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Methods and apparatus for embedding watermarks

  • US 8,351,645 B2
  • Filed: 10/27/2011
  • Issued: 01/08/2013
  • Est. Priority Date: 06/13/2003
  • Status: Expired due to Term
First Claim
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1. A method to embed a watermark in a compressed data stream, the method comprising:

  • obtaining a set of transform coefficients included in the compressed data stream, the set of transform coefficients comprising a first set of mantissa codes and a set of exponents, the first set of mantissa codes associated with a respective set of step sizes;

    identifying a first transform coefficient from the set of transform coefficients having a smallest magnitude among the set of transform coefficients;

    determining a second set of mantissa codes based on the first transform coefficient and the set of step sizes; and

    replacing the first set of mantissa codes in the compressed data stream with the second set of mantissa codes to embed the watermark without uncompressing the compressed data stream.

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