CONTENT RECEIVING DEVICE, CONTENT REPRODUCING DEVICE, CONTENT RECEIVING AND REPRODUCING DEVICE, CONTENT RECEIVING METHOD, AND PROGRAM

• US 20120288091A1
• Filed: 11/29/2010
• Published: 11/15/2012
• Est. Priority Date: 12/14/2009
• Status: Active Grant

• Current Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Original Assignee: Sumitomo Electric Networks, Inc. (Sumitomo Corporation)
• Inventors: Matsuda, Yoshinori, Honke, Yuusuke, Uemachi, Shinya
• Granted Patent: US 8,848,911 B2
• Time in Patent Office: Days
• US Class Current: 380/210
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 9/065 Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 21/23476 by partially encrypting, e.g. encrypting the ending portion of a movie
• CPC Class Codes: H04N 21/23605 Creation or processing of packetized elementary streams [PES]
• CPC Class Codes: H04N 21/4343 Extraction or processing of packetized elementary streams [PES]
• CPC Class Codes: H04N 21/44055 by partially decrypting, e.g. decrypting a video stream that has been partially encrypted
• CPC Class Codes: H04N 5/783 Adaptations for reproducing at a rate different from the recording rate
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection
• CPC Class Codes: H04N 9/8042 involving data reduction
• CPC Class Codes: H04N 9/8205 involving the multiplexing of an additional signal and the colour video signal

Abstract

Provided is a content receiving device that can reduce processing loads at a time when an encrypted stream is decrypted. A video recording and reproducing device 5 includes: a receiving section 20 that receives a video stream in which data of a content containing video is divided into a plurality of TS packets; an extraction section 23 that extracts from the video stream, in a case where the video stream received by the receiving section 20 is an encrypted stream, a scramble key for decrypting the encrypted stream; a decryption section 24 that decrypts, by using the scramble key, only a specific packet among the plurality of TS packets; and an obtaining section 25 that obtains predetermined information of the video stream, based on data decrypted by the decryption section 24.

Claims

1. A content receiving device comprising:

a receiving section that receives a stream in which data of a content containing video is divided into a plurality of packets;

an extraction section that extracts, in a case where the stream received by the receiving section is an encrypted stream, a key for decrypting the encrypted stream from the stream;

a first decryption section that decrypts, by using the key, only a specific packet among the plurality of packets; and

an obtaining section that obtains predetermined information of the stream, based on data decrypted by the first decryption section.

2. The content receiving device according to claim 1, further comprising:

an encryption section that encrypts the key extracted by the extraction section, by using a unique key of the content receiving device, wherein

the encrypted stream containing the key encrypted by the encryption section is recorded in a recording section.

3. The content receiving device according to claim 2, wherein

the content receiving device is connected to a predetermined local network,

the content receiving device further comprises:

a second decryption section that decrypts, by using the key, the encrypted stream recorded in the recording section;

a creation section that creates a new stream that suits the local network, based on the stream decrypted by the second decryption section; and

a transmission section that transmits the new stream created by the creation section toward another apparatus through the local network, and

the creation section includes

a table processing section that creates a new PMT that suits the local network, based on a PMT (Program Map Table) contained in the encrypted stream recorded in the recording section.

4. The content receiving device according to claim 3, further comprising:

a selection section that selects, in a case where contents of a plurality of channels are contained in the stream received by the receiving section, a content of one channel from among the contents of the plurality of channels, wherein

only the encrypted stream that corresponds to the content of the channel selected by the selection section, among the contents of the plurality of channels, is recorded in the recording section.

5. The content receiving device according to claim 4, further comprising:

a table processing section that creates, based on a PAT (Program Association Table) contained in the stream received by the receiving section, a new PAT that corresponds only to the content of the channel selected by the selection section among the contents of the plurality of channels, wherein

the new PAT is recorded in the recording section.

6. The content receiving device according to claim 1, further comprising:

an encryption section that encrypts, in a case where the stream received by the receiving section is a non-encrypted stream, the non-encrypted stream by using the unique key of the content receiving device, wherein

the stream encrypted by the encryption section is recorded in the recording section.

7. The content receiving device according to claim 1, further comprising:

a creation section that creates a reference file to be referred to when special reproduction of the content is performed, wherein

the first decryption section decrypts, as the specific packet, a predetermined packet containing a predetermined type of picture to be used in the special reproduction of the content, and

the obtaining section obtains, as the predetermined information, time information added to the predetermined packet and information indicating a position of the predetermined type of picture in the stream, and

regarding the predetermined packet, the creation section creates, based on the time information, elapsed-time information indicating an elapsed time from the beginning of the content, and causes the elapsed-time information and the information indicating the position of the predetermined type of picture in the stream to be included in the reference file.

8. The content receiving device according to claim 7, wherein

the predetermined packet contains a first predetermined packet to which first time information is added, and a second predetermined packet, which follows the first predetermined packet, and to which second time information is added, and

the creation section

creates, regarding the first predetermined packet, first elapsed-time information based on the first time information,

creates, regarding the second predetermined packet, second elapsed-time information based on the second time information, and

creates, when a difference between a value of the first time information and a value of the second time information is greater than or equal to a predetermined threshold due to a packet loss, the first elapsed-time information and the second elapsed-time information that are continuous to each other.

9. The content receiving device according to claim 7, wherein

in a case where the stream received by the receiving section is an encrypted stream, the creation section causes information indicating a position of the key in the stream to be included in the reference file.

10. The content receiving device according to claim 7, wherein

in a case where the stream received by the receiving section contains viewing limitation information for the content, the creation section causes information indicating a position of the viewing limitation information in the stream to be included in the reference file.

11. The content receiving device according to claim 7, wherein

in a case where the stream received by the receiving section contains duplication limitation information for the content, the creation section causes information indicating a position of the duplication limitation information in the stream to be included in the reference file.

12. The content receiving device according to claim 7, wherein

the creation section causes information indicating a position of a PAT (Program Association Table) in the stream to be included in the reference file.

13. The content receiving device according to claim 1, wherein

in a case where a compression method whereby one PES (Packetized Elementary Stream) contains one type of picture is employed as a compression method for the stream, the first decryption section decrypts only a packet located at the beginning among a plurality of packets constituting a PES.

14. The content receiving device according to claim 1, wherein

in a case where a compression method that allows one PES (Packetized Elementary Stream) to contain a plurality of types of pictures is employed as the compression method for the stream, the first decryption section sequentially performs decryption, starting from a packet located at the beginning of a plurality of packets constituting a PES, and ends the decryption for the PES upon detecting a predetermined end position.

15. The content receiving device according to claim 1, further comprising:

a detection section that detects a compression method for the stream received by the receiving section; and

a control section that controls the decryption performed by the first decryption section, based on a result of the detection performed by the detection section, wherein

under control by the control section, the first decryption section

decrypts, in a case where a compression method whereby one PES (Packetized Elementary Stream) contains one type of picture is employed as the compression method for the stream, only a packet located at the beginning of a plurality of packets constituting a PES, and

sequentially performs decryption, in a case where a compression method that allows one PES to contain a plurality of types of pictures is employed as the compression method for the stream, starting from a packet located at the beginning of a plurality of packets constituting a PES, and ends the decryption for the PES upon detecting a predetermined end position.

19. A content receiving and reproducing device comprising:

the content receiving device according to claim 1.

16. A content receiving device, comprising:

a receiving section that receives a stream in which data of a content containing video is divided into a plurality of packets;

a decryption section that decrypts, among the plurality of packets, a predetermined packet containing a predetermined type of picture to be used in special reproduction of the content;

an obtaining section that obtains, based on data decrypted by the decryption section, time information added to the predetermined packet and information indicating a position of the predetermined type of picture in the stream; and

a creation section that creates a reference file to be referred to when special reproduction of the content is performed, wherein

regarding the predetermined packet, the creation section creates, based on the time information, elapsed-time information indicating an elapsed time from the beginning of the content, and causes the elapsed-time information and the information indicating the position of the predetermined type of picture in the stream to be included in the reference file.

17. A content reproducing device comprising:

a reproduction section that reproduces, based on a stream of data of a content containing video, the stream read from a recording section in which a predetermined reference file and the stream are recorded, wherein

the reference file contains elapsed-time information indicating an elapsed time from the beginning of the content and information indicating a position of a predetermined type of picture in the stream, and

the reproduction section performs special reproduction of the content by use of the predetermined type of picture, by referring to the reference file.

18. The content reproducing device according to claim 17, wherein

the reproduction section performs, based on the elapsed-time information, the special reproduction of the content by using a plurality of the predetermined type of pictures located at approximately equal time intervals.

20. A content receiving method comprising the steps of:

(A) receiving a stream in which a content containing video is divided into a plurality of packets;

(B) extracting, in a case where the stream received in the step (A) is an encrypted stream, a key for decrypting the encrypted stream from the stream;

(C) decrypting, by using the key, only a specific packet among the plurality of packets; and

(D) obtaining predetermined information of the stream, based on data decrypted in the step (C).

21. A program for causing a computer included in a content receiving device to function as:

receiving means for receiving a stream in which data of a content containing video is divided into a plurality of packets;

extraction means for extracting, in a case where the stream received by the receiving means is an encrypted stream, a key for decrypting the encrypted stream from the stream;

decryption means for decrypting, by using the key, only a specific packet among the plurality of packets; and

obtaining means for obtaining predetermined information of the stream, based on data decrypted by the decryption means.