US 8,542,934 B2 · Transform space difference compression

Abstract

An invention is disclosed for performing differencing of graphical data in post-transform space for a remote presentation session. Graphical data is transformed from a first representation to a second representation (e.g. with a DWT), and then a difference is taken of the post-transform data and the post-transform data of the frame that preceded the current frame. This difference is then encoded and transmitted to a client, which decodes it, and creates a representation of the graphical data using the delta, and a previously determined representation of the previous frame. By performing differencing in post-transform space, fidelity of the remote presentation session is retained while it may decrease bandwidth. This may occur because the entropy of the delta representation is usually lower than a non-delta representation while the scheme retains the identical data of the final decoded image of the non-delta version of the same compression scheme.

Claims20

Dependent claims

A system for compressing a second graphical data that occurs in a sequence of graphical data after a first graphical data, comprising:

a processor;
and
a memory communicatively coupled to the processor when the system is operational, the memory bearing processor-executable instructions that, upon execution by the processor, cause the system at least to:
transform the first graphical data from a first representation to a second representation to produce a first transformed first data, the transformed first data comprising a first set of values;
transform the second graphical data from the first representation to the second representation to produce a transformed second data, the transformed second data comprising a second set of values;
determine a difference between the first set of values and the second set of values to produce a delta set of values;
encode the delta set of values to produce an encoded delta;
and
transmit the encoded delta to a computer across a communications network, such that the computer decodes the delta, combines the decoded delta with a representation of the first graphical data stored in a memory of the computer to produce a representation of the second graphical data in the second representation, converts the second graphical data in the second representation to the first representation, and displays the second graphical data in the first representation on a display device.

6 more elements

Dependencies are inferred from the claim text.

Transform space difference compression

Life of this patent

Transform space difference compression

Life of this patent

Abstract

Claims20