Abstract:
A method and apparatus for transferring protected digital AV content. The apparatus  10  includes a specially adapted microprocessor  12  with firmware allowing the microprocessor to control and transmit for storage and for display device  14  digital AV content data in the form of digital signals. A source storage device is connected to the microprocessor  12  by means of link  26.  At least one sink storage device  20  is also connected to microprocessor  12  by link  28.  The firmware allows the microprocessor to time the amount of material transferred to sink  20  to that allowed by the appropriate copy protection specification. The method limits the amount of data transferred to the programmed amount for example one second slices ending on a frame end. After each increment of data is transferred the amount remaining on source  16  is deleted. The process continues until all of the desired material is transferred from source  16  to sink  20.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    This invention relates generally to digital video and audio reproduction systems such as those used for home entertainment, and particularly to an apparatus and method for moving copy-protected content from one storage device to another. 
         [0003]    2. Background Art 
         [0004]    Video and audio entertainment content, comprising audiovisual (AV) objects such as movies, video programs, pictures, and music, is protected by copyright law and generally distributed with a limited use license. Formerly, some degree of security against copyright violation was afforded by the practical difficulty of making good copies, but now, content is produced and handled in the form of digital signals, which can be perfectly copied. Thus copy protection (also known as content protection), for example according to the Digital Transmission Content Protection (DTCP) specification known in the art, has become an important link in the distribution chain of commercial AV content to end users. In the current art, digital AV content is transmitted to the user over several different commercial distribution channels including cable, satellite, television (TV) and radio broadcast, short range wireless link, internet connection, and also delivered on prerecorded disks and other media. Many consumers want to store this content and move it between storage devices such as hard disk drives (HDDs), digital video disk (DVD) recorders (DVRs), flash drives, and the like, rather than use it when received, for greater convenience and accommodation of personal preferences about when to watch a movie or listen to music, and how to organize one&#39;s collection of AV objects, and on what type of media. For AV objects that have a copy protection status of “copy-no-more” according to the DTCP specification, the user can have only one (archival) copy of the object and another copy is not licensed to be made. However, conventional techniques of moving an AV object can create a temporary or even a permanent second copy of the object being moved, and in some systems, a nearly complete second copy can be obtained by powering down just before the end of a move. Thus there is a need for an apparatus and method to move digital AV content from one storage device to another that avoids making a copy, in compliance with the DTCP “copy-no-more” specification. 
       SUMMARY OF INVENTION 
       [0005]    The invention provides an apparatus and method to move protected AV content from one storage device (for example an HDD) to another storage device (for example another HDD), in compliance with DTCP “copy-no-more” specification, with a second copy limited to a one-second slice of the content bit stream at any time during the move, and with simple and convenient user control. 
         [0006]    The apparatus includes a specially adapted microprocessor with firmware allowing the microprocessor to control, i.e., to store, read, erase (delete), and transmit for storage and for display and operatively in cooperation with conventional driver circuits and programs of instructions of the source storage device digital AV content data in the form of digital signals for example according to the known IEC 61883 and 1394TA AV/C standards, to and from other AV devices. The firmware allows the microprocessor to time the amount of material transferred to specification. 
         [0007]    The method limits the amount of data transferred to the programmed amount, for example one second slices ending on a frame end. After each increment of data is transferred the amount remaining on the source is deleted. The process continues until all of the desired material is transferred. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0008]      FIG. 1  is a block diagram of an audiovisual system to which the present invention is applied; 
           [0009]      FIG. 2  is a schematic diagram of the data structure of the digital AV content being moved, showing frames and segments of content in a portion of storage space on a source storage device, superposed with corresponding 1 sec time intervals; 
           [0010]      FIG. 3  is a flow diagram of an embodiment of the method of moving protected content, according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]      FIG. 1  is a block diagram of an audiovisual system to which the first embodiment of the present invention is directed. The audiovisual (AV) system  10  includes a move processor  12  for moving protected AV content according to the invention. The AV system  10  also includes a digital television (TV) device  14 , a source storage device  16  (with included move processor  12 ), an attached user-accessible manual actuator  18 , a plurality of sink storage devices  20 ,  22 ,  24 , and interconnecting links  26 ,  28 ,  30 ,  32  over which control and AV content signals can be transmitted between the devices. Source storage device  16  may be a Hard Disk Drive (HDD) but also could be an equivalent. It will be apparent to those familiar with the art that other types of storage devices, other than HDDs, could alternatively be employed for this invention, for example flash drives, optical disk recorders such as DVRs and CDRs, card storage devices, and the like. Source storage device  16  is shown in  FIG. 1  to be a separate device that is externally connected to TV  14 , but it can alternatively be a subsystem component disposed inside the TV cabinet, with the manual actuator  18  remaining externally accessible to the user, for example on the control panel of TV  14 . In this embodiment, the IEEE 1394 (herein referred to as “1394”) serial bus known in the art, which has been adopted as the High Definition Audio-Video Network Alliance (HANA) standard connection interface for AV device communication and control, can be used for the interconnecting links. Alternatively, other known interconnection means including for example Ethernet, Universal Serial Bus (USB), and 155 Mb/s ATM can be employed. 
         [0012]    In the  FIG. 1  embodiment move processor  12  comprises digital circuits and a firmware program of instructions stored in ROM which can be provided in the form of physical subsystem components, and alternatively in the form of a virtual subsystem with appropriate operational capability implemented in circuits and components having also other functionality, within source storage device  16 , including also actuator  18 , which are adapted to control, i.e., to store, read, erase (delete), and transmit for storage and for display and operatively in cooperation with conventional driver circuits and programs of instructions of the source storage device  16 , digital AV content data in the form of digital signals for example according to the known IEC 61883 and 1394TA AV/C standards, to and from other AV devices. It is understood that appropriate control circuits in storage devices  16 ,  20 ,  22 ,  24  and TV  14  can interact with each other to implement links  26 ,  28 ,  30 ,  32  and the data transmission as required in moving AV content. The program of instructions can be implemented in a known computer language, for example C. 
         [0013]    Operation of move processor  12  according to the method of the invention may be understood with reference to  FIG. 2 , showing the data structure of an example of digital AV content that can be stored and moved, and also with reference to  FIG. 3  depicting a flow diagram of an embodiment of the move method. Digital AV content can be stored on a storage device, for example source device  16 , as a sequence of frames  42  of an AV content object, such as a movie, with each frame comprising a sequence of data bits, and alternatively a stack of data words. Frames generally have different lengths in time depending on the details of the content, and the compression employed.  FIG. 2  shows a portion  40  of data storage space on source storage device  16 , comprising a sequence of frames F 0 , F 1 , F 2 , F 3 , F 4 , F 5 , and F 6 , which represent a portion of an exemplary AV object. AV content is moved, according to the invention, for example to a sink device  20 , in consecutive approximately 1-second segments comprising a plurality of complete frames. It should be noted that the 1-second segment length is illustrative, and in alternate embodiments the segment can be shorter than 1 second, or longer than 1 second, as long as it is an insignificant portion of the AV object being moved, in terms of DTCP compliance. The example storage space portion  40  is shown in  FIG. 2  to comprise three segments S 0 , S 1 , S 2 , and the time direction of the data is indicated by time arrow  44 . Owing to the variable length of frames in time, the number of frames in a segment is not fixed. When the last complete frame of a segment is copied (read from source storage device  16  and transmitted) to sink device  20 , that segment is deleted (erased) from source device  16 , and copying of the next segment begins. A fixed 1-second timer implemented in the move processor  12 , is used to identify the last full frame to be copied, by setting a last-frame-of-segment (LFS) flag at fixed 1-second time intervals, and thus also the next frame, which becomes the first frame of the next segment to be copied. The timer can be implemented in the form of a firmware program of instructions in move processor  12 . The 1-second time points  46  generally fall within a frame, but copying, and deletion, starts at the beginning of a frame and stops at the end of another frame. Accordingly, for example, if frame F 1  is being moved and a 1-sec time point falls in that frame (or at the end of that frame), the LFS flag will be set, and F 1  will be identified as the last frame of segment S 0  and F 2  as the first frame of segment S 1 , as shown in  FIG. 2 . Thus at time point  48  at the end of frame F 1 , move processor  12  will stop copying the sequence of data bits, delete all prior stored content data of the AV object being moved, i.e., all frames of S 0  up to the end of F 1 , clear the LSF flag, and start copying segment S 1  at the beginning of frame F 2 . If the next 1-sec time point falls in frame F 4 , move processor  12  will operate in a like manner at time point  50  at the end of frame F 4  to stop copying, delete prior stored content, i.e., frames F 2 , F 3 , and F 4 , and start copying segment S 2  at the beginning of frame F 5 . It will be apparent that at the end of a complete move, all prior stored content on the source device will be deleted. Thus move processor  12  operates, according to the inventive method, to read content data from a source storage device and to transmit it and store it on a sink storage device, one 1-second segment at a time, and to delete previous segments of the source copy continually during the move. At the end of moving an AV content object, all prior stored content has been erased, and during a move there is no time at which a temporary second copy exists that represents more than 1 second of content length in time. 
         [0014]    A flow diagram of the move method of the invention is depicted in  FIG. 3 , showing a sequence of steps  60  of an embodiment of the method. Performance of the method starts with a user command step  62  in which a digital AV content object on the source device HDD  16 , and a target sink device to which the object will be moved, are identified, and which will be presently described in further detail hereinbelow. In the next step  64  a 1-second fixed interval timer is started, which continues in loop step  66  until the end of an interval, when a new 1-second interval is started by branching back to step  64  and also in the next step  68  the LFS flag described hereinabove is set. In parallel with the timer, and at the same time as step  64 , copying of the content from source to sink starts in step  70 , from the beginning of the first frame of the identified digital AV object, and continues serially in time until the end of the frame, when operation passes to the next step  72 . In step  72  the LFS flag is checked at suitable time intervals shorter than 1 second, and if the flag is clear, operation loops back to step  70  and the next frame is copied (read and transmitted) serially in time. If in step  72  the LFS flag is found to be set, then operation branches to step  74 , wherein copying stops, the LFS flag is cleared, and operation continues to step  76 , wherein prior source data, i.e., stored content on source storage device  16  of the object being moved, is deleted (erased), up to the current location in the data storage space, which is the end of the last frame copied, and also the end of the last segment. If in the next step  78  it is found that there is a next frame, and the last frame was not the end frame of the object, then operation branches back to step  70  and the next frame, which is also the first frame of the next segment, is copied. If the end of the object is found in step  78 , the move ends. 
         [0015]    It will be apparent to those familiar with the art that a program of instructions to perform the described sequence of steps  60  can be implemented in ways that may differ in detail, while accomplishing the same results and objectives, without departing from the scope and spirit of the invention. 
         [0016]    A convenient and user-friendly start command for a move can be provided in this embodiment by the manual actuator  18  shown in  FIG. 1 , which can be a push button switch operationally connected to move processor  12  and disposed on the storage device enclosure, and alternatively on the TV  14 , for example on the control panel as noted hereinabove, and labeled as the “move” button. In a system environment with only one (default) sink storage device  20 , the user command can be adapted to require no other control action than pushing the move button, and no interaction of the user with the TV  14 . Such a single-button command will be simpler and easier to use than the conventional method of entering a user command from a remote control with the help of a menu displayed on the TV. Some of the convenience of a single-button move command can be retained also with a plurality of sink storage devices, shown in  FIG. 1 , by providing for selection of a target sink device from a list of sink storage devices  20 ,  22 ,  24  displayed on TV  14 . For example, said list can be displayed in response to actuation of the move button by the user; and the selection can be implemented by means of multiple button pushes (manual actuations) that advance a pointer sequentially through the list; and further, the final choice can be registered by the last push that is actuated within a predetermined time limit between pushes. Alternatively, a manual selection wheel or lever can be provided for advancing the pointer; and the choice can be registered by an elapsed time, and alternatively, by a second actuation of the move button. Alternatively with a plurality of sink storage devices, the move processor  12  can be adapted to choose a predetermined default sink device, and yet alternatively, the first available sink device, from the 1394 bus interconnection links  28 ,  30 ,  32  according to conventional bus operation, upon user actuation of the move button. 
         [0017]    In an alternate AV system embodiment, a move processor  80  disposed inside the TV  14  cabinet can be provided, without a manual actuator accessible to the user, as shown in dashed lines in  FIG. 1 . In this embodiment the associated source storage device, for example an HDD, can be also disposed inside the TV cabinet, or alternatively, a source storage device can be externally disposed, the distinguishing feature of the embodiment being the absence of a manual move actuator or move button. User control of the move can be in this case initiated (and a sink selected, if that is required) by means of the display and the control devices of the TV in the conventional manner, for example front panel controls of the TV or a remote control unit. It will be necessary in this embodiment for the control signals of the TV to interact suitably with the move processor  80 , in order to initiate the move as described hereinabove, and for this purpose, vendor-unique commands can be provided in the TV command set, with appropriate corresponding modifications in the firmware of the move processor  80  so that it can in other respects operate in the same manner as move processor  12 , as described hereinabove. 
         [0018]    Various modifications may be made to the invention without altering its value or scope. For example, while this invention has been described herein using the example of the move processor  12 , many or all of the inventive aspects are readily adaptable to other AV designs, other sorts of entertainment equipment, and the like. 
         [0019]    It is expected that there will be a great many applications for these which have not yet been envisioned. Indeed, it is one of the advantages of the present invention that the inventive method and apparatus may be adapted to a great variety of uses. 
         [0020]    All of the above are only some of the examples of available embodiments of the present invention. Those skilled in the art will readily observe that numerous other modifications and alterations may be made without departing from the spirit and scope of the invention. Accordingly, the disclosure herein is not intended as limiting and the appended claims are to be interpreted as encompassing the entire scope of the invention. 
       INDUSTRIAL APPLICABILITY 
       [0021]    The inventive apparatus and method are intended to be widely used in a great variety of electronic applications. It is expected that they will be particularly useful in consumer electronic applications where significant storage capacity and speed is required. 
         [0022]    It is anticipated that the continually deleting (erasing) content move and the single-button push user command will have wide use in all types of media storage devices such as HDDs, flash memory card and stick recorders, DVDRs, TVs and other types of media players of audiovisual and musical content. 
         [0023]    Since the inventive storage system and method of the present invention may be readily produced and integrated with existing tasks, input/output devices and the like, and since the advantages as described herein are provided, it is expected that they will be readily accepted in the industry. For these and other reasons, it is expected that the utility and industrial applicability of the invention will be both significant in scope and long-lasting in duration.