US 6,008,847 AGranted

Temporal compression and decompression for video

AssigneeConnectix Corporation

InventorRoger A. Bauchspies

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Abstract

A temporal compression and decompression system is disclosed for color video. A video stream with red, green and blue pixel element values is input to a first computer. In the first computer, a new frame of video data is compared to the frame being displayed on a second computer and the similarity between corresponding blocks and sub-blocks is represented with one tolerance result per sub-block. Based on the number of sub-blocks for which tolerance results exceed a preset threshold and a user-specified quality level, an update quality level is selected that determines the quality at which the frame update is transmitted from the first computer to the second computer. Before the frame update is transmitted the updating information is compressed in a two-stage process. In the first stage 5-bit red, blue and green element values in sub-blocks being updated are is converted to 3-bit categories. In the second stage groups of categories are converted to variable-length Huffman words. The Huffman words are then transmitted over a communications channel to the second computer, which decompresses and displays the updated sub-blocks.

Claims23

Dependent claims

A method for performing temporal compression and decompression of color video data, comprising the steps of:

a) receiving a new frame of said video data;
b) determining differences between contents of said new frame and contents of an on-screen video image displayed from previous frames of said video data;
c) designating as updating information data from regions of said new frame for which said differences exceed an updating threshold;
d) determining updating quality of video compression to be applied to said updating information so that said updating information takes up no more than bandwidth available for a video transmission in which said updating information is transferred to a device displaying said video image;
e) when said updating information fits within said bandwidth, designating for inclusion in said updating information data from other regions of said new frame corresponding to other regions of said on-screen image displayed by said device with a display quality less than said updating quality;
f) compressing said updating information at a compression level consistent with said updating quality;
g) forming said video transmission by merging the compressed updating information with block marks indicating the on-screen blocks to be updated with the compressed updating information;
and
h) appending to said video transmission a representation of said updating quality.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/810,589Filed 3 Mar 1997 · continuation in part
Priority: 8 Apr 1996
Granted: 28 Dec 1999
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

H04N 1/648
Systems for the transmission or the storage of the colour picture signal; Details therefor, e.g. coding or decoding means therefor: transmitting…
H03M 7/42
Conversion to or from variable length codes, e.g. Shannon-Fano code, Huffman code, Morse code: using table look-up for the coding or decoding…
H04N 19/507
Involving temporal prediction: using conditional replenishment
H04N 19/593
Using predictive coding: involving spatial prediction techniques