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Title: US7027515: Sum-of-absolute-difference checking of macroblock borders for error detection in a corrupted MPEG-4 bitstream
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Country: US United States of America

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19 pages

Inventor: Lin, Tao; Shanghai, China

Assignee: Red Rock Semiconductor Ltd., Sunnyvale, CA, United States of America
other patents from REDROCK SEMICONDUCTOR, LTD. (832856) (approx. 3)
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Published / Filed: 2006-04-11 / 2002-10-15

Application Number: US2002000065404

IPC Code: Advanced: H04N 7/12; H04N 7/26; H04N 7/50; H04N 7/64; H04N 7/68;

ECLA Code: H04N19/00R3; H04N7/26A6C2; H04N7/26A8B; H04N7/26A10S; H04N7/26Y; H04N7/26Z6; H04N7/50; H04N7/64; H04N7/68;

U.S. Class: 375/240.25;

Field of Search: 348/351,425.2,466 375/240.25,240.27,240.24,240.12 382/268,267,262,266,309

Priority Number:
2002-10-15  US2002000065404

Abstract:     An MPEG decoder verifies a previous video packet by calculating the sum-of-the-absolute differences (SAD) for macroblock boundaries. When a macroblock counter goes off count, the macroblocks can be placed in the wrong relative locations in a frame. Image shapes are sliced when macroblock misplacement occurs, creating many new bisecting edges along macroblock boundaries. These image discontinuities along macroblock boundaries have a large SAD for pixels on either side of the macroblock boundary. The SAD is generated along the left and upper edges of a current macroblock, and a maximum SAD of all macroblocks in the previous video packet is generated. When the maximum SAD is above a threshold, the macroblock counter is likely to be in error, and the macroblock counter is reloaded with the header macroblock number from the next packet header. When the SAD is below threshold, a mis-matching header macroblock number is ignored.

Attorney, Agent or Firm: Auvinen, Stuart T. ;

Primary / Asst. Examiners: Le, Vu; Senfi, Behrooz

Maintenance Status: E1 Expired  Check current status

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First Claim:
Show all 20 claims
    1. A macroblock-counting error-detector comprising:

a macroblock decoder, coupled to a bitstream input, for decoding macroblocks in a bitstream;

a macroblock counter for counting a number of macroblocks decoded from the bitstream;

a header decoder, coupled to the bitstream input, for decoding a packet header that includes a header macroblock number;

a count comparator, coupled to the macroblock counter and to the header decoder, for comparing the header macroblock number to a macroblock count from the macroblock counter;

an error controller, activated by the count comparator, for controlling over-writing of the macroblock counter by the header macroblock number to recover from a macroblock counting error;

a discontinuity calculator, responsive to the error controller, receiving edge pixels from at least two macroblocks, the edge pixels being along at least one common edge between the at least two macroblocks, for calculating a degree of pixel discontinuity; and

a discontinuity comparator for comparing the degree of pixel discontinuity from the discontinuity calculator to a threshold, the error controller over-writing the macroblock counter with the header macroblock number when the threshold is met,

whereby the degree of pixel discontinuity controls over-writing of the macroblock counter with the header macroblock number.

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Forward References: Show 7 U.S. patent(s) that reference this one

U.S. References: Go to Result Set: All U.S. references   |  Forward references (7)   |   Backward references (3)   |   Citation Link

Patent  Pub.Date  Inventor Assignee   Title
Get PDF - 29pp US20030016864  2003-01 McGee et al.   Methods of and system for detecting a cartoon in a video data stream
Get PDF - 41pp US20030026343  2003-02 Kim et al.   Systems and methods for enhanced error concealment in a video decoder
Get PDF - 33pp US20030048208  2003-03 Karczewicz   Variable length coding and decoding of data symbols
Foreign References: None

Continuity Data:
Application Number Filed Notes

US2002000065404 2002-10-15  is a related to the prior publication
     US20040071217A1 issued 2004-04-15  Sum-of-absolute-difference checking of macroblock borders for error detection in a corrupted MPEG-4 bitstream

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