Method and apparatus for managing changes in a virtual screen buffer

• US 7,403,204 B2
• Filed: 08/23/2005
• Issued: 07/22/2008
• Est. Priority Date: 08/23/2004
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Emerson, Theodore F., Noonan, Robert L., Heinrich, David F., Dykes, Don
• Primary Examiner(s): Zimmerman; Mark
• Assistant Examiner(s): Xu; Kevin K
• Application Number:
  US11/209,897
• Publication Number:
  US 20060039466A1
• Time in Patent Office: 1,064 Days
• Field of Search: None
• US Class Current: 345/545
• CPC Class Codes: G06F 11/2294 by remote test
• CPC Class Codes: G06F 3/1454 involving copying of the display data of a local workstation or window to a remote workstation or window so that an actual copy of the data is displayed simultaneously on two or more displays, e.g. teledisplay
• CPC Class Codes: G06F 3/1462 with means for detecting differences between the image stored in the host and the images displayed on the remote displays
• CPC Class Codes: G09G 2340/02 Handling of images in compressed format, e.g. JPEG, MPEG
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 2001/0094 Bus
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/164 Feedback from the receiver or from the transmission channel
• CPC Class Codes: H04N 19/174 the region being a slice, e.g. a line of blocks or a group of blocks
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/42 characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation H04N19/635 takes precedence
• CPC Class Codes: H04N 19/436 using parallelised computational arrangements
• CPC Class Codes: H04N 19/507 using conditional replenishment
• CPC Class Codes: H04N 21/4334 Recording operations recording of a television signal H04N5/76; arrangements for recording or accumulating broadcast information or broadcast-related information H04H60/27
• CPC Class Codes: H04N 21/6332 directed to client

Abstract

A remote management controller may include a capture engine and a processor. The capture engine may be 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 such 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. The processor may be 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.

Claims

1. A remote management controller comprising:

a capture engine 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 such 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

a processor 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.

2. The remote management controller, as set forth in claim 1, wherein the processor locks the changed portion by preventing the capture engine from accessing the virtual screen buffer and the table associated with the virtual screen buffer.

3. The remote management controller, as set forth in claim 1, wherein the capture engine comprises a direct memory access engine configured to move the portion to the virtual screen buffer.

4. The remote management controller, as set forth in claim 1, wherein the at least one value calculated by the capture engine comprises a cyclic redundancy check.

5. The remote management controller, as set forth in claim 1, wherein a processor accesses only portions of video data in the virtual screen buffer that have changed.

6. The remote management controller, as set forth in claim 1, wherein the video data is obtained from a direct video output of the video graphics controller.

7. The remote management controller, as set forth in claim 1, wherein the processor is configured to process the video data by compressing the video data.

8. The remote management controller, as set forth in claim 1, wherein the processor is configured to process the video data by encoding the video data.

9. The remote management controller, as set forth in claim 1, wherein the processor is configured to process the video data by encrypting the video data.

10. The remote management controller, as set forth in claim 1, wherein the processor is configured to process the video data by forming the video data into at least one packet suitable for transmission to the remote system.

11. The remote management controller, as set forth in claim 3, wherein the act of the processor reading an indication of a changed portion in the change table automatically locks the direct memory access engine from accessing the virtual screen buffer.

12. 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.

13. The method, as set forth in claim 12, comprising locking the changed portion by preventing any updates of the virtual screen buffer and the table associated with the virtual screen buffer.

14. The method, as set forth in claim 12, comprising modifying the change table to indicate that the changed portion has been transmitted.

15. The method, as set forth in claim 14, wherein calculating the at least one value correlative to each portion in the slice and calculating the value correlative to each portion in the virtual screen buffer comprises calculating a cyclic redundancy check.

16. The method, as set forth in claim 12, comprising accessing only portions of the video data in the virtual screen buffer that have changed.

17. The method, as set forth in claim 12, wherein obtaining the slice of video data comprises obtaining the slice of video data from a direct video output of the video graphics controller.

18. The method, as set forth in claim 12, wherein processing comprises compressing the video data.

19. The method, as set forth in claim 12, wherein processing comprises encoding the video data.

20. The method, as set forth in claim 12, wherein processing comprises encrypting the video data.

21. The method, as set forth in claim 12, wherein processing comprises forming the video data into at least one packet suitable for transmission to the remote management controller.

22. 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.

23. The computer, as set forth in claim 22, wherein the processor locks the changed portion by preventing the capture engine from accessing the virtual screen buffer and the table associated with the virtual screen buffer.

24. The computer, as set forth in claim 22, wherein the capture engine comprises a direct memory access engine configured to move the portion to the virtual screen buffer.

25. The computer, as set forth in claim 22, wherein the at least one value calculated by the capture engine and the value calculated by the processor comprises a cyclic redundancy check.

26. The computer, as set forth in claim 22, wherein the processor accesses only portions of video data in the virtual screen buffer that have changed.

27. The computer, as set forth in claim 22, wherein the slice of video data is obtained from a direct video output of the video graphics controller.

28. The computer, as set forth in claim 22, wherein the processor is configured to process the video data by compressing the video data.

29. The computer, as set forth in claim 22, wherein the processor is configured to process the video data by encoding the video data.

30. The computer, as set forth in claim 22, wherein the processor is configured to process the video data by encrypting the video data.

31. The computer, as set forth in claim 22, wherein the processor is configured to process the video data by forming the video data into at least one packet suitable for transmission to the remote system.

32. The computer, as set forth in claim 24, wherein the act of the processor reading an indication of a changed portion in the change table automatically locks the direct memory access engine from accessing the virtual screen buffer.