Electronic device and content transfer method

An embodiment of the present invention relates to a content transfer technique for transferring content for which copyright protection is required via a transmission line such as a LAN (Local area network).

In recent years, electronic devices such as personal computers and smartphones that can handle digitized video and audio have become widespread. This type of electronic device is generally equipped with a data communication function, and can transmit and receive so-called AV (Audio and visual) content to and from other electronic devices.

On the other hand, there are many AV contents that require copyright protection, such as restrictions on copying. Therefore, various mechanisms for transmitting and receiving AV content between a plurality of electronic devices have been proposed while protecting the copyright.

<p><patcit num="1"><text>Japanese Unexamined Patent Publication No. 2009-71786</text></patcit></p>

<p> As a method for protecting the copyright of video, for example, HDCP (High-bandwidth digital content protection system) is known. Further, as a method for protecting the copyright of audio, for example, SCMS (Serial copy management system) is known. HDCP is a method that involves encryption of copyright-protected data, and SCMS is a method that does not involve encryption of copyright-protected data. Therefore, although the purpose of copyright protection is common between the video and audio contained in one AV content, one is required to be encrypted, while the other is not required to be encrypted. It is possible that the degree of measures required for copyright protection may differ.</p><p> By the way, until now, only one copyright protection method has been applied when sending one AV content to one transmission line, and when sending one AV content to one transmission line, there are a plurality of copyrights. The application of rights protection schemes is not considered at all. Therefore, for example, it is necessary to perform the encryption required for the video even for the audio that is not required until the encryption. However, doing so causes unnecessary cost increases such as installing a module for encrypting / decrypting audio (which is not originally necessary) on both the transmitting side and the receiving side electronic devices of the AV content.</p><p> An object of the present invention is to provide an electronic device and a content transfer method that realize a content transfer function for which copyright protection is required at low cost.</p>

<p> According to the embodiment, the electronic device applies the first copyright protection method involving encryption of the data subject to copyright protection to the copyright protection of the first data, and works for the copyright protection of the second data. A content transfer means for transmitting the content including the first data and the second data to one transmission line by applying a second copyright protection method that does not involve encryption of the data subject to rights protection is provided. To do.</p>

<figref num="1">The figure which shows the system structure of the copyright protection content transfer system which concerns on 1st Embodiment.</figref><figref num="2">The flowchart which shows the operation procedure of the content transmitter side of the copyright protection content transfer system of 1st Embodiment.</figref><figref num="3">The flowchart which shows the procedure of the video encoding processing executed by the content transmitter of the copyright protection content transfer system of 1st Embodiment.</figref><figref num="4">The flowchart which shows the procedure of the audio encoding processing executed by the content transmitter of the copyright protection content transfer system of 1st Embodiment.</figref><figref num="5">The flowchart which shows the operation procedure of the content receiver side of the copyright protection content transfer system of 1st Embodiment.</figref><figref num="6">The flowchart which shows the procedure of the video decoding process executed by the content receiver of the copyright protection content transfer system of 1st Embodiment.</figref><figref num="7">The flowchart which shows the procedure of the audio decoding process executed by the content receiver of the copyright protection content transfer system of 1st Embodiment.</figref><figref num="8">The figure which shows the functional block of the transfer function of the copyright-protected content mounted on the content transmitter of the copyright-protected content transfer system of 1st Embodiment.</figref><figref num="9">The figure which shows the system structure of the copyright protection content transfer system which concerns on 2nd Embodiment.</figref><figref num="10">The figure which shows the functional block of the transfer function of the copyright-protected content mounted on the content transmitter of the copyright-protected content transfer system of 2nd Embodiment.</figref>

Hereinafter, embodiments will be described with reference to the drawings.

(First Embodiment) First, the first embodiment will be described.

FIG. 1 is a diagram showing a system configuration of a copyright-protected content transfer system according to the present embodiment.

As shown in FIG. 1, the copyright-protected content transfer system of the present embodiment includes a content transmitter 1, a content receiver 2, and an audio player 3. The content transmitter 1 and the content receiver 2 are connected by, for example, an IEEE 802.11 standard wireless LAN (Wi-Fi), and the content receiver 2 and the voice player 3 are connected, for example, S / It shall be connected by PDIF.

The content transmitter 1 is, for example, a PC (Personal computer), encodes content (video output to a display or the like and audio output to a speaker or the like), and then transmits the content (video output to a display or the like and audio output to a speaker or the like) to the content receiver 2 via Wi-Fi.

The content receiver 2 is, for example, a television receiver, decodes the (encoded) content received from the content transmitter 1, and displays an image on the screen. After this decoding, the audio is output from the audio player 3 via the speaker built in the content receiver 2 or S / PDIF.

The data format of the content transferred between the content transmitter 1 and the content receiver 2 is, for example, the MPEG2-TS format, and the transfer protocol is, for example, RTP (Real-time transport protocol). The copyright-protected content transfer system of the present embodiment has, for example, HDCP (High-bandwidth digital content protection system) 2.0 or the relevant copyright protection method (first copyright protection method) for protecting the video ES. The successor standard of HDCP2.0 is applied, and SCMS (Serial copy management system) is applied as a copyright protection method (second copyright protection method) for protecting voice ES. That is, the copyright-protected content transfer system of the present embodiment applies a plurality of copyright protection methods to the one content when transferring one content through one transmission line.

First, referring to FIG. 2, the procedure from the content transmitter 1 transmitting the video and audio to the content receiver 2 reproducing the video and audio in the copyright-protected content transfer system of the present embodiment. Of these, the operation on the content transmitter 1 side will be described.

When the content transfer application (program) is started by a user operation after the power of the content transmitter 1 is turned on, the content transmitter 1 attempts to connect to the content receiver 2 via Wi-Fi. When the connection with the content receiver 2 is established (block A1), the content transmitter 1 performs authentication and key exchange processing according to HDCP 2.0 with the content receiver 2 (block A2). ). As a result, a part of the encryption key and initial vector (IV) for video ES when transferring copyright-protected content (content that requires copyright protection) r_ivIs determined.

The content transmitter 1 starts encoding the video output to the display or the like and the audio output to the speaker or the like (block A3). The details of the video encoding process and the audio encoding process will be described later with reference to FIGS. 4 and 5. For example, when the content with copyright protection written on the DVD is being played by a DVD player application or the like (YES in block A4), the content transmitter 1 turns on the CP (Copy protection) flag as a judgment of the presence or absence of copyright protection. (Block A5). In addition, since it is assumed here that the content to be transferred is played back by the content transmitter 1, the played content is re-encoded and transferred to the content receiver 2, the DVD is played back for simplification. Although the CP flag ON / OFF is judged by the presence / absence, the copyright protection information embedded in the DVD itself may be added to the judgment criteria.

Immediately after starting the content transfer application, if the CP flag is switched from ON to OFF, or if the CP flag is switched from OFF to ON (YES in block A6), the content transmitter 1 is set to the video ES, Generate a PMT (Program map table) that describes the PID of the voice ES (block A7), and when the CP flag is ON (YES in block A8), insert the registration_descriptor specified in HDCP 2.0 into the PMT. (Block A9). The content transmitter 1 inserts the MPEG2-TS packet including the generated PMT into the content data to be transferred to the content receiver 2. The PMT may be generated at regular intervals such as every second and inserted into the content data in order to confirm the stream information on the content receiver 2 side. The PMT generated at this time is the same data unless the CP flag is switched.

Subsequently, the content transmitter 1 generates MPEG2-TS format content data by MUX (multiplexing) processing using the PES format content data generated by the video encoding and audio encoding described later (block A10). , Send to content receiver 2 by RTP (block A11). The content transmitter 1 sequentially repeats the above operations while the content transfer application is running.

FIG. 3 is a flowchart showing the procedure of video encoding processing.

The content transmitter 1 first encodes the video output to the display or the like in the PES format according to a codec such as H.264 (block B1).

If the CP flag is ON (YES in block B2), the content transmitter 1 determines the inputCtr and streamCtr specified in HDCP2.0, which are part of the initial vector, and is also specified in HDCP2.0. Generate PES_private_data (block B3). Next, the content transmitter 1 has the determined inputCtr and streamCtr, and a part of the encryption key and the initial vector generated by the key exchange process (block A2)._ivIn combination with, the encryption key and initial vector are set (block B4). The content transmitter 1 encrypts the PES payload by the AES-CTR method adopted in HDCP 2.0 (block B5), and inserts the generated PES_private_data into the PES header (block B6). Then, the content transmitter 1 outputs the generated video PES to the MUX (block B7). The content transmitter 1 sequentially repeats the above operations while the content transfer application is running.

FIG. 4 is a flowchart showing the procedure of the audio encoding process.

The content transmitter 1 first encodes the sound output to the speaker or the like in the PES format according to a codec such as AAC (block C1). The content transmitter 1 outputs the generated audio PES to the MUX (block C2). The content transmitter 1 sequentially repeats the above operations while the content transfer application is running.

In the above procedure, the audio PES is not encrypted, but if it is connected by the WPA method or the like at the time of Wi-Fi connection, the transmission path is encrypted and the content data is transferred. That is, in this case, the entire content data in the MPEG2-TS format including the audio ES is encrypted.

Next, referring to FIG. 5, the procedure from the content transmitter 1 transmitting the video and audio to the content receiver 2 reproducing the video and audio in the copyright-protected content transfer system of the present embodiment. Of these, the operation on the content receiver 2 side will be described.

After the power of the content receiver 2 is turned on, when the content transfer mode is switched by the user operation, the content receiver 2 waits for the connection from the content transmitter 1 via Wi-Fi. When the connection request is received from the content transmitter and the connection with the content transmitter 1 is established (block D1), the content receiver 2 is authenticated and keyed with the content transmitter 1 according to HDCP 2.0. Perform the exchange process (block D2). As a result, a part of the decryption key and initial vector for video ES when transferring copyright-protected content r_ivIs determined.

Content receiver 2 begins decoding video and audio (block D3). The details of the video decoding process and the audio decoding process will be described later with reference to FIGS. 6 and 7.

The content receiver 2 receives the content data transferred from the content transmitter 1 by RTP (block D4) and analyzes the PMT (block D5). If registration_descriptor is included in the PMT (YES in block D6), content receiver 2 sets the CP flag to ON (block D7), while CP is not included (NO in block D6). Set the flag to OFF (block D8). The content receiver 2 filters MPEG2-TS packets using the stream information obtained by analyzing the PMT, and DEMUX (separates) the video ES and audio ES from the content data (block D9). The content receiver 2 sequentially repeats the above operation during content transfer from the content transmitter 1.

FIG. 6 is a flowchart showing the procedure of video decoding processing.

When the video ES is input by DEMUX (block E1), the content receiver 2 parses the PES header (block E2). When the CP flag is ON and PES_private_tag is included (YES in block E3), the content receiver 2 acquires PES_private_data (block E4) and the decryption key for video ES generated by the key exchange process. And part of the initial vector r_ivIs combined to set the decryption key and the initial vector (block E5). Then, the content receiver 2 decrypts the encrypted PES payload by the AES-CTR method (block E6).

Subsequently, the content receiver 2 decodes the content data in the PES format (block E7) and outputs the video to the display or the like (block E8). The content receiver 2 sequentially repeats the above operation during content transfer from the content transmitter 1.

FIG. 7 is a flowchart showing the procedure of the audio decoding process.

When voice ES is input by DEMUX (block F1), the content receiver 2 sets "copy prohibited" as the copy control information of SCMS when the CD flag is ON (YES in block F2) (block). F3) On the other hand, if the CP flag is OFF (NO in block F2), set "copy possible" as the copy control information of SCMS (block F4). That is, the copyright-protected content transfer system of the present embodiment is defined by HDCP 2.0, which is the first copyright protection method applied to the copyright protection of the video (to notify the presence or absence of the copyright protection of the video). )Registration_descriptor is also used as information for notifying the presence or absence of copyright protection of audio to which SCMS, which is the second copyright protection method, is applied.

Subsequently, the content receiver 2 decodes the content data in PES format (block F5) and outputs it to the audio player 3 together with the set copy control information (block F6). The content receiver 2 sequentially repeats the above operation during content transfer from the content transmitter 1.

The audio player 3 outputs the audio data received from the content receiver 2 to a speaker or the like, and performs audio copy control according to the copy control information received from the content receiver 2.

As described above, the copyright-protected content transfer system of the present embodiment applies a plurality of copyright protection methods to one content. As illustrated in the above explanation, when HDCP2.0 is applied to the copyright protection of the video and SCMS is applied to the copyright protection of the audio, the condition that the video encryption is required on the content transmitter 1 side. Below, as shown in FIG. 8, the module (12b) for encrypting / decrypting voice can be eliminated. Similarly, on the content receiver 2 side, it is possible to eliminate the need for a module for encrypting / decrypting voice. That is, the copyright-protected content transfer system of the present embodiment realizes a copyright-protected content transfer function at low cost.

In the above explanation, an example of using the presence or absence of registration_descriptor specified in HDCP 2.0 (applied to video) as audio copy control (applying SCMS) is shown, but the content transmitter 1 side Copy control is performed by communication using RTSP (Real time streaming protocol), etc., when the CP flag is switched from ON to OFF or when the CP flag is switched from OFF to ON immediately after the content transfer application is started. Information may be notified from the content transmitter 1 to the content receiver 2. The content receiver 2 switches the copy control information to be output to the audio player 3 according to the received copy control information.

In addition, although the copy control information is treated as either "copy prohibited" or "copy allowed" here, there are cases where "only one generation can be copied" depending on the content to be played on the content transmitter 1 side. Conceivable.

(Second Embodiment) Next, the second embodiment will be described.

FIG. 9 is a diagram showing a system configuration of the copyright protected content transfer system according to the present embodiment.

The difference from the first embodiment described above is that the transfer destination device for the video and audio from the content transmitter 1 is separated. As shown in FIG. 9, in the copyright-protected content transfer system of the present embodiment, the content transmitter 1 transfers video to the first content receiver 2a and audio to the second content receiver 2b. The first content receiver 2a is, for example, a television receiver, and the second content receiver 2b is, for example, an AV amplifier, as in the first embodiment.

The operation of the content transmitter 1 in the present embodiment is basically the same as the operation of the content transmitter 1 in the first embodiment, except for the following points.

(a) Establish a connection between the first content receiver 2a and the second content receiver 2b, respectively. (b) HDCP 2.0 authentication / key exchange processing is not required with the second content receiver 2b. (c) Content to be transferred to the first content receiver 2a and content data to be transferred to the second content receiver 2b are generated in MPEG2-TS format, respectively, and the content to be transferred to the first content receiver 2a. The data should include only the video ES as the ES, and the content data to be transferred to the second content receiver 2b should include only the audio ES as the ES. Further, the operation of both the first content receiver 2a and the second content receiver 2b in the present embodiment is basically the same as the operation of the content receiver 2 in the first embodiment, but the first The difference is that the content receiver 2a of the above outputs only video and the second content receiver 2b outputs only audio.

Also in the copyright-protected content transfer system of the present embodiment, in which the transfer destination of the video and audio from the content transmitter 1 is separated into the first content receiver 2a and the second content receiver 2b, 1 By applying multiple copyright protection methods to one content, as shown in Fig. 10, the content transmitter 1 side can eliminate the need for a module (12b) for encrypting / decrypting voice. it can. Content data containing only video ES as ES and content data containing only audio ES as ES can be generated, for example, by providing a switch 14 for supplying either video or audio to the multiplexing module (MUX) 13. .. The switch 14 may be drive-controllable to supply both video and audio to the multiplexing module (MUX) 13.

Further, the first content receiver 2a can also eliminate the need for a module for encrypting / decrypting voice. Further, on the second content receiver 2b side, the existence of the encryption / decryption module itself can be eliminated. That is, the copyright-protected content transfer system of the present embodiment also realizes the copyright-protected content transfer function at low cost.

Notification of copy control information about voice from the content transmitter 1 to the second content receiver 2b is performed by including registration_descriptor in the PMT of the content data transferred from the content transmitter 1 to the second content receiver 2b. It may be performed by communication by RTSP or the like.

When the registration_descriptor is included in the PMT, the second content receiver 2b turns on the CP flag when the PMT contains the registration_descriptor and turns off the CP flag when the PMT does not include the registration_descriptor. When voice ES is input by DEMUX, the second content receiver 2b is "copy prohibited" as SCMS copy control information when the CP flag is ON, and as SCMS copy control information when the CP flag is OFF. Set "Copy is possible".

On the other hand, in the case of communication by RTSP or the like, the second content receiver 2b switches the copy control according to the copy control information received from the content transmitter 1.

Here, the content transmitter 1 transfers the content data including only the video ES as the ES to the first content receiver 2a, and transfers the content data including only the video ES to the second content receiver 2b as the ES. An example of transferring content data containing only audio ES has been shown, but the present invention is not limited to this, and video ES and audio ES as ES for both the first content receiver 2a and the second content receiver 2b. The same content data including the above may be transferred by multicast. That is, each of the first content receiver 2a and the second content receiver 2b may select ES. In any case, the content transmitter 1 transmits the video ES and the audio ES from one communication module such as a Wi-Fi module to the outside.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

1 ... content transmitter, 2 ... content receiver, 2a ... first content receiver, 2b ... second content receiver, 3 ... audio player.