Abstract:
A host device, which may include a DVR, selects to record content on the host device DVR or in a network attached storage (NAS) unit. The recorded content remains bound to the host device from a DRM perspective when it is recorded on the host DVR and on the remotely located NAS. A client device can obtain access to content recorded on the NAS by negotiating DRM rights with the host device instead of the NAS. When access rights are approved, the host device provides access information to the client device so that the content is streamed directly to the client device from the NAS.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 61/239,148 filed on Sep. 2, 2009, titled Network Attached DVR Storage, herein incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    Many consumers record large volumes of audio video (A/V) content, such as television shows on home digital video recording devices (DVRs). DVRs may be included in a set top box (STB) or a stand alone device which is connected to a television signal source, such as an antenna or STB. 
         [0003]    A STB often receives encrypted content from a content provider. The STB decrypts and decodes the content to be provided to a display device, e.g. television. If the user selects to record the content, such as by individual content selection, a scheduled recording or a program series recording, and the STB includes a DVR function, the content may be recorded on the internal disk of the STB or on an external disk attached to that DVR. The content is typically recorded on the DVR in an encrypted form and with established digital rights management (DRM) protocols to ensure that the content is only accessed by the user/STB which requested the recording. 
         [0004]    Many consumers use multiple STBs in a local area network (LAN) connected to multiple televisions within their house. One STB (a client) may be able to access content stored on another (host) STB/DVR using various digital rights management (DRM) protocols. For example an IPRM (IP rights management) protocol may be used. Another exemplary protocol may be DTCP IP protocol associated with OCAP. Another exemplary approach used is a Home Media Architecture (HMA) which is a proprietary transport approach of Motorola, Inc. A key requirement of most DVR storage approaches, that content be playable only by the DVR that recorded it. The typical DRM approach requires the requesting client device to negotiate access with the host device prior to transferring content recorded on the host to the client. Such negotiation typically requires authentication of the client and a key exchange which enables the client to decrypt the encrypted content. The content typically remains encrypted during transport from the host to the client. 
         [0005]    However, despite having more than one digital video recorder (DVR), many consumers still do not have enough storage space for their needs. There is a need to provide additional storage for consumers which is easy to use for consumers, maintains DRM protections of content, and which minimizes bandwidth usage. 
       SUMMARY OF THE INVENTION 
       [0006]    In accordance with the principles of the invention, an apparatus for recording user selected content may comprise: a receiver which receives content from a network; a processing unit which identifies content to be recorded based on instructions from a user, determines digital rights management (DRM) rights to record content and access recorded content, and selects a recording location for recording the content, wherein the processing unit selects to record the content on a local digital video recorder (DVR) or a remotely located network attached server (NAS), and wherein the processing unit provides DRM negotiation for accessing content recorded on both the local DRV and the NAS. 
         [0007]    In the apparatus, the processing unit may be configured to provide access to content stored on the local DVR to the one or more client devices. The processing unit may negotiates access based on DRM rights with a requesting client of the one or more client devices, and provides access to content stored on the NAS to the requesting client based on the negotiation. 
         [0008]    The apparatus may include a network interface which provides communications from a distributed content provider network, and communications with the NAS. The network interface provides communications from one or more client devices and the apparatus is configured to provide access to content stored on the local DVR to the one or more client devices. The client device may be any device on the LAN which is requesting access to the content. The apparatus may be configured to provide access to content stored on the NAS to the one or more client devices. The processing unit may negotiate DRM rights with a requesting client of the one or more client devices, and provide access to content stored on the NAS to the requesting client based on the negotiation, whereby the requesting client does not negotiate DRM rights with the NAS to obtain access to content stored on the NAS. 
         [0009]    In accordance with the principles of the invention, a method of playing back recorded content may comprise the steps of: receiving a request at a DVR capable host device from a client device to access recorded content, the host device and the client device being contained in a local area network (LAN); determining a recording location of the recorded content to be at a network attached storage unit (NAS) within the LAN; performing a DRM dialog between the client device and the host device to obtain access to the recorded content; and providing instructions to the client device to enable the content to be provided to the client device from the NAS without performing a DRM dialog between the client device and the NAS. 
         [0010]    In the method the recorded content on the NAS will be bound to the host DVR device from which it was recorded, located in the LAN. The content may be recorded on the NAS in an encrypted form using a key unique to the content. The host device includes a digital video recording unit (DVR), and the host device negotiates with the client for DRM access rights when the client requests access to content stored on the DVR locally or stored (from the DVR) on to the NAS. 
         [0011]    In accordance with the principles of the invention, a non-transitory computer readable medium may carry instructions for a processor to perform a method of playing back recorded content comprising the steps of: receiving a request at a DVR capable host device from a client device to access recorded content, the host device and the client device being contained in a local area network (LAN); determining a recording location of the recorded content to be at a network attached storage unit (NAS) within the LAN; performing a DRM dialog between the client device and the host device to obtain access to the recorded content; and providing instructions to the client device to enable the content to be provided to the client device from the NAS without performing a DRM dialog between the client device and the NAS. 
         [0012]    A DVR host device, which may include a local disk, selects to record content on the host device disk or forward it to a network attached storage (NAS) unit. The recorded content remains bound to the host device from a DRM perspective when it is recorded on the host disk or on the remotely located NAS. A client device can obtain access to content recorded on the NAS by negotiating DRM rights with the host device instead of the NAS. When access rights are approved, the host device provides access information to the client device so that the content is streamed directly to the client device from the NAS. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Features of the present invention will become apparent to those skilled in the art from the following description with reference to the figures, in which: 
           [0014]      FIG. 1  illustrates an exemplary system architecture in accordance with the principles of the invention. 
           [0015]      FIG. 2  illustrates an exemplary STB architecture in accordance with the principles of the invention. 
           [0016]      FIG. 3  illustrates an exemplary NAS architecture in accordance with the principles of the invention. 
           [0017]      FIG. 4  illustrates an exemplary process flow in accordance with the principles of the invention. 
           [0018]      FIG. 5  illustrates an exemplary signal exchange flow in accordance with the principles of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    For simplicity and illustrative purposes, the present invention is described by referring mainly to exemplary embodiments thereof. In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail to avoid unnecessarily obscuring the present invention. 
         [0020]    In accordance with the invention a NAS solution (Network Attached Storage) may be installed in customer homes to increase their available storage space. The use of a home based NAS also places the storage and security of the storage under the control of the user. Ideally, the NAS may provide a large consumer purchased storage that could hold extra PC files as well as extra DVR video files, subject to DRM rules associated with such. 
         [0021]    One approach may be to modify each DVR so that content could be moved (file transfer) to external storage over the IP home network, then certainly those files could be brought back to be played. If however, the requesting client was in another room, the network bandwidth would be used twice to facilitate the move, once to bring the file back to the DVR, and once to stream it over to the client. Any of the other devices on the home local area network (LAN) may be a client device at any time, and a host device at another time. For example, IP STB  6  may be the client device which is requesting content stored on NAS  10  while STB  2  may be a host device. 
         [0022]    Another approach may be to build a digital rights management (DRM)- enabled NAS, or in this case, an HMA-enabled NAS. For example the content may need to be input to the NAS and identify that device essentially as a form of DVR. That device would need to be modified to support enough hardware security to be robust. Home network bandwidth would be used efficiently, as there would be a single stream from the NAS to the client, but the amount of development could be large. 
         [0023]      FIG. 1  illustrates an implementation in accordance with the principles of the invention. As shown in  FIG. 1 , a network attached storage unit (NAS)  10  may be coupled with a home media network (HMN) (1) contained in the home of a user. The home media network may include multiple set top boxes (STB)  2 ,  4 , an Internet Protocol STB (IP STB)  6 , and a PC client  12 . Each STB, IP STB and PC client may contain DVR capability. Several display devices  8 , such as televisions, may be connected to the STB, IP STB and PC in the home media network. The HMN  1  may be connected to a distributed content provider network system, such as a hybrid fiber coaxial HFC network, IPTV network, switched digital video network, a satellite service provider, etc., through a communications network (not shown). The communications network may include, for instance, a broadband connection to the content provider, such as, over optical fiber, hybrid fiber coaxial cable network, satellite signals, terrestrial signals, wireless, etc. The communications network may also include a cable modem, an integrated services digital network modem, a digital subscriber line modem, etc., that enables the HMN  1  to communicate to the content provider over the communications network. 
         [0024]      FIG. 2  illustrates an exemplary STB arrangement in accordance with the principles of the invention. As shown in  FIG. 2 , the STB  2  may include a network interface  22  which includes a home network data interface, such as Ethernet, and an optional receiver unit (not shown) which may receive QAM data, such as audio and video (A/V) content from a network through network interface  22 . A decoder  24  may decode the received content to be provided to a display through output  26 . STB  2  may also include a user input  29 , such as an infrared input to receive commands from a user. The STB may include a processor  23  for controlling the operation of the STB. The STB may include a DVR  25  for storing content. The STB may include a DVR  25  and may include a disk for storing content. 
         [0025]    The STB may be configured to receive the content in an encrypted form and in an encoding standard, which may be received from a content provider. The encrypted content may comprise media content, such as, network television programs, pay-per-view movies, pay-per-view events, video on demand, video file downloads, audio files, etc., from the content provider through the communications network. The encrypted content is protected using a DRM system. More particularly, the processor  23  preferably includes a DRM manager  30  configured to provide DRM protection for the content. For example, the DRM manager  30  may comprise a copy control information (CCI) manager configured to enforce content rights for the encrypted content. This may include determining content rights for the encrypted content from a rights data file, and then performing an action on the content in compliance with the rights. For example, the DRM manager  30  may determine whether the content rights include a right to transfer before transferring the content to another device. Each rights data file may include content rights, cryptographic key parameters, such as encryption/decryption methods, key types, key seeds, and a content ID. The content ID is a unique identifier of the content. Examples of the content rights include right to copy the content, right to transcode the content, right to play the content, right to move or transfer the content to a third party device, use on certain classed of devices, etc. 
         [0026]    The DVR functionality and optional data storage  25  may include a hard drive or other non-volatile data storage storing video and/or other data. The memory  21  may include RAM. The optional memory in  25  and memory  21  are examples of computer readable storage devices that may store computer code executed by the processor  23  to perform various functions described herein. The encrypted content may be stored in the data storage  25 . This may include programs from a MPEG stream. 
         [0027]    In one example, the processor  23  may include a DRM manager module  30  which implements a DRM system. DRM systems are known in the art and typically include software that imposes limitations on usage of the content determined, which may be set by the content provider, such as copying or content transfer limitations or other content limitations. The STB  2  thus contains hardware and/or software configured to decrypt the encrypted content for playback and/or storage on the memory in DVR function  25 . For example, the encrypted content may be protected by a DRM system in the service provider&#39;s head-end and delivered to the STB  2  in that encryption format. Thereafter, the STB  2  may perform all DRM operations without accessing an external license server. In a conventional DRM system, a device may be required to get approval or a license from an external license server each time a new class of action, such as a new copy or a transfer to a new device, is needed. According to an embodiment, the content rights for a broad class of DRM actions may be retrieved one time and stored in the STB so a connection to an external license server is not continually required. According to another embodiment, the DVR function may process rules embedded in the received content flow, and originate DRM protection of the video and rules. (examples: IPRM and HMA protection). The STB  2  may issue the access rights for content to other devices in the home network without be approved to an external license server. 
         [0028]      FIG. 3  illustrates an exemplary architecture for a NAS unit  10 . As shown, an exemplary NAS  10  preferably contains an input/output port for connection to the network for connection to the other devices on the HMN  1 . Those of skill in the art will appreciate that NAS  10  may be connected to a number of STBs or PCs service within the HMN. NAS  10  preferably contains a processor  33  which controls the operation, such as access to NAS  10 , connected on a bus  36 . A storage unit  37 , such as a hard disc drive or other types of non-volatile recording devices capable of recording A/V content. A data conditioning unit  35  may also be included which conditions or modifies transport packages for content received from the network to a suitable transport protocol for transport to a client device to be compatible with requirements of the client device, such as HTTP and/or DLNA. In one implementation, NAS  10  may receive content with a first transport protocol, such as HMA by Motorola, and provide content to clients with a second transport protocol, different from the first. The client may provide instructions identifying a preferred transport protocol, or a preferred protocol may be determined by NAS  10  based on information received from the client. 
         [0029]    In a preferred implementation, NAS  10  receives content which was encrypted by a host device with a DVR function (e.g. STB  2 ) and records the content in encrypted form. The STB  2 , or IP STB  6 , or PC  12  all may provide content to NAS  10 , and serve as a host device for providing content. The NAS preferably does not decrypt the received content, but stores the content in its received encrypted form. In doing so, the NAS  10  is not required to perform security protocols and the content remains secure by use of the encryption of the host (e.g. STB  2 ). The content also remains bound to the host while stored on NAS  10  such that the content remains under the protection of the DRM protocols of the host. The host (e.g. STB  2 ) preferably generates a unique key for the host which may be used as a common encryption key for all content, or another individual key may be generated for each piece of content a unique key for each piece of content. The latter may enable less robust clients like the PC to access content. In either case, the content is stored on the NAS  10  in the form in which it was encrypted by the host, e.g. STB  2 . Note that clients that require DTCP-IP link security bring an additional complexity factor in, as the NAS must re-encrypt under the DTCP-IP protocol after decryption of the underlying content. 
         [0030]      FIG. 4  illustrates an exemplary process in accordance with the principles of the invention. As illustrated, a DVR host, such as STB  2 , receives a request to record content from a user, step S 1 . The STB may optionally determine if the content should be recorded on the local disk of DVR  25  or on NAS  10  and record the content in step S 5 . In one implementation, the host may first record all content on its local DVR  25 , and move the content to NAS  10 . Such move may be performed by a user instruction or may be automatically performed based on a number of factors, such as remaining capacity of the storage space of local DVR  25  (e.g. 85% full may trigger a move), age of content on the local DVR, frequency of accessing the content (e.g. content which is accessed less frequently may trigger a move). The move may be performed during an inactive period of the STB, such as when other processing or content delivery is being performed. In any case, the host preferably may maintain a database of the content which is moved and display the listing of the content to a user as if it were located on the local DVR. In a preferred implementation, the storage location of the content may not be easily perceptible to the user. Content movement to the NAS will consume network resources during the transfer, so stream management may be desired in some implementations so as not to interfere with actual home network streaming, which should have priority. In a preferred implementation the transport of content to and from NAS  10  is done in a manner which promotes efficient use of the home network, that is, there is no duplicate bandwidth usage for any video flow. 
         [0031]    When a play request is received from a client, step S 7 , the host and client negotiate access to the content according to a predetermined set of rules and DRM rights, such as the HMA key management dialog in step S 9 . In step S 11  the STB determines the location of the content, and if the content is locally stored on the local DVR disk, provides the content to the client from the DVR in step S 19 . If the content is stored on NAS  10 , the STB provides instructions to the client to access the NAS  10 , such as providing an IP address for NAS  10  along with DRM and authentication messages, step S 13 . As shown in step S 15 , the client requests the content from NAS  10  and NAS  10  provides the content to the client, step S 17 . When any client in the home network desires to access content stored on the NAS  10  from the host, it completes the DRM (e.g. HMA or IPRM) key management dialog with host, but then is directed to the NAS, such as being directed to the IP address of the NAS for the content. The NAS preferably understands the transport protocol and flow control of the home network, but it would not have to implement any security or robustness. That is, the invention may provide access to content stored on the NAS  10  by a host device to a client device without the NAS  10  managing DRM rights, while preserving the DRM rights via the host device. 
         [0032]      FIG. 5  illustrates an exemplary signal flow between a host, client  203 , and NAS  10 . As shown, STB DVR function encrypts the content for storage, and forwards or moves the selected content on NAS  10  in message  401 , which illustrates the message to record. Client requests to access or play the content in message  403 . The STB and client negotiate access, such as through a DRM key management dialog in messages  405 . Once access is negotiated, the STB provides access instructions to the client in message  407 . The client requests access to the content stored on NAS  10  in message  409 . The content is provided to the client in message  411 . 
         [0033]    In the preferred implementation each STB/DVR continues to manage the content it recorded or moved to the NAS as its own recorded bound content. In this manner the STB/ DVR may move stored video content to the NAS  10  as needed, but retain the DRM content rights data internal to the STB/DVR. The content rights may include management of access rights to record, distribute and playback content. 
         [0034]    In one implementation, the NAS may store PC data as well as A/V DVR content. In this implementation, two different types of networks may be required. For example, PC&#39;s often expect home networks with DHCP support, while the DVRs may expect the network to have static IP addresses, assigned by default or by the HMA protocol. PC data may be accommodated by using conditioning unit  35  to modify protocols received, such as the HMA protocol, or having the consumer check that the DHCP assigned addresses does not conflict with current DVR IP address usage. 
         [0035]    Some or all of the operations set forth in  FIGS. 2-5  may be contained as a utility, program, or subprogram, in any desired computer readable storage medium. In addition, the operations may be embodied by computer programs, which can exist in a variety of forms both active and inactive. For example, they may exist as software program(s) comprised of program instructions in source code, object code, executable code or other formats. Any of the above may be embodied on a computer readable storage medium, which include storage devices. 
         [0036]    Exemplary computer readable storage media include conventional computer system RAM, ROM, EPROM, EEPROM, and magnetic or optical disks or tapes. Concrete examples of the foregoing include distribution of the programs on a CD ROM or via Internet download. It is therefore to be understood that any electronic device capable of executing the above-described functions may perform those functions enumerated above. 
         [0037]    Although described specifically throughout the entirety of the instant disclosure, representative embodiments of the present invention have utility over a wide range of applications, and the above discussion is not intended and should not be construed to be limiting, but is offered as an illustrative discussion of aspects of the invention. 
         [0038]    What has been described and illustrated herein are embodiments of the invention along with some of their variations. The terms, descriptions and figures used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that many variations are possible within the spirit and scope of the embodiments of the invention.