JP2009232069A - Encoding device, encoding program, decoding device, decoding program and distribution system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To encode and decode data concerned with respective pictures of a moving image, even if the area to be made invisible on the screen of the moving image is moved by screens. <P>SOLUTION: A distribution system is provided with a moving image provision apparatus, loaded with an encoding device for encoding a moving image in a block unit of a picture and a moving image receiving apparatus loaded with a decoding device for decoding the moving image in a block unit of the picture. The encoding device includes a means for storing the identification information of blocks, belonging to an invisible area in each picture and a means for encoding normal area blocks without referring to data concerned with the invisible area blocks and encoding the invisible area blocks so that the original image cannot be displayed in a normal manner without using key information. The decoding device includes a means for storing the identification information of the blocks, belonging to the invisible area and a means for decoding the image concerned with the invisible area blocks, by using the key information so as to display the original image, in a normal manner. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an encoding device, an encoding program, a decoding device, a decoding program, and a distribution system. For example, a system that distributes content to be distributed by providing some protection function to protect copyrights and portrait rights. Applicable to.

  Moving images in digital format encoded and compressed through the Internet can be easily obtained, but they can be easily copied without degrading the image quality, and are usually not restricted by hardware. In order to protect the rights and portrait rights, it is necessary to provide some protection function to the content itself.

  Conventionally, this type of content protection method has been called a visible watermark. For the application of the visible watermark, the following first and second methods are simply considered. Moreover, there was the following third method described in Patent Document 1.

  The first conventional method is a method in which a part of the screen is made invisible by a decryption device, and only a user having a key can view a normally decoded content.

  The second conventional method is a method in which a moving image is made invisible before encoding, and a special mask is applied to a part of the screen. Only the user waiting for the key can release this mask. Even a user who does not have a key can view only a portion without a visible watermark without a special decryption device.

A conventional third method is a method described in Patent Document 1, and is a method of applying a reversible transformation to a transform coefficient generated as intermediate data in an encoding process. Reverse conversion can be performed during decryption of the user who has the key, and normal content can be viewed.
JP 2004-336529 A

  However, in the conventional first to third methods, it is necessary that the parts to be made invisible have the same shape at the same position, so that the encoding and decoding cannot be performed when the part to be made invisible moves. was there.

  Therefore, an encoding device, an encoding program, and a decoding device that can encode and decode data related to each screen even if the region to be invisible on the screen of the moving image moves for each screen. Decryption programs and distribution systems are desired.

  The encoding device according to the first aspect of the present invention is (1) an encoding device that encodes each screen constituting a moving image in units of blocks divided at least vertically or horizontally, and (2) key information must be used. Invisible area information holding means for holding identification information of invisible area blocks belonging to different invisible areas on a screen including an invisible area block encoded in the screen, which is encoded so that the original image cannot be visualized, (3) Each screen is encoded in block units, and the invisible area block is encoded so that the original image cannot be visualized unless the key information is used, and does not belong to the invisible area. The normal area block includes encoding means for encoding without referring to data related to the invisible area block.

  A decoding device according to a second aspect of the present invention provides: (1) a decoding device that decodes a moving image encoded in units of blocks obtained by dividing each screen at least vertically or horizontally; Invisible area information that holds identification information of invisible area blocks belonging to different invisible areas on the screen including invisible area blocks encoded in the screen, which is encoded so that the original image cannot be visualized unless it is used. Holding means, and (3) decoding data encoded in block units for each screen, using the information held by the invisible area information holding means and the key information, And decoding means for decoding so as to normally display an image related to the invisible area block on each screen.

  A distribution system according to a third aspect of the present invention includes: (1) a moving image providing apparatus that encodes data relating to each screen constituting a moving image and provides encoded moving image data; and the moving image providing apparatus described above. And a moving image receiving device that receives and decodes the encoded moving image data. (2) The moving image providing device uses the encoding device according to claim 1 to move a moving image. And (3) the moving picture receiving apparatus decodes the encoded moving picture data using the decoding apparatus according to claim 6. To do.

  According to a fourth aspect of the present invention, there is provided an encoding program comprising: (1) a computer installed in an encoding device that encodes each screen constituting a moving image in units of blocks divided at least vertically or horizontally; (2) An invisible image that contains identification information of an invisible area block that belongs to an invisible area that is encoded so that the original image cannot be displayed normally unless key information is used for a screen that includes an invisible area block that is encoded in the screen. Area information holding means, and (3) encoding each screen in units of blocks so that the invisible area block cannot be displayed normally without using the key information. Encoding to encode normal area blocks that do not belong to the invisible area without referring to the data related to the invisible area block Characterized in that to function as a step.

  A decoding program according to a fifth aspect of the present invention includes: (1) a computer installed in a decoding device that decodes a moving image encoded in units of blocks obtained by dividing each screen at least vertically or horizontally; 2) Identification information of invisible area blocks belonging to different invisible areas on a screen including an invisible area block encoded in the screen, which is encoded so that the original image cannot be visualized without using key information. Invisible area information holding means to hold, and (3) information encoded in units of blocks for each screen, the information held by the invisible area information holding means and the key information And function as a decoding means for decoding so that an image related to an invisible area block on each screen is normally displayed. That.

  According to the present invention, even if the area to be invisible on the screen of the moving image moves for each screen, the invisible area is permitted only by inserting the position information of the invisible area into the corresponding intra-coded block. It is possible to disable viewing for those who have not.

(A) Main Embodiment Hereinafter, an embodiment of an encoding device, an encoding program, a decoding device, a decoding program, and a distribution system according to the present invention will be described in detail with reference to the drawings.

(A-1) Configuration of Embodiment FIG. 1 is an explanatory diagram showing an overall configuration of a distribution system 100 according to this embodiment.

  The distribution system 100 includes a moving image providing device 1 and a moving image receiving device 2.

  The moving image providing device 1 encodes data relating to each screen constituting the moving image and provides the encoded data to the moving image receiving device 2. The moving image providing apparatus 1 includes an encoding device 10, encodes data relating to each screen using the encoding device 10, and provides the encoded data to the moving image receiving device 2. It should be noted that the moving image providing apparatus 1 and the moving image receiving apparatus 2 may be connected by relaying other apparatuses or networks, and the connection method is not limited. In FIG. 1, in the distribution system 100, the moving image providing device 1 and the moving image receiving device 2 each have one configuration, but the number thereof is not limited.

  When receiving the encoded data from the moving image providing device 1, the moving image receiving device 2 decodes it and outputs a moving image. The moving image receiving device 2 has a decoding device 20, and decodes data received using the decoding device 20.

  Next, a detailed configuration of the encoding device 10 will be described.

  The encoding device 10 performs encoding so that the area set for each screen is not visible in a normal state, and the decoding device 20 appears to be in a normal state only when decoding is performed by applying a key. To do. In the following description, “not visible” means that each screen does not appear normal, and “visualization” means that the invisible screen appears normal. It shall represent.

  For example, the encoding device 10 may be constructed by installing the encoding program of the embodiment in the execution configuration of a program such as a CPU, ROM, RAM, EEPROM, and hard disk. This can be illustrated by FIG.

  In this embodiment, the encoding method of the moving image in the encoding device 10 is described as an example of the encoding format of the moving image in the encoding device 10 as MPEG (MPEG4 Advanced Video Coding; MPEG-4 AVC). However, it is not limited to MPEG, and may be in other formats.

  The encoding device 10 includes an input buffer 11, a block division unit 12, an encoding method determination unit 13, an intra-screen encoding unit 14, an inter-screen encoding unit 15, an output buffer 16, an invisibility control unit 17, and an invisible information list. 18.

  The input buffer 11 stores data related to each screen of the moving image captured by the moving image providing apparatus 1 (one image constituting the moving image), and stores the stored data related to each screen. To the block dividing unit 12. The input buffer 11 may take input data such as moving images from a recording medium or a storage device built in the apparatus, or may take in data from an external device, and the input method is not limited. .

  When the data related to each screen is given from the input buffer 11, the block dividing unit 12 divides the data related to the screen into blocks and extracts them one by one, and the intra-screen encoding unit 14 or the inter-screen encoding unit 15, or To both the intra-frame encoding unit 14 and the inter-screen encoding unit 15. When encoding within the screen (for example, compressing in units of blocks using local similarity of pixels within the screen), only the intra-screen encoding unit 14 is used. Data relating to the block may be given only to the encoding unit 15. Further, only the in-screen encoding unit 14 may be sent under the control of the invisibility control unit 17.

  The in-screen encoding unit 14 encodes the data related to the block passed from the block dividing unit 12 with reference to only the block in the screen to which the block belongs (hereinafter referred to as “in-screen encoding”). Basically, an optimal encoding method may be determined by comparison using several prediction modes. However, the encoding mode is independent from the surrounding blocks under the control of the invisibility control unit 17. There is a case where encoding is performed only by the above. This is the case when the peripheral block is in the invisible region. Further, under the control of the invisibility control unit 17, for example, data converted into a random value by reversible conversion or encryption of conversion coefficients may be output as encoded data. This is a process for the block in the invisible area, and the block in the invisible area of the screen to be processed next is referred to so that correct decoding cannot be performed.

  FIG. 2 is an explanatory diagram showing an example of motion vectors between screens.

  The inter-screen encoding unit 15 obtains and encodes a motion vector indicating how much each block moves as shown in FIG. That is, when encoding the data of a block to be encoded, the inter-screen encoding unit 15 refers to a block of a screen other than the screen to which the block belongs (hereinafter referred to as “inter-screen encoding”). Called "encoding"). In this embodiment, as an example, the inter-frame encoding unit 15 refers to the data of the block of the screen immediately before the screen to which the block to be encoded belongs when performing the inter-screen encoding. Thus, description will be made assuming that encoding is performed.

  The inter-screen encoding unit 15 is controlled by the invisibility control unit 17 so that the region in the reference screen referred to by the block in the specific region is limited to the specific region, and the reference other than the specific region refers to Control is performed so that the area in the screen is limited to areas other than the specific area.

  The invisibility control unit 17 receives input of information related to an invisible area (hereinafter referred to as “input invisible area information”) from the outside. The invisibility control unit 17 may take in information relating to the invisible area from a recording medium or a storage device built in the apparatus, or may take in from an external device, and the input method is not limited. In the invisible control unit 17, the input invisible area information includes an identification number of each area (hereinafter referred to as “area number”) and a block identification number (hereinafter referred to as “block number”) (hereinafter referred to as “block set”). It is expressed as a pair.

  The input invisible area information may be expressed in a format such as the following expression (1), for example. Block1, block2,... Represent block numbers.

(Area number, (block1, block2,..., BlockN)) (1)
In equation (1), the block specified by the block number is a portion that cannot be visualized unless there is a key. It is desirable to set the areas specified by the set of block numbers so as not to overlap each other. For example, if there is a set of blocks with area number I and a set of blocks with area number J, I and J have no common set. In this case, it is desirable that the blocks belonging to I and J are not in contact with each other. That is, it is desirable that the blocks belonging to the block set having the area number I and the blocks belonging to the block set having the area number J are not adjacent to each other.

  As for the input invisible area information, data created in advance by the user may be used, or pattern matching is performed for a predetermined pattern on each screen of the moving image input to the encoding device 10, and an image of the corresponding pattern is obtained. If found, the area of the pattern may be regarded as an invisible area, and the input invisible area information may be generated, and the generation method and the input method are not limited. In addition, the user may have means for designating an invisible region while viewing a screen to be encoded using a touch panel, a stylus pen, or the like, and inputting the input invisible region information to the invisible control unit 17.

  The invisible information list 18 is storage means for registering information based on the above-described input invisible area information (hereinafter referred to as “registered invisible area information”) and providing the information to the invisible control unit 17. Further, the information registered in the invisible information list 18 is updated by the invisible control unit 17.

  In the invisible information list 18, the registered invisible area information may be recorded in a format as shown in (2) below, for example. In the equation (2), Rnum indicates a region number. NewBlocks is a block set related to the latest input invisible area information. OldBlocks is a previous block set, that is, a block set related to input invisible area information in the previous screen. The flag is flag information indicating the update status of the registration invisible area information, and details will be described in the description of the operation of this embodiment described later.

(Area number, new block set, previous block set, update flag) =
(Rnum, NewBlocks, OldBlocks, flag) =
(Rnum, (block1, block2,..., BlockN),
(Block1, block2,..., BlockM), flag) (2)
The invisible area information is managed in the invisible information list 18 as follows. If the area number is not registered in the invisibility information list 18 for each invisible area information input before the processing of each frame starts, this pair is registered as new invisible area information. If the area number of the input invisible area information is already registered in the invisible information list 18, the contents of NewBlocks are moved to OldBlocks, and the contents of NewBlocks are updated to the input new block set. Further, if there is no invisible area information already registered in the invisible information list 18 that is the same as the area number of the input invisible area information, the invisible area information is deleted from the invisible area information list. Based on the registration information of the invisibility information list 18, the invisibility control unit 17 controls the block division unit 12, the encoding method determination unit 13, the intra-screen encoding unit 14, and the inter-screen encoding unit 15, and the corresponding block. To make the encoding invisible.

  The encoding method determination unit 13 compares the encoding results of the intra-screen encoding unit 14 and the inter-screen encoding unit 15, selects the one with the better encoding efficiency, and provides it to the output buffer 16. Further, when it is not necessary to determine each time whether to perform intra-screen encoding or inter-screen encoding, the encoding scheme determining unit 13 may be omitted in the encoding device 10. For example, if intra-frame coding is performed periodically and other screens are inter-frame coding, and intra-frame coding is not performed in the block of the screen that performs inter-screen coding, intra-frame coding is performed. Since it is not necessary to determine each time whether to perform the inter-frame encoding unit, the encoding method determining unit 13 may be omitted.

  The data given from the encoding method determination unit 13 to the output buffer 16 is, for example, “encoded data of a moving image (similar to that output from an existing encoding device)” + “invisible region block” Position ”(+“ encoded information of encrypted block ”).

  The “invisible area block position” is information corresponding to the input invisible area information of each screen. The encoding method determination unit 13 outputs “a block position of an invisible region” for a screen determined to perform intra-screen encoding as an encoding method, a screen in which an invisible region first appears, and the like. And In addition, “the position of the block in the invisible region” may be output for a screen in which a block to which intra-screen coding is applied and a block to which inter-screen coding is applied are mixed. At that time, only the block subjected to the intra-frame coding is output as the position of the block in the invisible region.

  Further, “encoded block encoding information” is obtained by encrypting data obtained by encoding a normal block. For example, when making a block invisible, it is a method of encrypting a normally transformed transform coefficient encoded and outputting information encoded with a random value together with the encrypted data. Is output when The output period is the same as “the block position in the invisible area”. In addition, for example, when reversible transformation dependent on a key without using the above-described method (transformation in which correct inverse transformation is impossible unless a key is present) is used, “encoded information of encrypted block” May be omitted.

  The output buffer 16 accumulates and outputs the data output from the encoding method determination unit 13, and the moving image providing apparatus 1 converts the data output from the output buffer 16 into the moving image receiving apparatus 2 (decoding apparatus). 20). In the output buffer 16, the output data may be stored in a storage device such as a disk device or may be provided to another device (for example, the moving image receiving device 2) as described above. It is not limited.

  Next, details of the configuration of the decoding device 20 will be described.

  As for the decryption apparatus, the above-described added data ("invisible area block position" (+ encoded block coding information)) is converted into a moving image for viewing with the invisible area simply invisible. If it is in the user area of the encoded data, it is only necessary to ignore the contents of the user area, the decoding process can be performed even with the configuration of the existing decoding apparatus. In this embodiment, it is assumed that the decryption apparatus 20 has a configuration for enabling viewing of content having no invisible area only when it is determined that the input key is correct, for example. In addition, even if the rewritten portion of the “encoded data of the moving image” is limited to the intra-coded block, the original state is restored based on the position information and the key described in the user data. It is necessary to have a configuration to do so.

  The decoding device 20 includes a moving image encoding analysis unit 21, a user data analysis unit 22, an entropy decoding unit 23, a key analysis unit 24, and a moving image configuration unit 25. For example, the decryption device 20 may be constructed by installing the decryption program of the embodiment in the execution configuration of a program such as a CPU, ROM, RAM, EEPROM, and hard disk. This can be illustrated by FIG.

  The moving image encoding / analyzing unit 21 divides the input data into user data and moving image encoded data, the user data is supplied to the user data analyzing unit 22, and the encoded data of the moving image is entropy decoding unit 23. To give. It is assumed that the user data includes the position of the invisible area block described above and the encoded information of the encrypted block.

  The user data analysis unit 22 analyzes the user data given from the moving image encoding analysis unit 21, cuts out and registers the position of the invisible area block and the encoded information of the encrypted block, The registered information is provided to the entropy decoding unit 23.

  The key analysis unit 24 reads information related to the key, and gives the information related to the read key to the entropy decoding unit 23. In the process of reading the information related to the key, the key analysis unit 24 takes in information input from the keyboard, takes in information from a recording medium or a built-in storage device, or takes in information from an external device by downloading. The method of reading the key is not limited.

  Further, the key analysis unit 24 may determine whether or not the information related to the key is correct, and may give the information related to the key to the entropy decoding unit 23 only when it is correct. Whether or not the key is correct may be determined by, for example, providing the authentication system with a separate authentication server and authenticating whether or not the key is correct by comparing with the key set in the decryption device 20. The method for determining whether or not the contents of the key are correct is not limited.

  The entropy decoding unit 23 decodes the moving image code and extracts a conversion coefficient, a motion vector, and the like. Further, the entropy decoding unit 23 decodes blocks belonging to the invisible region based on information registered in the user data analysis unit 22 and information related to keys given from the key analysis unit 24.

  When the decoded data is given from the entropy decoding unit 23, the moving image configuration unit 25 receives data related to the original moving image screen from the decoded transform coefficient and motion vector in the given data. (Signal) is configured and output. The moving image construction unit 25 may store the output data in a storage device such as a disk device, or may output the output data to a display device such as a display, and the output method is not limited.

Operation of Embodiment of (A-2) Next, the encoding device 10 (moving image providing device 1) and the decoding device 20 (moving image receiving device 2) in the distribution system 100 of this embodiment having the above-described configuration. ) Will be described.

  First, in the encoding device 10 (moving image providing device 1), the operation of the invisibility control unit 17 when a new screen and input invisible area information are input to the encoding device 10 will be described, and then divided. A description will be given of what control the invisibility control unit 17 performs on each block to operate each unit.

(A-2-1) Update Operation of Invisible Information List First, when the invisible control unit 17 is given input invisible area information, the registered invisible area information registered in the invisible information list 18 is updated. The operation when the contents are updated will be described.

  FIG. 3 is a flowchart showing an operation when the registration information of the invisible information list 18 is updated by the invisible control unit 17.

  When the invisible control unit 17 is given input invisible area information, first, variables used for updating the contents of the invisible information list are initialized. In FIG. 3, I and flag are used as variables to be used. Details of each variable will be described later. The initial value of I is the number of input invisible area information given from the outside (moving image providing apparatus 1). Also, the flags of all registered invisible area information registered in the invisible information list 18 are initialized to flag = 0 (S101).

  Next, the value of I is checked, and if it is 0, the operation starts from step S107 described later, and if it is not 0, the operation starts from step S103 described later (S102).

  If I = 0 in the above-described step S102, the registered invisible area information having the area number related to the arbitrary input invisible information among the input invisible information given in the above-described step S101 is It is searched whether or not it is registered in the invisible information list 18. Then, if the registered invisible area information of the area number has already been registered in the invisible information list 18, the operation starts from step S104 described later, and if not registered, the operation starts from step S105 described later. (S103).

  As described above, in step S103, when the registered invisible area information having the area number to be searched is already registered in the invisible information list 18, the contents of OldBlocks are changed to the contents of NewBlocks for the detected invisible area information. The block set of the input invisible area information is registered in NewBlocks. Then, in the detected invisible area information, the flag is updated to 1 (S104).

  On the other hand, when the registered invisible area information having the area number to be searched is not registered in the invisible information list 18 in the above-described step S103, new registered invisible area information is created using the input invisible area information. , It is registered in the invisibility information list 18. In the new registered invisible area information, the block set of the input invisible area information is registered in NewBlocks, and the flag is updated to 2 (S105).

  When the registration invisible area information is updated in the above-described step S104 or the registration invisible area information is newly registered in the above-described step S105, the variable I is updated to I-1 (S106), and the operation starts from the above-described step S102. . In this way, the processes of steps S102 to S106 described above are repeated until I = 0, that is, until the update of the registered invisible area information is completed based on all input invisible area information.

  If it is determined in step S102 that I = 0, the variable I is then changed to the number of registered invisible area information registered in the invisible information list 18 (S107).

  Next, the value of I is checked, and if it is 0, the process of updating the registration information in the invisible information list 18 is terminated. If it is not 0, the operation starts from step S109 described later ( S108).

  If I = 0 in step S108 described above, is the registered invisible area information (hereinafter referred to as “invisible information I”) registered in the invisible information list 18 updated? No is determined based on the flag information. If the invisible information I has been updated, the operation starts from step S111, which will be described later, and if not, the operation starts from step S110, which will be described later (S109). In the case of flag = 0 by the processing in steps S102 to S106 described above, it indicates that the registered invisible area information has not been updated, and in the case of flag = 1 or flag = 2, the registered invisible area. The information indicates that it has been updated.

  When it is determined in step S109 described above that the invisible information I has not been updated, the invisible information I is deleted from the invisible information list 18 (S110).

  If it is determined in step S109 that the invisible information I has been updated, or if the invisible information I is deleted in step S110, I is updated to I-1, The operation starts again from the process of step S108 (S111). In this way, it is determined whether or not all of the registered invisible area information registered in the invisible information list 18 has been updated until I = 0, and all that have not been updated are deleted.

(A-2-2) Peripheral Block Set Extraction Processing When the invisibility control unit 17 finishes updating the invisibility information list 18 (see the flowchart in FIG. 3 described above), then in the flowchart in FIG. , Flag = 1 or 2 is set around the block area specified by the registered invisible area information (hereinafter referred to as “invisible area”), and the block at the position in contact with the invisible area (hereinafter referred to as “peripheral area”). Blocks) are extracted (hereinafter referred to as “neighboring block sets”).

  FIG. 4 is an explanatory diagram showing an example of an invisible region and peripheral blocks.

  In this embodiment, for example, as shown in FIG. 4, assuming that blocks 201 to 205 are arranged, if any of the blocks 202 to 205 is a block belonging to an invisible area, Assume that 201 belongs to the peripheral block set. For example, when there is a possibility that the block 201 is encoded with reference to blocks other than the blocks 202 to 205, the block 201 is also included when the block at another position is a block belonging to an invisible area. May belong to the peripheral block set.

  The blocks in the peripheral block set are blocks that may be predicted by referring to the invisible area when performing intra-screen coding, so when these are obtained and coded before the screen coding process starts, Give limits. Also, in the inter-picture encoding process, it is assumed that a peripheral block set is obtained before the encoding process regardless of whether the flag of the registered invisible area information is 1 or 2.

  FIG. 5 is a flowchart illustrating an example of an operation of extracting a peripheral block set based on information registered in the invisible information list 18 in the invisible control unit 17.

  First, the variable I used for the loop processing is initialized to a value representing the image height of the moving image to be encoded in units of blocks in the current encoding apparatus 10 (S201). For example, if the moving picture image to be encoded is 50 blocks long, it is initialized to I = 50.

  Next, the value of I is checked, and if it is 0, the peripheral block set extraction process is terminated. If it is not 0, the operation starts from step S203 described later (S202).

  If I = 0 is not satisfied in step S202 described above, the variable J used for the loop processing is a value representing the image width of the moving image to be encoded in the current encoding device 10 in units of blocks. (S203).

  Next, the value of J is checked, and if it is 0, operation starts from step S208 described later, and if it is not 0, operation starts from step S205 described later (S204).

  If J = 0 is not satisfied in step S204 described above, the I-th block from the top and the J-th block from the left (hereinafter referred to as “Block [I]” on the screen of the moving image to be encoded. [J] ”) is determined whether it belongs to the peripheral block set, and if it is determined that it belongs to the peripheral block set, it operates from step S206 described later, and it is determined not to belong to the peripheral block set The operation starts from step S207, which will be described later (S205). The details of the method for determining whether or not Block [I] [J] belongs to the peripheral block set in step S205 will be described later.

  If it is determined in Step S205 described above that Block [I] [J] belongs to the peripheral block set, the block number of Block [I] [J] It is registered as a set (S206).

  When the block number of Block [I] [J] is registered as a neighboring block set in step S206 described above, or it is determined that Block [I] [J] does not belong to the neighboring block set in step S205 described above. Then, J is updated to J-1, and the operation starts from step S204 described above (S208).

  If it is determined in the above-described step S204 that J = 0, I is updated to I-1, and the operation further starts from the above-described step S202.

  As described above, in FIG. 5, loop processing is performed using the variables I and J, and whether or not Block [I] [J] belongs to the peripheral block set is determined as an encoding target. It can be determined whether or not all the blocks on the screen of a moving image belong to the peripheral block set, and the peripheral block set can be extracted.

  Next, details of determining whether or not Block [I] [J] belongs to the peripheral block set in step S205 described above will be described.

  FIG. 6 is an explanatory diagram showing the determination condition in step S205 described above in C language. In FIG. 6, for simplicity of explanation, expressions that are not in the C language, such as “does not belong to the invisible area” and “belongs to the invisible area”, are partially used. All are expressed in a programming language such as C language.

  The determination condition shown in FIG. 6 is the same as in FIG. 4 described above. For example, when any of the blocks 202 to 205 is a block belonging to the invisible area, the block 201 belongs to the peripheral block set. It is a condition for determining.

  In FIG. 6, when Block [I] [J] (block 201 in FIG. 4) does not belong to the invisible region, Block [I-1] [J-1] (corresponding to block 202 in FIG. 4), Block [I-1] [J] (corresponding to the block 203 in FIG. 4), Block [I-1] [J + 1] (corresponding to the block 204 in FIG. 4), Block [I] [J-1] (in FIG. 4) When any one of the blocks (corresponding to block 205) belongs to the invisible area, it indicates that Block [I] [J] is determined to belong to the peripheral block set.

  FIG. 7 shows the operation of extracting a peripheral block set in the invisible information list 18 shown in FIG. 5 described above in C language. In FIG. 7, as in FIG. 6 described above, in order to simplify the description, expressions that are not C language are used in part, but in actuality, all are expressed in a program language such as C language. The one written by is applied.

  7 represents processing corresponding to steps S201, S202, and S208 in FIG. 5 described above. A portion denoted by reference numeral 302 represents processing corresponding to steps S203, S204, and S207. Further, the part denoted by reference numeral 303 represents processing corresponding to step S205. Furthermore, the part denoted by reference numeral 304 represents processing corresponding to step S206.

(A-2-3) Encoding Process Next, the invisibility control unit 17 updates the information of the invisibility information list (see the flowchart in FIG. 3 described above) and extracts neighboring blocks (see the flowchart in FIG. 5 described above). After the process of) is completed, an operation in which the intra-frame encoding unit 14 and the inter-screen encoding unit 15 perform the encoding process for each block according to the control of the invisible information list 18 will be described.

  First, the intra-screen encoding process will be described, and then the inter-screen encoding process will be described.

  FIG. 8 is a flowchart illustrating an example of an operation in which intra-screen encoding is performed by the intra-screen encoding unit 14 under the control of the invisibility control unit 17.

  First, the variable I used for the loop processing index is initialized to the value of all the blocks in the screen of the moving image to be encoded in the current encoding device 10 (S301).

  Next, the value of I is checked, and if it is 0, the intra-coding process is terminated, and if it is not 0, the operation starts from step S303 described later (S302).

  In the above-described step S302, if I = 0, the block having the block number I (hereinafter referred to as “Block [I]”) is extracted by the processing such as the flowchart of FIG. When it is determined whether or not it belongs to the block set, and it is determined that it belongs to the peripheral block set, the operation starts from step S304 described later, and when it is determined that it does not belong to the peripheral block set, step S305 described later is performed. (S303).

  If it is determined in Step S303 that Block [I] belongs to the peripheral block set, the block near Block [I] (in this embodiment, Block [I] is a block in FIG. 4 described above). If it is 201, intra-frame coding is performed without referring to data relating to blocks 202 to 205 at positions corresponding to blocks 202 to 205 (S304). In intra-frame coding, there are cases where the pixel values of the neighboring blocks described above are referred to and coded, but there is also a mode in which prediction is performed without referring to data related to neighboring blocks. Intra-screen coding may be performed for Block [I] without referring to data relating to the block.

  On the other hand, when it is determined in Step S303 described above that Block [I] does not belong to the peripheral block set, Block [I] belongs to the invisible area based on the information registered in the invisible information list 18. In other words, it is determined whether Block [I] belongs to a block set of NewBlocks in any registered invisible area information. When it is determined that Block [I] belongs to the invisible region, the operation starts from step S306 described later. When it is determined that Block [I] does not belong to the invisible region, the operation starts from step S307 described later (S305). ).

  If it is determined in the above-described step S305 that Block [I] does not belong to the invisible region, Block [I] does not need to be particularly limited in the encoding method, and is similar to the existing encoding device. It is assumed that the data is encoded by the process (S306).

  On the other hand, if it is determined in the above-described step S305 that Block [I] belongs to the invisible region, there is no particular restriction on the encoding method for Block [I], and the existing encoding apparatus can be used. It is encoded by the same process. However, in order to allow only the user with the key to visualize the image of this block, it is encoded by applying a reversible transform (key-dependent) to the transform coefficient or by encrypting and inserting a random value instead. The data is encoded and output together with the encrypted data to the encoding method determination unit 13. Only the information to be encoded here is replaced in this way, and encoding is continued based on the correct transform coefficient in the encoding apparatus. Further, the block number of Block [I] is also output to the encoding method determination unit 13 (S307).

  After any of the processes in steps S304, S306, and S307 described above, I is updated to I-1, and the operation starts from step S302 described above (S308).

  Next, the inter-screen encoding process in the intra-screen encoding unit 14, the inter-screen encoding unit 15, and the invisibility control unit 17 will be described.

  First, on the screen to be encoded, in the update of the registration information of the invisibility information list 18 described above (see the flowchart of FIG. 3 above), when there is an invisible area where the flag is 2, that is, for the first time. A process when an invisible area that has appeared will be described. When there is an invisible area that appears for the first time on the screen, there is no invisible area corresponding to the reference screen when trying to perform inter-screen coding, so it is necessary to perform processing according to each screen. is there. In the first method, when there is an invisible region that appears for the first time on the screen, the screen is switched to the intra-screen coding without performing the inter-screen coding (see the flowchart of FIG. 8 described above). It is a method. The second method is a method in which, when there is an invisible region that appears for the first time on the screen, intra-frame coding is performed only for the coding of the block related to the invisible region that appears for the first time. In the encoding apparatus 10, when the inter-picture encoding cannot be performed for only some of the blocks when the inter-picture encoding is performed, the first method described above is applied, and the partial blocks are applied. The above-described second method is applied when only intra-frame coding can be performed.

  FIG. 9 is a flowchart illustrating an operation of performing inter-frame encoding in the encoding device 10.

  Note that the flowchart shown in FIG. 9 illustrates processing when the above-described second method is applied when there is an invisible region that first appears on the screen. As described above, in the encoding device 10, when there is an invisible region that first appears on the screen, a process to which the first method described above is applied may be performed. Since the processing is the same as in-screen coding (see FIG. 8 described above), the description thereof is omitted.

  FIG. 10 is an explanatory diagram showing restrictions on the search range of blocks to be referred to when inter-screen encoding is performed in the inter-screen encoding unit 15.

  First, in the invisibility control unit 17, a peripheral block set is extracted by the operation shown by the flowchart in FIG. 5 described above (S401).

  Then, the variable I used for the loop processing index is initialized to the value of all the blocks in the screen of the moving image to be encoded in the current encoding device 10 (S402).

  Next, the value of I is checked, and if it is 0, the intra-frame encoding process is terminated, and if it is not 0, the operation starts from step S404 described later (S403).

  In step S403 described above, if I = 0, it is determined whether or not Block [I] belongs to the peripheral block set extracted in step S401, and it is determined that it belongs to the peripheral block set. In this case, the operation starts from step S405 described later, and when it is determined that it does not belong to the peripheral block set, the operation starts from step S406 described later (S404).

  If it is determined in Step S404 that Block [I] belongs to the peripheral block set, intra-frame coding and inter-frame coding are performed, and the better one is selected. Receive. In the case of intra-picture coding, intra-picture coding using a prediction mode that does not refer to other neighboring blocks is performed. Inter-frame coding searches for the most similar block from the reference screen (screen previously coded) and obtains a motion vector representing the motion of the block. As shown in FIG. The search range for searching for a block from the reference screen is limited so that encoding is not performed by referring to the block of the area occupied by the block set of OldBlocks in all registered invisible area information registered in (S405).

  On the other hand, if it is determined in the above-described step S404 that Block [I] does not belong to the peripheral block set, Block [I] belongs to the invisible area based on the information registered in the invisible information list 18. In other words, it is determined whether Block [I] belongs to a block set of NewBlocks in any registered invisible area information. When it is determined that Block [I] belongs to the invisible region, the operation starts from step S408 described later. When it is determined that Block [I] does not belong to the invisible region, the operation starts from step S407 described later (S406). ).

  In Step S406 described above, when it is determined that Block [I] does not belong to the invisible region, basically, intra-frame coding and inter-frame coding are performed, and the more efficient one is selected. The visualization control unit 17 is restricted. There is no restriction in the case of intra-screen coding. In the case of inter-screen coding, as in step S405 described above, the search range is set so as not to perform coding with reference to the area occupied by OldBlocks of all registered invisible area information registered in the invisible information list 18. Restricted (S407).

  On the other hand, if it is determined in the above step S406 that Block [I] belongs to the invisible area, the registered invisible area information in which Block [I] is registered in the block set of NewBlocks in the invisible information list 18. The contents of the flag are checked. If flag = 1, the operation starts from step S410 described later, and if flag = 2, the operation starts from step S409 described later (S408).

  In the above-described step S408, when it is determined that flag = 2, intra-frame encoding is performed. However, in order for only the user with the key to be able to visualize this block, it is encoded by applying a reversible transformation to the transform coefficient or by encoding and inserting a random value instead, and then encrypting the information. Output together with Only the information to be encoded here is replaced in this way, and encoding is continued in the encoding apparatus based on the correct transform coefficient. The block number is also output together (S409).

  On the other hand, in the above-described step S408, when flag = 1 is determined, only inter-frame coding is performed. However, similarly to the above-described step S405, the search range is limited by the restriction of the invisibility control unit 17. Limited. If Block [I] belongs to NewBlocks of the registered invisible area information of area number Rnum in the invisible information list 18, only the area on the reference screen specified by OldBlocks of the registered invisible area information is referred to. The search range is limited (S410).

  After any of the above-described steps S403, S404, S407, S409, and S410, I is updated to I-1, and the operation starts from the above-described step S403 (S411).

(A-2-4) Output of Encoding Device Next, data output from the encoding device 10 (moving image providing device 1) will be described.

  As described above, the data given from the encoding method determination unit 13 to the output buffer 16 is “moving image encoded data” + “invisible area block position” + “encrypted block encoding information”. is there. Regarding “the position of the invisible area block” and “encoded information of the encrypted block”, the screen where the in-screen encoding process (see the flowchart of FIG. 8 described above) is performed, or the invisible area that appears for the first time This is output, for example, when intra-screen coding is performed only for existing screens, that is, for some blocks (see step S409 in FIG. 9 described above).

  Then, when output data is given to the output buffer 16 from the inter-screen encoding unit 15, the output data is accumulated and output, and the data output from the output buffer 16 is converted into a moving image by the moving image providing device 1. This is given to the image receiving device 2 (decoding device 20).

(A-2-5) Decoding Process Next, the decoding process in the decoding apparatus 20 will be described.

  FIG. 11 is a flowchart illustrating an operation of decoding data related to a moving image provided from the moving image providing apparatus 1 (encoding apparatus 10) in the decoding apparatus 20. As described above, if it is not necessary for the user to see the invisible area on the screen, the decryption may be performed by the process in the device having the same configuration as the existing decryption device, but the user uses a predetermined key. In order to visualize the invisible part, it is necessary to perform the processing of the flowchart shown in FIG.

  First, user data and a moving image code are extracted from the data given from the encoding device 10 by the moving image coding analysis unit 21, the user data is given to the user data analysis unit 22, and the moving image code is entropy decoded. Is provided to the conversion unit 23. The user data corresponds to the above-mentioned “invisible area block position” and “encrypted block encoding information”. In addition, it is assumed that information related to a key for visualizing an invisible image is input from the user to the key analysis unit 24. When the user data is given, the user data analysis unit 22 analyzes the user data and checks whether there is information output when the encoding apparatus 10 makes the data invisible (S501). If there is corresponding information, the user data analysis unit 22 reads the position information of the invisible block and encrypted data (only when the encryption method is used) from the user data. ) Is read (S502).

  Then, the variable I used for the loop processing index is initialized to the value of all the blocks in the screen of the moving image to be encoded in the current encoding device 10 (S503).

  Next, the value of I is checked, and if it is 0, the decoding process is terminated, and if it is not 0, the operation starts from step S505 described later (S504).

  Then, the entropy decoding unit 23 performs entropy decoding for one macroblock on the moving image code given from the moving image coding analysis unit 21. That is, entropy decoding is performed on Block [I] (S505).

  Then, the entropy decoding unit 23 determines whether or not Block [I] is an invisible block based on the information given from the user data analysis unit 22, and if it is an invisible block, The operation starts from step S507, which will be described later. If the block is not invisible, the operation starts from step S508, which will be described later (S506).

  If Block [I] is an invisible block in step S506 described above, the information related to the key read by the key analysis unit 24 in step S501 is further referred to, and the key is invalid. It is determined whether or not. If the key is invalid, the operation starts from step S509 described later. If the key is not incorrect, the operation starts from step S508 described later (S507).

  If it is determined in step S507 described above that the key is not illegal, inverse conversion is performed on Block [I] using the transform coefficient as a key argument so that it can be decoded into a normal block. If there is encrypted data, it is combined using the key to obtain the correct conversion coefficient and replaced with the correct conversion coefficient (S508).

  If it is determined in Step S506 that Block [I] is not an invisible block, or if it is determined in Step S507 that the key is invalid, the data related to Block [I] Are subjected to the same processing as the decoding performed by an existing decoding device such as inverse transformation, motion compensation, and intra prediction, and are given to the moving image construction unit 25. Also, in the above-described step S508, when Block [I] is converted using a key, decoding performed by a conventional decoding device such as inverse conversion, motion compensation, and intra prediction is performed on the converted data. This is performed and given to the moving image construction unit 25 (S509). Then, I is updated to I-1, and the operation starts from step S504 described above (S510).

  In this manner, the entropy decoding unit 23 decodes all the blocks of the moving image provided from the encoding device 10 and visualizes the invisible blocks, and the moving image configuration unit 25 displays the screen. Is constructed and output.

(A-3) Effects of Embodiment According to this embodiment, the following effects can be achieved.

  The encoding device 10 includes an intra-screen encoding unit 14, an inter-screen encoding unit 15, an invisible control unit 17, and an invisible information list 18, so that blocks belonging to an invisible region are determined according to input invisible region information. Encoding is performed to make it invisible. Thereby, even if an invisible area | region moves for every screen, there exists an effect that the image of the block which belongs to the invisible area cannot always be seen from the user who does not have a key. In other words, only the user having the key can visualize the image of the block belonging to the invisible region.

  The in-screen encoding unit 14 encodes the blocks belonging to the peripheral block set without referring to the data of the blocks belonging to the invisible area (see step S304 in FIG. 8 described above). As a result, the block other than the block belonging to the invisible region can be viewed even by a user who does not have a key.

  In the encoding device 10, since the original image is not modified at the time of encoding, the image encoded by the decoding device 20 is only reversibly converted using the key. Has the effect of not affecting the image quality of the original image.

  When the block belonging to the invisible area is encoded in the inter-screen encoding unit 15, only the data of the block belonging to the invisible area (OldBlocks) in the previous screen is referred to (see step S410 in FIG. 9 described above). , Limit motion search. In addition, the blocks that do not belong to the invisible area are encoded without referring to the data of the blocks that belong to the block set (OldBlocks) of the invisible area of the previous screen (steps S405 and S407 in FIG. 9 described above). (Refer to this) As a result, when the moved object is actually the same, the search range becomes narrower than the conventional search method, so that the motion search can be performed efficiently, improving the image quality and reducing the processing amount. can do.

  In the above embodiment, the data related to the position of the invisible region block is transmitted to the encoding device 10 (moving image receiving device 2) only when the intra-screen encoding is selected. In this case, when the block belonging to the invisible region is encoded in the inter-screen encoding unit 15, only the data of the block belonging to the invisible region (OldBlocks) in the previous screen is referred to (step of FIG. 9 described above) Therefore, the block data encrypted and randomized by the intra-screen coding is propagated in the subsequent inter-screen coding. Thereby, even when the data related to the input invisible region information is transmitted to the encoding device 10 (moving image receiving device 2) only when the inter-screen coding is selected, the image of the block belonging to the invisible region is It is possible to achieve an effect that the user who does not have the key cannot see it. That is, there is no need to transmit data related to the input invisible area information for all the screens of the moving image, and the amount of transmission data and the processing amount are reduced. In addition, with respect to a screen on which inter-screen coding has been performed, the decoding device 20 omits the decoding process using the data related to the key and the input invisible region information, and does not perform the visualization process in particular. Since only the same processing as that of the encoding device is required, the amount of processing necessary for decoding can be reduced.

(B) Other Embodiments The present invention is not limited to the above-described embodiments, and may include modified embodiments as exemplified below.

(B-1) In the above embodiment, the key used for encoding in the encoding device 10 and the key used for decoding in the decoding device 20 have been described as being the same, but the encoding device 10 In this case, a key dedicated to encryption may be used, and a key dedicated to decryption may be used in the decryption apparatus 20.

(B-2) In the above embodiment, the encoding device 10 is described as being mounted on the moving image providing device 1, but may be realized as a single device. Similarly, the decoding device 20 may be realized as a single device.

(B-3) In the above embodiment, the encoding device 10 and the decoding device 20 have been described with respect to the example in which the screen is encoded / decoded in units of blocks divided vertically and horizontally. Alternatively, encoding / decoding may be performed in units of blocks divided into either of the horizontal directions.

It is explanatory drawing which showed the whole structure of the delivery system which concerns on embodiment. It is explanatory drawing which showed the example of the motion vector between screens based on embodiment. It is the flowchart shown about the operation | movement when the content of the invisible information list is updated by the invisible control part based on embodiment. It is explanatory drawing shown about the example of the invisible area | region and peripheral block which concern on embodiment. It is the flowchart shown about the example of the operation | movement which extracts a periphery block set in the invisibility control part which concerns on embodiment. In the invisibility control part which concerns on embodiment, it is explanatory drawing shown about the conditions which determine whether it corresponds to a surrounding block. It is explanatory drawing represented in C language about the example of the operation | movement which extracts a surrounding block set in the invisibility control part which concerns on embodiment. It is the flowchart explaining the example of the operation | movement which the encoding apparatus based on embodiment performs in-screen encoding. It is the flowchart explaining the example of the operation | movement which the encoding apparatus which concerns on embodiment performs inter-screen encoding. It is explanatory drawing shown about the restriction | limiting of the search range of the block referred when performing the inter-screen encoding in the inter-screen encoding part based on embodiment. 6 is a flowchart showing an operation of decoding data in the decoding device according to the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Distribution system, 1 ... Moving image provision apparatus, 2 ... Moving image receiving apparatus, 10 ... Encoding apparatus, 11 ... Input buffer, 12 ... Block division part, 13 ... Coding system determination part, 14 ... In-screen encoding 15, inter-screen encoding unit, 16, output buffer, 17, invisibility control unit, 18, invisibility information list, 20, decoding device, 21, moving image encoding analysis unit, 22, user data analysis unit , 23... Entropy decoding unit, 24... Key analysis unit, 25.

Claims (9)

In an encoding device that encodes each screen constituting a moving image in units of blocks divided at least vertically or horizontally,
An invisible area that stores identification information of invisible area blocks that belong to different invisible areas on a screen including invisible area blocks that are encoded in the screen, so that the original image cannot be visualized unless key information is used. Information holding means;
Each screen is encoded in units of blocks, and the invisible area block is encoded so that the original image cannot be visualized unless the key information is used, and a normal area block that does not belong to the invisible area And a coding means for coding without referring to the data related to the invisible area block.   In the encoding of an invisible area block, the encoding means, when performing in-screen encoding that refers to data related to a block in the screen to which the invisible area block belongs, further encodes the data in which the invisible area block is encoded, The encoding apparatus according to claim 1, wherein the encoding is performed using the key information or encryption key information corresponding to the key information.   In the encoding of an invisible area block, the encoding means performs inter-frame encoding that refers to data related to a block in a reference screen other than the screen to which the invisible area block belongs, and the invisible area block in the reference screen The encoding apparatus according to claim 1 or 2, wherein the data according to (1) is referred to.   In the encoding of the normal area block, the encoding means refers to the data related to the invisible area block in the screen when performing the intra-screen encoding referring to the data related to the block in the screen to which the normal area block belongs. The encoding apparatus according to claim 1, wherein the encoding apparatus is not.   In the case of encoding a normal area block, the encoding means performs inter-frame encoding that refers to data related to a block in a reference screen other than the screen to which the normal area block belongs. The encoding apparatus according to claim 1, wherein the data according to claim 1 is not referred to. In a decoding apparatus that decodes a moving image encoded in units of blocks obtained by dividing each screen at least vertically or horizontally,
Holds identification information for invisible area blocks belonging to different invisible areas on a screen including invisible area blocks encoded in the screen that are encoded so that the original image cannot be visualized without using key information. Invisible area information holding means;
For each screen, the data encoded in units of blocks is decoded, and the invisible area block on each screen is obtained using the information held by the invisible area information holding means and the key information. And a decoding means for decoding so as to normally display the image according to the above. A moving image providing device that encodes data relating to each screen constituting a moving image and provides encoded moving image data, and receives and decodes encoded moving image data from the moving image providing device. In a distribution system comprising a moving image receiving device
The moving image providing device uses the encoding device according to claim 1 to encode data related to each screen constituting the moving image,
The distribution system characterized in that the moving image receiving apparatus decodes encoded moving image data using the decoding apparatus according to claim 6. A computer mounted on an encoding device that encodes each screen constituting a moving image in units of blocks divided at least vertically or horizontally,
An invisible image that contains identification information of an invisible area block that belongs to an invisible area that is encoded so that the original image cannot be displayed normally unless key information is used for a screen that includes an invisible area block that is encoded in the screen. Area information holding means;
Each screen is encoded in units of blocks, and the invisible area block is encoded so that the original image cannot be displayed normally unless the key information is used, and it does not belong to the invisible area. An encoding program that functions as an encoding unit that encodes an area block without referring to data related to the invisible area block. A computer mounted on a decoding device that decodes a moving image encoded in units of blocks obtained by dividing each screen at least vertically or horizontally,
Holds identification information of invisible area blocks belonging to different invisible areas on a screen including invisible area blocks encoded in the screen that are encoded so that the original image cannot be visualized without using key information. Invisible area information holding means;
For each screen, the data encoded in units of blocks is decoded, and the invisible area block on each screen is obtained using the information held by the invisible area information holding means and the key information. A decoding program that functions as decoding means for decoding so that an image according to the above is normally displayed.

Images