Methods and apparatus for embedding codes in compressed audio data streams
First Claim
1. A method to embed a watermark in a compressed audio stream, the method comprising:
- accessing a first scale factor and a first set of mantissas for a first set of transform coefficients included in the compressed audio stream, the first set of transform coefficients corresponding to a first band of a compression standard;
quantizing, with a processor, a second set of transform coefficients based on a second scale factor corresponding to the first scale factor reduced by a unit of resolution to determine a second set of mantissas, the second set of transform coefficients corresponding to the first band of the compression standard and including the watermark;
replacing, with the processor, the first scale factor with the second scale factor and the first set of mantissas with the second set of mantissas to modify the first set of transform coefficients to embed the watermark in the compressed audio stream to produce a watermarked compressed audio stream; and
outputting the watermarked compressed audio stream for transmission.
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Accused Products
Abstract
Example methods disclosed herein to embed a watermark in a compressed audio stream include accessing a first scale factor and a first set of mantissas for a first set of transform coefficients included in the compressed audio stream, the first set of transform coefficients corresponding to a first band of a compression standard. Such disclosed example methods also include quantizing a second set of transform coefficients based on a second scale factor corresponding to the first scale factor reduced by a unit of resolution to determine a second set of mantissas, the second set of transform coefficients corresponding to the first band of the compression standard and including the watermark. Such disclosed example methods further include replacing the first scale factor with the second scale factor and the first set of mantissas with the second set of mantissas to embed the watermark in the compressed audio stream.
209 Citations
18 Claims
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1. A method to embed a watermark in a compressed audio stream, the method comprising:
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accessing a first scale factor and a first set of mantissas for a first set of transform coefficients included in the compressed audio stream, the first set of transform coefficients corresponding to a first band of a compression standard; quantizing, with a processor, a second set of transform coefficients based on a second scale factor corresponding to the first scale factor reduced by a unit of resolution to determine a second set of mantissas, the second set of transform coefficients corresponding to the first band of the compression standard and including the watermark; replacing, with the processor, the first scale factor with the second scale factor and the first set of mantissas with the second set of mantissas to modify the first set of transform coefficients to embed the watermark in the compressed audio stream to produce a watermarked compressed audio stream; and outputting the watermarked compressed audio stream for transmission. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An article of manufacture comprising machine readable instructions which, when executed, cause a machine to at least:
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access a first scale factor and a first set of mantissas for a first set of transform coefficients included in a compressed audio stream, the first set of transform coefficients corresponding to a first band of a compression standard; quantize a second set of transform coefficients based on a second scale factor corresponding to the first scale factor reduced by a unit of resolution to determine a second set of mantissas, the second set of transform coefficients corresponding to the first band of the compression standard and including the watermark; and replace the first scale factor with the second scale factor and the first set of mantissas with the second set of mantissas to modify the first set of transform coefficients to embed a watermark in the compressed audio stream. - View Dependent Claims (8, 9, 10, 11, 12)
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13. An apparatus to embed a watermark in a compressed audio stream, the apparatus comprising:
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an embedding unit to; access a first scale factor and a first set of mantissas for a first set of transform coefficients included in the compressed audio stream, the first set of transform coefficients corresponding to a first band of a compression standard; quantize a second set of transform coefficients based on a second scale factor corresponding to the first scale factor reduced by a unit of resolution to determine a second set of mantissas, the second set of transform coefficients corresponding to the first band of the compression standard and including the watermark; and replace the first scale factor with the second scale factor and the first set of mantissas with the second set of mantissas to modify the first set of transform coefficients to embed the watermark in the compressed audio stream to produce a watermarked compressed audio stream; a modification unit to; reconstruct an uncompressed audio stream based on the first set of transform coefficients; and embed the watermark in the reconstructed audio stream to determine the second set of transform coefficients; and a repacking unit to output the watermarked compressed audio stream for transmission. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification