Video compression encoder

• US 8,385,429 B2
• Filed: 09/28/2006
• Issued: 02/26/2013
• Est. Priority Date: 10/01/2002
• Status: Active Grant

• Current Assignee: Vertiv IT Systems, Inc. (Vertiv Holdings Co.)
• Original Assignee: Avocent Corporation (Vertiv Holdings Co.)
• Inventors: Dambrackas, William A., Costa, Mario, Goodley, George Richard
• Primary Examiner(s): SENFI, BEHROOZ M
• Application Number:
  US11/528,569
• Publication Number:
  US 20070019743A1
• Time in Patent Office: 2,343 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, 375/240, 375/240.01, 375/240.26, 375/240.02, 375/240.2, 375/240.24, 375/240.11, 375/240.25, 375/240.13, 375/240.18, 375/240.1
• US Class Current: 375/240.26
• CPC Class Codes: G09G 2370/24 Keyboard-Video-Mouse [KVM] switch
• CPC Class Codes: H04N 19/105 Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
• CPC Class Codes: H04N 19/182 the unit being a pixel
• CPC Class Codes: H04N 19/20 using video object coding
• CPC Class Codes: H04N 19/426 using memory downsizing methods
• CPC Class Codes: H04N 19/507 using conditional replenishment
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/93 Run-length coding

Abstract

A video compression encoder which does not require a video frame buffer is disclosed. Without a frame buffer, incoming pixels can not be compared to pixels previously sent to the decoder. Instead, the disclosed encoder only stores check values for groups of pixels sent. If a group'"'"'s check value has not changed, the encoder sends a command to the decoder not to change that pixel group. Also, without a frame buffer, an incoming video frame can not be captured and later sent to the decoder as network throughput permits. Instead, if throughput is insufficient to send an encoded group of pixels, the encoder leaves the check value for that group unchanged and sends a command instructing the decoder not to change those pixels. This defers updating that group until the next screen update is sent to the decoder. Grouping of pixels can be done in any fashion, for example; a group can be a single video line, a portion of a line, multiple lines or screen rectangles containing portions of multiple lines.

Claims

1. A video encoder receiving a serial stream of pixel data corresponding to groups of pixels in a video frame of information, comprising:

a processor in a chip, with a local operating buffer also in the chip, programmed to;

determine a check value for the pixels of a given group based on a check value algorithm,

store the check value for the given group in a memory location of the local operating buffer corresponding to the given group,

encode the pixels of the given group into a code stream based on an encoding algorithm,

continue the determining, storing, and encoding operations until the frame of information is encoded, and

for a next video frame of information;

determine a current check value for the current group of pixels based on the same check value algorithm,

encode the pixels of a given current group into a current code stream based on the same encoding algorithm,

compare the current check value with the stored value for the corresponding given group of the previous frame, and

if the current check value is the same as the stored value for the corresponding given group of the previous frame, preparing a copy command instructing a decoder to copy the pixel values of the given group of the previous frame, and

if the current check value is not the same as the stored value for the corresponding given group of the previous frame, sending the current code stream to the decoder and overwriting the current check value to the memory location of the local operating buffer corresponding to the given group.

2. The video encoder of claim 1, wherein a group of pixels is defined as a single line of a video frame.

3. A method of encoding a video stream comprising the steps of:

defining corresponding groups of pixels for video frames of a video stream;

receiving a serial stream of pixel data corresponding to a given group of pixels in a first video frame;

determining a check value for the pixels of the given group based on a check value algorithm;

storing the check value for the given group in a memory location corresponding to the given group;

encoding the pixels of the given group into a code stream based on an encoding algorithm;

continuing the determining, storing, and encoding steps for all the groups of pixels within the frame until the frame of information is encoded;

receiving a serial stream of pixel data corresponding to a given group of pixels in a next video frame of information and;

for a next video frame of information;

determining a current check value for the given group of pixels based on the same check value algorithm,

comparing the current check value with the stored value for the corresponding given group of the previous frame, and

if the current check value is the same as the stored value for the corresponding given group of the previous frame, preparing a copy command instructing a decoder to copy the pixel values of the given group of the previous frame, and

if the current check value is not the same as the stored value for the corresponding given group of the previous frame, sending the current code stream to the decoder and overwriting the current check value to the memory location of the local operating buffer corresponding to the given group.

4. The method of claim 3, wherein the defining step defines groups of pixels as a single line of a video frame.

5. A video encoder receiving a serial stream of pixel data corresponding to groups of pixels in a video frame of information, comprising:

a processor in a chip, with a local operating buffer also in the chip, programmed to;

determine a check value for the pixels of a given group based on a check value algorithm,

store the check value for the given group in a memory location of the local operating buffer corresponding to the given group,

encode the pixels of the given group into a code stream based on an encoding algorithm,

continue the determining, storing, and encoding operations until the frame of information is encoded, and

for a next video frame of information;

determine a current check value for the current group of pixels based on the same check value algorithm,

compare the current check value with the stored value for the corresponding given group of the previous frame, and

if the current check value is the same as the stored value for the corresponding given group of the previous frame, preparing a copy command instructing a decoder to copy the pixel values of the given group of the previous frame, and

if the current check value is not the same as the stored value for the corresponding given group of the previous frame, encoding the pixels of a given current group into a current code stream based on the same encoding algorithm, sending the current code stream to the decoder and overwriting the current check value to the memory location of the local operating buffer corresponding to the given group.

6. The video encoder of claim 5, wherein a group of pixels is defined as a single line of a video frame.

7. A method of encoding a video stream comprising the steps of:

determining a check value for the pixels of a given group based on a check value algorithm,

storing the check value for the given group in a memory location of the local operating buffer corresponding to the given group,

encoding the pixels of the given group into a code stream based on an encoding algorithm,

continuing the determining, storing, and encoding operations until the frame of information is encoded, and

for a next video frame of information;

determining a current check value for the current group of pixels based on the same check value algorithm,

comparing the current check value with the stored value for the corresponding given group of the previous frame, and

if the current check value is the same as the stored value for the corresponding given group of the previous frame, preparing a copy command instructing a decoder to copy the pixel values of the given group of the previous frame, and

if the current check value is not the same as the stored value for the corresponding given group of the previous frame, encoding the pixels of a given current group into a current code stream based on the same encoding algorithm, sending the current code stream to the decoder and overwriting the current check value to the memory location of the local operating buffer corresponding to the given group.

8. The method of claim 7, wherein a group of pixels is defined as a single line of a video frame.