Guaranteed Data Compression
AssigneeImagination Technologies Limited
InventorsPeter Malcolm Lacey, Simon Fenney
Life of this patent
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Abstract
A method of data compression in which the total size of the compressed data is determined and based on that determination, the bit depth of the input data may be reduced before the data is compressed. The bit depth that is used may be determined by comparing the calculated total size to one or more pre-defined threshold values to generate a mapping parameter. The mapping parameter is then input to a remapping element that is arranged to perform the conversion of the input data and then output the converted data to a data compression element. The value of the mapping parameter may be encoded into the compressed data so that it can be extracted and used when subsequently decompressing the data.
Claims20
A method of compressing a data block comprising data from four channels, the method comprising, for each channel or each sub-set of channels:
- determining a total size of the compressed data using at least partial data compression technique;
- determining a mapping parameter by comparing the total size to a plurality of thresholds;
- deducing a bit depth of each data value based on the mapping parameter;
- compressing the reduced bit depth data using the full data compression technique;
- and
- encoding the mapping parameter in the compressed reduced bit depth data.
A data compression unit arranged to compress a data block comprising data from four channels, the data compression unit comprising, for each channel or each sub-set of channels:
- a bit predictor element arranged to determine a total size of the compressed data using at least partial data compression technique and determine a mapping parameter by comparing the total size to a plurality of thresholds;
- a first remapping element arranged to reduce a bit depth of each data value based on the mapping parameter;
- a data compression element arranged to compress the reduced bit depth data using the full data compression technique;
- and
- a bit depth encoding element arranged to encode the mapping parameter in the compressed reduced bit depth data.
Dependencies are inferred from the claim text.