Preprocessing multiple bit per pixel sampled data for Lempel-Ziv compression
AssigneeInternational Business Machines Corporation
InventorOscar Conrad Strohacker
Life of this patent
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Abstract
A preprocessor for processing sample data, particularly digital video data, to improve lossless sliding window type Lempel-Ziv compression of the data. Sliding window Lempel-Ziv compression is improved by transposing the multiple bit per pixel data samples before compression so that the relatively repetitive higher order bits of successive pixels are compressed separately from the relatively volatile lower order bits of the successive pixels. The transposition is particularly suited for bit plane configured frame buffers in that compression and decompression grouping is readily performed by the manipulation of data within the individual bit planes.
Claims10
A system suited to the compression of video data, comprising:
- a frame buffer means with multiple bit planes for storing digital format video data composed of multiple data bits per pixel;
- means for serially reading the video data from a selected bit plane of the frame buffer means;
- means for forming the serially read video data into groups;
- means for transmitting formed groups in ordered succession;
- means for compressing the video data as represented in the ordered succession of groups;
- and
- means for transmitting token s representing the ordered succession of groups in compressed form.
A method of compressing video data, comprising the steps of:
- storing digital format video data composed of multiple data bits per pixel in a frame buffer using multiple bit planes;
- serially reading the video data from a selected bit plane of the frame buffer;
- forming the serially read video data into groups;
- transmitting formed groups in ordered succession;
- and
- compressing the video data as represented in the ordered succession of groups into an output string of tokens representing multiple groups in compressed form.
Dependencies are inferred from the claim text.