Compression rate control system and method with variable subband processing
A system, method and computer program product provide finer rate control in data compression by processing a data stream through a plurality of parallel subbands, wherein a first subband processes the data differently than a second subband. Separate shift quantization parameters for each separate run-of-zeros compressed storage area or pile can be provided, instead of a single common shift parameter for every coefficient as in the prior art. The parameter value for each such area or pile can be recorded in the compressed output file. The separate shift quantization parameters can also be adjusted dynamically as data is being compressed.
1. A method of compressing data, comprising: processing a data stream through a plurality of parallel subbands, wherein a first subband processes the data differently than a second subband, and wherein the processing comprises quantizing wherein the first and second subbands each quantize the data by applying a shift parameter, and wherein the shift parameter of the first subband is different than the shift parameter of the second subband.
2. The method of claim 1 , wherein the first subband is a low-pass subband and the second subband is a high-pass subband.
3. A method of compressing data, comprising: processing a data stream through a plurality of parallel subbands, wherein a first subband processes the data differently than a second subband, and wherein the processing comprises quantizing, further comprising a third subband that processes the data differently than either the first or the second subbands, wherein the first, second and third subbands each quantize the data by applying a shift parameter, and wherein the shift parameter of each of the first, second and third subbands is distinct.
4. A method of compressing data, comprising: processing a data stream through a plurality of parallel subbands, wherein a first subband processes the data differently than a second subband, and wherein the processing comprises quantizing, wherein of the plurality of subbands each quantize the data by applying either a first shift parameter or a different second shift parameter.
5. A method of compressing data, comprising: processing a data stream through a plurality of parallel subbands, wherein a first subband processes the data differently than a second subband, and wherein the processing comprises quantizing, wherein of the plurality of subbands each quantize the data by applying either a first shift parameter or a different second shift parameter, wherein the first shift parameter differs from the second shift parameter by 1.
6. A method of compressing data, comprising: processing a data stream through a plurality of parallel subbands, wherein a first subband processes the data differently than a second subband, and wherein the processing comprises quantizing, wherein the processing of at least one of the subbands is changed dynamically, wherein the processing of at least one of the subbands is changed in response to feedback from a downstream measurements, the downstream measurement to sample the at least one of the subbands after a compression process of the at least one subband.
7. A method of compressing data, comprising: processing a data stream through a plurality of parallel subbands, wherein a first subband processes the data differently than a second subband, and wherein the processing comprises quantizing, wherein the processing of at least one of the subbands is changed dynamically, wherein the processing of at least one of the subbands is changed in response to a feedforward signal from an upstream measurement, the upstream measurements to sample the at least one subbands before the compression process of the at least one of the subbands.
8. A method of compressing data, comprising: processing a data stream through a plurality of parallel subbands, wherein a first subband processes the data differently than a second subband, and wherein the processing comprises quantizing, wherein the processing step comprises entropy coding and wherein the first and second subbands each quantize the image data by applying a shift parameter, and wherein the shift parameter of the first subband is different than the shift parameter of the second subband.