Abstract:
A method, system and computer program provide a mechanism for intelligently synchronizing a portable video device with a digital video recorder. The intelligent synchronization handles conditions under which a complete transfer of difference content is not possible due to available storage limitations of the portable video device. The synchronization process determines a content difference between the content on the portable video device and the content on the DVR, determines available storage space on the portable video device and compares the available storage space on the portable video device to a size of the content difference. If the size of the content difference is greater than the available storage space, the size of the content difference is reduced, by compression or truncation, without completely excluding video programs from the transfer.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to consumer portable video devices, and more particularly to a method and system that intelligently synchronize the contents of a portable video device with content recorded by a digital video recorder (DVR). 
     2. Description of Related Art 
     Synchronization software and hardware mechanisms provide enhanced portability in portable video devices such as personal video recorders (PVRs). Recently, portable personal devices that were traditionally audio playback-only devices (e.g., so-called “mp3 players”) have been enhanced by the addition of video playback capability, providing portable video players. Typical synchronization techniques used in conjunction with such devices either automatically match the content between the portable device and another device, or provide the user with a selection of which content to transfer, in particular when there is insufficient space on the portable device. The user may also delete content from the portable device in order to make room for the new content that has not been synchronized. 
     However, when the difference between the content of the portable device and the other device is in excess of the available storage capability of the portable device, it may not be desirable under all circumstances to require the user to perform the above-described tasks in order to synchronize content. In particular, selection of a subset of video content or selection of video content to delete from the portable device can be a time-consuming process, which runs counter to the idea of portability. Further, selection of a subset of the new content that has been recorded on the DVR for transfer to the portable video device provides that some content may be missed that the user of the portable device may want to review further. 
     Therefore, it would be desirable to provide a method and system that can provide for synchronizing content between a DVR and a portable video device when insufficient space is present on the portable video device without requiring the user to manually select content to transfer or select content to delete from the portable video device. It would further be desirable to provide such a method and system that provide that new, unviewed content will not be missed. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention is embodied in a method, system and a computer program product that synchronize content between a portable video device such as a personal video recorder (PVR) and a digital video recorder (DVR). The synchronization may be performed by a program executed by a general-purpose computer such as a personal computer (which may also serve as the DVR) or within a DVR. Another program executed within the portable video device provides cooperation with the synchronization program and can provide further storage and user input for various features in accordance with embodiments of the invention, and in some embodiments, provide the synchronization function by implementing a “pull” type synchronization architecture. 
     The method and system of the present invention, as operated by computer program products of the present invention, initiate a synchronization process between the portable video device and the DVR. The synchronization is performed over a wired or wireless interface between the DVR and the portable video device. The synchronization process determines a content difference between the content on the portable video device and the content on the DVR, determines available storage space on the portable video device and compares the available storage space on the portable video device to the size of the content difference. If the size of the content difference is greater than the available storage space, the size of the content difference is reduced, without completely excluding video programs from the transfer. 
     The size of the content difference is reduced by either automatically truncating multiple video programs that comprise the content difference, or by compressing at least one video program of the content difference in a manner that reduces quality and storage requirements. The reduced size content difference is then transferred to the portable video device over the interface. 
     If the size of the content difference is reduced by compression, the particular video program(s) compressed may be selected according to a program type, e.g., compression may be applied to news or information programs, but not to movies or sports programs. If the size of the content difference is reduced by truncation, a number of truncated clips may be concatenated to provide a preview of content that was not completely transferred. Further, selection of a subset of the truncated clips may be stored as an indication in a memory of the portable video device that the user desires the corresponding full programs. The stored indication is then used by the next synchronization process to transfer the complete program(s). The selection may be explicitly based on a selection by the user, or implied from the user&#39;s viewing of particular programs, which are then selected for complete transfer. 
     The foregoing and other objectives, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiment of the invention, as illustrated in the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of the invention when read in conjunction with the accompanying Figures, wherein like reference numerals indicate like components, and: 
         FIG. 1  is a block diagram illustrating a system according to an embodiment of the present invention. 
         FIG. 2  is a block diagram illustrating a system in accordance with another embodiment of the present invention. 
         FIG. 3  is a flowchart of a method in accordance with an embodiment of the present invention. 
         FIG. 4  is a flowchart of a method in accordance with another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to synchronization methods and systems that synchronize content from a digital video recorder (DVR) with content on a portable video device such as a personal video recorder (PVR). When a synchronization process is initiated, a content difference between the portable video device and the DVR is determined, and the available space on the portable video device is compared with the size of the content difference. If sufficient space is unavailable on the portable device to transfer the full content difference, one or more video programs is either compressed or truncated to reduce the size of the content difference to fit within the storage space available on the portable video device. The content difference is then transferred to the portable video device. In one embodiment of the invention, truncated video programs are used as “previews” and either user selection or viewer history is used to determine which video programs should be fully transferred to the portable video device at the next synchronization. 
     Referring now to  FIG. 1 , a system in accordance with an embodiment of the invention is shown. A digital video recorder (DVR)  10  is connected to an external digital television (DTV) display  14 , and is also coupled to a portable video device  5 , as illustrated, by a wireless interface  7 A, such as a Bluetooth or wireless local area network (WLAN) interface. Portable video device includes a processor  16 B and a program/video memory  17 B that contains program instructions for execution by processor  16 B in support of synchronization between DRV  10  and portable video device  5 . DVR  10  also contains a processor  16 A for executing program instructions that stored in a program/video memory  17  that implement the synchronization techniques of the present invention. While the description of the synchronization technique as described herein generally refer to a push-type synchronization, in which DVR  10  controls the transfer process, in an alternative embodiment, pull-type synchronization can be initiated by and controlled by a program executed by processor  16 B of portable video device  5 . Therefore, the location of the program that implements the methods described in further detail below is understood to be flexible and is not a limitation of the present invention. Functionality of the synchronization operations described below may also be split between two programs, one within portable video device  5  and executed by processor  16 B and another within DVR  10  and executed by processor  16 A. 
     User input to portable video device  5  is generally provided to processor  16 B via a touchscreen or buttons integrated on the housing of portable video device  5 . A remote control  12  is used to control operation of DVR  10 , in the exemplary embodiment according to methods of the present invention, in order to provide user input. However, it is understood that other user input methodologies can be employed, such as buttons and other controls integral to DVR  10 . DVR  10  includes an infrared (IR) interface  13  for receiving commands from remote control  12  A radio-frequency (RF)/video interface  18  receives video signals or RF signals from broadcast, closed-circuit or other video streaming sources and provides them for selection by processor  16  for ultimate display by DTV display  14 . A network interface  19  provides connection to public or private networks such as the Internet, for receiving additional information such as program guide information for generating a user interface used to schedule recording within DVR  10 . A digital versatile disc (DVD) drive  15  and hard disk drive (HDD)  11  are also included in DVR  10  both for recording video program and other information. When a synchronization process is initiated between portable video device  5  and DVR  5 , either by a user input or proximity of the portable video device  5  to DVR  10  in certain wireless configurations, programs within portable video device  5  and DVR  10  interact to transfer content that is different between DVR  10  and portable video device  5 . 
     Since DVR  10  generally contains more storage space than portable video device  5 , the synchronization process described below is illustrated as a uni-directional synchronization that transfers new content recorded by DVR  10  to portable video device  5 . However, techniques of the present invention can be used in bi-directional synchronization as well as uni-directional synchronization from portable video device  5  to DVR  10 . In general, the techniques of the present invention can be used any time the target device for video transfer has insufficient storage capacity to receive the content difference between the source device and the target device. Further, it is understood that the techniques of the present invention do not supplant other synchronization techniques that filter the content to be transferred. For example, the synchronization techniques of the present invention may also avoid transferring portions of video programs that have already been viewed, in order to reduce storage space, may ignore content that is older than a certain date or time, or content that has been previously selected or categorized as not intended for transfer. Further, fully automatic transfer is not a requirement of the present invention, as the content difference size reduction techniques of the present invention can be applied to a manually selected list of content to transfer, as well as to automatically determined content differences. 
     Referring now to  FIG. 2 , a system in accordance with another embodiment of the invention is illustrated, in which a personal computer system may implement a DVR, synchronize video obtained from other external sources such as the Internet or pre-recorded media, or controls an external DVR  21 . Personal computer  20 , includes a processor  26  coupled to a memory  27  for storing program instructions including program instructions for controlling synchronization between external DVR  21  and/or between personal computer  20  and portable video device  5 . Personal computer  20  is interfaced to portable video device  5  by a suitable wired or wireless interface, which is illustrated here as a USB interface cable  7 B connected to a USB interface  23  of personal computer  20 . The program within memory  27  for controlling synchronization according to the present invention may be integrated in a DVR program that also provides control and other functionality as generally associated with DVR operations, or may be provided a stand-alone application, in accordance with methodologies described in further detail below. The program may be loaded into memory  27  or HDD  23  from a DVD drive  24  from a data storage media forming a computer program product in accordance with an embodiment of the present invention, such as DVD disc DVD. In order to receive video information from closed-circuit or broadcast sources, personal computer  20  includes an RF/Video interface  28 . However, techniques in accordance with an embodiment of the present invention can be performed on video received from a network interface  29  and RF/Video interface  28  is not required in such embodiments. Further, as mentioned above, if personal computer is used to provide synchronization between external DVR  21  and portable video device  5 , then there is no requirement that personal computer  20  provide any source of video content. Personal computer  20  also includes a human interface device (HID) interface  22  for connection of HIDs, such as keyboards and pointing devices. Personal computer  20  is also illustrated as connected to an external display  25 . However, if personal computer  20  is a laptop, tablet or other integrated device, display  25  will generally be internal to personal computer  20 . 
     Referring now to  FIG. 3 , a method according to an embodiment of the present invention is illustrated in a flowchart. A synchronization process is initiated between the portable video device and the DVR according to a command or via proximity detection (step  40 ) and a new content difference is determined between the DVR and the portable video device (step  41 ). The available storage space on the portable video device is determined (step  42 ) and the content difference size is compared to the available storage space on the portable video device (decision  43 ). If the storage space available on the portable video device is sufficient to receive the full content difference (decision  43 ), then the content is transferred to the portable video device (step  46 ). Otherwise, a video program is selected (step  44 ), which may be based on a content type (e.g., compress news programs before sports programs), the video program is compressed, reducing video quality and storage space requirements for the selected program and the content difference size is updated (step  45 ). Step  44  and step  45  are repeated until decision  43  indicates that the content difference will fit within the available storage space on the portable video device, which may include adjusting the compression factor of the entire content difference, or selected programs based on program type, so that step  45  may be repeated for the same video program if necessary. Finally, once the content difference has been reduced so that the storage space available on the portable video device is sufficient to receive the content difference (decision  43 ), then the content is transferred to the portable video device (step  46 ). The algorithm may also be terminated if the compression applied exceeds a usable limit and a warning may be issued. Alternatively, the algorithm may selectively change to a truncation algorithm as illustrated below in  FIG. 4 . 
     Referring now to  FIG. 4 , a method according to another embodiment of the present invention is illustrated in a flowchart. A synchronization process is initiated between the portable video device and the DVR according to a command or via proximity detection (step  50 ) and a new content difference is determined between the DVR and the portable video device (step  51 ). The available storage space on the portable video device is determined (step  52 ) and the content difference size is compared to the available storage space on the portable video device (decision  53 ). If the storage space available on the portable video device is insufficient to receive the full content difference (decision  53 ), a video program is selected for truncation (step  54 ), which may be based on a content type (e.g., truncate news programs before sports programs), but excluding programs which are flagged for full transfer by an indication stored in the portable video device that directs the synchronization process to fully-transfer selected video programs. The selected video program is truncated reducing storage space requirements for the selected program and the content difference size is updated (step  55 ). Step  54  and step  55  are repeated until decision  53  indicates that the content difference will fit within the available storage space on the portable video device, which may include adjusting the length of the truncated clips for the entire content difference, or for selected programs based on program type, so that step  55  may be repeated for the same video program if necessary. Finally, once the content difference has been reduced so that the storage space available on the portable video device is sufficient to receive the content difference (decision  53 ), the truncated clips are optionally concatenated into an interactive “preview” clip (step  56 ), then the content is transferred to the portable video device (step  57 ). After the transfer is complete, the portable video device stores the result of an interaction of the user with the interactive preview clip in memory, or uses the viewing history of the truncated clips to flag the truncated clips in memory, and stores an indication that a full synchronization of the indicated content is requested. At a next synchronization, full transfer is performed (thereby avoiding truncation in step  54 ) for the selected content (step  58 ). A rating scheme may be employed to prefer some video programs over others that have been flagged by the user interacting with a program within the portable video device, so that if sufficient space is again unavailable at the next synchronization, higher-ranked programs will be transferred whole or truncated/compressed less than lower-ranked programs. Other techniques for flagging/ranking content include indications received from peer-to-peer systems that rank programs, retrieval of rating information from “critic” databases, e.g., prefer programs rated “5-star”, and other sources of information that would indicate the desirability of some content over others, which may be generalized rankings, or tailored to preferences of a particular user. 
     The original full content of the video programs that have been truncated by the method illustrated in  FIG. 4  or compressed by the method illustrated in  FIG. 3  may be subsequently retrieved remotely, by network transfer, using an association of the truncated/compressed video programs/clips with the original content, e.g., by a unique identifier, once content has been removed from the portable video device to provide sufficient storage space. The synchronization processes described above may themselves be provided over a remote network, so that as storage space is made available, subsequent synchronization attempts can be used to retrieve media that was previously truncated, and optionally to retrieve copies of media that were compressed. Further, the truncation length and/or compression factor can be based on user selection and/or user category preferences, in addition to determining whether or not truncation or compression should be applied to difference content. 
     While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form, and details may be made therein without departing from the spirit and scope of the invention.