JPH10229552A - Scramble/descramble method for mpeg video data and supply and reproduction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method that applies scramble processing similar to the case of analog data to moving picture image coding experts group MPEG video data themselves. SOLUTION: By applying position recomposition instruction of a slice layer to a video PES packetizer 52 according to correspondence relation between a value of a scrambling control flag in an internal memory and a recomposition pattern with a central controller 30, a PES scrambling control flag in a header part is set to a prescribed value in the case that video data inputted from a video encoder 51 are PES-packeted by the video PES packetizer 52. Then a multiplexer acquires a corresponding recomposition pattern from the central controller 30 to recompose the position of a PES packet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to MPEG (Movin).
g In a system that supplies and reproduces video data encoded according to the Picture Image Coding Experts Group (Graphic Image Coding Experts Group), the data itself is scrambled and supplied as a countermeasure when data is illegally acquired, and the reproduction side And a technique that enables restoration only when a predetermined descrambling process is performed.

[0002]

2. Description of the Related Art Conventionally, in an MPEG video data reproducing apparatus, control header information indicated in a system part of the MPEG standard is analyzed to determine whether or not the data is data to be decoded. Had been adopted.

[0003]

SUMMARY OF THE INVENTION However, MPE
Even if video data is played back by a playback device that does not perform decoding processing that complies with the system part of the G standard, the video data itself is not scrambled, so playback is performed in an appropriate state. There is a high possibility that it will be done. That is, the video data is not physically changed at all, but merely controls whether to decode or not.

Of course, since it is digital data,
Although it is possible to perform so-called "encryption" processing, special means for encryption is required, and processing is performed in relatively small units that compose data such as bits or bytes. Encrypting video data having a relatively large capacity each time is problematic in practice. And, of course, a device for decrypting the encryption is also required on the reproducing side, and similarly, the processing load for decryption is also increased.

[0005] In addition, scrambling performed by rearrangement of video scanning lines and the like performed in analog television broadcasting and the like is a simple change.
It cannot be directly used for digital data such as video data. Signal scrambling in the case of analog signals uses the physical properties of analog signals, such as polarity reversal, interference wave superposition, sine or square wave multiplication, synchronization signal removal, intra-scan line signal switching, and scan line relocation. Because it is a method.

Accordingly, the present invention provides a method for supplying and reproducing MPEG video data by performing a scrambling process and a descrambling process similar to the case of analog data by the MPE.
It is an object of the present invention to provide a method which can be applied to G video data itself, and a supply device used for performing the scrambling process and a reproducing device used for performing the descrambling process.

[0007]

SUMMARY OF THE INVENTION In order to achieve this object, a method of scrambling and descrambling MPEG video data according to the present invention is provided. Based on the key information set in the scrambling control field, data is rearranged in slice units in the MPEG video data hierarchical structure, and the MPE of one picture is changed.
The G video data is scrambled and then supplied to the playback side. On the playback side, the supplied MPEG video data that has been rearranged in slice units is
A descrambling process for restoring based on key information set in the scrambling control field is performed.

The scramble of the MPEG video data
According to the descrambling method, when scrambling is performed on the supply side, slices in the MPEG video data hierarchical structure are determined based on key information set in a scrambling control field in a packet header indicated in a system part of the MPEG standard. Data is rearranged in units. Thereby, scramble processing can be performed on MPEG video data of one picture.

Therefore, even if data is stolen in this state, for example, if the data is rearranged in units of slices, when displayed as one picture on the screen, it is not possible to properly grasp the contents. The display is in a difficult state. In other words, a scramble state similar to the scramble due to rearrangement of video scanning lines performed in analog television broadcasting or the like can be achieved.

This scrambling method utilizes the original structure of the MPEG video data hierarchical structure, ie, shuffling in slice units, and sets the scrambling control field originally released to the user in the packet header. Since it is only a mere rearrangement process using information to be performed as key information, it can be realized very easily.

As described above, since the data is digital data, "encryption" can be performed. However, special means for encryption is required. Since the processing is performed in small units, it is practically problematic to encrypt MPEG video data having a relatively large capacity each time. On the other hand, when the present method is adopted, basically, only the data rearrangement process is performed, and the data itself such as encryption is not processed. The processing load is small because the unit of rearrangement is also the unit of slice. For example, considering the case of the NTSC system, 480 pixels vertically
If one macroblock is 16 pixels × 16 pixels and one macroblock is composed of 45 macroblocks to constitute 720 pixels × horizontal 720 pixels, one slice becomes one slice.
It becomes a line, and one screen (picture) is composed of 30 slices. Therefore, it is easy to see that the processing load is smaller in the case of the reassembly in slice units than in the above-described encryption.

On the other hand, on the reproducing side, the opposite of the above-described scramble processing may be executed as descrambling processing. In other words, the supplied MPEG video data that has been rearranged in slice units is restored based on the key information set in the scrambling control field. In the case of the above-described encryption, a device for decrypting the encryption is of course required on the reproducing side, and similarly, the processing load for decryption increases, but this method is also advantageous in that respect. Become.

As described above, according to the method of the present invention, MP
When supplying and reproducing EG video data, scramble processing and descrambling processing similar to the case of analog data can be performed on MPEG video data itself. As an apparatus for supplying MPEG video data used for performing the above-mentioned scrambling processing, for example, as set forth in claim 2, a setting in a scrambling control field in a packet header indicated in a system part of the MPEG standard Rearrangement pattern storage means for storing a correspondence relationship between the obtained key information and a predetermined position rearrangement pattern, and acquiring key information in the packet header,
A position rearrangement pattern corresponding to the key information is read out from the rearrangement pattern storage means, and data is rearranged on a slice-by-slice basis in the MPEG video data hierarchical structure based on the position rearrangement pattern, thereby scrambling one picture of MPEG video data. And scramble control means for applying the scrambled MPEG video data.

The MPEG video data reproducing apparatus used for performing the above-mentioned descrambling process is, for example, based on key information set in a scrambling control field in a packet header. M with data rearranged in slice units
A reproduction apparatus capable of reproducing PEG video data, comprising: restoration pattern storage means for storing a correspondence relationship between the key information and a predetermined position restoration pattern; and acquiring key information in the packet header; A descrambling control unit for reading out a position restoration pattern corresponding to information from the restoration pattern storage unit and restoring the MPEG video data in which the data is rearranged in slice units based on the position restoration pattern; And decoding means for decoding the MPEG video data.

The contents of the scramble processing and descrambling processing executed in the MPEG video data supply apparatus and the reproduction apparatus, and the functions and effects thereof are the same as those described above, so that they will not be described here. The supplementary description will be further made on the position rearrangement pattern and the position restoration pattern stored in the restoration pattern storage means.

These are both stored as corresponding to the key information set in the scrambling control field released to the user in the packet header. For example, since the PES packet in MPEG2 has only two bits, , “00”, “01”, “1”
Only four patterns of "0" and "11" can be obtained. For example, if one pattern is allocated when the position is not rearranged, only three types of position rearrangement and position restoration patterns can be set at the same time. For this purpose, for example, a method of updating the position rearrangement and position restoration patterns based on date and time information or the like can be considered. Alternatively, it may be obtained from a storage medium such as an IC card in which the position rearrangement and position restoration patterns are stored.

[0017] By updating the position rearrangement and position restoration patterns in this way, even if only three types exist at the same time, scrambling and descrambling with a large number of patterns can be performed in the entire "period". Therefore, it is preferable in terms of security improvement such as prevention of data theft.

[0018]

Next, embodiments of the present invention will be described in detail. As shown in FIG. 1, an information supply / reproduction system 10 according to an embodiment of the present invention includes an information supply device 20 and an information reproduction device 100 which are connected via a transmission line 90 configured by a coaxial cable or the like. It is configured. Also,
An encoding device 50 is mounted on the information supply device 20. Although only one information reproducing apparatus 100 is shown in FIG. 1, a plurality of information reproducing apparatuses 100 are generally connected to one information supply apparatus 20. Further, the transmission path 90 may be of any type regardless of whether it is wired or wireless.

The configuration of the information supply device 20 will be described. The information supply device 20 uses the PE
S-packetized MPEG video data and MPEG audio data are multiplexed into an information reproducing apparatus 1
It is a device for supplying to 00. As shown in FIG.
The encoding device 50 includes a video encoder 51, a video PES packetizer 52, and an audio encoder 5.
3 and an audio PES packetizer 54.

The video encoder 51 can encode an analog video signal input from the outside and convert it into a digital data sequence. The video signal converted into the digital data sequence is converted by a video PES packetizer 52 into a video signal.
In this case, PES packets are formed according to the MPEG2 standard and output as video PES packets.

Similarly, the audio encoder 53 is capable of encoding an externally input analog audio signal and converting it into a digital data string. The audio signal converted into the digital data string is an audio PES signal.
According to the MPEG2 standard, the packetizer 54
It is converted into S packets and output as audio PES packets.

Here, the data structure of the PES packet will be described with reference to FIG. PES packet is video
This is a format commonly used for audio and, as shown in FIG. 6, is largely composed of a header section and an effective data section. The header part includes a 24-bit packet start code prefix, an 8-bit stream ID,
16-bit PES packet length and optional PES
Consists of a header. The effective data portion is composed of 8 × N-bit PES packet data bytes.

As shown in FIG. 6, a 2-bit value "10" for discriminating from MPEG1 and an optional PES header in the above-mentioned header portion, and data for scrambling data for use in confidential information or a commercial billing system are used. In addition to the 2-bit PES scrambling control flag, a PES priority flag for distinguishing important packets from non-important packets by an application, a data alignment indicator, copyright, original or copy,
Other 7 flags, a PES packet data length, an optional field, an 8 × M bit stuffing byte, and the like are included.

Returning to the description of the information supply device 20, FIG. As shown in FIG. 1, a video PES packet as an output of the video PES packetizer 52 is input to the input interface 21, and an audio PES packet as an output of the audio PES packetizer 54 is input to the input interface 2.
2 is the structure to be input.

The video PES packet input to the input interface 21 is transferred to the video buffer memory 31 via the bus 24, and the audio PES packet input to the input interface 22 is transferred to the audio buffer memory 32 via the bus 24. Will be transferred. The video buffer memory 31 can temporarily store the transferred video data and output it in response to a request from the multiplexer 35. Similarly, the audio buffer memory 32 can temporarily store the transferred audio data and output the audio data in response to a request from the multiplexer 35.

Multiplexer 35 as multiplexing means
Is a PES packet sequence of video data read from the two buffer memories 31 and 32 and a PES packet of audio data.
The packet stream can be multiplexed into one transport stream (TS) and output to the head end 37 through the output interface 36.

Although not shown, the information supply device 20 is provided with a plurality of data output mechanisms including the above-described video buffer memory 31, audio buffer memory 32, multiplexer 35 and output interface 36. , The head end 37 can transmit the TS transmitted from the plurality of data output mechanisms to the transmission path 90 through the channel allocated to each output interface 36. In addition, the head end 37 can transmit a signal transmitted from the modem 47 through a channel for bidirectional communication, and can transfer a signal input from the transmission line 90 through a channel for bidirectional communication to the modem 47. .

The modem 47 is connected to the central control unit 30 as control means via the bus 24, and the central control unit 30
Information reproducing apparatus 100 connected by transmission line 90
, Or receive data from the information reproducing apparatus 100.

The central control unit 30 can control the operation of each unit of the information supply device 20 described above.
Along with the basic control for instructing the encoding device 50 to start encoding, as a characteristic control, a slice layer position change instruction to be described later can also be issued. This position rearrangement instruction is input from the central control unit 30 to the video PES packetizer 52 as shown in FIG. Specifically, when the video PES packetizer 52 converts the video data input from the video encoder 51 into a PES packet, the PES in the header portion of the PES packet described above is used.
The ES scrambling control flag (see FIG. 6) is set to a predetermined value. Since the PES scrambling control flag is prepared by 2 bits, in the present embodiment, when the value is "00", the normal pattern is used without repositioning. In the case of the remaining "01", "10", and "11", Indicates the position change in the A pattern, the B pattern, and the C pattern, respectively.

Here, the rearrangement of positions in the above-mentioned A pattern, B pattern and C pattern will be described. In this position rearrangement, the positions of the slice layers are rearranged in any of the patterns. First, the hierarchical structure of MPEG video data will be described with reference to FIG. MPEG video data has a six-layer hierarchical structure including a sequence layer, a group of pictures (GOP) layer, a picture layer, a slice layer, a macroblock (MB) layer, and a block layer. In MPEG2, the GOP layer can be omitted. As can be seen from this hierarchical structure, the picture layer is composed of one or more slice layers. And MPE
In the case of G2 video data, slices A, B, D, and G in FIG. 8 are used for parallel processing and effective error tolerance.
One slice extends only to the right of the screen and does not extend downward.

Therefore, in the present embodiment, in order to facilitate understanding and processing, one pixel is defined by 720 horizontal pixels × 480 vertical pixels.
It is assumed that a screen (1 picture) is configured, and 16 horizontal ×
It is set so that 45 slices of macroblocks each composed of 16 pixels constitute one slice, and one slice is composed of 30 lines. In FIG. 9, the # 1 slice indicates a slice corresponding to the first line of one screen (one picture). The same applies to the following.

The position rearrangement in the A, B, and C patterns is to rearrange the positions of three consecutive slice layers in each of the patterns. First, A
As shown in FIG. 10, the position of the pattern is changed.
The third slice moves to the third, the second slice moves to the first, and the third slice moves to the second. In addition, the position change of the B pattern is a pattern in which the first slice moves to the third position, the second slice remains as it is, and the third slice moves to the first position, as shown in FIG. . Further, as shown in FIG. 10, the position rearrangement of the C pattern is a pattern in which the first slice moves to the third position, the second slice moves to the third position, and the third slice moves to the first position. is there.

Therefore, as described above, the video PE
When the S packetizer 52 converts the video data into a PES packet, the PES scrambling control flag in the header portion is set to “01”, “10”, or “11”, so that the A pattern, the B pattern, and the C pattern are used. Can be specified, and if it is "00", it is a normal pattern in which the position is not rearranged.

As described above, the video PES packetizer 52
The central control unit 30 which sends the instruction to set the flag value for the position rearrangement to the PES scrambling control flag and the position rearrangement pattern of the slice layer is stored in an internal memory (not shown). I have. On the other hand, when multiplexing the PES packet sequence of the video data and the PES packet sequence of the audio data sent from the buffer memories 31 and 32, the multiplexer 35 reads the PES scrambling control flag in the PES packet, Are acquired from the central control unit 30. Then, the multiplexer 35 rearranges the position of the PES packet of the video data so that the position of the slice layer is rearranged according to the obtained position rearrangement pattern.

The internal memory of the central control unit 30 corresponds to "rearrangement pattern storage means", and the central control unit 30 and the multiplexer 35 correspond to "scramble control means". Next, the configuration of the information reproducing apparatus 100 will be described with reference to FIGS.

The information reproducing apparatus 100 receives the transport stream (TS) transmitted from the information supply apparatus 20 via the transmission line 90 via the external input I / F 110, and the received TS is transmitted to the system decoder 120. Video PES packet stream and audio PE
And S packet stream.

In the system decoder 120, an RO storing a program for processing the system decoder 120 is stored.
RAM for work of M121 and system decoder 120
122 and is connected to the system decoder 1
Reference numeral 20 includes a video PES transfer buffer 120a and an audio PES transfer buffer 120b. Then, the video PES packet and the audio PES packet on the video PES transfer buffer 120a and the audio PES transfer buffer 120b are transferred via a video channel and an audio channel to an audio / video decoder (hereinafter abbreviated as A / V decoder). .) 13
Input to 0.

The A / V decoder 130 corresponds to "decoding means", and performs MPEG decoding on each of the input video PES packet and audio PES packet. The A / V decoder 130 has a work RAM 135 for the A / V decoder 130 and an A / V decoder 1.
The CPU 140 is connected as control means for controlling the control unit 30.

The CPU 140 includes a ROM 141 storing a program for the CPU 140 and a CPU 141.
A work RAM 142 is connected to the system decoder 120, and information can be exchanged with the system decoder 120. The RAM 142 corresponds to “restoration pattern storage means”, and stores the correspondence between the value of the PES scrambling control flag and the position restoration pattern of the slice layer. The correspondence is based on the correspondence between the value of the PES scrambling control flag stored in the central control unit 30 of the information supply device 20 and the position change pattern of the slice layer,
The position restoration pattern for returning the picture in the state where the position of the slice layer has been rearranged by the position rearrangement pattern to the original state is stored.

The digital / A / V decoder 130
The digital video data output from the video output is input to the video DA converter 150,
In the converter 150, the video signal NT
It is converted to an SC signal and output to the outside. On the other hand, the digital audio data output from the digital audio output of the A / V decoder 130 is input to the audio DA converter 155, and is converted into an analog audio signal by the audio DA converter 155 and output to the outside.

The A / V decoder 130 converts the video PES packet and the audio PE
Each packet classified into S packets is input from an audio channel and a video channel. The inside of the A / V decoder 130 is divided into two processing blocks of a pre-processing unit 131 and a post-processing unit 132 as shown in FIG. Then, the pre-processing unit 131 separates the header part and the effective data part of each packet of audio and video, and separates them into a header buffer (Header buffer).
Buffer) and the channel buffer (Channel Buffer).

The header buffer and the channel buffer are used for the work RAM 13 of the A / V decoder 130.
5 and a video PES as shown in FIG.
A header buffer 136 and an audio PES header
Buffer 137 and video channel buffer 138
And an audio channel buffer 139.

On the other hand, the post-processing unit 1 of the A / V decoder 130
Reference numeral 32 denotes MPEG decoding of the data in both the video and audio channel buffers 138 and 139 actually assembled by the preprocessing unit 131, and digital video data and digital audio output from each of the digital video output and the digital audio output. -Output audio data.

The information supply / reproduction system 10 having the above configuration
Then, scrambling and descrambling of MPEG video data is executed as follows. First, in the video encoder 51 of the encoding device 50 of the information supply device 20, the M of one picture encoded according to the video part of the MPEG2 standard in accordance with the slice configuration shown in FIG.
PEG picture data is generated.

When an instruction not to perform scrambling is issued from the central control unit 30, the video PES packetizer 52 converts the generated MPEG picture data into a PE.
When the packet is converted into an S packet, the PES scrambling control flag in the header portion is set to “00”. On the other hand, when an instruction to perform scrambling is issued from the central control unit 30, any one of the A, B, and C rearrangement patterns is instructed, and accordingly, the PES scrambling control flag in the header unit is set to “ 01 "," 10 ",
Set to “11”. As described above, the video PES packet with the PES scrambling control flag set is transferred to the video buffer memory 31. In the case of the present embodiment, the audio PES packet does not have the PES scrambling control flag set. For example, if “00” is set as the initial value, it remains as it is. Then, the data is transferred to the audio buffer memory 32.

When multiplexing the PES packet sequence of the video data and the PES packet sequence of the audio data read from the buffer memories 31 and 32, the multiplexer 35 reads the PES scrambling control flag in the PES packet. If the value is “00”, normal multiplexing processing is executed as usual, that is, without rearranging positions. On the other hand, if the value of the PES scrambling control flag is “01”, “10”, or “11”, the position reassignment pattern corresponding to the value is acquired from the central control unit 30 and the slice is performed according to the acquired position reassignment pattern. PES of video data so that layer position can be changed
Multiplexing is performed while rearranging the positions of the packets.

As a result, scramble processing can be performed on MPEG video data of one picture. Therefore, even if data is stolen in this state, for example, data is rearranged in slice units, so that when displayed on the screen as one picture, it is difficult to properly grasp the contents. Will be displayed.
In other words, a scramble state similar to the scramble due to rearrangement of video scanning lines performed in analog television broadcasting or the like can be achieved. And
This scrambling method uses the original mechanism of the MPEG video data hierarchical structure called re-slicing in units of slices. The information set in the scrambling control field originally released to the user in the packet header is used as key information. It's just a rearrangement process,
It can be realized very easily.

In addition, since the data being handled is digital data, "encryption" can be performed. In that case, however, special means for encryption is required, and data such as bits or bytes is not included. Since the processing is performed in relatively small units, encrypting video data having a relatively large capacity each time is problematic in practice. On the other hand, in the present embodiment, basically, only data rearrangement processing is performed, and data itself such as encryption is not processed. The processing load is small because the unit of rearrangement is also the unit of slice. In particular, in the present embodiment, one screen (picture) is composed of 30 slices composed of 45 macroblocks as shown in FIG. 9. It is easy to see that the processing load is smaller than the above-mentioned encryption.

On the other hand, in the information reproducing apparatus 100, the opposite of the above-described scramble processing may be executed as descrambling processing. That is, the supplied MPEG video data that has been rearranged in slice units is
The restoration is performed based on the key information set in the scrambling control field.

Before describing the descrambling process, a basic operation of the information reproducing apparatus 100 will be described. The information reproducing apparatus 100 receives the TS transmitted from the information supply apparatus 20 via the external input I / F 110, and separates the TS into a video PES packet stream and an audio PES packet stream by the system decoder 120. Then, a video PES transfer buffer 120a and an audio PES transfer buffer 120b are respectively provided.
To the A / V decoder 130.

The A / V decoder 130 MPEG-decodes the input video PES packet and audio PES packet. More specifically, the preprocessing unit 131 (see FIG. 4) of the A / V decoder 130 recognizes a PES packet of video or audio when it recognizes the PES packet.
The ES header portion is written into the video PES header buffer 136 or the audio PES header buffer 137. Then, the PES header is stored in the video PES header buffer 136 or the audio PES header.
At the same time as writing to the buffer 137, an audio PESReady interrupt is generated for the CPU 140.

The interrupt processing executed by the CPU 140 will be briefly described. A video or audio channel buffer write pointer and a header buffer write pointer are acquired from the A / V decoder 130, and the header buffer write pointer is obtained. Based on this, the video or audio PES header is read. If there is a time stamp in the PES header, the time stamp is obtained, and the time stamp and the previously obtained channel buffer write pointer (Write Pointer) are stored in the video or audio time stamp table (see FIG. 5). Is set. As a result, a time stamp table is created. The audio and video time stamp tables are stored in the CPU 140.
Is stored in the work RAM 142.

On the other hand, separately from the processing of the CPU 140, the post-processing unit 132 of the A / V decoder 130 actually stores the data in the video or audio channel buffers 138 and 39 assembled by the pre-processing unit 131. To M
PEG decoding is performed, and digital video data is output from the digital video output to the video DA converter 150, or digital audio data is output from the digital audio output to the audio DA converter 155.

For video data, the video channel buffer 138 is checked, and if the video data in the buffer 138 has accumulated up to the size of one predetermined picture, video decoding is started. by this,
The decoded video data is converted to a video DA converter 1
Output to 50. On the other hand, with regard to audio, the audio channel buffer 139 is checked, and when the audio data in the buffer 139 has accumulated up to the size of one predetermined frame, audio decoding is started. As a result, the decoded audio data is output to the audio DA converter 155.

During such a basic decoding process, the descrambling process of the video data is executed as follows. As described above, with respect to the video data, the video data assembled by the preprocessing unit 131 of the A / V decoder 130 is sequentially stored in the video channel buffer 138, and the video data in the video channel buffer 138 is stored in a predetermined manner. When the size of one picture has been stored, video decoding is started. Then, the descrambling is performed during a process in which the preprocessing unit 131 assembles video data and sequentially stores the video data in the video channel buffer 138.

Specifically, the CPU 140 causes the system decoder 120 to notify the value of the PES scrambling control flag in the header of the PES packet of the video data. Then, as described above, since the correspondence between the value of the PES scrambling control flag and the position restoration pattern of the slice layer is stored in the RAM 142, the CPU 140 executes the PES scrambling control notified based on the correspondence. The preprocessing unit 131 of the A / V decoder 130 reads out the position restoration pattern corresponding to the value of the flag and restores the picture whose slice layer position has been rearranged to the original state (see FIG. 4).
Give instructions to In response to this instruction, the preprocessing unit 131 changes the order of normal storage when assembling and sequentially storing video data in the video channel buffer 138 and stores the data so that the position of the slice layer can be restored. It will be.

By doing so, the information supply device 20
Thus, the scrambled video data can be descrambled and restored appropriately. As described in the description of the effect when scrambling is performed by the information supply device 20, in the case of encryption, a device for decrypting the encryption is naturally required on the reproducing side. The processing load for this also increases. The present information reproducing apparatus 1
00 is also advantageous in that respect.

In the above embodiment, the A / V decoder 130 and the CPU 140 correspond to "descrambling control means". As described above, according to the present information supply / reproduction system, when supplying / reproducing MPEG video data, it is possible to perform scramble processing and descrambling processing similar to analog data on the MPEG video data itself.

As described above, the present invention is not limited to such an embodiment, and can be implemented in various forms without departing from the gist of the present invention. For example, in the above-described embodiment, the term “PES packet” is used because of the premise of MPEG2. However, in other MPEG standards, the key information set in the scrambling control field released to the user in the packet header is also used. If it is used, it can be similarly realized.

Also, in the above embodiment, since the scrambling control flag has only two bits, if "00" is used in the case where it is not rearranged, at most "01" and "1"
Only three types, "0" and "11", can be set. Therefore, in this case, only three types of patterns of the position rearrangement and the position restoration can be set at the same time. For this reason, for example, a method of updating the position rearrangement and position restoration patterns based on date and time information or the like is also conceivable. That is, in the above-described embodiment, the number of slices to be rearranged is three, and the position rearrangement patterns are A to C shown in FIG. 10, but the number of slices to be rearranged may be four or more. For example, other than this, a rearrangement pattern can be considered. Therefore, by setting a large number of recombination patterns and based on the date and time information and the like as described above, it is possible to execute a recombination control in which the same value of “01” and a different recombination pattern are different if the date and time are different. it can.

As described above, if the position rearrangement and position restoration patterns are updated, even if only three types of rearrangement patterns are present at the same time, scrambling / descrambling with a large number of patterns is considered in the entire “period”. This is preferable in terms of security improvement such as prevention of data theft.

In the above embodiment, the pre-processing unit 13 of the A / V decoder 130 receiving an instruction from the CPU 140
1 (see FIG. 4) executes descrambling processing for restoring the position of the slice layer when video data is assembled and sequentially stored in the video channel buffer 138, but the post-processing unit 132 executes the descrambling processing. May be executed. In this case, the pre-processing unit 131 sequentially stores the data in the video channel buffer 138 as before, and when the post-processing unit 132 reads out the data, the pre-processing unit 132 changes the order so that the position of the slice layer can be restored and reads the data. do it. Further, a means for descrambling may be newly provided in a stage preceding the pre-processing unit 131 or in a stage subsequent to the post-processing unit 132.
It is preferable to realize it with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration mainly on an information supply device side of an information supply / reproduction system according to an embodiment.

FIG. 2 is a block diagram illustrating a configuration of an encoding device.

FIG. 3 is a block diagram illustrating a configuration of an information reproducing apparatus.

FIG. 4 is an explanatory diagram showing a configuration of a buffer provided in a work RAM of the A / V decoder.

FIG. 5 is an explanatory diagram of a time stamp table.

FIG. 6 is an explanatory diagram showing a data configuration of a PES packet.

FIG. 7 is an explanatory diagram showing a hierarchical structure of MPEG video data.

FIG. 8 is an explanatory diagram showing a slice configuration example of MPEG2 video data.

FIG. 9 is an explanatory diagram illustrating a slice configuration example according to the embodiment;

FIG. 10 is an explanatory diagram of a scramble process in the embodiment.

[Description of Signs] 10 Information supply system 20 Information supply device 30 Central control unit 31 Video buffer memory 32 Audio buffer memory 35 Multiplexer 36 Output interface 37 Headend 50 Encoding device 51 Video encoder 52 ... Video PES packetizer 53 ... Audio encoder 54 ... Audio PES packetizer 100 ... Information reproducing device 110 ... External input I
/ F 120: System decoder 120a: Video PES transfer buffer 120b: Audio PES transfer buffer 121: ROM 122: RAM 1
30 A / V decoder 131 Pre-processing unit 132 Post-processing unit 1
35 RAM 136 Video PES header buffer 137 Audio PES header buffer 138 Video channel buffer 139 Audio channel buffer 140 CPU 141 ROM 1
42 RAM 150 Video D / A converter 155 Audio D / A converter

Claims (3)

[Claims] 1. An MPEG video data hierarchical structure in which data is rearranged in units of slices on the basis of key information set in a scrambling control field in a packet header indicated in a system part of the MPEG standard, and one picture of MPEG is The video data is subjected to a scrambling process and then supplied to the reproducing side. On the reproducing side, the supplied MPEG video data which has been rearranged in slice units is converted into key information set in the scrambling control field. A scramble / descramble method for MPEG video data, wherein a descrambling process for restoring the MPEG video data based on the scramble is performed. 2. A rearrangement pattern storage means for storing a correspondence between key information set in a scrambling control field in a packet header indicated in a system part of the MPEG standard and a predetermined position rearrangement pattern, Obtaining key information in the packet header, reading out a position rearrangement pattern corresponding to the key information from the rearrangement pattern storage means, and performing data rearrangement in slice units in the MPEG video data hierarchical structure based on the position rearrangement pattern. And a scramble control means for performing scramble processing on one picture of MPEG video data, and supplying the scrambled MPEG video data. 3. A reproducing apparatus capable of reproducing MPEG video data in which data is rearranged in units of slices based on key information set in a scrambling control field in a packet header, wherein the key information and a predetermined position Restoration pattern storage means for storing a correspondence relationship with a restoration pattern; acquiring key information in the packet header; reading a position restoration pattern corresponding to the key information from the restoration pattern storage means; On the basis of,
MP in which data rearrangement is performed in the slice unit
An MPEG video data reproducing apparatus, comprising: descrambling control means for restoring EG video data; and decoding means for decoding the restored MPEG video data.