Data Compression for Video

1 . An encoded bit stream of compressed video data, representing a plurality of successive video frames with each frame being divided into a plurality of portions and each portion corresponding to a plurality of pixels, the encoded bit stream comprising:

a set of quantized transform domain coefficients representing a first one of said portions;

difference data for a second one of said portions to be predicted from the first portion, wherein the difference data defines a difference between transform domain coefficients of the first portion and the second portion; and

an address specifying the location of the first portion in terms of a whole number of said portions.

2 . An encoded bit stream according to claim 1 , wherein the first portion is from a first one of said frames, the second portion is from a second one of said frames, and the bit stream comprises motion data encoded in the form of said block address.

3 . An encoded bit stream according to claim 1 , wherein the address is an absolute address of the first portion within a frame.

4 . An encoded bit stream according to claim 1 , wherein the address is a relative address being a difference between an address of the first portion and a block address of the second block.

5 . An encoded bit stream according to claim 1 , wherein each of said portions is one of a block or a sub-block, and the address comprises at least one of a block address and a sub-block address accordingly.

6 . An encoded bit stream according to claim 5 , wherein each frame is divided into a plurality of blocks and each block is divided into a plurality of sub-blocks, each of said portions being a sub-block, and the address comprises both a block address and a sub-block address

7 . An encoded bit stream according to claim 5 , wherein the address further comprises a macro-block address.

8 . An encoded bit stream according to claim 5 , wherein the address further comprises a frame number.

9 . An encoded bit stream according to claim 1 , further comprising an indication of a prediction method to be used to predict the second portion from the first portion.

10 . An encoded bit stream when embodied in a physical medium representing a plurality of successive video frames with each frame being divided into a plurality of portions and each portion corresponding to a plurality of pixels, the encoded bit stream comprising:

a set of quantized transform domain coefficients representing a first one of said portions;

difference data for a second one of said portions to be predicted from the first portion, wherein the difference data defines a difference between transform domain coefficients of the first portion and the second portion; and

an address specifying the location of the first portion in terms of a whole number of said portions.

11 . A network equipment comprising a transmission medium carrying a bit stream of compressed video data, representing a plurality of successive video frames with each frame being divided into a plurality of portions and each portion corresponding to a plurality of pixels, the bit stream including:

a set of quantized transform domain coefficients representing a first one of said portions;

difference data for a second one of said portions to be predicted from the first portion, wherein the difference data defines a difference between transform domain coefficients of the first portion and the second portion; and

an address specifying the location of the first portion in terms of a whole number of said portions.

12 . A decoder for decoding video data, the decoder comprising:

an input for receiving an encoded bit stream of compressed video data, representing a plurality of successive video frames with each frame being divided into a plurality of portions and each portion corresponding to a plurality of pixels, the encoded bit stream having:

a set of quantized transform domain coefficients representing a first one of said portions;

difference data for a second one of said portions to be predicted from the first portion, wherein the difference data defines a difference between transform domain coefficients of the first portion and the second portion; and

an address specifying the location of the first portion in terms of a whole number of said portions;

processing apparatus configured to identify the first portion based on the address received in the encoded bit stream, and to determine a set of transform domain coefficients for the second portion based on the difference data and the transform domain coefficients of the first portion, thereby decoding part of the encoded bit stream for generating a decoded bit stream; and

an output for outputting the decoded bit stream to an output device.

13 . A decoder program product for decoding an encoded bit stream of compressed video data having a plurality of successive video frames with each frame being divided into a plurality of portions and each portion corresponding to a plurality of pixels, the encoded bit stream including a set of quantized transform domain coefficients of a first one of said portions, difference data defining a difference between transform domain coefficients, and an address of the location of the first portion, the decoder program product comprising code embodied on a computer-readable medium and configured so as when executed on a processor to:

identify the first portion based on the address received in the encoded bit stream;

determine a set of transform domain coefficients for a second portion based on the difference data and the transform domain coefficients of the first portion, thereby decoding part of the encoded bit stream for generating a decoded bit stream; and

output the decoded bit stream to an output device.