MULTI-LEVEL REPRESENTATION OF REORDERED TRANSFORM COEFFICIENTS
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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.
12 Citations
40 Claims
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1-20. -20. (canceled)
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21. 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 (22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. 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 (33, 34, 35, 36, 37, 38, 39)
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40. A computing device for decoding video, comprising a processing unit, memory coupled to the processing unit, and storage storing computer-executable instructions for causing the computing device to perform a 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, wherein the plurality of scan orders includes plural pre-determined scan orders, and wherein the selecting comprises; creating a new scan order of the plurality of scan orders; 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, wherein the second symbol represents one of the frequency coefficients outside of the first set, the first symbol and the second symbol having been jointly coded; 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, wherein the applying the selected scan order includes traversing a one-dimensional string of the frequency coefficients according to the selected scan order and reordering the frequency coefficients into a two-dimensional block.
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Specification