Multi-level representation of reordered transform coefficients
First Claim
1. A method of decoding video in a computing device that implements a video decoder, the method comprising:
- receiving information indicating a scan order in a bit stream;
selecting one of a plurality of scan orders based on the information indicating the scan order;
receiving entropy coded frequency coefficients of a block in the bit stream;
with the computing device that implements the video decoder, entropy decoding the entropy coded frequency coefficients of the block, the frequency coefficients having been encoded using a multi-level nested-set representation, wherein the entropy decoding the entropy coded frequency coefficients includes;
entropy decoding a first symbol and a second symbol at a first level of the multi-level nested-set representation, the first symbol representing a first set of one or more of the frequency coefficients as a summary representation at the first level of the multi-level nested-set representation;
at a given level of the multi-level nested-set representation that is lower than the first level;
decoding plural symbols at the given level, each of the plural symbols at the given level representing a set of one or more of the frequency coefficients; and
for each of the plural symbols at the given level, determining whether to split the set for the symbol into plural subsets and, if so, decoding plural sub-symbols at a lower level of the multi-level nested-set representation, each of the plural sub-symbols at the lower level representing one of the plural subsets; and
applying the selected scan order to reorder the frequency coefficients of the block.
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Abstract
Techniques and tools for encoding and decoding a block of frequency coefficients are presented. An encoder selects a scan order from multiple available scan orders and then applies the selected scan order to a two-dimensional matrix of transform coefficients, grouping non-zero values of the frequency coefficients together in a one-dimensional string. The encoder entropy encodes the one-dimensional string of coefficient values according to a multi-level nested set representation. In decoding, a decoder entropy decodes the one-dimensional string of coefficient values from the multi-level nested set representation. The decoder selects the scan order from among multiple available scan orders and then reorders the coefficients back into a two-dimensional matrix using the selected scan order.
219 Citations
27 Claims
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1. A method of decoding video in a computing device that implements a video decoder, the method comprising:
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receiving information indicating a scan order in a bit stream; selecting one of a plurality of scan orders based on the information indicating the scan order; receiving entropy coded frequency coefficients of a block in the bit stream; with the computing device that implements the video decoder, entropy decoding the entropy coded frequency coefficients of the block, the frequency coefficients having been encoded using a multi-level nested-set representation, wherein the entropy decoding the entropy coded frequency coefficients includes; entropy decoding a first symbol and a second symbol at a first level of the multi-level nested-set representation, the first symbol representing a first set of one or more of the frequency coefficients as a summary representation at the first level of the multi-level nested-set representation; at a given level of the multi-level nested-set representation that is lower than the first level; decoding plural symbols at the given level, each of the plural symbols at the given level representing a set of one or more of the frequency coefficients; and for each of the plural symbols at the given level, determining whether to split the set for the symbol into plural subsets and, if so, decoding plural sub-symbols at a lower level of the multi-level nested-set representation, each of the plural sub-symbols at the lower level representing one of the plural subsets; and applying the selected scan order to reorder the frequency coefficients of the block. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A computing device for decoding video, comprising a processing unit and memory coupled to the processing unit, that is configured for:
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receiving information indicating a scan order in a bit stream; selecting one of a plurality of scan orders based on the information indicating the scan order; receiving entropy coded frequency coefficients of a block in the bit stream; entropy decoding the entropy coded frequency coefficients of the block, the frequency coefficients having been encoded using a multi-level nested-set representation, wherein the entropy decoding the entropy coded frequency coefficients includes; entropy decoding a first symbol and a second symbol at a first level of the multi-level nested-set representation, the first symbol representing a first set of one or more of the frequency coefficients as a summary representation at the first level of the multi-level nested-set representation; at a given level of the multi-level nested-set representation that is lower than the first level; decoding plural symbols at the given level, each of the plural symbols at the given level representing a set of one or more of the frequency coefficients; and for each of the plural symbols at the given level, determining whether to split the set for the symbol into plural subsets and, if so, decoding plural sub-symbols at a lower level of the multi-level nested-set representation, each of the plural sub-symbols at the lower level representing one of the plural subsets; and applying the selected scan order to reorder the frequency coefficients of the block. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A computer system comprising a processing unit and memory that implement a decoding tool, the decoding tool comprising:
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an entropy decoder configured to perform; receiving entropy coded frequency coefficients of a block in the bit stream; and entropy decoding the entropy coded frequency coefficients of the block, the frequency coefficients having been encoded using a multi-level nested-set representation, wherein the entropy decoding the entropy coded frequency coefficients includes; entropy decoding a first symbol and a second symbol at a first level of the multi-level nested-set representation, the first symbol representing a first set of one or more of the frequency coefficients as a summary representation at the first level of the multi-level nested-set representation; at a given level of the multi-level nested-set representation that is lower than the first level; decoding plural symbols at the given level, each of the plural symbols at the given level representing a set of one or more of the frequency coefficients; and for each of the plural symbols at the given level, determining whether to split the set for the symbol into plural subsets and, if so, decoding plural sub-symbols at a lower level of the multi-level nested-set representation, each of the plural sub-symbols at the lower level representing one of the plural subsets; and a scan order decoder configured to perform; receiving information indicating a scan order in the bit stream; selecting one of a plurality of scan orders based on the information indicating the scan order; and applying the selected scan order to reorder the frequency coefficients of the block. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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Specification