Abstract:
The invention provides an apparatus, system and method for allowing multiple television (TV) sets to communicate with each other in synchronizing their audiovisual signal output (when set to the same TV channel) to allow simultaneous viewing of common programming content.

Description:
TECHNICAL FIELD 
     The invention relates to synchronizing a common broadcast signal among multiple television units. 
     BACKGROUND 
     Many television (TV) users prefer to view multiple TV set units simultaneously tuned to the same broadcast station and/or television program (for example in a bar or restaurant displaying multiple TV sets tuned to the same sporting event) and many homes have televisions in different rooms of the house (such as the kitchen and/or living room and/or bedroom) that are all simultaneously tuned to the same TV channel to allow a user to view the same program while moving between rooms. 
     With the advent of cable and satellite TV control units along with digital video recorders (DVRs) as well as high-definition (HD) TV sets (and other “pass-through” electronic devices) for processing television signals, delay can be introduced into one or more of the signals during processing to cause the timing of commonly displayed programming content to become unsynchronized (i.e., “out of sync”) when simultaneously viewed on multiple TV sets, which in turn can create audio “sound echoes” and mismatched video streams. There are no known solutions to this problem other than to “splice” (or manually split) a single signal between two or more television sets in order to “sync” the audio and visual images so that they are all displayed in concert with each other. 
     SUMMARY OF THE INVENTION 
     The invention provides an apparatus, system and method for allowing multiple television (TV) sets to communicate with each other in synchronizing the timing of their audio and/or video signal output (when set to the same TV channel) to allow simultaneous viewing of common programming content (irrespective of the different “pass through” electronic devices that may be used to process the displayed TV signals) for each individual television. One of the TV sets is provided with a “master timing device” that communicates with “slave timing device(s)” incorporated into one or more other TV set(s) in the system to coordinate the synchronization of commonly received television signal(s) (by introducing a processing delay into one or more of the signals) so that they are all simultaneously displayed on each TV set. The system can work with any number of television sets in order to synchronize the timing of common audiovisual programming content. 
     It is therefore an object of the present invention to provide an apparatus, system and method for allowing multiple television (TV) sets to communicate with each other in synchronizing their audiovisual signal output. 
     It is another object of the present invention to provide a TV set with a “master timing device” that communicates with “slave timing device(s)” incorporated into other TV set(s) to coordinate the synchronization of commonly received television signal(s) (by introducing a processing delay into one or more of the signals) so that they are simultaneously displayed on each TV set. 
     The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DETAILED DRAWINGS 
         FIG. 1  illustrates a diagram outlining operation of a television (TV) system according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  illustrates a diagram outlining operation of a television (TV) system according to a preferred embodiment of the invention, where a television user electronically and/or programmatically configures a “master timing device” M (connected to a single TV set) to communicate with timing devices connected to any number of other system televisions (“slave TV set timing device(s)” S 1  and/or S 2 ) in order to synchronize display of their audio and/or video signal(s) with that of the “master TV” set (and with each other) when the same television channel and/or program is being simultaneously viewed on the master TV set M as well as the slave TV set(s) S 1  and/or S 2 . For example, if television set M (the “master TV set”) and television set(s) S 1  and/or S 2  (the “slave TV set(s)”) are viewing the same television channel (and/or program) and TV set M has a DVR unit attached (while the other(s) do not) then the audio and/or visual signal(s) processed for display on TV set M will ordinarily be lagging behind that of TV set(s) S 1  and/or S 2  by a certain period of time (for example approximately 5 seconds) unless the “master” and “slave” timing device(s) are employed to cause TV set(s) S 1  and/or S 2  to delay (or “buffer”) the timing of its/their signal(s) in order to synchronize them with the signal(s) displayed on TV set M. 
     In an example initial state, master television (TV) set (M) is activated (or “turned on”) at the same time that one slave TV set (S 1 ) is deactivated (or “turned off”) and another slave TV set (S 2 ) is turned on (but tuned to a different channel and/or program than TV set M). The status of each slave TV set is tracked by a “slave timing device” (S 1  and/or S 2 ) that notifies the “master timing device” of TV set M of its presence and broadcasting status (similar in operation to a “bluetooth device” installed in a cellular telephone). As shown in  FIG. 1 , the following operations are preferably carried out to synchronize common television signal(s) for simultaneous display by TV sets M and S 1  and/or S 2 : (1) TV set S 1  is turned on and its “slave timing device” alerts the “master timing device” M of the television channel and/or program to which S 1  is tuned; (2) TV set M then determines if it and TV set S 1  are tuned to the same station (and/or programming content) and if so then M queries S 1  for the current position of its displayed media (as indicated by a “frame position” of the received analog or digital audiovisual broadcast signal); (3) S 1  returns its current “media position” to M; (4) M evaluates the S 1  “media position” to determine if one of their signal(s) is more delayed in reception timing than the other (and if the signal for TV set M is not the most delayed then it automatically sets the “master timing device” to introduce an appropriate processing delay into its own signal so that it is the most delayed in time) and M sends this “delayed media position” to S 1 ; (5) S 1  synchronizes its “media position” with that of M (by “buffering” its own signal if necessary) to introduce a processing delay that will cause both signals to be simultaneously displayed in “real time”; (6) TV set S 2  then tunes its signal to the same program also being viewed on TV set(s) M and S 1  (and M is alerted of this via communication between the “slave timing device” for S 2  and the “master timing device”); (7) M queries S 2  for its current “media position”; (8) S 2  returns its current “media position” to M; (9) if the “media position” for S 2  is more delayed than that of M then M waits to synchronize for a pre-defined amount of time (e.g., for a commercial break as indicated by a “black frame”) in order to set its (already) “delayed media position” to be greater than that of S 2 , and if the “(already delayed) media position” for M is more delayed than that of S 2  then that current time delay value is maintained for M and it sends the “delayed media position” to S 2 ; (10) M sends its current (adjusted/updated) “delayed media position” to S 1  if necessary (i.e., only if its value has changed from that originally sent to S 1 ); (11) S 2  synchronizes its “media position” with that of M (by “buffering” if necessary as described for S 1 ); (12) S 1  re-synchronizes its “media position” with that of M if necessary (if the “delayed media position” for M has changed). 
     The “master timing device” M can also detect whether the same program is being viewed on different television channels (i.e. on a “high definition” (HD) channel using an HDTV set and also on a “standard definition” (SD) channel using another non-HD TV set) and/or using different means of signal reception (i.e., via an antenna as opposed to cable or satellite transmission or using “wifi”/internet technology) for different televisions within the system. Such determinations can be based on signal-defining “media position metadata” that is attached to each received signal (indicating its source and nature) and can be used to adjust the processing delay introduced into each different TV accordingly. (If a television is tuned to a different program then there is no need to synchronize its signals with the rest of the TVs in the system.) 
     While certain preferred features of the invention have been shown by way of illustration, many modifications and changes can be made that fall within the true spirit of the invention as embodied in the following claims, which are to be interpreted as broadly as the law permits to cover the full scope of the invention, including all equivalents thereto.