block 1B to the storage recording block 1D is a non-I picture. Called the first packet.)
[0045]
On the other hand, if it is determined that the value indicates that the head of the PES packet is included, whether or not the TS packet includes a sequence header code (that is, the TS packet includes data at the head of the PES packet including the I picture). Whether or not it is included) is determined (step S4). If it is determined that the sequence header code is not included, this TS packet (non-I picture head packet) is delivered to the storage recording block 1D, and the processing of the stream thinning block 1B is returned to step S1. On the other hand, if it is determined that the sequence header code is included, the process of the stream thinning block 1B proceeds to step S5.
[0046]
If the mother board 1 determines in step S5 that the value indicates that the head of the PES packet is included, the mother board 1 determines whether or not the TS packet includes a PSC. If it is determined that the PSC is included, the mother board 1 advances the processing of the stream thinning block 1B to step S9 described later.
[0047]
On the other hand, if it is determined that the PSC is not included, the mother board 1 delivers the next TS packet from the demultiplexer 1A to the stream decimation block 1B (step S6), and the PID included in the delivered TS packet is an object to be accumulated. It is determined whether or not the content is indicated (step S7). If it is determined that the PID does not indicate the content to be accumulated, the TS packet including this PID is discarded, and the process of the stream thinning block 1B is returned to step S6.
[0048]
On the other hand, if it is determined that the content to be stored is indicated, the mother board 1 determines whether or not the TS packet including the PID includes the PSC (step S8). If it is determined that the PSC is included, the mother board 1 advances the processing of the stream thinning block 1B to step S9 described later. On the other hand, if it is determined that the PSC is not included, this TS packet (non-I picture head packet) is transferred to the storage recording block 1D, and the processing of the stream thinning block 1B is returned to step S6.
[0049]
In step S9, the mother board 1 writes the TS packet (I picture head packet) delivered to the stream decimation block 1B most recently in step S1 or S6 into the content storage internal memory 33 of the receiving unit 3, and the stream decimation block 1B. Is returned to step S1.
[0050]
The motherboard 1 writes the I picture head packet to the content storage internal memory 33 by accessing the content storage internal memory 33 via the PCI bus bridge 32 and the IDE bus bridge 34. That is, when the motherboard 1 accesses the content storage internal memory 33 and the I picture head packet is supplied to the receiving unit 3, the PCI bus bridge 32 of the receiving unit 3 sends the I picture head packet to the IDE bus bridge 34. The IDE bus bridge 34 accesses the content storage internal memory 33 and stores the I picture head packet in the storage area of the content storage internal memory 33.
[0051]
On the other hand, when the mother board 1 performing the stream thinning block 1B delivers the non-I picture head packet to the storage recording block 1D, the I picture head packet of the original data stream received by the receiving unit 3 is converted to a dummy packet. To the storage recording block 1D in the form of a replaced data stream. The dummy packet may be a packet whose value of a predetermined portion of the TS packet is different from the value of the portion of the TS packet included in the original data stream, for example.
[0052]
It is assumed that the content of the payload portion of the dummy packet is different from the content of the payload portion of the I picture head packet replaced by the dummy packet. It is desirable that there is substantially no correlation between the content of the payload portion of the dummy packet and the content of the payload portion of the I picture head packet at the position of the dummy packet.
[0053]
When the non-I picture head packet is delivered to the storage recording block 1D, the mother board 1 accesses the motherboard storage 2 according to the control of the storage recording block 1D, and as shown in FIG. The data is stored in the storage area of the motherboard storage 2.
[0054]
Further, the mother board 1 that performs the processing of the stream thinning block 1B creates a position information table that indicates the position of each I picture head packet in the original data stream, and this position information table is also transferred to the storage recording block 1D. hand over. 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 what content the I-picture head packet whose position is represented by the position information table represents, for example, the motherboard 1 indicates the position information table, and the position is represented by this position information table. What is necessary is just to make it associate and store with the non-I picture head packet obtained from the data stream common to the I picture head packet which is being.
[0055]
(Replay recorded content)
When playing back the recorded content, the motherboard 1 reads out and executes the broadcast recording / playback program from the motherboard storage 2 in response to a content playback instruction supplied from the outside in accordance with the operation of the operator.
[0056]
Then, the motherboard 1 accesses the content storage internal memory 33 via the PCI bus bridge 32 and the IDE bus bridge 34 and reads the I picture head packet. The read I picture head packet is supplied to the IDE bus bridge 34. The IDE bus bridge 34 transfers the I picture head packet to the PCI bus bridge 32, and the PCI bus bridge 32 passes the I picture head packet to the connection bus. B is supplied to the mother board 1 via B.
For example, the I-picture head packet to be read is read from the storage 2 for the mother board according to the control of the storage read block 1F by reading the position information table associated with the non-I-picture head packet representing the content to be played back. What is necessary is just to specify by doing.
[0057]
As shown in FIG. 6, the mother board 1 delivers the I picture head packet read from the receiving unit 3 to the stream synthesis block 1C.
[0058]
On the other hand, when the I picture head packet is delivered to the stream synthesis block 1C, the mother board 1 transfers the non-I picture head packet (replaced data stream) whose content is the same as this I picture head packet to the motherboard storage 2 Read from.
[0059]
Specifically, the mother board 1 uses, for example, information (for example, a file name or an address of a storage area stored) indicating a non-I picture head packet associated with the previously referred position information table. Then, the data is delivered 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, and the non-I picture head packet indicated by this information is read from the motherboard storage 2 and delivered to the stream synthesis block 1C.
[0060]
The mother board 1 also reads out a table indicating the position of the I picture head packet in the original data stream from the mother board storage 2 according to the control of the stream synthesis block 1C and the storage read block 1F.
[0061]
Next, in accordance with the control of the stream synthesis block 1C, the motherboard 1 thins out the arrangement order of the I picture head packet and the non-I picture head packet delivered to the stream synthesis block 1C according to the contents of the read position information table. Restore to the previous state. Specifically, a dummy packet included in the replaced data stream (that is, a set of non-I picture head packets) delivered to the stream synthesis block 1C is matched with the position of the dummy packet by the read position information table. The original data stream is restored by substituting it with the I-picture head packet specified to be correct.
Then, the TS packets whose arrangement order is restored are delivered to the MPEG decoding block 1E as shown in FIG.
[0062]
When the TS packet is delivered to the MPEG decode block 1E, the mother board 1 decodes the image and sound represented by the TS packet according to the control of the MPEG decode block 1E, and outputs it as content data as shown in FIG.
[0063]
This digital broadcast recorder that performs the operation described above stores, in the content storage internal memory 33, the TS packet including the PSC (I picture head packet) among the TS packets including the data constituting the PES packet including the I picture in the payload portion. Let Then, even if the I picture head packet is read out without following the control of the broadcast recording / reproducing program, the access is substantially blocked. Therefore, for example, even if the motherboard storage 2 is disconnected and an external computer or the like is used and content is reproduced based on the stored contents of the motherboard storage 2, the data range of the picture layer representing the contents of the I picture cannot be specified. The video cannot be played correctly. As a result, the content can be protected.
[0064]
The I picture head packet stored in the content storage internal memory 33 by the digital broadcast recorder is a very small part of the TS packet including the I picture. Therefore, the storage capacity of the content storage internal memory 33 may be much smaller than the storage capacity required for a configuration in which, for example, all TS packets including I pictures are stored in the content storage internal memory 33. .
[0065]
The configuration 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 MPEG2 format data, and may include, for example, MPEG4 format data. The receiving unit 3 may include a plurality of content storage internal memories 33, and the data stream may be distributed into three or more groups.
Further, the non-I picture head packet is not necessarily stored in the motherboard storage 2 in the form of a replaced data stream. That is, the dummy packet is not necessary.
[0066]
Further, the mother board 1 stores, in the content storage internal memory 33, the TS packet including the PSC among the TS packets including the data constituting the PES packet including the B picture and the P picture in the payload portion instead of the I picture head packet. You may do it. Further, a packet including predetermined data for identifying a range in which data constituting a PES packet including predetermined data including but not limited to an I picture, B picture, or P picture exists is stored in the content storage internal memory 33. You may make it make it.
[0067]
In addition, the digital broadcast recorder may include a video circuit that controls display of an image represented by the content data generated by the motherboard 1 and a display device such as a liquid crystal panel that displays an image according to this control. Further, an amplifier circuit, a speaker, and the like for reproducing the sound represented by the content data may be provided. A video circuit and an amplifier circuit may be mounted on the motherboard 1.
[0068]
Further, the motherboard 1 stores a position information table indicating the position of the I picture head packet in the content storage internal memory 33 in association with the I picture head packet, and when playing back the recorded content, the position information table. May be read from the content storage internal memory 33 and used.
[0069]
Further, the connection bus B is not necessarily limited to the PCI bus, and may be a bus conforming to an arbitrary standard. Therefore, the connection bus B may be composed of, for example, a bus conforming to PC Card Standard or may be composed of an ISA (Industry Standard Architecture) bus. However, when the connection bus B is not a PCI bus, the reception unit 3 is provided with a bus controller or the like that mediates data exchange conforming to the standard to which the connection bus B conforms instead of the PCI bus bridge 32.
[0070]
The bus connecting the content storage internal memory 33 and the IDE bus bridge 34 is not necessarily limited to the IDE bus, and may be a bus conforming to an arbitrary standard. Therefore, this bus may comprise a memory dedicated bus, for example. However, when this bus is not an IDE bus, the receiving unit 3 is provided with a bus controller or the like that mediates data exchange conforming to the standard to which this bus conforms instead of the IDE bus bridge 34, and for content storage It is assumed that the interface circuit provided in the internal memory 33 also mediates data exchange conforming to the standard to which this bus complies.
[0071]
Further, the mother board 1 encrypts the non-I picture head packet when recording the content and stores it in the motherboard storage 2, and reads the encrypted non-I picture head packet when reproducing the recorded content. The data stream may be restored after decoding.
Similarly, when recording content, the I-picture head packet is encrypted and then written to the content storage internal memory 33. When playing back the recorded content, the encrypted I-picture head packet is read and decrypted. Alternatively, the data stream may be restored.
[0072]
Further, the motherboard 1 does not necessarily have to store all TS packets representing P picture and including PSC in the content storage internal memory 33. Therefore, for example, the mother board 1 stores, in the content storage internal memory 33, every n number of TS packets determined to include the PSC in step S5 (m and n are arbitrary positive numbers, where m> n). Other TS packets that are stored and determined to include PSC in step S5 may be delivered to the storage recording block 1D in the same manner as the non-I picture head packet.
[0073]
Although the embodiment of the present invention has been described above, the data stream device according to the present invention can be realized using a normal computer system, not a dedicated system.
For example, by installing the program from a medium (CD-ROM, MO, flexible disk, etc.) storing a program for causing the personal computer to execute the operations of the mother board 1, the mother board storage 2 and the receiving unit 3 described above, A digital broadcast recorder that performs the above-described processing can be configured.
[0074]
Further, for example, the program may be posted on a bulletin board (BBS) of a communication line and distributed via the communication line. Also, a carrier wave is modulated by a signal representing the program, and the obtained modulated wave is An apparatus that transmits and receives the modulated wave may demodulate the modulated wave to restore the program.
Then, the above-described processing can be executed by starting the program and executing it in the same manner as other application programs under the control of the OS.
[0075]
When the OS shares a part of the processing, or when the OS constitutes a part of one component of the present invention, a program excluding the part is stored in the recording medium. May be. 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.
[0076]
【The invention's effect】
As described above, according to the present invention, a data stream recording apparatus and a data stream recording method for sufficiently protecting data are realized.
[Brief description of the 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 illustrating a data structure of a data stream and a TS packet.
FIG. 3 is a diagram illustrating 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.
[Explanation of symbols]
1 Motherboard
2 Motherboard storage
3 receiving unit
31 Digital broadcast receiver
32 PCI bus bridge
33 Internal memory for content storage
34 IDE Bus Bridge
B Connection bus

Claims (9)

An MPEG2 ( Moving Picture Expert Group 2 ) format image data or a data stream including image data having substantially the same data structure as the MPEG2 format image data is acquired, and among the plurality of packets constituting the acquired data stream , At least a part of packets including identification data composed of PSC ( Picture Start Code ) for identifying the range of the picture layer of the image data including the I picture is assigned to the first group, and the remaining packets are assigned to the second group A thinning-out means for distributing;
First storage means having a first storage area that substantially prevents access from other than the thinning means;
Second storage means having a second storage area,
The thinning-out means stores the packets belonging to the first group in the first storage area, and replaces the acquired data stream with the packets assigned to the first group with dummy packets. Converting into a replaced data stream, and storing the replaced data stream in the second storage area as a packet belonging to the second group;
A data stream recording apparatus. The thinning-out unit distributes packets satisfying a predetermined condition among the packets including the identification data to the first group, and distributes packets not satisfying the condition to the second group.
The data stream recording apparatus according to claim 1 , wherein: The thinning unit includes a combining unit that reads packets distributed to the first or second group from the first and second storage areas and restores the data stream based on the read packets.
The data stream recording apparatus according to claim 1 or 2, characterized in that. The thinning unit generates information representing a position occupied in the data stream by the packet allocated to the first or second group, and stores the information in the first or second storage area.
The data stream recording apparatus according to any one of claims 1 to 3, characterized in that. The thinning means includes a processor, and the processor accesses the first storage area by executing a predetermined program.
The data stream recording apparatus according to any one of claims 1 to 4, characterized in that. The first storage unit and the thinning unit are connected to each other via a bus that enables data transmission by the processor executing a predetermined program.
6. The data stream recording apparatus according to claim 5 , wherein The thinning-out means encrypts the packets distributed to the first and / or second groups and stores them in the first and / or second storage areas.
The data stream recording apparatus according to any one of claims 1 to 6, characterized in that. An MPEG2 ( Moving Picture Expert Group 2 ) format image data or a data stream including image data having substantially the same data structure as the MPEG2 format image data is acquired, and among the plurality of packets constituting the acquired data stream , At least a part of packets including identification data composed of PSC ( Picture Start Code ) for identifying the range of the picture layer of the image data including the I picture is assigned to the first group, and the remaining packets are assigned to the second group Sorting,
Storing packets belonging to some groups in a first storage area that substantially prevents access from other than a predetermined access device;
The acquired data stream is converted into a replaced data stream in which the packet distributed to the first group is replaced with a dummy packet, and the replaced data stream is a packet belonging to the second group. As a second storage area,
A data stream recording method. Computer
An MPEG2 ( Moving Picture Expert Group 2 ) format image data or a data stream including image data having substantially the same data structure as the MPEG2 format image data is acquired, and among the plurality of packets constituting the acquired data stream , At least a part of packets including identification data composed of PSC ( Picture Start Code ) for identifying the range of the picture layer of the image data including the I picture is assigned to the first group, and the remaining packets are assigned to the second group A thinning-out means for distributing;
First storage means having a first storage area that substantially prevents access from other than the thinning means;
A program for functioning as a second storage means having a second storage area,
The thinning-out means stores the packets belonging to the first group in the first storage area, and replaces the acquired data stream with the packets assigned to the first group with dummy packets. Converting into a replaced data stream, and storing the replaced data stream in the second storage area as a packet belonging to the second group;
A program characterized by that.

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