De-Blocking Filtering Control
First Claim
1. A filtering control method applicable to a block of multiple pixels in a video frame, each pixel having a respective pixel value, said method comprising:
- calculating a first filter decision value for said block representative of how smooth pixel values in a first line of pixels in said block and in a corresponding first line of pixels in a neighboring block of multiple pixels in said video frame are in a direction parallel to a filtering direction;
calculating a second filter decision value for said block representative of how close pixel values in a current line of pixels in said block approximate a flat line and how close pixel values in a corresponding current line of pixels in said neighboring block approximate a flat line;
comparing said first filter decision value with a first threshold and said second filter decision value with a second threshold;
selecting a strong de-blocking filter to filter at least one pixel value in said current line of pixels if said first filter decision value is below said first threshold and said second filter decision value is below said second threshold and otherwise selecting a weak de-blocking filter to filter at least one pixel value in said current line of pixels, wherein said strong de-blocking filter has a comparatively higher filtering strength as compared to said weak de-blocking filter.
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Accused Products
Abstract
First and second filter decision values are calculated for a pixel block in a video frame. The first filter decision value is representative of how smooth pixel values in a first line of pixels in the block and in a corresponding first line of pixels in a neighboring pixel block in the video frame are in a direction parallel to a filtering direction. The second filter decision value is representative of how close pixel values in a current line of pixels in the block approximate a flat line and how close pixel values in a corresponding current line of pixels in the neighboring block approximate a flat line. The two filter decision values are compared to respective thresholds and a strong de-blocking filter is selected for the current line if the filter decision values are below the thresholds, otherwise a weak de-blocking filter is selected to combat any blocking artifacts.
60 Citations
32 Claims
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1. A filtering control method applicable to a block of multiple pixels in a video frame, each pixel having a respective pixel value, said method comprising:
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calculating a first filter decision value for said block representative of how smooth pixel values in a first line of pixels in said block and in a corresponding first line of pixels in a neighboring block of multiple pixels in said video frame are in a direction parallel to a filtering direction; calculating a second filter decision value for said block representative of how close pixel values in a current line of pixels in said block approximate a flat line and how close pixel values in a corresponding current line of pixels in said neighboring block approximate a flat line; comparing said first filter decision value with a first threshold and said second filter decision value with a second threshold; selecting a strong de-blocking filter to filter at least one pixel value in said current line of pixels if said first filter decision value is below said first threshold and said second filter decision value is below said second threshold and otherwise selecting a weak de-blocking filter to filter at least one pixel value in said current line of pixels, wherein said strong de-blocking filter has a comparatively higher filtering strength as compared to said weak de-blocking filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A filtering control device comprising:
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a first decision value calculator configured to calculate a first filter decision value for a block of multiple pixels in a video frame, each pixel having a respective pixel value, said first filter decision value representative of how smooth pixel values in a first line of pixels in said block and in a corresponding first line of pixels in a neighboring block of multiple pixels in said video frame are in a direction parallel to a filtering direction; a second decision value calculator configured to calculate a second filter decision value for said block representative of how close pixel values in a current line of pixels in said block approximate a flat line and how close pixel values in a corresponding current line of pixels in said neighboring block approximate a flat line; a first threshold comparator configured to compare said first filter decision value calculated by said first decision value calculator to a first threshold; a second threshold comparator configured to compare said second filter decision value calculated by said second decision value calculator to a second threshold; and a filter selector configured to select a strong de-blocking filter to filter at least one pixel value in said current line of pixels if said first filter decision value is below said first threshold, as determined by said first filter threshold comparator, and said second filter decision value is below said second threshold, as determined by said second threshold comparator, and to otherwise select a weak de-blocking filter to filter at least one pixel value in said current line of pixels, wherein said strong de-blocking filter has a comparatively higher filtering strength as compared to said weak de-blocking filter. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. An encoder comprising a filtering control device, the filtering control device comprising:
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a first decision value calculator configured to calculate a first filter decision value for a block of multiple pixels in a video frame, each pixel having a respective pixel value, said first filter decision value representative of how smooth pixel values in a first line of pixels in said block and in a corresponding first line of pixels in a neighboring block of multiple pixels in said video frame are in a direction parallel to a filtering direction; a second decision value calculator configured to calculate a second filter decision value for said block representative of how close pixel values in a current line of pixels in said block approximate a flat line and how close pixel values in a corresponding current line of pixels in said neighboring block approximate a flat line; a first threshold comparator configured to compare said first filter decision value calculated by said first decision value calculator to a first threshold; a second threshold comparator configured to compare said second filter decision value calculated by said second decision value calculator to a second threshold; and a filter selector configured to select a strong de-blocking filter to filter at least one pixel value in said current line of pixels if said first filter decision value is below said first threshold, as determined by said first filter threshold comparator, and said second filter decision value is below said second threshold, as determined by said second threshold comparator, and to otherwise select a weak de-blocking filter to filter at least one pixel value in said current line of pixels, wherein said strong de-blocking filter has a comparatively higher filtering strength as compared to said weak de-blocking filter.
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31. A decoder comprising a filtering control device, the filtering control device comprising:
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a first decision value calculator configured to calculate a first filter decision value for a block of multiple pixels in a video frame, each pixel having a respective pixel value, said first filter decision value representative of how smooth pixel values in a first line of pixels in said block and in a corresponding first line of pixels in a neighboring block of multiple pixels in said video frame are in a direction parallel to a filtering direction; a second decision value calculator configured to calculate a second filter decision value for said block representative of how close pixel values in a current line of pixels in said block approximate a flat line and how close pixel values in a corresponding current line of pixels in said neighboring block approximate a flat line; a first threshold comparator configured to compare said first filter decision value calculated by said first decision value calculator to a first threshold; a second threshold comparator configured to compare said second filter decision value calculated by said second decision value calculator to a second threshold; and a filter selector configured to select a strong de-blocking filter to filter at least one pixel value in said current line of pixels if said first filter decision value is below said first threshold, as determined by said first filter threshold comparator, and said second filter decision value is below said second threshold, as determined by said second threshold comparator, and to otherwise select a weak de-blocking filter to filter at least one pixel value in said current line of pixels, wherein said strong de-blocking filter has a comparatively higher filtering strength as compared to said weak de-blocking filter.
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32. A media terminal comprising:
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a memory configured to store encoded video frames; a decoder configured to decode said encoded video frames into decoded video frames, said decoder including a filtering control device, the filtering control device comprising; a first decision value calculator configured to calculate a first filter decision value for a block of multiple pixels in a video frame, each pixel having a respective pixel value, said first filter decision value representative of how smooth pixel values in a first line of pixels in said block and in a corresponding first line of pixels in a neighboring block of multiple pixels in said video frame are in a direction parallel to a filtering direction; a second decision value calculator configured to calculate a second filter decision value for said block representative of how close pixel values in a current line of pixels in said block approximate a flat line and how close pixel values in a corresponding current line of pixels in said neighboring block approximate a flat line; a first threshold comparator configured to compare said first filter decision value calculated by said first decision value calculator to a first threshold; a second threshold comparator configured to compare said second filter decision value calculated by said second decision value calculator to a second threshold; and a filter selector configured to select a strong de-blocking filter to filter at least one pixel value in said current line of pixels if said first filter decision value is below said first threshold, as determined by said first filter threshold comparator, and said second filter decision value is below said second threshold, as determined by said second threshold comparator, and to otherwise select a weak de-blocking filter to filter at least one pixel value in said current line of pixels, wherein said strong de-blocking filter has a comparatively higher filtering strength as compared to said weak de-blocking filter. a media player configured to render said decoded video frames into video data displayable on a display.
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Specification