METHOD AND DEVICE FOR VIDEO TRANSCODING USING QUAD-TREE BASED MODE SELECTION
First Claim
1. A method of encoding a downsampled video, wherein the downsampled video is a spatially downsampled version of a full-resolution video, the downsampled video including a frame having a macroblock that corresponds to at least two full-resolution macroblocks in a corresponding frame of the full-resolution video, each of the at least two full-resolution macroblocks having an associated full-resolution coding mode that defines partitioning of that full-resolution macroblock, the method comprising:
- determining an initial partitioning of the macroblock based on downsampling of the at least two full-resolution macroblocks subject to a minimum partition size, wherein the initial partitioning divides the macroblock into a plurality of partitions;
storing the initial partitioning in a quad-tree data structure, wherein each of the plurality of partitions is a leaf node, each leaf node has a parent node, and the quad-tree data structure represents spatial relationships amongst said plurality of partitions;
recursively,identifying candidate mergers, wherein each candidate merger comprises the combination of two or more leaf nodes to create a larger partition, and wherein the two or more leaf nodes in each combination have a common parent node, and determining whether the larger partition has a rate-distortion cost smaller than a cumulative rate-distortion cost of the two or more leaf nodes and, if so, merging the two or more leaf nodes to generate an updated partitioning with the larger partition as a new leaf node; and
encoding the downsampled video to generate an encoded downsampled video, including encoding the macroblock using the updated partitioning, after determining that no further candidate mergers are identifiable.
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Accused Products
Abstract
An encoder for encoding a downsampled video in which macroblock partitioning is based upon downsampled partitioning of full-resolution macroblocks. The refinement of the downsampled partitioning involves storing the downsampled partitioning in a quad-tree data structure and recursively identifying and evaluating possible mergers of leaf nodes having a common parent node. Using rate-distortion analysis possible mergers are evaluated and advantageous mergers are performed, thereby creating larger partitions and new leaf nodes. The traversing of the quad-tree to identify possible leaf node mergers is stopped when no further possible mergers may be identified that would result in a rate-distortion advantage.
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Citations
21 Claims
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1. A method of encoding a downsampled video, wherein the downsampled video is a spatially downsampled version of a full-resolution video, the downsampled video including a frame having a macroblock that corresponds to at least two full-resolution macroblocks in a corresponding frame of the full-resolution video, each of the at least two full-resolution macroblocks having an associated full-resolution coding mode that defines partitioning of that full-resolution macroblock, the method comprising:
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determining an initial partitioning of the macroblock based on downsampling of the at least two full-resolution macroblocks subject to a minimum partition size, wherein the initial partitioning divides the macroblock into a plurality of partitions; storing the initial partitioning in a quad-tree data structure, wherein each of the plurality of partitions is a leaf node, each leaf node has a parent node, and the quad-tree data structure represents spatial relationships amongst said plurality of partitions; recursively, identifying candidate mergers, wherein each candidate merger comprises the combination of two or more leaf nodes to create a larger partition, and wherein the two or more leaf nodes in each combination have a common parent node, and determining whether the larger partition has a rate-distortion cost smaller than a cumulative rate-distortion cost of the two or more leaf nodes and, if so, merging the two or more leaf nodes to generate an updated partitioning with the larger partition as a new leaf node; and encoding the downsampled video to generate an encoded downsampled video, including encoding the macroblock using the updated partitioning, after determining that no further candidate mergers are identifiable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 21)
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11. An encoder for encoding a downsampled video, wherein the downsampled video is a spatially downsampled version of a full-resolution video, the downsampled video including a frame having a macroblock that corresponds to at least two full-resolution macroblocks in a corresponding frame of the full-resolution video, each of the at least two full-resolution macroblocks having an associated full-resolution coding mode that defines partitioning of that full-resolution macroblock, the encoder comprising:
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a processor; a memory; a communications system for outputting an encoded downsampled video; and an encoding application stored in memory and containing instructions for configuring the processor to encode the downsampled video by determining an initial partitioning of the macroblock based on downsampling of the at least two full-resolution macroblocks subject to a minimum partition size, wherein the initial partitioning divides the macroblock into a plurality of partitions; storing the initial partitioning in a quad-tree data structure in the memory wherein each of the plurality of partitions is a leaf node, each leaf node having a parent node, and the quad-tree data structure represents spatial relationships amongst said plurality of partitions; recursively, identifying candidate mergers, wherein each candidate merger comprises the combination of two or more leaf nodes to create a larger partition, and wherein the two or more leaf nodes in each combination have a common parent node, and determining whether the larger partition has a rate-distortion cost smaller than a cumulative rate-distortion cost of the two or more leaf nodes and, if so, merging the two or more leaf nodes to generate an updated partitioning with the larger partition as a new leaf node; and encoding the downsampled video to generate an encoded downsampled video, including encoding the macroblock using the updated partitioning, after determining that no further candidate mergers are identifiable. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification