System and method for providing substantially uninterrupted digital video during a switching event between a first digital video source and a second digital video source

Abstract

When switching sources, resolutions or refresh rates in a video distribution network, switching times are reduced by maintaining video lock and security authentication between a video switcher and a video sink. The scaler maintains video lock and security authentication by continuing to generate video timing data during switching events. The scaler also facilitates an aesthetically pleasing transition by generating image content data prior to and after the switching event.

What is claimed is: 
     
         1 . A digital video switcher device (switcher device) comprising:
 an output board;   at least two input boards, each of the at least two input boards adapted to receive digital audiovisual data from a digital video source over a security protocol link; and   a multiplexer communicatively coupled between the at least two input boards and the output board, and wherein the multiplexer is adapted to
 dynamically route the digital audiovisual data from the at least two input boards to the output board, 
   and wherein the output board is adapted to
 generate a continuous stream of uninterrupted digital video timing data in the absence of digital video timing data received from either or both of the at least two input boards. 
   
     
     
         2 . The switcher device according to  claim 1 , wherein
 the output board is further adapted to
 transmit the digital audiovisual data to a downstream video sink over a security protocol link, and 
 maintain the security protocol link in an authenticated interface with the downstream video sink during a switching event between the at least two input boards by outputting a continuous stream of uninterrupted digital video timing data during the switching event. 
   
     
     
         3 . The switcher device according to  claim 2 , wherein the output board comprises:
 a scaler adapted to generate the continuous stream of uninterrupted digital video timing data in the absence of digital video timing data received from either or both of the at least two input boards.   
     
     
         4 . The switcher device according to  claim 3 , wherein the output board comprises:
 a receiver adapted to receive the digital audiovisual data routed from the multiplexer;   a scaler adapted to
 convert the digital audiovisual data received via the multiplexer to a native resolution of the digital video sink, 
 generate a continuous stream of uninterrupted video timing data during the switching event at the native resolution of the video sink during the switching event, and 
 generate image content data for a period of time until achieving video lock in response to receiving the prepare signal; and 
   a transmitter adapted to encrypt and transmit digital audiovisual data to the digital video sink over an HDCP interface and maintain the security protocol link in an authenticated interface with the video sink by outputting the continuous stream of uninterrupted video timing data during the switching event.   
     
     
         5 . The switching device according to  claim 4 , wherein
 the scaler is further adapted to operate in a free running mode by generating digital video timing data during the switching event.   
     
     
         6 . The switcher device according to  claim 3 , wherein
 the scaler is further adapted to generate the continuous stream of uninterrupted digital video timing data in the absence of digital video timing data received from either or both of the at least two input boards at a native resolution of the digital video sink.   
     
     
         7 . The switcher device according to  claim 2  wherein
 the scaler is further adapted to generate black frames of digital image content data during the switching event. 
 
     
     
         8 . The switcher device according to  claim 7  wherein
 the scaler is further adapted to continue to generate black frames of digital image content data until receiving a sufficient amount of digital image content data to generate a stable output of converted digital image content data. 
 
     
     
         9 . The switcher device according to  claim 2 , wherein the security protocol comprises:
 High-Bandwidth Digital Content Protection (HDCP).   
     
     
         10 . The switcher device according to  claim 2  wherein the switching event comprises:
 at least one of
 a switch from receiving first digital video from a first digital video source to receiving second digital video from a second digital video source, 
 a switch from receiving digital video at a first resolution to receiving digital video at a second resolution, and 
 a switch from receiving digital video at a first refresh rate to receiving digital video at a second refresh rate. 
 
 
     
     
         11 . The switcher device according to  claim 1  further comprising:
 a processing unit in communication with the multiplexer and the output board and wherein the processing unit transmits a prepare signal to the output board a predetermined amount of time before transmitting a switch signal to the multiplexer. 
 
     
     
         12 . An output board in a digital video switcher device for use in a digital video transmission system, the digital video switcher device transmitting digital audiovisual data to a digital video sink over a security protocol link, the output board comprising:
 a receiver adapted to receive the digital audiovisual data from at least two input boards;   a scaler adapted to convert the received digital audiovisual data to a native resolution of the video sink and to generate switched digital audiovisual data during a switching event between the at least two input boards, the switched digital audiovisual data comprising a substantially continuous stream of uninterrupted digital video timing data, wherein the substantially continuous stream of uninterrupted digital video timing data is generated in the absence of digital video timing data received from each of the at least two input boards; and   a transmitter adapted to encrypt and transmit the output of the scaler, and is further adapted to maintain the security protocol link in an authenticated interface with the digital video sink.   
     
     
         13 . The output board according to  claim 12 , wherein the switching event comprises:
 at least one of
 a switch from receiving audiovisual data from a first source to receiving audiovisual data from a second source, 
 a switch from receiving audiovisual data at a first resolution to receiving audiovisual data at a second resolution, and 
 a switch from receiving audiovisual data at a first refresh rate to receiving audiovisual data at a second refresh rate. 
   
     
     
         14 . The output board according to  claim 12 , wherein
 the scaler is adapted to generate image content data during the switching event.   
     
     
         15 . The output board according to  claim 14 , wherein
 the scaler is adapted to generate image content data after a switching event until receiving a sufficient amount of digital audiovisual data to generate a stable output of converted digital audiovisual data.   
     
     
         16 . The output board of  claim 12  wherein,
 the security protocol comprises High-Bandwidth Digital Content Protection (HDCP). 
 
     
     
         17 . A method for reducing switching delay when switching sources in a digital video distribution network, the method comprising:
 receiving digital audiovisual data at a first input board from a first digital video source;   receiving digital audiovisual data at a second input board from a second digital video source;   routing audiovisual data from the first input board to an output board;   transmitting the digital audiovisual data from the output board to a digital video sink;   receiving a user control signal to switch from the first digital video source to the second digital video source;   generating a substantially continuous stream of uninterrupted digital video timing data at the output board during a delay when switching between digital audiovisual data from the first input board and digital audiovisual data from the second input board, the switching comprising a switching event, wherein the generated substantially continuous stream of uninterrupted digital video timing data is generated in the absence of digital video timing data received from either or both of the first input board and the second input board during the switching event.   
     
     
         18 . The method according to  claim 17 , further comprising:
 routing the digital audiovisual data from the second input board to the output board; and   transmitting the digital audiovisual data from the output board to the video sink.   
     
     
         19 . The method according to  claim 17  further comprising:
 scaling the digital audiovisual data received from the first input board to a native resolution of the display; and 
 scaling the digital audiovisual data received from the second input board to the native resolution of the display. 
 
     
     
         20 . The method according to  claim 17  further comprising:
 generating image content data during the switching event. 
 
     
     
         21 . The method according to  claim 21  further comprising:
 continuing to generate digital audiovisual data at the output board until an amount of digital audiovisual data sufficient to produce stable scaled digital audiovisual data is received from the second input board. 
 
     
     
         22 . The method according to  claim 17  further comprising:
 transmitting a prepare signal to the output board. 
 
     
     
         23 . The method according to  claim 17 , wherein the step of generating a continuous stream of uninterrupted video timing data comprises:
 automatically generating video timing data in a free funning mode at the output board.