DVC Delta commands

• US 20090290647A1
• Filed: 07/23/2009
• Published: 11/26/2009
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: Vertiv IT Systems, Inc. (Vertiv Holdings Co.)
• Original Assignee: Avocent Corporation (Vertiv Holdings Co.)
• Inventors: Lazenby, William, Shelton, Gary William, Potter, Michael
• Granted Patent: US 8,660,194 B2
• Time in Patent Office: Days
• US Class Current: 375/240.26
• CPC Class Codes: H04N 19/182 the unit being a pixel
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/93 Run-length coding

Abstract

A video compression system compresses video frames comprising pixels defined by n-bit color values. Encoder of video compression system determines the difference between a current pixel value and a plurality reference pixel values. Encoder sends difference value to decoder. Decoder determines current pixel value by adjusting a reference pixel color value by delta value.

Claims

1-5. -5. (canceled)

6. A method of encoding video, comprising the steps of:

predefining a set of pixel-copy commands based on frame location relationships between the present pixel and other pixels;

for the present pixel, encoding in a video encoder according to a hierarchy selection from one of;

(1) copy-pixel encoding that makes data packets defining the number of consecutive pixels that can be represented by copying the color of a respective pixel with a frame location relationship that is redundant to the respective pixel;

(2) individually colored pixel encoding that makes data packets each defining each color of the pixels in said given set of consecutive pixels; and

(3) delta value pixel encoding that makes data packets each defining the difference between the color of a current pixel and a respective pixel with a frame location relationship;

(4) a series pixel encoding that makes a data packet including bits each indicating which color, from an n-color set, applies to each of the pixels in said series of consecutive pixels, wherein pixels in said given set of consecutive pixels are comprised only from a set of n number of unique colors, the bits of the data packet representing a consecutive series of color identifiers in which (1) the color identifiers correspond respectively to the set of n number of unique colors, (2) the consecutive series is identical in length to the consecutive run of pixel colors, and (3) the color identifiers are ordered in the consecutive series to correspond to an order of the consecutive run of pixel colors.

7. A method according to claim 6, wherein the encoding includes making fixed-size data packets including an opcode portion that identifies said copy-pixel encoding, delta value pixel encoding, two-color series pixel encoding, and individually colored pixel encoding and a payload portion.

8. A method according to claim 7, wherein for at least some of the fixed-size data packets:

said opcode includes one bit identifying whether the corresponding data packet be associated with said individually colored pixel encoding;

said opcode of the data packet associated with said copy-pixel encoding and said two-color series pixel encoding includes two additional bits identifying the hierarchy selections associated with three different pixel copy commands and the two-color series pixels command; and

said payload portion has a length of at least n-bits.

9. A method according to claim 8, wherein others of the fixed-size data packets include an extension bit linking payload of the data packet with the payload of a previous data packet and including a payload of greater than n-bits.

10. A method according to claim 9, wherein others of the fixed-size packets include an extension bit linking the payload of the current data packet with the payload of the next data packet, which next data packet then includes a payload of greater than n-bits.

11-12. -12. (canceled)

13. A method of compressing a video frame comprising pixels defined by n-bit color values partitioned into three y₁-bit, y₂-bit, and y₃-bit channels, comprising the steps of:

for the y₁-bit channel;

for a plurality of directional relationship types of a current pixel relative to a reference pixel, generating a (y₁−

x₁)-bit delta value by determining a difference between a y₁-bit reference pixel color value and a respective y₁-bit current color value, where x₁ is a predetermined number of significant bits of y₁;

for the y₂-bit channel;

for a plurality of directional relationship types of a current pixel relative to a reference pixel, generating a (y₂−

x₂)-bit delta value by determining a difference between a y₂-bit reference pixel color value from a respective y₂-bit current color value, where x₂ is a predetermined number of significant bits of y₂;

for the y₃-bit channel;

for a plurality of directional relationship types of a current pixel relative to a reference pixel, generating a (y₃−

x₃)-bit delta value by determining a difference between a y₃-bit reference pixel color value from a respective y₃-bit current color value, where x₃ is a predetermined number of significant bits of y₃;

if the x₁, x₂, and x₃ significant bits of respective y₁-bit, y₂-bit, and y₃-bit channels are equal for the n-bit reference pixel color and the n-bit current color value, determining in a video encoder the n-bit current color value by adjusting each channel of the n-bit reference pixel color value by the respective delta values.

14-17. -17. (canceled)

18. A method dynamically adjusting the performance of a video compression system that compresses a video frame comprising pixels defined by n-bit color value channels by comparing the x most significant n-bits of a current pixel to the respective x most significant bits of a reference pixel, comprising the steps of:

specifying a bytes per pixel ratio (BP);

for a group of compressed pixels in video frame, determining an actual number of bytes required to compress the group of pixels;

determining a threshold number of bytes by multiplying BP and the number of pixels in the group;

comparing the actual number of bytes to the threshold number of bytes; and

if the actual number of bytes is greater than the threshold number of bytes, reducing x in a video encoder.

19. The method of 18, wherein BP is defined by the following equation:

BP=(bytes/second)/(frame width*frame height*frames per second); and

wherein the step of setting a bytes per pixel ratio (BP) further comprises setting the (bytes/second) value.