JP5051290B2 - Content playback apparatus and content playback method - Google Patents

Description

The present invention relates to a receiving apparatus and a receiving method for acquiring, storing and using digital contents such as video and audio by downloading.

In recent years, digital broadcasting using satellites or terrestrial waves has become popular. In addition, transmission of digital content data such as video and audio via a broadband home communication network has been used.

In these services, in general, video and audio content is compressed by a method such as MPEG and transmitted in the form of a stream or file, and the receiving apparatus decompresses it with a decoder and reproduces it. When the receiving device has a storage function, the received content can be stored and played back later when necessary.

In addition, in the case of services that provide video and audio content for a fee, the content may be encrypted, and when the content is read from the storage function and played back, separately acquired key information is used. To decrypt and play (for example,
Patent Document 1).

JP 2003-174439 A

Patent Document 1 does not specifically mention the acquisition timing of key information. However, when the content encryption key information is given to the user by downloading before the content data is downloaded, such as immediately after the content purchase procedure, the content data There was no consideration of the possibility of unauthorized viewing by pretending that the download was interrupted. For this problem, this risk can be avoided by passing the key information after the download of the content data is completed.
Also, in the system that acquires the key information after the download is completed by the above method, if it is desired to start the reproduction after the download of the content data before the download is completed, the reproduction cannot be performed because there is no key information. There's a problem.

An object of the present invention is to provide a safe service for content distributors by determining procedures for downloading content data and downloading key information, and providing a method capable of starting playback before content data download is completed This is to provide a user-friendly technology to the user.

The object can be achieved by the configuration described in the claims as an example.

According to the present invention, when downloading content, it is confirmed that downloading of encrypted content data has been completed and then the encryption key information is downloaded, thereby eliminating the possibility of unauthorized use. Can do.

Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to the illustrated example.

When playing back video by downloading, as shown in FIG.
From 0, the receiving apparatus 10 downloads the content data and key information via the IP network 200. In FIG. 6, the server that distributes the content data and the key information is the same. However, a server that distributes the key information may be provided separately from the server that distributes the content data.

FIG. 1 shows an example of a functional block diagram of a receiving apparatus to which the present invention is applied. The receiving device 10 connected to the communication line 1 includes a communication line interface 2, a storage control unit 3, a storage unit 4,
A descrambling unit 5, a decoder 6, an output device 7, a CPU 8, and an input control unit 9 are provided.

When content is downloaded from the communication line 1 through the communication line interface 2 and the user selects the content from a menu such as a home page of a service that provides the content and performs purchase accounting processing, the content including encrypted video and audio The data is downloaded from the communication line 1 through the communication line interface 2. In addition, a download control metafile describing the download method is also downloaded from the communication line interface 2.

The accumulation control unit 3 is connected to the communication line interface 2 and accumulates data such as contents and key information downloaded via the communication line interface 2 in the accumulation unit 4.

  The storage unit 4 is configured by a storage medium that can store downloaded content, such as an HDD or an optical disk. Connected to the accumulation control unit 3, content data including encrypted video and audio output from the accumulation control unit 3 and key information for decrypting the content data are accumulated. Yes.

The descrambling unit 5 decrypts the encrypted content output from the storage unit 4 using the encryption key output from the storage unit 4.

When the user instructs the reproduction of the content through the input control unit 9 by a remote controller (not shown) or the like, the CPU 8 reads the content data and the encryption key information from the storage unit 4,
The content data is input to the descrambling unit 5 to be decrypted and sent to the display device 7 through the decoder 6 for reproduction.

FIG. 2 is a flowchart showing the above operation. When the content is purchased through the download service (S1), the receiving device 10 acquires a download control metafile describing the download method (S2), and the CPU 8 starts downloading the content data accordingly (S2). S3). Thereafter, when the CPU 8 confirms that the download is completed (S4), the key information is acquired through the communication line (S5). This completes the download of the content data and key information. Thereafter, when the user scans a remote controller (not shown) and instructs the reproduction of the content downloaded from the input control unit 9 (S6), the reproduction is started using the stored content data and key information (S7). .

As described above, according to the invention according to the present embodiment, it is possible to realize a highly secure method of downloading key information after downloading of content data is completed.

In other words, you can download the encrypted content using a paid service,
When storing in the storage unit 4, when downloading of content data is started, the download is normally completed as it is, and the content data is stored in the storage unit 4. However, there may be a case where downloading to the end is impossible due to a line, a terminal, a user, or the like. As a case where the download is not completed to the end, there is a line abnormality or the like, but there are also a case where the download is interrupted due to the user's reversion or a malicious obstruction to sending a download completion notification to the distribution side.

In general, when a content purchase process is performed, the user has the right to view the content. Therefore, it is conceivable that the key information is downloaded to the receiving device 10 at that time, and then download of the content data is started. , If the delivery completion notification is interrupted to the delivery side as described above, this content has not been downloaded,
When viewing contracts such as 5 per month, there is a risk that viewing may be performed illegally from the already obtained key information.

In order to improve the security on the distributor side against such an illegal act, it is effective to download the encryption key information to the receiver after confirming the completion of the download of the content data.

Next, Example 2 will be described. A description of the same elements as those described in the first embodiment is omitted. In the second embodiment, the case of progressive download will be described. In general, progressive download starts downloading content data, and when a certain amount of data has been accumulated for a while, while continuing to download the content data, The reproduction can be started from the beginning of the accumulated content. According to such a method, it is possible to shorten the waiting time of the user for downloading.

FIG. 4 is a graph comparing the operation in the normal download method and the operation in the progressive download method.

FIG. 4A is a graph showing a temporal relationship between the download and the reproduction operation in the normal download method. The vertical axis of the graph represents the data amount of content to be downloaded, and the horizontal axis represents time. TD0 indicates the download start time, and TD1 indicates the download completion time. TP0 indicates the start of generation, and TP1 indicates the end of reproduction.

In the graph of FIG. 4 (a), when the download is started from TD0, the amount of downloaded data gradually increases, and the download is completed at TD1. At this point, 100% of the content is stored in the storage unit 4. It will be. Thereafter, playback is started at TP0, and playback is completed at TP1. As shown in FIG. 4A, the graph 45 and the graph 46 do not overlap on the time axis, and reproduction cannot be performed during downloading in the normal download method. Note that the slopes of the graphs 45 and 46 in FIG. 4A are not limited to those shown in FIG. 4A, and differ depending on the data download speed and the playback speed. The same applies to FIG. 4B.

Next, FIG. 4B is a graph showing a temporal relationship between download and playback operation in the progressive download method. In FIG. 4B, TD0, TD1, TP0, and TP1 are the same as in FIG. 4A.

As shown in FIG. 4B, when download is started from TD0, playback is started from TP0 before TD1 where the download is completed. Playback continues after TD1 when the download is completed, and playback is completed at TP1. By overlapping download and playback in this way, playback can be started earlier, and the total time can be shortened.

In the following, in the second embodiment where progressive download is employed, the CPU 8 obtains key information from the server when a content reproduction instruction is input from the user to the input control unit 9. However, the CPU 8
When a content playback instruction is input to the input control unit 9, the current download data amount and download data speed are compared with the playback speed of the playback data, and key information is acquired only when TD1 is faster than TP1. Can be charged. The current download data amount and the download data rate are compared with the playback rate of the playback data. If TD1 is slower than TP1, playback cannot be performed correctly, and the CPU 8 does not request the server to obtain key information.

If no content playback instruction is input to the input control unit 9 during downloading, the CPU
No. 8, after confirming the completion of the download of the content data, the key information is downloaded and acquired from the server.

The CPU 8 acquires key information from the server and stores it in the storage unit 4 when the user instructs acquisition of key information through the input control unit 9 using a remote controller (not shown) or the like.

  The present embodiment will be described below with reference to the flowchart shown in FIG.

When content is purchased through the download service (S11), the receiving apparatus 10 acquires a download control metafile (S12), and starts downloading content data accordingly (S13). After that, when the download is completed normally (S14), key information is acquired through the communication line (S15). This completes the download of the content data and key information. Thereafter, when the user instructs the reproduction of the content (S16)
Playback is started (S17).

After the download of content data is started (S13) and before the download is completed, if the user gives a reproduction instruction (S18), the data amount of the content that has already been accumulated is confirmed, and at this rate If the download is continued, it is determined that reproduction can be performed to the end of the content, assuming that reproduction is started from the beginning in parallel (S19). Specifically, the current download data amount, the download data rate and the playback rate of the playback data are compared and calculated to determine whether TD1 is faster than TP1.

If the stored data amount is insufficient and if it is determined that the content has not been downloaded and cannot be played to the end when the playback is predicted to end at the current playback speed, the display device 7 is informed. A message is displayed and notified to the user, and a reproduction start instruction is prompted later (S20). If the amount of data already stored is sufficient, the content download has been completed when playback is expected to end at the current playback speed, and if it is determined that playback is possible to the end, the encryption key information is received next. It is confirmed whether or not it has been acquired by the device 10 (S21). If the key information has not been acquired, the key information is acquired through the communication line (S22),
As a result, the reproduction of the content can be started (S17). When the progressive download method is adopted, when the user instructs the reproduction even during the download, if there is no key information in the receiving apparatus 10, this is performed. Since it is possible to add a process for acquiring the information via the communication line, it can be reproduced.

As described above, according to the invention of this embodiment, encrypted video and audio content is downloaded from a communication line and stored, and reproduced using separately downloaded key information. In addition, it is possible to realize an easy-to-use receiving apparatus capable of progressive download. As a result, it is possible to promote the provision of high-quality content and enable a new content service business.

Also, according to the invention according to the present embodiment, when the user gives an instruction to start playback before the download of the content data is completed, by obtaining the key information at that time, it is possible to improve both security and convenience. Can be secured.

In other words, by defining the procedures for downloading content data and acquiring key information, it is possible to eliminate unauthorized use of content and enable content providers to provide high-quality content. It is possible to provide an easy-to-use system that can also be used for playback on the Internet.

In the receiving apparatus 10, it is assumed that both content data and key information are acquired from a communication line. However, in the broadcast receiving apparatus 60, content data is acquired from other media such as broadcast waves. The key information may be obtained from a communication line.

Further, in this embodiment, it is confirmed whether or not there is key information in the receiving apparatus, and reproduction is performed when there is key information, but when an expiration date is set in the key information, When the reproduction is started, the expiration date of the key information is confirmed and compared with the current date and time. When the expiration date has expired, new key information is acquired again via the communication line. Accordingly, it is possible to properly reproduce the content while keeping the expiration date of the key information.

Although the first embodiment and the second embodiment have been described using a simple receiving device, the present invention can also be applied to a receiving device configured as a broadcast receiving device. As a configuration of the broadcast receiving device, for example, as shown in FIG. 5, a broadcast receiving device 60 configured by adding a tuner 52 and a demodulator 53 to 1 to 9 which are components of the receiving device 10 shown in FIG. 1. Can be given.

In the broadcast receiving device 60, the broadcast wave 51 is input to the tuner 52, converted into a transport stream by the demodulation unit 53, and input to the accumulation control unit 3. After that, when the data is stored in the storage unit 4 or without being stored, the data is directly played back on the display device 7 through the descrambling unit 5 and the decoder 6.
The above-described problem can be solved by the following configuration, for example.
In order to solve the above-described problem, for example, in a receiving device, an interface unit that downloads content data encrypted from a communication line and key information for decrypting the content data, and the content downloaded from the interface unit A storage unit that stores data and the key information; and a control unit that decrypts the content data output from the storage unit using the key information, wherein the control unit converts the key information into the content It is configured to download after all the data has been downloaded.
The above-described embodiments disclose at least the following.
(1)
An interface unit for downloading content data encrypted from a communication line and key information for decrypting the content data;
A storage unit that stores the content data downloaded from the interface unit and the key information;
A control unit that decrypts the content data output from the storage unit using the key information;
A receiving device comprising:
The control unit downloads the key information after all the content data has been downloaded.
(2)
An input control unit to which an instruction is input from the user;
An interface unit for downloading content data encrypted from a communication line and key information for decrypting the content data;
A storage unit that stores the content data downloaded from the interface unit and the key information;
A control unit capable of decrypting the content data output from the storage unit using the key information even during downloading of the content data;
A receiving device comprising:
The control unit downloads the key information when a content data reproduction instruction is input to the input control unit, and reproduces the content data using the downloaded key information. .
(3)
(2) The control unit downloads the key information when the download of the content data is finished and the key information is not stored in the storage unit. Receiver device.
(4)
Even when an instruction to reproduce the downloaded content data is input to the input control unit, the control unit is provided with an expiration date for the downloaded key information, and when the reproduction is instructed, the expiration date is used. (2) or (3), wherein the key information for decrypting the downloaded content is downloaded again.
(5)
A content data download step for downloading content in response to a content download instruction signal;
A key information acquisition command acquisition step for acquiring a key information acquisition command;
If there is a content playback command during the content download, all content data is downloaded based on the content data download speed, content data playback speed, and content data download amount at the time of content playback command acquisition. A reproducibility determination step for determining whether or not the reproduction of the content data ends after the point in time,
A key for downloading key information for decrypting the content in response to a key information acquisition command when it is determined in the reproducibility determining step that the reproduction of the content data is finished after the time when all the content data is downloaded An information acquisition step;
A receiving method comprising:
(6)
When the key information acquired in the key information acquisition step has an expiration date, and the expiration date has passed at the time of receiving the content data reproduction instruction, the downloaded content is decrypted. (5) The reception method according to (5), further comprising a key information reacquisition step of downloading key information for the purpose again.

It is a block diagram which shows the structure of the receiver which concerns on this invention. 6 is a flowchart illustrating an operation of download processing according to the first exemplary embodiment. 10 is a flowchart illustrating an operation of progressive download processing according to the second embodiment. It is a graph which shows the comparison of operation | movement of normal download and progressive download. It is a block diagram which shows the structure of the broadcast receiver which concerns on this invention. 1 is an example of a network configuration to which the present invention is applied.

DESCRIPTION OF SYMBOLS 1 ... Communication line, 2 ... Communication line interface, 3 ... Storage control part, 4 ... Storage part, 5 ... Decryption part, 6 ... Decoder, 7 ... Display apparatus, 8 ... CPU, 9 ... Input control part, 10 ... Reception Device, 4
5 ... Download data amount, 46 ... Reproduction data amount, 51 ... Broadcast wave, 52 ... Tuner, 53
... demodulator, broadcast receiver ... 60, 100 ... server, 200 ... IP network

Claims (4)

A content playback device that downloads and plays back content data,
The content data is data encrypted with one key information,
A receiving unit that downloads the content data encrypted with the key information and obtains the key information for decrypting the content data encrypted with the key information;
A storage unit that stores the content data encrypted with the downloaded key information;
A decryption unit that decrypts the encryption of the content data encrypted with the stored key information using the key information;
An input unit for receiving a playback instruction;
A control unit for controlling the receiving unit and the decoding unit;
The control state of the control unit is:
Wherein acquiring the key information after all the download completes the content data encrypted by key information, the key information in the first to be reproduced by decoding the encrypted the contents data encrypted State and
Before downloading the content data encrypted with the key information, when the input unit accepts the reproduction instruction during downloading of the content data encrypted with the key information, before the download of all the content data encrypted with the key information is completed. Whether or not the key information has been acquired. If the key information has not been acquired, the key information is acquired and stored in the content reproduction device, and the stored key information is used to store the key information. If the information has been acquired, the content data encrypted using the key information before the download of all the content data encrypted using the key information is completed using the acquired key information the encryption and a second state to be reproduced are sequentially decoded starting from the beginning of the content data, the content reproduction apparatus. A content playback method in a content playback device for downloading and playing back content data,
Download the content data encrypted with one key information,
Obtaining the key information for decrypting the content data encrypted with the key information;
Storing the content data encrypted with the downloaded key information;
Decrypting the encryption of the content data encrypted with the stored key information using the key information;
Wherein acquiring the key information after all the download completes the content data encrypted by key information, the key information in the first to be reproduced by decoding the encrypted the contents data encrypted State and
When a reproduction instruction is received during downloading of the content data encrypted with the key information, the key information is stored before all of the content data encrypted with the key information is downloaded. It is determined whether or not the key information has been acquired. If the key information has not been acquired, the key information is acquired and stored in the content playback device, and the key information is acquired using the stored key information. using already acquired the key information if any, the key information in an encrypted encryption of the content data that has been encrypted with the key information prior to all of the download of the content data are to complete the content and a second state in which reproduction are sequentially decoded starting from the beginning of the data, a content reproduction method. A content transmission / reception system including a content transmission device and a content reproduction device, wherein the content transmission device includes:
A transmission unit that distributes content data encrypted with one key information;
A receiving unit that downloads the content data encrypted with the key information and obtains the key information for decrypting the content data encrypted with the key information;
A storage unit that stores the content data encrypted with the downloaded key information;
A decryption unit that decrypts the encryption of the content data encrypted with the stored key information using the key information;
An input unit for receiving a playback instruction;
A control unit for controlling the receiving unit and the decoding unit;
The control state of the control unit of the content reproduction device is obtained by acquiring the key information after all the downloads of the content data encrypted with the key information are completed, and encrypting with the key information. a first state to be reproduced by decoding the encrypted content data,
Before downloading the content data encrypted with the key information, when the input unit accepts the reproduction instruction during downloading of the content data encrypted with the key information, before the download of all the content data encrypted with the key information is completed. Whether or not the key information has been acquired. If the key information has not been acquired, the key information is acquired and stored in the content reproduction device, and the stored key information is used to store the key information. If the information has been acquired, the content data encrypted using the key information before the download of all the content data encrypted using the key information is completed using the acquired key information second comprising state and the contents transmitting and receiving system for reproducing encryption are sequentially decoded starting from the beginning of the content data. A content transmission / reception method,
Deliver content data encrypted with one key information,
Download the content data encrypted with the key information,
Obtaining the key information for decrypting the content data encrypted with the key information;
Storing the content data encrypted with the downloaded key information;
Decrypting the encryption of the content data encrypted with the stored key information using the key information;
Wherein acquiring the key information after all the download completes the content data encrypted by key information, the key information in the first to be reproduced by decoding the encrypted the contents data encrypted State and
When a reproduction instruction is received during downloading of the content data encrypted with the key information, the key information is stored before all of the content data encrypted with the key information is downloaded. It is determined whether or not the key information has been acquired. If the key information has not been acquired, the key information is acquired and stored in the content playback device, and the key information is acquired using the stored key information. using already acquired the key information if any, the key information in an encrypted encryption of the content data that has been encrypted with the key information prior to all of the download of the content data are to complete the content and a second state in which reproduction are sequentially decoded starting from the beginning of the data, the content receiving method.

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