Video image processing system having variable data compression
First Claim
1. A video image processing system comprising:
- an input store for temporarily storing input video data representing plural images of an input video sequence;
data compressing means for compressing in sequence each image of the video data stored in the input store to a given initial degree to produce respective data files each comprising multiple bytes of compressed data representing the input video data in compressed form, the compressing means operating to compress the video data at a rate faster than that at which it is input for storage in the input store;
an output store comprising divisions of like by storage capacity temporarily storing for output respective files of compressed data produced by the data compressing means; and
processing means for comparing the number of bytes in each compressed data file with the byte storage capacity of one said division of the output store to determine whether the compressed data file will;
occupy at least a desired fraction of the byte storage capacity of said one of said divisions of the output store, or less than said fraction of said one of said division, orexceed the storage capacity of one of said divisions,and for causing the compressing means when the compressed data file comprises fewer bytes than are required for occupancy of at least said fraction of the byte storage capacity of said one of said divisions or comprises more bytes than the byte storage capacity of said one of said divisions, to effect at least one repeat compressions to adjust the number of bytes in the compressed data file so that the ratio of said number of bytes of the recompressed data file to the byte capacity of said one of said divisions amounts to at least said desired fraction, thereby optimizing the utilization of storage in the output store.
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Abstract
A video image processing system comprises an input cache store for temporarily storing input video data, compressors for compressing image data from the input store and an output store comprising multiple storage areas of known fixed size for storing respective files of compressed data from the compressors. The compressors are arranged to compress each image of the input video data to a given initial degree to produce respective data files. A processor compares the number of bytes in each data file with the known size of one storage area in the output store to determine whether the data file will occupy a predetermined proportion of said storage area. In the event that the data file will not occupy said predetermined portion of said storage area, the processor causes one of the compressors to effect one or more repeat compressions to a different degree in order to produce a data file of a size which will occupy said predetermined proportion of said storage. The system thereby optimises the compression of data and the utilisation of storage in the storing of the compressed data.
121 Citations
11 Claims
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1. A video image processing system comprising:
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an input store for temporarily storing input video data representing plural images of an input video sequence; data compressing means for compressing in sequence each image of the video data stored in the input store to a given initial degree to produce respective data files each comprising multiple bytes of compressed data representing the input video data in compressed form, the compressing means operating to compress the video data at a rate faster than that at which it is input for storage in the input store; an output store comprising divisions of like by storage capacity temporarily storing for output respective files of compressed data produced by the data compressing means; and processing means for comparing the number of bytes in each compressed data file with the byte storage capacity of one said division of the output store to determine whether the compressed data file will; occupy at least a desired fraction of the byte storage capacity of said one of said divisions of the output store, or less than said fraction of said one of said division, or exceed the storage capacity of one of said divisions, and for causing the compressing means when the compressed data file comprises fewer bytes than are required for occupancy of at least said fraction of the byte storage capacity of said one of said divisions or comprises more bytes than the byte storage capacity of said one of said divisions, to effect at least one repeat compressions to adjust the number of bytes in the compressed data file so that the ratio of said number of bytes of the recompressed data file to the byte capacity of said one of said divisions amounts to at least said desired fraction, thereby optimizing the utilization of storage in the output store. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification