Electrical computers and digital processing systems: memory – Storage accessing and control – Control technique
Reexamination Certificate
2000-06-30
2003-06-24
Ellis, Kevin L. (Department: 2186)
Electrical computers and digital processing systems: memory
Storage accessing and control
Control technique
Reexamination Certificate
active
06584552
ABSTRACT:
This application is a U.S. national phase application of PCT international application PCT/JP99/06000.
TECHNICAL FIELD
The present invention relates to a recording and reproducing apparatus in the case where EMI information of an AV data is added to the AV data, a recording and reproducing apparatus in the case where copy right information of an AV data is added to the AV data, and a caching apparatus which handles a copyrighted data in the case where plural apparatuses are connected, a transmitting apparatus, and a program recording medium.
BACKGROUND ART
Demands for a home multimedia system and a home network are rapidly rising in the wave of digitization. In an office and a business system, needs for digitization and a multimedia system are rising at a higher degree than those in a home system. In such a situation, recently, attention is given to IEEE 1394-1995. This is a standard for a high speed serial bus which was standardized by IEEE in 1995 while focusing on a physical layer and a link layer, and also a hardware and software standard for data transfer of 100 Mbps, 200 Mbps, and 400 Mbps. IEEE 1394 has characteristic functions for plug and play and multimedia data transfer. Specifically, it is provided with isochrpnous data transfer in which a band for transferring data such as a video or audio data is ensured to enable real time transfer. Furthermore, a control program of a PC connected through an IEEE 1394 bus can simultaneously perform controls of video data of a digital camera or the like (switching of video data, and a control of the camera) by means of IEEE 1394 control commands (asynchronous data).
When a digital AV data flowing through IEEE 1394-1995 which is a standard as described above is to be recorded in a recording and reproducing apparatus, it is conventionally judged whether the data is an AV data which can be copied or not, based on a CGMS (Copy Generation Management System) which is embedded into a stream.
A CGMS exists in a transport stream which is sent from a broadcasting station. A CGMS is a 2-bit data. A CGMS takes the following values, and the meanings of the values are as follows.
Namely, when CGMS=11, it means “copy never”; when CGMS=10, it means “copy one generation”; and, when CGMS=00, it means “copy free.” There is no CGMS=01. In the above, “copy never” means copy inhibit, and permits only viewing or listening of the AV data, “copy one generation” permits only a copy of one generation, or allows a copied AV data to be repeatedly viewed or listened any number of times, and “copy free” means that the data can be freely copied.
A DVC which records and reproduces a DV stream among digital AV data flowing through IEEE 1394-1995 has a DV stream decoder, extracts a CGMS from a predetermined position of the stream, and judges whether a copy is permitted or not. If CGMS=11 or “copy never,” recording of the AV data is not performed. In an apparatus having a configuration in which no internal decoder is disposed, only recording and reproduction of a data are performed, and decoding of an AV data is committed to an external decoder, such as a DVHS, an HDD, or a DVD-RAM which records and reproduces an MPEG2 transport stream, a transport stream decoder circuit or the like is necessary for detecting a CGMS, and hence the hardware configuration is complicated.
In a digital broadcast stream using an MPEG2 transport stream, particularly, the place where a CGMS is to be embedded is varied depending on the service provider. In many cases, such a place is not made public. Even when a transport stream decoder circuit is provided, therefore, a CGMS cannot be sometimes detected.
On the other hand, when signal information for sending copy right information (hereinafter, referred to as EMI) is added into a header of an IEEE 1394 packet data, hardware such as a transport stream decoder circuit is not necessary.
EMI takes the following values. Namely, when EMI=11, it means “copy never”; when EMI=10, it means “copy one generation”; and, when EMI=00, it means “copy free.” Furthermore, when EMI=01, it means “no more copy.” In the above, “copy never” means copy inhibit, and permits only viewing or listening of the AV data, “copy one generation” permits only a copy of one generation, or allows a copied AV data to be repeatedly viewed or listened any number of times, and “copy free” means that the data can be freely copied. Moreover, “no more copy” means an AV data after copying an AV data of “copy one generation,” or prohibition of further copying.
In IEEE 1394, such EMI is used for designating a method of encryption, and that of authentication. In “copy free” in the case of EMI=00, for example, encryption is not performed in transmission of an AV data. In “copy one generation” in the case of EMI=10 and “no more copy” in the case of EMI=11, a key used in encryption, and a method of authenticating an apparatus are different from those in “copy never” in the case of EMI=11.
EMI is produced from a CGMS by an STB (Set Top Box: a satellite broadcasting receiver). Namely, a CGMS is added to a data in a broadcasting station, and an STB which receives a broadcast wave transmitted from the broadcasting station sends a received program to an IEEE 1394 bus. At this time, the CGMS is embedded into a portion of service information of an MPEG2 transport stream of an isochronous packet data. In one isochronous packet data, plural MPEG data are stored, and corresponding CGMSs exist for the MPEG data, respectively.
EMI is produced from such a CGMS by the STB. The STB checks a CGMS of each data of the MPEG2 transport stream received from the broadcasting wave [sic; broadcasting station], and, as its typical value, gives one EMI to one isochronous packet data. The EMI is held in a header portion of the isochronous packet data.
The value of the EMI is equal to that of a CGMS in which the copyright is most severely restricted, among CGMSs of data existing in data of the received MPEG2 transport stream. When CGMSs of data in data of the received MPEG2 transport stream are 11, 10, and 10, for example, the value of the EMI is 11 in which the restriction is most severe. When CGMSs are 10, 10, 00, and 00, the value of the EMI is 10 in which the restriction is most severe, among them. In this way, the value of EMI is determined.
Conventionally, when a CGMS indicates that the contents of a copyright are “copy never,” the corresponding data can be viewed or listened only once, but the time zone when viewing or listening is allowed is limited to that when the program is broadcast. In the case where the author intends to permit only one time of viewing or listening, therefore, also the time zone when viewing or listening is allowed is limited. In other words, even when a user wishes to view or listen a program in a time zone convenient for the user, the user is allowed to view or listen the program, only in the time zone when the program is broadcast. In the case where a CGMS indicates that the contents of a copyright are “copy one generation,” when a data is once recorded onto a certain recording medium, the data cannot be thereafter moved into another recording medium.
In the case where an apparatus is configured so as not to have a transport decoder, the contents of a copyright are judged by using EMI. The same process as in the case of a CGMS applies also to the case of using EMI.
Conventionally, EMI added to the header of an IEEE 1394 packet data is deleted together with the header of the packet data when an AV data is output into a recording apparatus. Therefore, EMI is not recorded into the recording apparatus. This causes a problem in that, when an AV data is to be output, it is impossible to judge the contents of a copy right of the AV data, and which key and authentication method are to be used.
Even when EMI is recorded onto a recording medium by any method, there is a problem in that the user can tamper with the recorded EMI to modify the terms of the copy right.
In consideration of the prob
Goto Shoichi
Iitsuka Hiroyuki
Kuno Yoshiki
Nishimura Takuya
Takechi Hideaki
Ellis Kevin L.
Matsushita Electric - Industrial Co., Ltd.
RatnerPrestia
LandOfFree
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