Abstract:
A first controllable appliance receives from a second controllable appliance a command for causing the first controllable appliance to be placed into a state and, in response, determines a trust level of the second controllable appliance. When it is determined that the second controllable appliance is trustworthy, the first controllable appliance executes the command. When it is determined that the second controllable appliance is untrustworthy, the first controllable appliance ignores the command. Otherwise, the first controllable appliance enters into a state in which the first controllable appliance waits for at least a predetermined period of time for a user to confirm whether or not the first controllable appliance should be caused to execute the command.

Description:
BACKGROUND 
     Interconnections between consumer appliances such as televisions, set top boxes for receiving and decoding cable and satellite signals, AV receivers, DVD players, game systems, streaming media adapters, etc., may take the form of digital interfaces based upon, for example, the High-Definition Multimedia Interface (HDMI) standard. In addition to supporting high quality audio/video signals, such digital interconnections may facilitate the exchange of commands, identity information, and capability data between devices. In particular, when interfaced via an HDMI connection, devices which support a feature known as Consumer Electronic Control (CEC) may be enabled to command and control each other over the HDMI connection without user intervention. This feature allows one button control of various functions such as system-wide power on, etc., in those systems where HDMI connected devices support the CEC feature. However, while generally useful, the CEC feature may become problematical if one or more source devices in an HDMI-interconnected system are not well behaved and command a device such as an AV receiver or television to change inputs at inopportune and/or random times. Such unexpected operation is sufficiently prevalent that many television and AV receiver manufacturers may ship their product with the CEC control feature defaulted to “off.” 
     SUMMARY 
     The following generally describes home entertainment systems comprising various media source and rendering devices interconnected via HDMI technology and supporting CEC functionality, and more particularly describes a system and method for filtering CEC commands by a recipient device in order to eliminate or minimize unexpected operation and/or continuous messages which may be caused by ill-behaved devices. To this end, an input-switchable device such as an AV receiver or a television set may be provisioned with software which serves to identify the originator of a CEC input switching request and ascertain a trust level parameter associated with that originating device. The action subsequently taken by the receiving device may then be determined based on the trust level of the requesting device. By way of example, actions based on the trust level may include acting on the request immediately, prompting the user to confirm before performing the requested action, or ignoring the request completely. Whenever a new device is introduced into the system an initial trust rating may be assigned to that device, either directly by a user or, in some embodiments, by reference to a local or remote database of known devices. Provision may also be made for trust ratings to be subsequently adjusted by the user if desired. 
     A better understanding of the objects, advantages, features, properties and relationships of the described systems and methods will be obtained from the following detailed description and accompanying drawings which set forth illustrative embodiments and which are indicative of the various ways in which the principles of the claimed invention may be employed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the various aspects of the described system and method, reference may be had to preferred embodiments shown in the attached drawings in which: 
         FIGS. 1A and 1B  illustrate exemplary systems in which the described methods may be utilized; 
         FIG. 2  illustrates a block diagram of the exemplary AV receiver of  FIGS. 1A and 1B ; 
         FIGS. 3A and 3B  illustrate exemplary device trustworthiness tables which may be utilized by the programming of the AV receiver of  FIG. 2 ; 
         FIG. 4  illustrates in flow chart form an exemplary series of steps which may be performed by an AV receiver operating program; and 
         FIGS. 5 and 6  illustrate exemplary user GUI displays which may be utilized in conjunction with the program steps of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     Turning now to  FIG. 1A , there is illustrated an exemplary home entertainment system in which the audio and/or video outputs of a group of various media source devices such as for example a set top box (“STB”)  102 , a DVD player  104 , a game console  106 , and a media streaming adapter  108  are all connected to audio and/or video inputs of an AV receiver  100 . AV receiver  100  in turn functions to switch the currently desired input media stream, being received at one or more of the audio and/or video inputs of the AV receiver, to a designated audio and/or video output of AV receiver  100  which is connected to an output capable device, such as television  110 . In some embodiments AV receiver  100  may also include a wired or wireless network interface which may be used for the routing of media, for example media being wirelessly streamed via a WiFi connection  114 , from or to other areas of the home. When included, such a network interface may also be available for Internet access  116 , downloading of firmware updates and/or other data into AV receiver  100  from a remote database  118 , etc., as is well known in the art. Also illustrated is a user input device  112 , such as a remote control, smartphone app, etc., which may be used to command functional operation of various devices, navigate GUI menu systems provided by various devices, etc., using any convenient IR, RF, Point-to-Point, or networked protocol. In keeping with the teachings of the subject disclosure which follow, AV receiver  100  may be provisioned with methods to filter CEC command requests received from source devices  102  through  108 . 
     With reference to  FIG. 1B , in an alternate exemplary embodiment the various media source appliances  102  through  108  may be connected directly to a television  120 . In this example, a television  120  may be provisioned with methods to filter CEC command requests received from source devices  102  through  108 . As will be appreciated, the implementation of such methods in TV  120  may be generally analogous to those of AV receiver  100  and accordingly, the following detailed exemplary embodiment will be presented in terms of AV receiver  100 , it being understood that those principles may be applied, mutatis mutandis, to television  120 , or for that matter, to any other device which may benefit from such capability. 
     With reference now to  FIG. 2 , an exemplary AV receiver  100  may include, as needed for a particular application, a control processor  200  coupled to a non-transient memory element  202  which may comprise any combination of ROM, RAM, and/or non-volatile read/write memory; video and audio processing sections  204 ,  206 ; a tuner  208  for reception of radio broadcast channels; a front panel  210  including user controls and/or a display; a remote control interface  212  for communicating with a controlling device  112 ; a wired or wireless network interface  214  for communication with a local and/or wide area network; audio inputs  220   a  through  220   c ; video inputs  224   a  through  224   c ; digital AV interfaces such as HDMI ports  222   a  through  222   c ; audio outputs  230   a ,  230   b ; and video outputs  234   a  and  234   b . As will be appreciated, audio and video inputs and outputs (which may be more or less in number than illustrated) may comprise analog or digital signals and exemplary AV receiver  102  may be provisioned with analog-to-digital (ADC) converters, digital-to-analog (DAC) converters, video decoders, HDMI encoder/decoders, CODECs, format converters, etc., all as necessary to implement the input/output switching and routing functionality. It will be further appreciated that the functionality of video and audio processing blocks  204  and  208  may be implemented in separate components such as a specialized digital signal processors (DSP), may be implemented as part of control processor  400 , or any combination thereof, and that portions of memory  202  may be allocated to or associated with audio and video processing blocks  202 , 208 . 
     It will also be appreciated that some or all of devices that comprise the memory element  202  may take the form of a chip, a hard disk, a magnetic disk, an optical disk, FLASH memory, and/or the like, and that all or portion of the devices that comprise the memory element  202  may be physically incorporated within the same IC chip as the control processor  200  and/or audio or video processing blocks  204 , 206  and, as such, memory element  202  is shown separately in  FIG. 2  only for the sake of clarity. 
     As will be understood by those skilled in the art, some or all of devices that comprise the memory element  202  may include executable instructions that are intended to be executed by the processor  200  to control the operation of the AV receiver  100  (hereafter, the “AV receiver operating program”). In this manner, the processor  200  may be programmed to control the various electronic components within the AV receiver, e.g., to monitor the front panel  210  and or remote control interface  212 , to cause the routing of video and/or audio signals between the various inputs and outputs, to control selection of radio broadcast channel by tuner  208 , to control volume and equalization settings of audio outputs  230   a  and  230   b ; to act on commands received from remote control  112  or on CEC commands received over HDMI interfaces  222   a  through  222   c ; etc. Further, the AV receiver operating program, in conjunction with video processing block  204 , may provide GUI-based setup menus for AV receiver functions such as input and output assignments, levels, balances, equalization, etc., via a connected video monitor device such as for example TV  108 . Since such GUI-based AV receiver setup is well known in the art, for the sake of brevity it will not be described further herein, however if greater detail is desired regarding such features and functionality the interested reader may reference, for example, documents such as the Denon AV Surround Receiver STR-DA5500ES Owner&#39;s Manual (D&amp;M Holdings Inc. publication number 5411 10255 000D), the Sony STR-DH820 Multi Channel AV Receiver Operating Instructions (Sony Corp. publication 4-266-497-12), or the like. 
     In addition, in an exemplary embodiment described herein the AV receiver operating program may include programming which functions to assign and utilize a trustworthiness rating for each CEC-enabled connected source device in order to minimize or eliminate unwanted input switching, which will now be described in further detail. 
     Referring to  FIG. 3A , an exemplary AV receiver operating program may maintain a trustworthiness table  300  in memory element  202  in which is recorded a current trust level for each connected device, i.e. each active HDMI input port. The table size may be dynamic, i.e. with entries created as devices are connected to an HDMI input port (and possibly deleted if a device is disconnected from an HDMI input port); or may be static, i.e. with a fixed number of entries corresponding to the total number of HDMI input ports available, as appropriate for a particular implementation. In the exemplary embodiment presented herein, there are four possible HDMI inputs, and each of the four device entries in the table may comprise a device identity field  302 , a device name field  304 , and a device trust level field  306 . In the event that a device is not connected to an available HDMI input, a “device not connected” data entry may be placed into the table, no data may be placed into the table entry, or the like. As will be appreciated, the AV receiver may be programmed to know which table entry corresponds to which AV input port of the AV receiver. 
     Within the table, device identity  302  comprises information sufficient to uniquely identify a specific device and may include items such as a CEC vendor ID, data from HDMI Source Product Description (SPD) information frames embedded in the source appliance digital video stream (in accordance with the Consumer Electronics Association specification CEA-861), or any other appropriate information. In this context, for a more detailed description of device identification over digital media interfaces the interested reader may wish to refer to U.S. Pat. No. 8,812,629 “System and Method for Configuring the Remote Control Functionality of a Portable Device” and/or pending U.S. patent application Ser. No. 12/148,444 “Using HDMI-CEC to Identify a Codeset,” both of common ownership and incorporated herein by reference in their entirety. 
     Device name  304  is a user friendly name by which this device is to be referenced in OSD GUI displays. This may be the value obtained in response to a CEC “Device OSD Name” request by the AV receiver operating program, or in other embodiments provision may be made for alternative names, for example downloaded from a device database or manufacturer web site, user-defined, etc. For example, on AV receiver devices in which user-supplied display names may be assigned to input ports as part of a receiver set-up process, device name  302  may comprise those values. 
     In the exemplary embodiment presented herein, trust level  306  may be assigned one of three possible values, corresponding to the actions to be taken by the AV receiver operating program upon receipt of a CEC input selection request from the listed device: “Trusted,” means that the AV receiver operating program will always respond to a request from the listed device by selecting that HDMI input port as the source for the AV stream being rendered, i.e. will always switch inputs to that device when requested by that device. “Untrusted” means that the AV receiver operating program upon receipt of a request from that device will solicit a confirmation from the user, e.g. via a remote control  112  command transmission or the like, prior to performing any input switching operation. The third possible value “Excluded” means that the AV receiver operating program will always ignore input switching requests from the listed device. 
     In some embodiments, it may be desirable to dynamically adjust the trustworthiness rating of the various devices forming the system based upon the state of certain other devices. For example, if a first device is powered on by a user (e.g., a device identifiable via a received transmission, such as a DVD player, a device that is known to the AV receiver, or a device that is otherwise generally connected to given input port or output port of the AV receiver) while associated other devices are powered off (e.g., a device identifiable via a received transmission, such as a TV monitor, a device that is known to the AV receiver, such as the AV receiver itself, or a device that is otherwise generally connected to given input or output port of the AV receiver), it may be desirable, in this example, that the DVD player issue CEC commands to initiate “power on” and input switching sequences at the AV receiver and TV devices. However, in the same system example, if the AV receiver and TV are already powered on and switched to a different input, it may be appropriate for these devices to ignore such CEC commands from a just-powered DVD player. In this manner, the exemplary system may support “one button” start up when appropriate while still allowing a user to power on the DVD player, for example to remove a disk, without affecting the active state of other devices in the system such as viewing cable DVR content. To this end, in certain implementations the AV receiver operating program input switching logic of a device such as AV receiver  100  may support multiple trustworthiness tables as illustrated in  FIG. 3B , each corresponding to a particular state of device  100 , for example one table  310  for use when AV receiver  100  is “powered on” and another table  312  for use when AV receiver is “powered off.” 
     An exemplary series of steps which may be performed by an AV receiver operating program in implementing the above described methods will now be discussed in greater detail in conjunction with the flowchart presented  FIG. 4 . 
     Upon receipt of a CEC input selection request  400  which would be issued from a requesting device, for example in response to a state change thereof, at step  402  the exemplary AV receiver operating program may first check if the requested input is already the AV receiver input source. If so, no further action is required. If not, at step  404 , in those implementations which support multiple trustworthiness tables, the appropriate table is selected based on the current state of AV receiver  100 , i.e. in the illustrative example one of  310  or  312  based on the powered-up status of AV receiver  100 . Next, at step  406  the AV receiver operating program may determine if the requesting device is known to the system, i.e. has a valid entry in the selected trustworthiness table. If so, at step  408  the AV receiver operating program may retrieve the device trust status value  306  corresponding to the requesting device. At step  410  and  414  the AV receiver operating program may examine the retrieved status. If “trusted,” then at step  412  the AV receiver operating program may perform the requested input switching operation and processing is complete. If “excluded,” then processing ends with no further action taken. If the status is neither “trusted” nor “excluded,” then by default the status may be “untrusted” and at step  416  the user may be prompted to confirm or deny the requested action, for example as illustrated in  FIG. 5 , via a display on television  110 . At steps  418  through  426 , the exemplary AV receiver operating program may now wait for user input. With reference to  FIG. 5 , in the exemplary embodiment possible user inputs are: “1—Allow once,” step  418 , in which case at step  412  the AV receiver operating program may perform the requested input switching operation and processing is complete; “2—Don&#39;t allow,” step  420 , in which case the AV receiver operating program processing ends with no further action taken; “3—Allow always,” step  422 , in which case at step  446  the AV receiver operating program may update the trust level status field  306  corresponding to this device to “trusted,” and thereafter may perform the requested input switching operation at step  412 , after which processing is complete; and “4—Never allow,” step  424 , in which case at step  448  the AV receiver operating program may update the trust level status field  306  corresponding to this device to “excluded,” and end processing with no further action taken. If no user input is received within an appropriate period of time, then at step  426  the AV receiver operating program may complete processing with no action taken, i.e. in the event a user is not present, is inattentive, etc. 
     Returning now to step  406 , if the requesting device is not known to the system, i.e. is associated with a previously unused HDMI input port, is a replacement for a previously connected and identified device, etc., at step  428  the AV receiver operating program may create or initialize a new device entry in the device trustworthiness table. Next, at step  430 , the AV receiver operating program may cause identity data obtained from the new device to be compared against a database of trusted devices. Such identity data may comprise Consumer Electronic Control (CEC) retrievable data, Extended Display Identification Data (EDID), data from Source Product Description (SPD) information frames, or any other available information as appropriate to uniquely identify the device by make and model, for example by using the methods described in previously referenced U.S. Pat. No. 8,812,629 or pending U.S. patent application Ser. No. 12/148,444, both incorporated herein by reference. The database of trusted devices may be local, i.e. stored in AV receiver memory  202 , or may be located at a remote server  118  accessible via Internet connection  114 , 116 . As appropriate for a particular embodiment, an exemplary database of trusted devices may be as simple as a stand-alone list of trusted devices (for example a manufacturer-supplied list of compatible models of the same brand as AV receiver  100 ), or may comprise part of a larger database of device capabilities, for example in the form of an additional entry in the appliance data record described in U.S. Pat. No. 8,812,629. At step  422 , if the new device can be located in the trusted device database, at step  446  the corresponding device entry in the newly created or initialized trustworthiness table  300  may be marked as “trusted,” after which at step  412  the AV receiver operating program may perform the requested input switching operation and processing is complete Although not illustrated, it will be appreciated that in certain embodiments a “black list” of devices which are to be automatically excluded may also be maintained and processed in a similar manner. 
     If the requesting device identity does not correspond to any entry in the database of trusted devices, then at step  434  the user may be prompted to assign a trust category for the new device, for example as illustrated in  FIG. 6 , via a display on television  110 . At steps  436  through  442 , the exemplary AV receiver operating program may now wait for user input. With reference to  FIG. 6 , in the exemplary embodiment possible user inputs are: “1—Always,” step  436 , in which case at step  446  the AV receiver operating program may cause the corresponding device entry in the newly created or initialized trustworthiness table  300  may be marked as “trusted,” after which at step  412  the AV receiver operating program may perform the requested input switching operation and processing is complete; “2—Ask,” step  438 , in which case at step  450  the AV receiver operating program may cause the corresponding device entry in the newly created or initialized trustworthiness table  300  may be marked as “untrusted,” after which processing may continue at step  416 , soliciting further user input as described previously in conjunction with  FIG. 5 ; and “3—Never,” step  440 , in which case at step  448  the AV receiver operating program may cause the corresponding device entry in the newly created or initialized trustworthiness table  300  may be marked as “excluded” and processing may end with no further action taken. If no user input is received within an appropriate period of time, then at step  442  the AV receiver operating program may cause the corresponding device entry in the newly created or initialized trustworthiness table  300  to be marked as “untrusted” and processing may end with no further action taken, i.e. in the event a user is not present, is inattentive, etc., the default is to assign an “untrusted” status to a newly detected device. 
     As will appreciated, in additional to the above described initial assignment of a trustworthiness level to a newly connected device, in some embodiments the user may also be offered the ability to modify the trustworthiness levels of existing devices as one of the choices in an AV receiver or television device&#39;s conventional GUI based set-up and configuration menu. 
     While various concepts have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those concepts could be developed in light of the overall teachings of the disclosure. For example, while the exemplary embodiment presented herein is focused on the prevention of unwanted CEC-initiated input switching operations, it will be appreciated that the teachings and techniques presented may readily be extended to encompass other CEC or otherwise enabled functionalities such as control of power, volume, transport operations, etc. Similarly, in the event that the AV receiver recognizes a command received from a particular input port as originating from a device connected thereto, the table need not maintain device identity data. Rather, the mere receipt of a command at a given input port can be used by the AV receiver as the equivalent of a command being received with a specific device identifier. Further, in such a use case it will incumbent upon the user to assign a trust category for a device attached to an input as the above-described lookup methodology will not be useful. 
     It is also to be understood that, while described in the context of functional modules and illustrated using block diagram format, unless otherwise stated to the contrary, one or more of the described functions and/or features may be integrated in a single physical device and/or a software module, or one or more functions and/or features may be implemented in separate physical devices or software modules. It will also be appreciated that a detailed discussion of the actual implementation of each module is not necessary for an enabling understanding of the invention. Rather, the actual implementation of such modules would be well within the routine skill of an engineer, given the disclosure herein of the attributes, functionality, and inter-relationship of the various functional modules in the system. Therefore, a person skilled in the art, applying ordinary skill, will be able to practice the invention set forth in the claims without undue experimentation. It will be additionally appreciated that the particular concepts disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any equivalents thereof. All patents cited within this document are hereby incorporated by reference in their entirety.