Method and device for variable complexity decoding of motion-compensated block-based compressed digital video
First Claim
1. A method for computing an inverse discrete cosine transform by using a number of non-zero coefficients and an associated function mapping method based on video compression standard syntax cues, the method comprising the steps of:
- generating a set of reduced complexity implementation candidates for the inverse discrete cosine transform;
using video compression standard syntax cues to obtain the number of non-zero coefficients for the inverse discrete cosine transform; and
mapping the number of non-zero coefficients to a corresponding reduced complexity implementation candidate inverse transformation.
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Abstract
A method and device compute the inverse discrete cosine transform (IDCT) in a block based motion compensated digital video decoder, such that the computational complexity is dependent on syntax cues from an input block, and the resulting overall complexity is greatly reduced on average. The method and device provide a means for selecting a set of pruned IDCT algorithms based on the statistics of generic coded video data. The classification of input IDCT blocks uses the last non-zero coefficient obtained as a by-product of decompression and dequantization. The mapping from the last non-zero coefficient to a corresponding set of separable one-dimensional IDCT algorithms is performed efficiently with the careful consideration of memory requirements, mapping complexity, and pruned IDCT-complexity tradeoffs.
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Citations
8 Claims
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1. A method for computing an inverse discrete cosine transform by using a number of non-zero coefficients and an associated function mapping method based on video compression standard syntax cues, the method comprising the steps of:
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generating a set of reduced complexity implementation candidates for the inverse discrete cosine transform; using video compression standard syntax cues to obtain the number of non-zero coefficients for the inverse discrete cosine transform; and mapping the number of non-zero coefficients to a corresponding reduced complexity implementation candidate inverse transformation. - View Dependent Claims (2, 3, 4)
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5. A device for computing an inverse discrete cosine transform by using a number of non-zero coefficients and an associated function mapping method based on video compression standard syntax cues, the device comprising:
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means for generating a set complexity implementation candidates for the inverse discrete cosine transform; means for using syntax cues to obtain the number of non-zero coefficients for the inverse discrete cosine transform; and means for mapping the number of non-zero coefficient to a corresponding reduced complexity implementation candidate inverse transformation. - View Dependent Claims (6, 7, 8)
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Specification