Compression systems and methods

• US 20050104892A1
• Filed: 09/23/2004
• Published: 05/19/2005
• Est. Priority Date: 11/14/2003
• Status: Active Grant

• Current Assignee: Avocent Huntsville Corporation (Vertiv Holdings Co.)
• Original Assignee: Avocent Huntsville Corporation (Vertiv Holdings Co.)
• Inventors: Li, Sheng, Moore, Richard L., Covington, C. David, Lally, Charles, Huntly-Playle, Iain
• Granted Patent: US 7,627,186 B2
• Time in Patent Office: Days
• US Class Current: 345/555
• CPC Class Codes: G06F 2203/0384 Wireless input, i.e. hardware and software details of wireless interface arrangements for pointing devices
• CPC Class Codes: G06F 3/0231 Cordless keyboards
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G06T 9/001 Model-based coding, e.g. wire frame
• CPC Class Codes: G06T 9/20 Contour coding, e.g. using detection of edges
• CPC Class Codes: G09G 2340/02 Handling of images in compressed format, e.g. JPEG, MPEG
• CPC Class Codes: G09G 2370/16 Use of wireless transmission of display information
• CPC Class Codes: G09G 2370/24 Keyboard-Video-Mouse [KVM] switch
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/90 using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals

Abstract

In a wireless keyboard-video-mouse (“KVM”) system in which a remote computer accesses the video output data of a target computer, a method of providing video data from the target computer to the remote computer, a method includes compressing at least some of the video data using a line fitting compression scheme to produce at least one sequence of absolute coded pixel segments and relative coded pixel segments which combine to represent the video data; and providing the sequence of absolute coded pixel segments and relative coded pixel segments to the remote computer.

Claims

1. In a wireless keyboard-video-mouse (“

KVM”

) system in which a remote computer accesses the video output data of a target computer, a method of providing video data from the target computer to the remote computer, the method comprising;

compressing at least some of the video data using a line fitting compression scheme to produce at least one sequence of absolute coded pixel segments and relative coded pixel segments which combine to represent the video data; and

providing the sequence of absolute coded pixel segments and relative coded pixel segments to the remote computer.

2. A method as in claim 1, wherein each absolute coded pixel segment represents a single pixel and encodes the most significant bits of each color component of that pixel.

3. A method as in claim 2 wherein the most significant bits of each color component of a pixel comprise the top five bits of each color component of that pixel.

4. A method as in claim 1, wherein each relative coded pixel segment represents a sequence of pixels and defines a difference in value between a starting point of the first pixel in the sequence and an ending point of the last pixel in the sequence.

5. A method as in claim 4 wherein the sequence of pixels is between two and nine pixels in length and wherein the relative coded pixel segment provides a signed delta value of the difference between the starting point and the ending point of the segment.

6. A method as in claim 1 wherein the video data represents red, green and blue (RGB) pixel components and wherein a segment is formed to be as long as possible such that the curvature of each of the red, green, and blue component values that form the segment is constrained to be less than a threshold.

7. A method as in claim 6 wherein the measure of curvature is the magnitude of the output of a finite impulse response filter with coefficients (1, −

2,

     1) applied to the RGB pixel component values forming each segment.

8. A method as in claim 7 wherein the curvature is measured as the magnitude of the output of each of a set of finite impulse response filters with coefficients (1, −

2,

     1) and other filter coefficients derived from said finite impulse response filter by interspersing zeros, specifically producing first (1, 0, −

2, 0,

     1), then (1, 0, 0, −

2, 0, 0,

     1), and so on up to the maximum segment length.

9. In a wireless keyboard-video-mouse (“

KVM”

) system in which a remote computer accesses the video output data of a target computer, a method of providing video data from the target computer to the remote computer, the method comprising;

compressing at least some of the video data using a line fitting compression scheme to produce at least one sequence of absolute coded pixel segments and relative coded pixel segments which combine to represent the video data, wherein each absolute coded pixel segment represents a single pixel and encodes the five most significant bits of each color component of that pixel and wherein each relative coded pixel segment represents a sequence of pixels and defines a difference in value between a starting point of the first pixel in the sequence and an ending point of the last pixel in the sequence, wherein the sequence of pixels is between two and nine pixels in length and wherein the relative coded pixel segment provides a signed delta value of the difference between the starting point and the ending point of the segment; and

providing the sequence of absolute coded pixel segments and relative coded pixel segments to the remote computer.

10. In a wireless keyboard-video-mouse (“

KVM”

) system in which a remote computer accesses the video output data of a target computer, a device for providing video data from the target computer to the remote computer, the device comprising;

a compressing mechanism constructed and adapted to compress at least some of the video data using a line fitting compression scheme to produce at least one sequence of absolute coded pixel segments and relative coded pixel segments which combine to represent the video data; and

a mechanism constructed and adapted to provide the sequence of absolute coded pixel segments and relative coded pixel segments to the remote computer.

11. A device as in claim 10, wherein each absolute coded pixel segment represents a single pixel and encodes the most significant bits of each color component of that pixel.

12. A device as in claim 11 wherein the most significant bits of each color component of a pixel comprise the top five bits of each color component of that pixel.

13. A device as in claim 12, wherein each relative coded pixel segment represents a sequence of pixels and defines a difference in value between a starting point of the first pixel in the sequence and an ending point of the last pixel in the sequence.

14. A device as in claim 12 wherein the sequence of pixels is between two and nine pixels in length and wherein the relative coded pixel segment provides a signed delta value of the difference between the starting point and the ending point of the segment.

15. In a wireless keyboard-video-mouse (“

KVM”

) system in which a remote computer accesses the video output data of a target computer, a device for providing video data from the target computer to the remote computer, the device comprising;

a mechanism constructed and adapted to compress at least some of the video data using a line fitting compression scheme to produce at least one sequence of absolute coded pixel segments and relative coded pixel segments which combine to represent the video data, wherein each absolute coded pixel segment represents a single pixel and encodes the five most significant bits of each color component of that pixel and wherein each relative coded pixel segment represents a sequence of pixels and defines a difference in value between a starting point of the first pixel in the sequence and an ending point of the last pixel in the sequence, wherein the sequence of pixels is between two and nine pixels in length and wherein the relative coded pixel segment provides a signed delta value of the difference between the starting point and the ending point of the segment; and

a mechanism constructed and adapted to provide the sequence of absolute coded pixel segments and relative coded pixel segments to the remote computer.

16. In a wireless keyboard-video-mouse (“

KVM”

) system in which a remote computer accesses the video output data of a target computer, a method of providing video data from the target computer to the remote computer, wherein the video data represents sequences of video frames, each frame comprising a sequence of video lines, the method comprising;

compressing at least some of the video data using a line fitting compression scheme to produce at least one sequence of absolute coded pixel segments and relative coded pixel segments which combine to represent the video data;

providing the sequence of absolute coded pixel segments and relative coded pixel segments to the remote computer; and

sending only a part of each video line from a left margin point to the end of the line, where the left margin point is defined as the left-most pixel of the video line to differ from the corresponding pixel in the corresponding line and in the prior frame by more than a programmable threshold amount.

19. A method as in any one of claims 16, 17 and 18 wherein the pixel difference is computed according to the city-block distance metric.

17. In a wireless keyboard-video-mouse (“

KVM”

) system in which a remote computer accesses the video output data of a target computer, a method of providing video data from the target computer to the remote computer, wherein the video data represents sequences of video frames, each frame comprising a sequence of video lines, the method comprising;

compressing at least some of the video data using a line fitting compression scheme to produce at least one sequence of absolute coded pixel segments and relative coded pixel segments which combine to represent the video data;

providing the sequence of absolute coded pixel segments and relative coded pixel segments to the remote computer; and

sending only a part of each video line from the beginning of the line to a right margin point, where the right margin point is defined as the last pixel of the line to differ from corresponding pixel in the corresponding line and in the prior frame by more than a programmable threshold amount.

18. In a wireless keyboard-video-mouse (“

KVM”

) system in which a remote computer accesses the video output data of a target computer, a method of providing video data from the target computer to the remote computer, wherein the video data represents sequences of video frames, each frame comprising a sequence of video lines, the method comprising;

compressing at least some of the video data using a line fitting compression scheme to produce at least one sequence of absolute coded pixel segments and relative coded pixel segments which combine to represent the video data;

providing the sequence of absolute coded pixel segments and relative coded pixel segments to the remote computer; and

sending only a part of each video line from a left margin point to a right margin point, where the left margin point is defined as the first pixel of the video line to differ from the corresponding pixel in the corresponding line and in the prior frame by more than a programmable threshold amount, and the right margin point is defined as the last pixel of the video line to differ from the corresponding pixel in the corresponding line and in the prior frame by more than the programmable threshold amount.