Post-filtering for decoded video signals
First Claim
1. A computer-implemented process for transforming encoded video signals into decoded video frames, comprising the steps of:
- (a) providing encoded video signals corresponding to a video frame, wherein the encoded video signals comprise a first set of transform coefficients corresponding to a first region of the video frame and a second set of transform coefficients corresponding to a second region of the video frame;
(b) applying an inverse transform to the first set of transform coefficients to generate a decoded first region of a decoded video frame;
(c) applying the inverse transform to the second set of transform coefficients to generate a decoded second region of the decoded video frame;
(d) generating an original discontinuity measure for a boundary between the decoded first region and the decoded second region;
(e) adjusting at least one transform coefficient of the second set of transform coefficients in accordance with the original discontinuity measure to generate an adjusted second set of transform coefficients for the second region; and
(f) generating a filtered second region of a filtered video frame in accordance with the adjusted second set of transform coefficients.
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Abstract
Encoded video signals comprise sets of transform coefficients (e.g., DCT coefficients) corresponding to different regions of a video frame. An inverse transform is applied to sets of transform coefficients to generate decoded regions of a decoded video frame. The discontinuities for boundaries between adjacent regions are used to adjust one or more of the transform coefficients. The adjusted sets of transform coefficients are then used to generate filtered regions of a filtered video frame corresponding to the decoded video frame. In a preferred embodiment, the transform coefficients are DCT coefficients and the DC and first two AC DCT coefficients are sequentially adjusted to correct for quantization errors in the encoding process.
201 Citations
30 Claims
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1. A computer-implemented process for transforming encoded video signals into decoded video frames, comprising the steps of:
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(a) providing encoded video signals corresponding to a video frame, wherein the encoded video signals comprise a first set of transform coefficients corresponding to a first region of the video frame and a second set of transform coefficients corresponding to a second region of the video frame; (b) applying an inverse transform to the first set of transform coefficients to generate a decoded first region of a decoded video frame; (c) applying the inverse transform to the second set of transform coefficients to generate a decoded second region of the decoded video frame; (d) generating an original discontinuity measure for a boundary between the decoded first region and the decoded second region; (e) adjusting at least one transform coefficient of the second set of transform coefficients in accordance with the original discontinuity measure to generate an adjusted second set of transform coefficients for the second region; and (f) generating a filtered second region of a filtered video frame in accordance with the adjusted second set of transform coefficients. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus for transforming encoded video signals into decoded video frames, comprising:
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(a) means for providing encoded video signals corresponding to a video frame, wherein the encoded video signals comprise a first set of transform coefficients corresponding to a first region of the video frame and a second set of transform coefficients corresponding to a second region of the video frame; (b) means for applying an inverse transform to the first set of transform coefficients to generate a decoded first region of a decoded video frame; (c) means for applying the inverse transform to the second set of transform coefficients to generate a decoded second region of the decoded video frame; (d) means for generating an original discontinuity measure for a boundary between the decoded first region and the decoded second region; (e) means for adjusting at least one transform coefficient of the second set of transform coefficients in accordance with the original discontinuity measure to generate an adjusted second set of transform coefficients for the second region; and (f) means for generating a filtered second region of a filtered video frame in accordance with the adjusted second set of transform coefficients. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification