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US 8,553,763 B2Granted
Iterative computation of adaptive interpolation filter
AssigneeSony Corporation
InventorsCheung Auyeung, Ali Tabatabai
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Abstract
The invention is an apparatus and method for estimating an optimized sub-pixel interpolation filter using iterative estimations as needed for sub-pixel motion compensation and motion estimation in a video codec for improving coding efficiency. Multiple iterations of adaptive interpolation filter estimation are performed including more than one iteration based on sub-pixel motion vectors. During testing of the inventive apparatus and method on various video segments, average bit rate reductions were exhibited of approximately 5%.
Claims20
An apparatus for optimizing encoding in a video codec, comprising:
- a computer configured for receiving a video having a plurality of pictures;
- a memory coupled to said computer;
- and
- programming configured for retention in said memory and executable on said computer for:
- performing first pass encoding of said plurality of pictures within said video in response to executing transforms, quantization, and filtering by a predetermined interpolation filter optimized for sub-pixel motion vectors, and estimating an adaptive interpolation filter;
- performing at least one additional iteration pass of encoding said plurality of pictures within said video in response to executing transforms, quantization, and filtering by an adaptive interpolation filter using estimates for the adaptive interpolation filter determined in a previous pass of encoding, and estimating an adaptive interpolation filter optimized for sub-pixel motion vectors;
- wherein a last said additional iteration pass of encoding is an nth pass of encoding;
- encoding the current picture again in a final n+1th iteration pass of an adaptive interpolation filter to create a final pass encoded representation;
- selecting either the first pass encoded representation or the final pass encoded representation as an optimally efficient encoded representation for the current picture;
- and
- outputting an encoded video stream of the optimally efficient encoded representation.
8 more elements
An apparatus for optimizing encoding in a video codec, comprising:
- a computer configured for receiving a video having a plurality of pictures;
- a memory coupled to said computer;
- and
- programming executable on said computer for:
- encoding said plurality of pictures within said video in response to executing transforms and quantization, and in response to using a predetermined interpolation filter optimized for pixel level motion vectors and sub-pixel motion vectors;
- performing a first estimation of an adaptive interpolation filter, and determining a set of filter coefficients, said filter optimized for sub-pixel motion vectors to create a first pass encoded representation;
- performing at least one additional iteration pass of encoding with an additional estimation of the adaptive interpolation filter in an n-th iteration optimized for sub-pixel motion vectors determined in said n-th iteration;
- determining that said n-th iteration is the last iteration prior to encoding the current picture again;
- encoding the current picture again in a final n+1th iteration pass to create a final pass encoded representation;
- selecting either the first pass encoded representation or the final pass encoded representation as an optimally efficient encoded representation for the current picture;
- and
- outputting an encoded video stream of the optimally efficient encoded representation.
9 more elements
A method for optimizing encoding in a video codec, comprising:
- encoding a current picture within a video, using transforms and predictions and in response to using a predetermined interpolation filter optimized for pixel level motion vectors, and estimating an adaptive interpolation filter within a first pass of encoding;
- performing at least one additional iteration pass of encoding said picture within said video in response to executing transforms, quantization, and filtering by an adaptive interpolation filter using estimates for the adaptive interpolation filter determined in a previous pass of encoding, and estimating an adaptive interpolation filter optimized for sub-pixel motion vectors for a subsequent pass of encoding;
- wherein a last said additional iteration pass of encoding is an nth pass of encoding;
- encoding the current picture again in a final n+1th iteration pass to create a final pass encoded representation;
- selecting either the first pass encoded representation or the final pass encoded representation as an optimally efficient encoded representation for the current picture;
- and
- outputting an encoded video stream of the optimally efficient encoded representation.
4 more elements
Dependencies are inferred from the claim text.