Method and apparatus for controlling access to image data

A method of decoding encoded image data, comprising:

• entropy decoding said encoded image data to produce quantized coefficients;
• obtaining first key data and scrambling table data associated with said encoded image data;
• inverse quantizing said quantized coefficients to recover coefficients;
• de-shuffling at least a first portion of said coefficients using said scrambling table data;
• shifting at least a second portion of said coefficients using said first key data;
• and
• frequency translating said coefficients to produce a set of image data samples.

Apparatus for encoding image data, comprising:

• a discrete cosine transform (DCT) unit for frequency translating a set of samples associated with said image data to produce coefficients;
• a quantizer for quantizing said coefficients;
• a first intra-level shifter for shifting at least a first portion of said coefficients using first key data;
• a shuffler for shuffling at least a second portion of said coefficients using scrambling table data;
• and
• an entropy encoder for entropy coding said coefficients to produce encoded image data.

Apparatus for decoding encoded image data, comprising:

• an entropy decoder for entropy decoding said encoded image data to produce quantized coefficients;
• means for obtaining first key data and scrambling table data associated with said encoded image data;
• an inverse quantizer for inverse quantizing said quantized coefficients to recover coefficients;
• a de-shuffler for de-shuffling at least a first portion of said coefficients using said scrambling table data;
• a first intra-level shifter for shifting at least a second portion of said coefficients using said first key data;
• and
• an inverse discrete cosine transform (IDCT) unit for frequency translating said coefficients to produce a set of image data samples.

A computer readable carrier including program instructions that instruct a computer to perform a method of encoding image data, comprising:

• frequency translating a set of samples associated with said image data to produce coefficients;
• quantizing said coefficients;
• shifting at least a first portion of said coefficients using first key data;
• shuffling at least a second portion of said coefficients using scrambling table data;
• and
• entropy coding said coefficients to produce encoded image data.

A computer readable carrier including program instructions that instruct a computer to perform a method of decoding encoded image data, comprising:

• entropy decoding said encoded image data to produce quantized coefficients;
• obtaining first key data and scrambling table data associated with said encoded image data;
• inverse quantizing said quantized coefficients to recover coefficients;
• de-shuffling at least a first portion of said coefficients using said scrambling table data;
• shifting at least a second portion of said coefficients using said first key data;
• and
• frequency translating said coefficients to produce a set of image data samples.