US5654759A
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US
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Methods and apparatus for reducing blockiness in decoded video
Assignee: Hitachi America Ltd
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Filing: 1995-02-15
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Granted: 1997-08-05
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Expires: 2015-02-15
Abstract
Abstract Methods and apparatus directed to reducing blockiness resulting from encoding digital video data using, e.g., DCTs are disclosed. An encoder which encodes video signals into a digital video bitstream including information identifying blocky video and instructions for processing the blocky video is also disclosed. A plurality of methods of identifying blocky video in an encoded bitstream by analyzing the encoded bitstream are also disclosed. In addition, various methods of filtering both non-blocky and blocky video, without adversely affecting the non-blocky video, are described.
Inventors
- 👤 Joseph E. Augenbraun
- 👤 Jill MacDonald Boyce
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:37
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/85; H04N19/86; H04N5/00; H04N5/14; H04N5/21
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
134 words
A method of operating a video decoder, comprising the steps of: receiving encoded digital video data, the encoded video data representing blocky and non-blocky predictively coded video frames and including motion vectors required for the decoding of the encoded video data; monitoring the received encoded digital bitstream to identify the motion vectors required for the decoding of the encoded video data; identifying video data corresponding to blocky video frames by detecting motion vectors, indicative of blocky video frames, that are larger than a preselected minimum size; and decoding the received encoded video data using the motion vectors included in the received encoded video data, the decoding step including the step of performing a blockiness reduction operation on video frames which are decoded using detected motion vectors that are larger than the preselected minimum size.
Claim 2
Independent Claim
134 words
A method of operating a video decoder, comprising the steps of: receiving encoded digital video data, the encoded video data representing blocky and non-blocky predictively coded video frames and including motion vectors required for the decoding of the encoded video data; monitoring the received encoded digital bitstream to identify the motion vectors required for the decoding of the encoded video data; identifying video data corresponding to blocky video frames by detecting motion vectors, indicative of blocky video frames, that are larger than a preselected minimum size; and decoding the received encoded video data using the motion vectors included in the received encoded video data, the decoding step including the step of performing a blockiness reduction operation on video frames which are decoded using detected motion vectors that are larger than the preselected minimum size.
Claim 3
Independent Claim
106 words
A method of operating a video decoder, comprising the steps of: receiving an encoded digital bitstream including encoded digital video data corresponding to blocky and non-blocky video images, the encoded digital video data corresponding to blocky and B non-blocky predictively coded video frames, each predictively coded video frame including intra-coded blocks and predictively coded blocks required for the decoding of the encoded video data; monitoring the received encoded digital video data to identify the intra-coded blocks; and identifying video data corresponding to blocky video images by detecting video data corresponding to predictively coded video frames that include more than a preselected minimum percentage of intra-coded blocks.
Claim 4
Independent Claim
106 words
A method of operating a video decoder, comprising the steps of: receiving an encoded digital bitstream including encoded digital video data corresponding to blocky and non-blocky video images, the encoded digital video data corresponding to blocky and B non-blocky predictively coded video frames, each predictively coded video frame including intra-coded blocks and predictively coded blocks required for the decoding of the encoded video data; monitoring the received encoded digital video data to identify the intra-coded blocks; and identifying video data corresponding to blocky video images by detecting video data corresponding to predictively coded video frames that include more than a preselected minimum percentage of intra-coded blocks.
Claim 5
Independent Claim
132 words
A method of operating a video decoder comprising the steps of: receiving encoded digital video data corresponding to blocky and non-blocky video images, the encoded video data including blocks of video data required for the decoding of the encoded video data, each block corresponding to an array of pixels; monitoring the received encoded digital video data to identify the blocks of video data required for the decoding of the encoded video data; identifying video data corresponding to blocky video images by using information included in the blocks of video data to calculate a blockiness cost function using pixel differences at block boundaries; and decoding the received encoded video data, the decoding step including the step of performing a blockiness reduction operation on the video data identified as corresponding to blocky video images.
Claim 6
Independent Claim
132 words
A method of operating a video decoder comprising the steps of: receiving encoded digital video data corresponding to blocky and non-blocky video images, the encoded video data including blocks of video data required for the decoding of the encoded video data, each block corresponding to an array of pixels; monitoring the received encoded digital video data to identify the blocks of video data required for the decoding of the encoded video data; identifying video data corresponding to blocky video images by using information included in the blocks of video data to calculate a blockiness cost function using pixel differences at block boundaries; and decoding the received encoded video data, the decoding step including the step of performing a blockiness reduction operation on the video data identified as corresponding to blocky video images.
Claim 7
Dependent Claim
122 words
The method of claim 3, wherein the blockiness cost function is calculated for at least three adjacent blocks, represented by the letters A, B, and C, block A, block B and Block C each representing an array of 8×8 pixels, and wherein the cost function is expressed using the following equation: ##EQU3## where A(0,Y) refers to the (0,Y) pixels in the array of 8×8 pixels which comprise block A; where B(7,Y) refers to the (7,Y) pixel in the array of 8×8 pixels which comprise block B; where A(X,0) refers to the (X,0) pixel in the array of 8×8 pixels which comprise block A; and where C (X,7) refers to the (X,7) pixel in the array of 8×8 pixels which comprise block C.
Claim 8
Dependent Claim
51 words
The method of claim 2, further comprising the steps of: decoding the encoded digital video data to generate decoded video data; and processing the decoded video data generated by decoding the encoded digital video data identified as corresponding to blocky video images by performing a Gaussian low pass filter operation thereon.
Claim 9
Dependent Claim
58 words
The method of claim 2, further comprising the steps of: decoding the encoded digital video data to generate decoded video data including blocks having block boundaries; and processing the decoded video data generated by decoding the encoded digital video data identified as corresponding to blocky video images by performing a low pass filter operation across the block boundaries.
Claim 10
Independent Claim
142 words
A method of operating a video decoder comprising the steps of: receiving an encoded digital bitstream including encoded digital video data corresponding to blocky and non-blocky video images, the encoded video data including information required for the decoding of the encoded video data; monitoring the received encoded digital bitstream to identify the information required for the decoding of the encoded video data; using the information required for the decoding of the encoded video data to identify video data corresponding to blocky video images; decoding the encoded digital video data to generate decoded video data including predictively coded blocks having blocking artifact boundaries located within the predictively coded blocks; and performing a blockiness reduction operation on at least a portion of the decoded video data by performing a low pass filter operation across the blocking artifact boundaries located within the predictively coded blocks.
Claim 11
Independent Claim
142 words
A method of operating a video decoder comprising the steps of: receiving an encoded digital bitstream including encoded digital video data corresponding to blocky and non-blocky video images, the encoded video data including information required for the decoding of the encoded video data; monitoring the received encoded digital bitstream to identify the information required for the decoding of the encoded video data; using the information required for the decoding of the encoded video data to identify video data corresponding to blocky video images; decoding the encoded digital video data to generate decoded video data including predictively coded blocks having blocking artifact boundaries located within the predictively coded blocks; and performing a blockiness reduction operation on at least a portion of the decoded video data by performing a low pass filter operation across the blocking artifact boundaries located within the predictively coded blocks.
Claim 12
Independent Claim
162 words
A method of operating a video decoder comprising the steps of: receiving an encoded digital bitstream including encoded digital video data corresponding to blocky and non-blocky video images, the encoded digital video data including blocks of video data, each block corresponding to an array of pixels; monitoring the received encoded digital bitstream to identify encoded digital video data corresponding to blocky video images, the monitoring step including the step of: calculating a blockiness cost function using pixel differences at block boundaries; decoding the encoded digital video data to generate decoded video data, the decoding step including the step of performing an IDCT operation on a block represented by DCT coefficients; and processing the decoded video data generated by decoding the encoded digital video data identified as corresponding to blocky video images by performing a blockiness reduction operation thereon, the blockiness reduction operation including the steps of: altering at least one DCT coefficient of the block; and calculating the IDCT for the block.
Claim 13
Independent Claim
162 words
A method of operating a video decoder comprising the steps of: receiving an encoded digital bitstream including encoded digital video data corresponding to blocky and non-blocky video images, the encoded digital video data including blocks of video data, each block corresponding to an array of pixels; monitoring the received encoded digital bitstream to identify encoded digital video data corresponding to blocky video images, the monitoring step including the step of: calculating a blockiness cost function using pixel differences at block boundaries; decoding the encoded digital video data to generate decoded video data, the decoding step including the step of performing an IDCT operation on a block represented by DCT coefficients; and processing the decoded video data generated by decoding the encoded digital video data identified as corresponding to blocky video images by performing a blockiness reduction operation thereon, the blockiness reduction operation including the steps of: altering at least one DCT coefficient of the block; and calculating the IDCT for the block.
Claim 14
Dependent Claim
23 words
The method of claim 8, wherein the at least one DCT coefficient of the block is altered to minimize the blockiness cost function.
Claim 15
Independent Claim
79 words
A method of processing video data representing predictively coded images and bi-directionally coded images that were generated by performing motion compensation on a video signal, the method comprising the steps of: identifying video data corresponding to blocky video images by detecting motion vectors having a value exceeding a preselected minimum motion vector value indicative of blocky video images; and performing a blockiness reduction operation on the identified blocky video data when the preselected minimum motion vector value is exceeded.
Claim 16
Independent Claim
79 words
A method of processing video data representing predictively coded images and bi-directionally coded images that were generated by performing motion compensation on a video signal, the method comprising the steps of: identifying video data corresponding to blocky video images by detecting motion vectors having a value exceeding a preselected minimum motion vector value indicative of blocky video images; and performing a blockiness reduction operation on the identified blocky video data when the preselected minimum motion vector value is exceeded.
Claim 17
Independent Claim
97 words
A method of processing digital video data including predictively coded video frames represented by intra-coded and predictively coded blocks, the method comprising the steps of: monitoring the number of intra-coded blocks in the predictively coded video frames; identifying blocky predictively coded video frames by: i. monitoring the number of intra-coded blocks in the predictively coded video frames; and ii. detecting which ones of the predictively coded video frames include more than a preselected minimum number of intra-coded blocks, the detected predictively coded video frames; and performing a blockiness reduction operation on the detected predictively coded video frames.
Claim 18
Independent Claim
97 words
A method of processing digital video data including predictively coded video frames represented by intra-coded and predictively coded blocks, the method comprising the steps of: monitoring the number of intra-coded blocks in the predictively coded video frames; identifying blocky predictively coded video frames by: i. monitoring the number of intra-coded blocks in the predictively coded video frames; and ii. detecting which ones of the predictively coded video frames include more than a preselected minimum number of intra-coded blocks, the detected predictively coded video frames; and performing a blockiness reduction operation on the detected predictively coded video frames.
Claim 19
Independent Claim
60 words
A method of detecting and processing blocky video images in a series of encoded video images, the method comprising the steps of: examining video images in the series of encoded video images to identify fade or scene changes indicative of blocky video images; and performing a blockiness reduction on the video images in which fade or scene changes are identified.
Claim 20
Independent Claim
60 words
A method of detecting and processing blocky video images in a series of encoded video images, the method comprising the steps of: examining video images in the series of encoded video images to identify fade or scene changes indicative of blocky video images; and performing a blockiness reduction on the video images in which fade or scene changes are identified.
Claim 21
Independent Claim
54 words
A method of performing a blockiness reduction operation on blocky decoded video data including predictively coded blocks having blocking artifact boundaries located within the predictively coded blocks, the method comprising the step of: performing a filtering operation across the blocking artifact boundaries located within the predictively coded blocks of the blocky decoded video data.
Claim 22
Independent Claim
54 words
A method of performing a blockiness reduction operation on blocky decoded video data including predictively coded blocks having blocking artifact boundaries located within the predictively coded blocks, the method comprising the step of: performing a filtering operation across the blocking artifact boundaries located within the predictively coded blocks of the blocky decoded video data.
Claim 23
Dependent Claim
15 words
The method of claim 13, wherein the filtering operation is a low pass filtering operation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-08-04 | 2001-02-03 | 2001-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-04 | 2005-02-03 | 2005-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-04 | 2009-02-03 | 2009-08-05 | $7700.00 | Window Closed / Lapsed |