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 processing of at least one of the subbands is changed in response to a change in a compression rate requirement.
2. The method of claim 1 , wherein the first and second subbands each entropy code the image data by applying an algorithmic transformation, and wherein the algorithmic transformation used for the first subband differs from that used for the second subband.
3. The method of claim 1 , wherein a coding table used for the first subband differs from that used for the second subband.
4. A method of compressing data, comprising: processing a data stream through a plurality of parallel subbands, wherein a first sub band processes the data differently than a second sub band, and wherein the processing comprises quantizing, wherein the first subband entropy codes the data, and wherein the second subband omits to entropy code the data.
5. A method of sending video data over a cellular phone network, comprising the steps of:
providing information reflecting a change in at least one of an available bandwidth and signal strength for sending video data over a cellular phone network;
processing the video data through a plurality of parallel subbands including the step of processing a first one of the plurality of subbands differently from a second one of the plurality of subbands based on the information reflecting a change in the available bandwidth and signal strength for sending video data over a cellular phone network.