EP0615384A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Adaptive compression of digital video data
Assignee: Arris Technology Inc
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Filing: 1994-03-10
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Granted: —
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Expires: 2014-03-10
Abstract
Abstract Digital video signals are adaptively compressed for communication to a receiver. Superblocks (230), each containing a plurality of blocks (232) of digital video data, are compressed using PCM, DPCM with a general motion vector for the entire superblock, and DPCM with a specific motion vector for each block contained within a superblock. The result of each compression mode is compared (58) after accounting for overhead data, to determine which results in the least amount of data for each block (232). These blocks are assembled into a superblock (230), and compared (80) together with necessary overhead and motion vector data to the same superblock processed using all PCM as well as the superblock processed using all DPCM. The comparison determines which compression mode produces the least amount of data for the superblock. The most compact superblock is selected for transmission. The transmitted superblocks are decoded by a decoder (Fig. 5) that recovers the necessary motion vectors and overhead information which identifies the type of compression used to provide the superblock.
Inventors
- 👤 Allen Wu
- 👤 Edward A. Krause
- 👤 Woo H. Paik
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 22:24
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/90; H04N19/10; H04N19/102; H04N19/12; H04N19/169; H04N19/186; H04N19/50; H04N19/503; H04N19/51; H04N19/513; H04N19/517; H04N19/60; H04N19/61
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
235 words
Apparatus for adaptively compressing digital video data provided in the form of superblocks containing a plurality of blocks of said digital video data, comprising: means for compressing a superblock using first, second and third different compression modes to provide three compressed outputs for comparison; first means for comparing the amount of compressed data for each block of said superblock resulting from each of said compression modes after accounting for selection overhead necessary to identify a selection made by said first comparing means, said first comparing means selecting the compression mode for each block that results in the least amount of compressed data, including selection overhead, for the block; second means for comparing the amount of compressed data for said superblock resulting from: (i) said first compression mode together with first compression mode overhead data associated therewith, (ii) said second compression mode together with second compression mode overhead data associated therewith, and (iii) the blocks selected by said first comparing means together with adaptive mode overhead data associated with the selected blocks in addition to said selection data for each selected block, said second comparing means determining which of (i), (ii) and (iii) represents the least amount of data to be transmitted for said superblock; and means for outputting said superblock in a compressed form obtained using the compression mode that said second comparing means determines will result in the least amount of data for transmission.
Claim 2
Dependent Claim
62 words
Apparatus in accordance with claim 1 wherein: said first compression mode compresses said superblock without motion compensation; said second compression mode compresses each block forming said superblock with motion compensation based on a general motion vector for said superblock; and said third compression mode compresses each block forming said superblock with motion compensation based on a specific motion vector for each block.
Claim 3
Dependent Claim
27 words
Apparatus in accordance with claim 1 or 2 wherein said first compression mode overhead data comprises: a codeword identifying the compressed data as first compression mode data.
Claim 4
Dependent Claim
34 words
Apparatus in accordance with one of claims 2 or 3 wherein said second compression mode overhead data comprises: said general motion vector, and a codeword identifying the compressed data as second compression mode data.
Claim 5
Dependent Claim
101 words
Apparatus in accordance with one of claims 2 to 4 wherein said adaptive mode overhead data comprises: said general motion vector, a codeword identifying the blocks as those selected by said first comparing means, a codeword identifying each block selected by said first comparing means as one of PCM data generated by said first compression mode, DPCM data generated by said second compression mode, and DPCM data generated by said third compression mode, and data indicative of the specific motion vector associated with each block selected by said first comparing means that comprises DPCM data generated by said third compression mode.
Claim 6
Dependent Claim
39 words
Apparatus in accordance with one of the preceding claims wherein said superblocks are luminance blocks, said apparatus further comprising: means for including corresponding chrominance data in each of categories (i), (ii) and (iii) compared by said second comparing means.
Claim 7
Dependent Claim
66 words
Apparatus in accordance with claim 6 wherein: the chrominance data included in category (i) is PCM chrominance data; the chrominance data included in category (ii) is DPCM chrominance data; and the chrominance data included in category (iii) for each block is PCM chrominance data when PCM provides the least chrominance data for transmission, and DPCM chrominance data when DPCM provides the least chrominance data for transmission.
Claim 8
Dependent Claim
115 words
Apparatus in accordance with claim 6 wherein said second comparing means comprise: a first accumulator for accumulating the data resulting from said first compression mode for said superblock together with said first compression mode overhead data and corresponding chrominance data; a second accumulator for accumulating the data resulting from said second compression mode for said superblock together with said second compression mode overhead data and corresponding chrominance data; a third accumulator for accumulating the data resulting from the blocks selected by said first comparing means together with said adaptive mode overhead data, the selection data for each block, and corresponding chrominance data; and a comparator for comparing the amount of data accumulated by each accumulator.
Claim 9
Dependent Claim
40 words
Apparatus in accordance with one of the preceding claims further comprising: motion compensation means responsive to said second comparing means for generating predictor signals for said second and third compression modes and for generating said general and specific motion vectors.
Claim 10
Dependent Claim
24 words
Apparatus in accordance with claim 9 further comprising means for compressing said specific motion vectors by differentially encoding them with said general motion vector.
Claim 11
Dependent Claim
162 words
Apparatus in accordance with one of the preceding claims wherein said superblocks are luminance blocks, said apparatus further comprising: means for compressing chrominance data using a first chrominance compression mode and a second chrominance compression mode; third means for comparing the amount of compressed chrominance data for each block of said superblock resulting from each of said first and second chrominance compression modes after accounting for selection overhead necessary to identify a selection made by said third comparing means, said third comparing means outputting the lesser amount of compressed chrominance data including selection overhead for each block; means for including compressed chrominance data from said first chrominance compression mode in category (i) compared by said second comparing means; means for including compressed chrominance data from said second chrominance compression mode in category (ii) compared by said second comparing means; and means for including the compressed chrominance data output by said third comparing means in category (iii) compared by said second comparing means.
Claim 12
Dependent Claim
86 words
Apparatus in accordance with claim 11 wherein: said first compression mode compresses said superblock without motion compensation; said second compression mode compresses each block forming said superblock with motion compensation based on a general motion vector for said superblock; said third compression mode compresses each block forming said superblock with motion compensation based on a specific motion vector for each block; said first chrominance compression mode compresses said chrominance data without motion compensation; and said second chrominance compression mode compresses said chrominance data with motion compensation.
Claim 13
Dependent Claim
57 words
Apparatus in accordance with claim 12 further comprising: motion compensation means responsive to said second comparing means for generating predictor signals for said second and third compression modes and for generating said general and specific motion vectors; and motion compensation means responsive to said second comparing means for generating predictor signals for said second chrominance compression mode.
Claim 14
Dependent Claim
24 words
Apparatus in accordance with claim 13 further comprising means for compressing said specific motion vectors by differentially encoding them with said general motion vector.
Claim 15
Independent Claim
177 words
A method for selecting compression modes for different portions of data to be transmitted, comprising the steps of: compressing a plurality of said portions using first, second, and third different compression modes; accumulating said plurality of portions compressed using said first compression mode together with first overhead data to provide a first set of accumulated data; accumulating said plurality of portions compressed using said second compression mode together with second overhead data to provide a second set of accumulated data; accumulating, together with third overhead data to provide a third set of accumulated data, said plurality of portions each compressed using whichever of said compression modes meets a first selection criterion for that portion, said first selection criterion accounting for selection data included in said third overhead data; comparing the first, second and third sets of accumulated data to determine which set meets a second selection criterion; and providing said plurality of portions for transmission in a compressed form determined by whichever of said first, second and third sets of accumulated data meets said second selection criterion.
Claim 16
Dependent Claim
36 words
A method in accordance with claim 15 wherein said first selection criterion selects the least amount of compressed data for each of said portions and said second selection criterion selects the least amount of accumulated data.
Claim 17
Independent Claim
71 words
A method in accordance with one of claims 15 or 16 wherein: said portions comprise video image data; said first compression mode compresses said plurality of portions without motion compensation; said second compression mode compresses each portion with motion compensation based on a general motion vector for said plurality of portions; and said third compression mode compresses each portion with motion compensation based on a specific motion vector for each portion.
Claim 18
Dependent Claim
184 words
Decoder apparatus comprising: means for receiving superblocks of compressed video data, said superblocks containing individual blocks each compressed using one of a plurality of compression modes; means coupled to said receiving means for retrieving, from each received superblock, one of: first overhead data indicative of a first compression mode used to compress the whole superblock, second overhead data indicative of a second compression mode used to compress the whole superblock, and third overhead data indicating that the individual blocks contained in said superblock were compressed using a plurality of different compression modes; means responsive to said first overhead data for decoding a received superblock using a decompression mode corresponding to said first compression mode; means responsive to said second overhead data for decoding a received superblock using a decompression mode corresponding to said second compression mode; and means responsive to said third overhead data for identifying the compression mode used to compress each individual block in a received superblock and for decoding the received superblock using a decompression mode for each individual block that corresponds to the compression mode used to compress the block.
Claim 19
Dependent Claim
72 words
A decoder in accordance with claim 18 wherein: a first one of said compression modes compresses said superblocks without motion compensation; a second one of said compression modes compresses each block in a superblock with motion compensation based on a general motion vector for said superblock; and a third one of said compression modes compresses each block in a superblock with motion compensation based on a specific motion vector for each block.
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