Selection of the maximum dynamic range of transformed data and the data precision of transform matrices according to the bit depth of input data

A data encoding apparatus for encoding image data, comprising circuitry configured to:

• frequency-transform input image data to generate an array of frequency-transformed image coefficients by a matrix-multiplication process based on a maximum dynamic ranged of frequency-transformed data,
• select, based on an encoding profile for the input image data, the maximum dynamic range of the transformed data by an offset number added to the bit depth of the image data, the bit depth corresponding to the encoding profile, and
• encode the image data based on the maximum dynamic range,
• wherein the offset number has a number of bits which is less than the bit depth of the image data before the offset number is added to the bit depth of the image data.

A method of decoding image data, comprising:

• frequency-transforming input frequency-transformed image data to generate an array of output image data by a matrix-multiplication process based on a maximum dynamic range of frequency-transformed data;
• selecting, based on an encoding profile for the input image data, the maximum dynamic range of the transformed data by an offset number added, by circuitry, to the bit depth of the image data, the bit depth corresponding to the encoding profile;
• and
• decoding the image data using the maximum dynamic range,
• wherein the offset number has a number of bits which is less than the bit depth of the image data before the offset number is added to the bit depth of the image data.

A data decoding apparatus for decoding image data, comprising circuitry configured to:

• frequency-transform input frequency-transformed image data to generate an array of output image data by a matrix-multiplication process based on a maximum dynamic range of frequency-transformed data,
• select, based on an encoding profile for the input image data, the maximum dynamic range of the transformed data by an offset number added, by circuitry, to the bit depth of the image data, the bit depth corresponding to the encoding profile, and
• decode the image data using the maximum dynamic range,
• wherein the offset number has a number of bits which is less than the bit depth of the image data before the offset number is added to the bit depth of the image data.