JP5168366B2 - Server apparatus, client apparatus, and content transmission system including server apparatus and client apparatus - Google Patents

Description

  The present invention relates to a server device that can communicate with a display device. In particular, the present invention relates to a server device that transmits video data (for example, video data) to a display device.

  With the spread of information technology, most of AV contents are digitized, and media for recording / reproducing digital contents such as CDs and DVDs are widely used. In recent years, devices that digitally record content such as HDD recorders and HDD-equipped DVD recorders have become popular in the home. Furthermore, content distribution / distribution services such as video and music via the network have become popular, and content distribution is performed between remote terminals via the network without moving media such as CDs and DVDs.

  However, since digitized content is relatively easy to perform illegal operations such as copying and falsification, it is necessary to protect against unauthorized use while allowing the use of personal or household content. In particular, the replacement of analog broadcast receivers with digital broadcast receivers is rapidly progressing toward the terrestrial analog broadcast stoppage in 2011, and technology to protect content against the digitization of AV content in the home. Realization is considered essential.

  DTCP (Digital Transmission Content Protection) developed by DTLA (Digital Transmission Licensing Administrator) is one of the industry standard technologies for protecting digital transmission content. (For example, see Non-Patent Document 1).

  In DTCP, an authentication protocol between devices at the time of content transmission and a transmission protocol for encrypted content are decided. To summarize, the DTCP-compliant device is required to decrypt compressed content that is easy to handle, such as MPEG (Moving Picture Experts Group), in an unencrypted state and to decrypt encrypted content. To perform key exchange according to a predetermined mutual authentication and key exchange (AKE) algorithm, and to limit the range of devices that perform key exchange using the AKE command. In DTCP, a plurality of types such as Copy Free, Copy Once, No More Copies, and Copy Never are defined as copy control information, and the operations of the sink and source devices are determined based on the control information. Among the above, No More Copies is a state in which copying is no longer permitted because the content originally set in Copy One Generation is copied only once (first generation). In DTCP-IP, a MOVE function is prepared as means for transmitting content encoded as No More Copies (see, for example, Non-Patent Document 2 and Non-Patent Document 3). MOVE in network communication corresponds to moving data between devices, and basically does not leave data at the source. The MOVE function in DTCP-IP is encrypted under the condition that the Sink encodes the received content as No More Copies, and the source side erases or disables the content after transmission. This means that the content is transmitted from the source to the sink. For example, when the content of Copy One Generation is encoded and recorded as No More Copies in a source such as a personal video recording device (PVR), Copy One Generation is satisfied while satisfying the above conditions by using the MOVE function. Can be encoded and transmitted to a single sink. Also, MOVE is allowed only between a single source and a single sink.

  When moving copyright-protected data to another recording device, the copy data is encrypted and held with a unique copy encryption key. If the data after the transfer is defective due to a failure during transfer, etc. Has proposed a device that handles content data that invalidates the moved data and restores the original data from the copied data, thereby protecting the copyright and preventing the loss of the original data. (For example, see Patent Document 1 and Patent Document 2).

JP 2005-250567 A JP 2010-231787 A

DTCP Specification Volume 1 (Informational Version) Revision 1.4 (http://www.dcp.com/) DTCP Volume 1 Supplement E (V1SE) Mapping DTCP to IP (Information Version) Revision 1.1 (http://www.dcp.com/) DIGITAL TRANSMISSION PROTECTION LICENSE AGREEMENT, Adapter Agreement-May 2005

  However, in this apparatus, it is not assumed that the content is moved after format conversion such as lowering the resolution in accordance with the playback performance of the destination device when moving the content. Therefore, the apparatus has a problem that the original content is lost against the user's intention in accordance with the move operation.

  Accordingly, an object of the present invention is to provide a server device that can reduce the loss of the original content inadvertently during the move operation of the content in order to solve the above-described problem.

  In order to achieve the above object, a server device of the present invention transmits content data to a client terminal. Then, the server device of the present invention, based on the reception means for receiving a transfer request for content data from the client terminal, the number of times of copying and the protection information associated with the content data for which the transfer request has been received by the reception means, Determining means for determining whether or not the content data can be transferred to the client terminal.

  According to said structure, it can reduce that an original content lose | disappears carelessly at the time of the move operation of a content.

Configuration diagram of video content transmission system Illustration for explaining video content attribute information Video content transmission sequence diagram Video content transmission availability determination processing flowchart Figure showing an example of the copy count warning message Transmission sequence diagram for protected content Protected content determination processing flowchart Video content transmission sequence diagram in automatic transmission mode Automatic transmission discrimination process flowchart

(Embodiment 1)
1. Definition 1-1. 1. Description of video content Configuration 2-1. Configuration of video content transmission system 2-2. Configuration of server 2-3. Configuration of client 3. Operation of video content transmission system 3-1. Overall operation 3-2. Server transmission data creation processing 3-3. 3. Client transmission target discrimination process Other Embodiments 4-1. Server transmission availability determination process 4-2. 4. Automatic transmission processing of client Summary [1. Definition]
The attribute information of the video content handled by the video content transmission system of the present embodiment will be described with reference to FIG. In this system, the server 1 publishes the attribute information of each video content to the client 2 prior to content transmission. As shown in FIG. 2, the attribute information is composed of a title, a content length, a content ID, a format, a copyable number of times, and an automatic transfer enable / disable flag. The title is composed of a character string representing the content contents that can be identified by the user. The content length represents the video playback time. The content ID is identification information used for uniquely specifying the content in the server 1 and for the client 2 to specify the transmission target. The format indicates an encoding method of video content such as MPEG_TS_JP_T, AVC_AAC_HD_T, and the like, and can be used as information for determining whether or not the client 2 can reproduce the content. This format information is defined as a profile name for a combination of a video encoding system and an audio encoding system format by a standards organization such as DLNA. The number of copies that can be copied is information given to the copyright-protected video content, and is information that indicates the number of copies that can be made to another device or recording medium. In Japan, operations are being made that allows 10 copies to be made immediately after recording terrestrial digital broadcasting and BS digital broadcasting. In this case, the number of times of copying is subtracted every time copying to another device or a recording medium such as a BD, and when the number of possible copies reaches 0, the content is deleted from the device or cannot be used. There must be. In some cases, only one generation of recording is possible depending on the broadcaster, and copying to other devices or recording media is not permitted. In this case, the number of copies is always zero. Also, video content recorded on a personal device such as a camcorder is not protected by copyright, so there is no upper limit on the number of copies that can be made. Indicates.

The automatic transfer enable / disable flag indicates whether or not to permit automatic transfer at a predetermined time without performing a transmission start operation by the user when transmitting video content in the server 1 to the client 2. It is information to show. When this flag is set to ON, for example, all the video contents in the server 1 that can be automatically transferred are automatically transmitted at night every day by the timer setting of the client 2, and the next morning, the client 2 The video content can be viewed.
[2. Constitution]
[2-1. Configuration of video content transmission system]
An outline of the video content transmission system will be described. FIG. 1 is a block diagram showing a configuration of a video content transmission system. The server 1 is a server that transmits video content via a network. The client 2 receives video content from the server 1 via the network, and stores and stores it in the flash memory 22 or the memory card 8. Thereby, even after the client 2 is disconnected from the network, the video content can be read from the flash memory 22 or the memory card 8 and reproduced. The client 2 becomes a client terminal of the server 1. The router 3 is a router device that connects the server 1 and the client 2 via a network and enables data transmission / reception. The remote controller 4 is a remote controller used by the user to operate the server 1.

  The server 1 and the client 2 are connected by, for example, a LAN cable or a wireless LAN. In that case, the router 3 is often used, but a form in which the router 3 is directly connected without using the router 3 is also conceivable. The means for connecting the server 1 and the client 2 may not be a LAN.

  The remote controller 4 transmits user operation information for the server 1 to the server 1 using, for example, infrared rays or radio.

  The digital camera 5 is a device that generates video content stored in the server 1. For example, a digital still camera or a digital video camera can be considered.

  The memory card 6 is a portable non-volatile storage medium, and is stored in the digital camera 5 to store video content generated by the digital camera 5. The memory card 6 is also used for the purpose of copying and storing the video content in the server 1 by being mounted on the server 1 by taking advantage of its portability. As a form of the memory card 6, for example, a card with a built-in flash memory such as an SD card can be considered.

  The antenna 7 is an antenna for receiving digital broadcasting. For example, a UHF antenna is considered for digital terrestrial broadcasting, a parabolic antenna is considered for BS / CS digital broadcasting, and the antenna 7 is connected to the server 1 by a coaxial cable or the like.

  The memory card 8 is a portable non-volatile storage medium, and the client 2 stores the video content transmitted from the server 1. The client 2 can copy or move the video content transmitted from the server 1 and stored in the internal memory of the main body to the memory card 8.

The television 9 is a video display device such as a digital television, and is connected to the server 1 via, for example, an HDMI cable, a composite signal cable, etc., and presents video and audio output from the server 1.
[2-2. Server configuration]
Next, the configuration of the server 1 will be described in detail. The server 1 includes a controller 11, a flash memory 12, a buffer memory 13, a memory slot 14, a power supply 15, an HD drive 16, a receiving unit 17, a network I / F 18, a tuner 19, and a video output unit. 20 is included.

  The controller 11 operates the memory slot 14, the power supply 15, the HD drive 16, the receiving unit 17, the network I / F 18, the tuner 19, and the video output unit 20 based on a control program held in the flash memory 12 using the buffer memory 13 as a work area. To control the operation of the server 1.

  The flash memory 12 holds a control program necessary for the operation of the controller 11 and information necessary for operation control of the controller 11. In general, the flash memory 12 is a non-volatile memory capable of holding data even when power supply is cut off.

  The buffer memory 13 temporarily holds data necessary for the operation of the controller 11. Normally, a volatile memory such as a DRAM that requires power supply to hold data is used as the buffer memory 13.

  The memory slot 14 reads data from the memory card 6 and writes data to the memory card 6.

  The power supply 15 is a device that supplies power necessary for the operation of the server 1. The power supply 15 is turned on / off under the control of the controller 11.

  The HD drive 16 is a hard disk drive, and stores and reads data under the control of the controller 11.

  The receiving unit 17 receives user operation information from the remote controller 4.

  The network I / F 18 transmits / receives data to / from the network under the control of the controller 11.

  The tuner 19 is a digital tuner that demodulates and decodes the broadcast radio wave received by the antenna 7 and outputs the digital data that can be reproduced by the server 1 to the controller 11.

The video output unit 20 is connected to the television 9 via a video signal cable and superimposes on-air digital broadcast received by the tuner 19 or content playback video stored in the HD drive 16 or a user operation screen as a GUI on the playback video. Output to the TV 9.
[2-3. Client configuration diagram]
Next, the configuration of the client 2 will be described in detail. The client 2 includes a controller 21, a flash memory 22, a buffer memory 23, a memory slot 24, a power supply 25, a button 27, a network I / F 28, and a display device 29.

  The controller 21 controls the operations of the memory slot 24, the power supply 25, the button 27, the network I / F 28, and the display device 29 based on a control program held in the flash memory 22 using the buffer memory 23 as a work area, and controls the operation of the client 2. Control.

  The flash memory 22 holds a control program necessary for the operation of the controller 21 and information necessary for operation control of the controller 21. The video content transmitted from the server 1 is held. In general, the flash memory 22 is a non-volatile memory capable of holding data even when power supply is cut off.

  The buffer memory 23 temporarily holds data necessary for the operation of the controller 21. Usually, a volatile memory such as a DRAM that requires power supply to hold data is used for the buffer memory 23.

  The power supply 25 is a device that supplies power necessary for the operation of the client 2, and performs power supply ON / OFF under the control of the controller 21.

  The button 27 detects user operation information for the client 2. The button 27 is configured as a hardware switch, for example.

  The network I / F 28 transmits / receives data to / from the network under the control of the controller 21.

  The display device 29 presents video content data held in the flash memory 22 to the user under the control of the controller 21. For example, an LCD (Liquid Crystal Display) is used for the display device 29.

The timer 30 is a timer used to activate a predetermined function by transmitting a signal to the controller 21 at a time designated by the user. Usually, the timer 30 is an oscillator using a crystal.
[3. Operation of video content transmission system]
Next, the operation of the still image transmission system will be described.
[3-1. Overall behavior]
When a user uses a video content transmission system, it is necessary to first generate video content on the server 1. In order to generate video content, a digital broadcast received by the antenna 7 connected to the client 2 is recorded, or a video created by an external device such as the digital camera 5 is copied via the memory card 6.

  When recording a digital broadcast, the user operates the remote controller 4 to instruct the server 1 to record a predetermined channel. The server 1 demodulates and decodes the designated channel via the tuner 19 and then stores it in the HD drive 16. In addition to the video content, the server 1 also stores in the HD drive 16 attribute information such as program name, format information, and the number of copies that can be made.

  Next, the user operates the client 2 to copy or move the video content stored in the server 1 to the client 2. A communication sequence performed between the server 1 and the client 2 at this time will be described with reference to FIG.

  The client 2 first requests the server 1 to acquire a list of video contents stored in the server 1 via the network I / F 28 (timing T1).

  The server 1 creates a video content list based on the data stored in the HD drive 16, and transmits it to the client 2 via the network I / F 18 (timing T2). At this time, together with the identifier for specifying the video content, the presence / absence of encryption, the format, the number of times of copying and the automatic transfer flag are included in the content list and transmitted to the client 2.

  The client 2 stores, in the buffer memory 23, the received video content list that can be played back by its own device and that can be transmitted with a copy count other than 0, and displays it on the display device 29 (timing T3). ). While viewing the screen displayed on the display device 29, the user uses the button 27 to select video content as a transmission target. Subsequently, the client 2 determines whether or not the selected content can be transmitted, and determines whether or not the selected content can be transmitted (timing T4). As a result of determining whether or not transmission is possible, if it is determined that transmission is possible, the client 2 acquires video content from the server 1. If the content information acquired from the server 1 is encrypted, the encryption key is exchanged with the server 1 prior to the actual content request (timing T4-2). The client 2 requests the server 1 to transmit the content (timing T5). The server 1 reads the designated video content from the HD drive 16, encrypts the content using the encryption key exchanged at timing T4-2, and transmits it to the client 2 via the network I / F 18 (timing T6). . The client 2 stores the content data received from the server 1 via the network I / F 28 in the flash memory 22 or the memory card 8 while using the decryption key exchanged at timing T4-2.

  If the target video content is subject to copyright protection, a commit process is executed between the server 1 and the client 2 immediately after the transmission ends (timing T7). In the commit processing, the video content transmitted to the client 2 is made available after the number of times that the management information of the server 1 can be copied is decremented by one. Further, in the server 1, when the number of times that copying is possible is 0 as a result of the subtraction process, the content is deleted or cannot be used.

The user of the client 2 operates the button 27, and the client 2 displays the video content list stored in the flash memory 22 or the memory card 8 on the display device 29, and uses the button 27 to select an arbitrary content from the displayed content list. select. Further, the selected content is read from the flash memory 22 or the memory card 8, decrypted by the controller 21, and then displayed and reproduced on the display device 29.
[3-2. Server transmission data creation process]
Next, generation of video content in the server 1 will be described in detail. The user operates the remote controller 4 to select a channel in an arbitrary channel of the digital broadcast received by the antenna 7. The receiving unit 17 transmits channel information designated by an operation from the user to the controller 11. The controller 11 designates a channel to be demodulated and decoded to the tuner 19. The tuner 19 demodulates and decodes the channel specified by the controller 11 and transmits digital data that can be reproduced by the controller 11 to the controller 11.

  Next, the user operates the remote controller 4 to instruct the server 1 to start recording. When receiving the recording start instruction sent from the remote controller 4, the receiving unit 17 transmits the recording start instruction to the controller 11 as a recording start instruction. The controller 11 confirms that the digital data is input from the tuner 19 and then stores the digital data in the HD drive 16. The controller 11 acquires additional information such as program name, video, audio, and system format included in the digital data, and assigns a content ID as management information separately from the digital data and stores it in the HD drive 16 as shown in FIG. To do. Further, when the recording target program is copyright-protected, the number of times that copying is possible is acquired, set in the management information, and stored in the HD drive 16.

  Furthermore, when the client 2 is a mobile device such as a mobile phone, the digital data input from the tuner 19 may not be able to be reproduced in the format as it is due to limitations on resolution or the like. For this reason, the controller 11 stores the digital data converted into a format reproducible by the client 2 together with the original digital data in the HD drive 16.

  During recording, the controller 11 writes the digital data to be recorded into the HD drive 16 at a fixed time interval, for example, 0.5 second interval, and also stores the time length of the program being recorded and the recording position of the HD drive 16 in a buffer memory. 13 is temporarily stored.

  When the recording end time is reached, the user operates the remote controller 4 to instruct the server 1 to end recording. When receiving the recording stop instruction sent from the remote controller 4, the receiving unit 17 transmits the recording stop instruction to the controller 11 as a recording stop instruction. The controller 11 stops the output of the digital data to the HD drive 16 and uses the length of the currently recorded program and the recording position information temporarily stored in the buffer memory 13 as management information of the video content already recorded in the HD drive 16. Record additional.

Next, the attribute setting of the recorded content by user operation will be described. The user operates the remote controller 4 to instruct display of the recorded content list stored in the server 1. When the controller 11 receives the recorded content list display instruction via the receiving unit 17, the controller 11 reads the management information stored in the HD drive 16 and transmits a content list screen to the video output unit 20. The video output unit 20 outputs the content list screen transmitted from the controller 11 to the memory card 8 as video information. Subsequently, the user uses the up / down / left / right keys of the remote controller 4 to specify the content to be operated, and designates attributes for the program. The user performs a protection setting for preventing the selected program from being inadvertently deleted, and when the client 2 performs automatic transfer using a timer or the like, sets whether automatic transfer is to be performed or not. . The program attribute setting is transmitted to the controller 11 via the receiving unit 17. The controller 11 updates the automatic transfer flag and the protect flag of the content management information of the HD drive 16 based on the received attributes.
[3-3. Client transmission target determination process]
The transmission availability determination process at timing T4 will be described in detail with reference to FIG.

  (Step S1) The user selects content to be copied or moved to the client 2 from the video content stored in the server 1 displayed on the display device 29. The user's selection operation is performed by the button 27 and transmitted to the controller 21. The controller 21 receives from the server 1 and reads the attribute information for the content selected from the content list stored in the buffer memory 23.

  (Step S2) The controller 21 checks whether or not the number of possible copies exceeds 1 in the read attribute information. If it exceeds 1, the controller 21 transitions to timing T4-2 to continue the transmission operation.

  (Step S3) When the number of possible copies is 1, the controller 21 displays a warning message as shown in FIG. 2 on the display device 29 to indicate to the user that it will be deleted from the server 1 after moving the video content.

  (Step S4) The user operates the button 27 to determine whether or not to continue the operation.

(Step S5) When the user selects to continue the operation, the controller 21 transitions to timing T4-2. On the other hand, if the user selects transmission cancellation, the process proceeds to step S1 so that the content can be selected again.
[4. Other Embodiments]
Embodiment 1 was illustrated as embodiment of this invention. However, the present invention is not limited to this. Therefore, another embodiment of the present invention will be described below. In addition, this invention is not limited to these, It is applicable also to embodiment modified suitably.
[4-1. Server transmission availability determination process]
In the first embodiment, at timing T6, the server 1 starts content transmission unconditionally in response to a content transmission request from the client 2. However, if protection is set for the content, transmission is performed. The operation may be rejected.

  FIG. 6 is a diagram illustrating one form of the server 1 when the corresponding content is protected.

  In FIG. 6, after receiving the content transmission request transmitted from the client 2 (timing T5), the server 1 executes transmission permission / inhibition determination processing (timing T5-1). The server 1 transmits a response message to the content transmission request to the client 2 according to the result of transmission permission / inhibition determination (timing T6).

  If transmission is not permitted as a result of the transmission permission / inhibition discrimination process (timing T5-1), a negative response is returned (timing T6).

  Next, details of the transmission permission / inhibition determination processing (timing T5-1) will be described with reference to FIG.

  (Step M0) The controller 11 reads from the HD drive 16 the number of possible copies and the protection setting flag from the attribute information of the corresponding content from the content identifier specified by the content transmission request received from the client 2.

  (Step M1) The controller 11 determines whether or not the read copy allowable number is 1 or less and the protection setting is ON.

  If the number of copies is 1 or less and the protect setting is ON, the process proceeds to step M2.

  If the number of copies is 2 or more or the protect setting is OFF, the process proceeds to step M3.

  (Step M2) The controller 11 prepares a negative response as a response message to be transmitted to the client 2.

(Step M3) The controller 11 prepares an affirmative response as a response message to be transmitted to the client 2, and prepares to read the target video content from the HD drive 16.
[4-2. Client automatic transmission processing]
In the first embodiment, the client 2 user selects an arbitrary content from the content list received from the server 1 and then transmits the selected content. However, if the client 2 is a mobile device such as a mobile phone, the contents set automatically transferred by the server 1 at night are transmitted to the client 2 so that the client 2 can be taken out of the house at the next morning commuting. A usage mode of viewing content is conceivable.

  Details of the dynamic transfer process will be described with reference to FIG.

  The client 2 starts an automatic transfer process by transmitting an electrical signal that triggers the timer 30 to the controller 21 at a time preset by the user. The controller 21 that has received the activation trigger from the timer 30 starts the automatic transmission process. The client 2 first requests the server 1 to acquire a list of video contents stored in the server 1 via the network I / F 28 (timing T1). The server 1 creates a video content list based on the data stored in the HD drive 16, and transmits it to the client 2 via the network I / F 18 (timing T2). At this time, together with the identifier for specifying the video content, the presence / absence of encryption, the format, the number of times of copying, and the automatic transfer flag are included in the content list and transmitted to the client 2. The client 2 stores the received video content list that can be played back by its own device and that can be transmitted with a copy count other than 0 as a transmission candidate list in the buffer memory 23 (timing T3). Subsequently, the controller 21 executes a process for each take-out determination process content to determine a content to be transmitted (timing T10).

  If the content information determined to be transmitted at timing T10 is encrypted, the controller 21 exchanges the encryption key with the server 1 prior to the actual content request (timing T4- 2). The client 2 requests the server 1 to transmit the content (timing T5). The server 1 reads the designated video content from the HD drive 16, encrypts the content using the encryption key exchanged at timing T4-2, and transmits it to the client 2 via the network I / F 18 (timing T6). . The client 2 stores the content data received from the server 1 via the network I / F 28 in the flash memory 22 or the memory card 8 while using the decryption key exchanged at timing T4-2.

  If the target video content is subject to copyright protection, a commit process is executed between the server 1 and the client 2 immediately after the transmission ends (timing T7). In the commit processing, the video content transmitted to the client 2 is made available after the number of times that the management information of the server 1 can be copied is decremented by one.

  The controller 21 continues to execute the processes indicated by the timing T4-2, the timing T5, the timing T6, and the timing T7 until the transmission of all the content determined to be the transmission target at the timing T10 is completed.

  The carry-out determination process for each content at timing T10 will be described in detail with reference to FIG.

  (Step N1) The controller 21 acquires content information including attribute information related to one content from the transmission candidate content list stored in the buffer memory 23.

  (Step N2) The controller 21 checks the copyable number of times and the automatic transfer flag in the read content information of the content, and if the copyable number exceeds 1 and the automatic transfer flag is ON, the process proceeds to Step N3. On the other hand, if the number of copies is 1 or the automatic transfer flag is OFF, the process proceeds to step N4.

  (Step N3) The controller 21 records the content read in step N1 in the buffer memory 23 as a transmission target.

(Step N4) The controller 21 confirms the transmission candidate list stored in the buffer memory 23. If the discrimination of all contents has been completed, the controller 21 exits the transmission discrimination process and proceeds to timing T4-2. If there is unidentified content, the process proceeds to step N1.
[5. Summary]
According to the embodiment of the present invention described above, when the video content stored in the server 1 with one copyable number is taken out to the client 2, it is made public including the copyable number of times as attached information of the content, When the number of remaining copies in the client 2 is 1, a warning message is displayed and a user confirmation step is provided, so that content deletion due to an erroneous operation by the user can be prevented in advance.

  The present invention relates to a server device that can communicate with a display device. In particular, the present invention can be applied to a server device that transmits video data (for example, video data) to a display device.

1 Server 2 Client 3 Router 4 Remote Control 5 Digital Camera 6 Memory Card 7 Antenna 8 Memory Card 9 Television 11 Controller 12 Flash Memory 13 Buffer Memory 14 Memory Slot 15 Power Supply 16 HD Drive 17 Receiver 18 Network I / F
19 Tuner 20 Video Output Unit 21 Controller 22 Flash Memory 23 Buffer Memory 24 Memory Slot 25 Power Supply 27 Button 28 Network I / F
29 Display device 30 Timer

Claims (2)

A server device that transmits content data to a client terminal,
Receiving means for receiving a transmission request for content data from the client terminal;
A determination unit that determines that the content data is not transmitted to the client terminal when the permitted number of copies associated with the content data for which the transmission request has been received by the reception unit is 1 and the protection information is protected. And comprising
Server device. A content data transmission method for transmitting content data to a client terminal,
  Accepts content data transmission requests from client terminals,
  If the number of possible copies associated with the content data for which the transmission request has been received is 1 and the protect information is protected, it is determined not to transmit the content data to the client terminal;
  How to send content data.

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