JP3865375B2 - 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 data or MPEG2 format image data has substantially the same data structureA data stream including image data is acquired, and among a plurality of packets constituting the acquired data stream,SSC (in a slice layer representing a predetermined slice of an I picture ( Slice Start Code )Thinning means for distributing packets including partial 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.
[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 data or MPEG2 format image data has substantially the same data structureA data stream including image data is acquired, and among a plurality of packets constituting the acquired data stream,SSC (in a slice layer representing a predetermined slice of an I picture ( Slice Start Code )Packets containing partial data are distributed to the first group, the remaining packets are distributed to the second group,
  Storing packets belonging to the first group 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 data or MPEG2 format image data has substantially the same data structureA data stream including image data is acquired, and among a plurality of packets constituting the acquired data stream,SSC (in a slice layer representing a predetermined slice of an I picture ( Slice Start Code )Thinning means for distributing packets including partial 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, a picture layer, and k pieces (k is determined based on a vertical size of an image represented by the PES packet. PES data including (positive number) slice layers.
[0028]
Of these, the picture layer includes data (any one of an I picture, a B picture, and a P picture) indicating the attributes of the screen represented by the PES packet including the picture layer.
[0029]
The jth slice layer (j is an arbitrary positive number less than or equal to k) is the jth slice when the screen represented by the PES packet including the slice layer is divided into k small screens (slices). Contains data indicating attributes.
[0030]
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.
[0031]
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.
[0032]
In addition, as shown in FIG. 3, an SSC (Slice Start Code) having a predetermined value is included at the head of each slice layer of the PES packet representing the image.
The SSC included in the jth slice layer is data for identifying a range in which data belonging to the jth slice layer exists. Therefore, if a device attempting to reproduce a moving image from a data stream including data in the MPEG2 format cannot obtain a TS packet including an SSC in the jth slice layer of a PES packet including an I picture, the jth The slice cannot be played correctly.
[0033]
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.
[0034]
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.
[0035]
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.
[0036]
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.
[0037]
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.
[0038]
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.
[0039]
(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.
[0040]
(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.
[0041]
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.
[0042]
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.
[0043]
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.
[0044]
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.
[0045]
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.
[0046]
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.
[0047]
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-sampling target slice packet) is transferred to the storage recording block 1D, and the process of the stream thinning block 1B is returned to step S1. (In the present specification and drawings, TS packets supplied from the mother board 1 to the receiving unit 3 are called extraction target slice packets, and TS packets delivered from the stream thinning block 1B to the storage recording block 1D are not extracted. (This is called a slice packet.)
[0048]
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, the TS packet (non-sampling target slice packet) is transferred 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.
[0049]
In step S5, the motherboard 1 determines that the TS packet determined to include the sequence header code is a predetermined slice layer (hereinafter referred to as a sampling target slice layer, which is to be stored in the content storage internal memory 33). It is determined whether or not it includes an SSC for identifying each PES packet. If it is determined that the SSC is included, the process of the stream thinning block 1B proceeds to step S9 described later.
[0050]
In addition, as a method for the mother board 1 to specify the sampling target slice layer, for example, the motherboard storage 2 may store data specifying the sampling target slice layer in advance. Then, the mother board 1 may read this data and specify the sampling target slice layer based on the read data.
[0051]
On the other hand, if the mother board 1 determines in step S5 that it does not include the SSC for identifying the sampling target slice layer, the mother TS 1 delivers the next TS packet from the demultiplexer 1A to the stream thinning block 1B (step S6). It is determined whether or not the PID included in the packet indicates the content to be accumulated (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. On the other hand, if it is determined that the content to be accumulated is indicated, the process of the stream thinning block 1B proceeds to step S8.
[0052]
In step S8, the mother board 1 determines whether or not the TS packet determined in step S7 includes an SSC for identifying the sampling target slice layer when indicating the content to be stored. If it is determined that the SSC is not included, the TS packet (non-sampling target slice packet) is transferred 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.
[0053]
In step S 9, the mother board 1 uses the TS packet (sampling target slice packet) delivered to the stream thinning block 1 B most recently in step S 1, step S 6 or step S 10 described later, as the content storage internal memory 33 of the receiving unit 3. Write to.
[0054]
Note that the motherboard 1 writes the extraction target slice 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 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. The IDE bus bridge 34 accesses the content storage internal memory 33 and stores the extraction target slice packet in the storage area of the content storage internal memory 33.
[0055]
When the processing of step S9 is completed, the mother board 1 delivers the next TS packet from the demultiplexer 1A to the stream decimation block 1B (step S10), and the PID included in the delivered TS packet stores the content to be accumulated. (Step S11). 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 S10. On the other hand, if it is determined that the content to be accumulated is indicated, the processing of the stream thinning block 1B proceeds to step S12.
[0056]
In step S12, when the mother board 1 indicates the content to be accumulated, the SSC (or other than slice layer) identifies the slice layer (non-sampling target slice layer) other than the sampling target slice layer in the TS packet determined in step S11. It is determined whether or not (data belonging to) is included. If it is determined that the stream is not included, the process of the stream thinning block 1B is moved to step S9.
[0057]
On the other hand, if it is determined in step S12 that the TS packet includes an SSC that identifies the non-sampling target slice layer (or data belonging to other than the slice layer), the motherboard 1 immediately before the TS packet in the received data stream. It is determined that the TS packet located at the end includes data at the end of the sampling slice layer to be extracted, and the processing of the stream thinning block 1B is returned to step S3.
[0058]
When the mother board 1 that performs the processing of the stream thinning block 1B delivers the non-sampling target slice packet to the storage recording block 1D while performing the processing shown in FIG. 5, the sampling target of the original data stream received by the receiving unit 3 is used. The slice packet is transferred to the storage recording block 1D in the form of a replaced data stream in which the dummy packet is replaced. 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.
[0059]
Note that the content of the payload portion of the dummy packet is different from the content of the payload portion of the sampling slice 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 slice packet to be sampled at the position of the dummy packet.
[0060]
When the non-sampling target slice packet is delivered to the storage recording block 1D, the motherboard 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.
[0061]
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 sampling target slice 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 sampling target slice packet whose position is represented by the position information table represents, for example, the motherboard 1 represents this position information table, and the position is represented by this position information table. What is necessary is just to make it match with the non-sampling object slice packet obtained from the data stream common to the sampling object slice packet currently stored.
[0062]
(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.
[0063]
Then, the mother board 1 accesses the content storage internal memory 33 via the PCI bus bridge 32 and the IDE bus bridge 34 and reads out the extraction target slice packet. The read target slice packet is supplied to the IDE bus bridge 34, and the IDE bus bridge 34 transfers the target slice packet to the PCI bus bridge 32. The PCI bus bridge 32 transfers the target slice packet to the connection bus. B is supplied to the mother board 1 via B.
Note that the extraction target slice packet to be read is read out from the storage 2 for the motherboard, for example, by reading 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. What is necessary is just to specify by doing.
[0064]
As shown in FIG. 6, the mother board 1 delivers the sampling slice packet read from the receiving unit 3 to the stream synthesis block 1C.
[0065]
On the other hand, when the sampling target slice packet is delivered to the stream synthesis block 1C, the mother board 1 converts the non-sampling target slice packet (replaced data stream) whose content is common with the sampling target slice packet into the motherboard storage 2 Read from.
[0066]
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-sampling target slice 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 according to the control of the storage read block 1F, the non-sampling target slice packet indicated by this information is read from the motherboard storage 2, and delivered to the stream synthesis block 1C.
[0067]
The mother board 1 also reads out a table indicating the position of the sampling slice packet in the original data stream from the mother board storage 2 under the control of the stream synthesis block 1C and the storage read block 1F.
[0068]
Next, in accordance with the control of the stream synthesis block 1C, the motherboard 1 thins out the arrangement order of the sampling slice packets and non-sampling slice packets 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-sampling target slice 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 the extracted slice packet that is identified as the original.
Then, the TS packets whose arrangement order is restored are delivered to the MPEG decoding block 1E as shown in FIG.
[0069]
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.
[0070]
This digital broadcast recorder that performs the above-described operation is for storing contents that contain SSC of a sampling slice layer (sampling target slice packet) among TS packets that include data constituting a PES packet including an I picture in a payload portion. Store in the internal memory 33. Then, even if the extraction target slice 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 to play back the content based on the stored contents of the motherboard storage 2, the range of the slice layer to be extracted cannot be specified, and the sampling target in the moving image The slice corresponding to the slice layer cannot be played back correctly. As a result, the content can be protected.
[0071]
Further, the sampling target slice 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. .
[0072]
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-sampling target slice 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.
[0073]
Further, the mother board 1 causes the content storage internal memory 33 to store the TS packet including the SSC of the sampling target slice layer among the TS packets including the data constituting the PES packet including the B picture and the P picture in the payload portion. Also good. Further, among PES packets including arbitrary image data not limited to I pictures, B pictures, and P pictures, a packet including data representing a predetermined portion of an image represented by the image data is stored in the content storage internal memory 33. You may make it memorize | store.
[0074]
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.
[0075]
Further, the mother board 1 stores a position information table indicating the position of the extraction target slice packet in the content storage internal memory 33 in association with the extraction target slice packet, and when reproducing the recorded content, the position information table May be read from the content storage internal memory 33 and used.
[0076]
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.
[0077]
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.
[0078]
Further, the mother board 1 encrypts the non-sampling target slice packet when recording the content and stores it in the motherboard storage 2, and reads the encrypted non-sampling target slice packet when reproducing the recorded content. The data stream may be restored after decoding.
Similarly, when recording content, the extraction target slice packet is encrypted and then written to the content storage internal memory 33, and when the recorded content is reproduced, the encrypted extraction target slice packet is read and decrypted. Alternatively, the data stream may be restored.
[0079]
Further, there may be a plurality of sampling target slice layers per PES packet. When there are a plurality of slice layers to be extracted per PES packet, the mother board 1 may perform, for example, the processes shown in FIGS. 7 and 8 as the process of the stream thinning block 1B.
[0080]
As shown in the figure, the processes in steps S101 to S111 in the process of FIG. 7 are substantially the same as the processes in steps S1 to S11 shown in FIG.
[0081]
In step S112, when the mother board 1 indicates the content to be accumulated, whether or not the TS packet determined in step S111 includes SSC (or data belonging to other than the slice layer) identifying the non-sampling target slice layer. Is determined. If it is determined that the stream is not included, the process of the stream thinning block 1B is moved to step S109.
[0082]
On the other hand, if it is determined in step S112 that the TS packet includes SSC (or data belonging to other than the slice layer) identifying the non-sampling target slice layer, the mother board 1 sets the payload unit start indicator included in the TS packet. It is determined whether or not the value is a value indicating that the head of the PES packet is included (FIG. 8, step S113). If it is determined that the value indicates that the head of the PES packet is included, the processing of the stream thinning block 1B is returned to step S104.
[0083]
On the other hand, if it is determined in step S113 that the value of the payload unit start indicator is a value indicating that the beginning of the PES packet is not included, the motherboard 1 delivers the TS packet to the storage recording block 1D, and the next TS packet From the demultiplexer 1A to the stream decimation block 1B (step S114).
[0084]
Then, it is determined whether or not the PID included in the TS packet newly delivered in step S114 indicates the content to be accumulated (step S15). 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 processing of the stream thinning block 1B is returned to step S114. On the other hand, if it is determined that the content to be accumulated is indicated, the process of the stream thinning block 1B proceeds to step S116.
[0085]
In step S116, when the content to be accumulated is indicated, the motherboard 1 determines whether the TS packet determined in step S115 includes an SSC for identifying the sampling target slice layer. If it is determined that it is not included, the process of the stream decimation block 1B is returned to step S113. If it is determined that it is included, the process of the stream decimation block 1B is returned to step S109.
[0086]
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.
[0087]
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.
[0088]
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.
[0089]
【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.
FIG. 7 is a flowchart illustrating a modification of the stream thinning block process.
FIG. 8 is a flowchart showing the continuation of the process 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 content storage
34 IDE Bus Bridge
B Connection bus

Claims (8)

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 A decimation unit that distributes packets including partial data including a portion including SSC ( Slice Start Code ) of a slice layer representing a predetermined slice of an I picture to a first group, and distributes remaining packets to a 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 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 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 , wherein: 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 claim 1 , wherein the data stream recording apparatus is a data stream recording apparatus. 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 3, 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.
The data stream recording apparatus according to claim 4 , 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 5, 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 A packet including partial data composed of a portion including an SSC ( Slice Start Code ) of a slice layer representing a predetermined slice of an I picture is allocated to a first group, and the remaining packets are allocated to a second group;
Storing packets belonging to the first group in a first storage area that substantially prevents access from other than a predetermined access device;
The obtained the data stream, the packets distributed to the first group is converted to a substituted Data stream was replaced with the dummy packet, the packets belonging to the substituent already data stream 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 A decimation unit that distributes packets including partial data including a portion including SSC ( Slice Start Code ) of a slice layer representing a predetermined slice of an I picture to a first group, and distributes remaining packets to a 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 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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