Abstract: A method for the Costa problem includes turbo-like nested code. In one embodiment, the method includes providing a turbo-like trellis-coded quantization for source coding. The method also includes providing a turbo trellis-coded modulation for channel coding.

Abstract: An apparatus for generating a fingerprint of a digital medium having a partial decoder for generating a partially decoded form of a compressed datastream, feature extractor for extracting at least one invariant feature from the partially decoded form, a fingerprint calculator for computing at least one fingerprint from the extracted invariant feature. An apparatus for authenticating fingerprints and methods for generating and authenticating fingerprints.

Abstract: A method is provided for enhanced spread spectrum watermarking. The improved watermarking method includes: receiving host data which is expressed in a transform domain by a plurality of host transform parameters; reducing variance between the plurality of host transform parameters, thereby forming an enhanced sequence of host transform parameters; and adding a watermark to the enhanced sequence of host transform parameters using a spread spectrum technique. The enhanced sequence of host transform parameters may be formed by arranging the plurality of host transform parameters in at least one of an ascending order or descending order; determining a difference for each pair of consecutive host transform parameters; and alternating the sign of every other difference value, thereby forming the enhanced sequence of host transform parameters.

Abstract: A method for concealing errors in an audio signal includes digitally encoding the audio signal into a plurality of audio data packets representative of the audio signal; determining a perceptually tolerable distortion limit for the audio packets; and altering a value of at least one audio packet by an amount within the perceptually tolerable distortion limit utilizing information representative of a different audio data packet.

Abstract: An apparatus for generating a fingerprint of a digital medium having a partial decoder for generating a partially decoded form of a compressed datastream, feature extractor for extracting at least one invariant feature from the partially decoded form, a fingerprint calculator for computing at least one fingerprint from the extracted invariant feature. An apparatus for authenticating fingerprints and methods for generating and authenticating fingerprints.

Abstract: A method is provided for enhanced spread spectrum watermarking. The improved watermarking method includes: receiving host data which is expressed in a transform domain by a plurality of host transform parameters; reducing variance between the plurality of host transform parameters, thereby forming an enhanced sequence of host transform parameters; and adding a watermark to the enhanced sequence of host transform parameters using a spread spectrum technique. The enhanced sequence of host transform parameters may be formed by arranging the plurality of host transform parameters in at least one of an ascending order or descending order; determining a difference for each pair of consecutive host transform parameters; and alternating the sign of every other difference value, thereby forming the enhanced sequence of host transform parameters.

Abstract: A method for concealing errors in an audio signal includes digitally encoding the audio signal into a plurality of audio data packets representative of the audio signal; determining a perceptually tolerable distortion limit for the audio packets; and altering a value of at least one audio packet by an amount within the perceptually tolerable distortion limit utilizing information representative of a different audio data packet.

Abstract: The present invention embeds watermark into quantization indices of the compressed data stream rather than the coefficients, thereby avoiding loss of speed from dequantization or requantization. Further, a heuristic technique is preferably chosen for selecting the indices and respective modification amounts, thereby avoiding the need for comparison with the original signal. Specific to this technique, indices are chosen corresponding to ranges within a sensitive portion of a human sensory range, zero indices are discarded, and a minimum amount is always determined. Still further, the same codebook is used to partially compress and partially decompress the compressed data stream, thereby avoiding complexity associated with multiple searches for optimum codebooks.