DVC delta commands

• US 8,660,194 B2
• Filed: 07/23/2009
• Issued: 02/25/2014
• 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: Shelton, Gary William, Lazenby, William, Potter, Michael
• Primary Examiner(s): SENFI, BEHROOZ M
• Application Number:
  US12/458,818
• Publication Number:
  US 20090290647A1
• Time in Patent Office: 1,678 Days
• Field of Search: 348/384, 348/415, 348/416, 348/391, 348/393, 348/394, 348/417, 348/418, 348/409, 348/420, 348/408, 382/56, 382/232, 382/233, 382/236, 382/245, 382/253, 382/239, 382/238, 382/240, 37524001-24026
• 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. 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 according to a hierarchy selection from;

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

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

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

(4) two-color series pixel encoding that makes a data packet including each bit indicating which color, from a two-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 of colors from a two color set.

2. A method according to claim 1, 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.

3. A method according to claim 2, 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.

4. A method according to claim 3, 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.

5. A method according to claim 4, 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.

6. 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 the n-bit current color value by adjusting each channel of the n-bit reference pixel color value by the respective delta values.

7. A method dynamically adjusting the performance of a video compression system that compresses a video frame comprising pixels defined by n-bit color values channels by comparing the x most significant n-bits of 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 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.

8. The method of 7, 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.