Method and apparatus for managing changes in a virtual screen buffer

A method of processing video data for transmission to a remote system, the method comprising:

• obtaining a slice of video data output from a video graphics controller;
• calculating at least one value correlative to the slice of video data;
• determining whether any portion of the slice has been locked;
• if any portion has not been locked and if the calculated value for such portion of the slice differs from a value for a previously obtained corresponding portion, moving the portion to a virtual screen buffer, updating a table associated with the virtual screen buffer with the calculated value, and modifying a change table to indicate that the portion has changed;
• reading the change table to determine whether any portion of video data in the virtual screen buffer has changed;
• and
• if any portion has changed, locking any changed portion from being accessed by the capture engine, accessing the changed portion from the virtual screen buffer, and processing the changed portion in the virtual screen buffer for transmission to a remote system.

A computer comprising:

• at least one central processing unit;
• main memory accessible by the at least one central processing unit;
• a video graphics controller configured to receive video data from the at least one central processing unit and to generate a video data output;
• a remote management controller coupled to receive the video data output from the video graphics controller, the remote management controller comprising a capture engine and a processor,
• the capture engine being configured to:
• obtain a slice of video data output from a video graphics controller,
• calculate at least one value correlative to the slice of video data,
• determine whether any portion of the slice has been locked, and
• if any portion has not been locked and if the calculated value for any portion of the slice differs from a value for a previously obtained corresponding portion, move the portion to a virtual screen buffer, update a table associated with the virtual screen buffer with the calculated value, and modify a change table to indicate that the portion has changed;
• and
• the processor being configured to:
• read the change table to determine whether any portion of video data in the virtual screen buffer has changed, and
• if any portion has changed, lock any changed portion from being accessed by the capture engine, access the changed portion from the virtual screen buffer, and process the changed portion in the virtual screen buffer for transmission to a remote system.