Abstract: A method of modifying the operation of the encoder function and/or the decoder function of a perceptual coding system in accordance with supplemental information, such as a watermark, so that the supplemental information may be detectable in the output of the decoder function. One or more parameters are modulated in the encoder function and/or the decoder function in response to the supplemental in formation.

Abstract: The perceived quality of an audio signals obtained from very low bit-rate audio coding system is improved by using expanding quantizers and arithmetic coding in a transmitter and using complementary compression and arithmetic decoding in a receiver. An expanding quantizer is used to control the number of signal components that are quantized to zero and arithmetic coding is used to efficiently code the quantized-to-zero coefficients. This allows a wider bandwidth and more accurately quantized baseband signal to be conveyed to the receiver, which regenerates an output signal by synthesizing the missing components.

Abstract: A receiver in an audio coding system receives a signal conveying frequency subband signals representing an audio signal. The subband signals are examined to assess one or more characteristics of the audio signal. Spectral components are synthesized having the assessed characteristics. The synthesized spectral components are integrated with the subband signals and passed through a synthesis filterbank to generate an output signal. In one implementation, the assessed characteristic is temporal shape and noise-like spectral components are synthesized having the temporal shape of the audio signal.

Abstract: Audio coding processes like quantization can cause spectral components of an encoded audio signal to be set to zero, creating spectral holes in the signal. These spectral holes can degrade the perceived quality of audio signals that are reproduced by audio coding systems. An improved decoder avoids or reduces the degradation by filling the spectral holes with synthesized spectral components. An improved encoder may also be used to realize further improvements in the decoder.

Abstract: An audio signal is conveyed more efficiently by transmitting or recording a baseband of the signal with an estimated spectral envelope and a noise-blending parameter derived from a measure of the signal's noise-like quality. The signal is reconstructed by translating spectral components of the baseband signal to frequencies outside the baseband, adjusting phase of the regenerated components to maintain phase coherency, adjusting spectral shape according to the estimated spectral envelope, and adding noise according to the noise-blending parameter. Preferably, the transmitted or recorded signal also includes an estimated temporal envelope that is used to adjust the temporal shape of the reconstructed signal.

Abstract: Techniques like Huffman coding can be used to represent digital audio signal components more efficiently using non-uniform length symbols than can be represented by other coding techniques using uniform length symbols Unfortunately, the coding efficiency that can be achieved by Huffman coding depends on the probability density function of the information to be coded and the Huffman coding process itself requires considerable processing and memory resources. A coding process that uses gain-adaptive quantization according to the present invention can realize the advantage of using non-uniform length symbols while overcoming the shortcomings of Huffman coding. In gain-adaptive quantization, the magnitudes of signal components to be encoded are compared to one or more thresholds and placed into classes according to the results of the comparison. The magnitudes of the components placed into one of the classes are modified according to a gain factor that is related to the threshold used to classify the components.

Abstract: An audio encoder applies an adaptive block-encoding process to segments of audio information to generate frames of encoded information that are aligned with a reference signal conveying the alignment of a sequence of video information frames. The audio information is analyzed to determine various characteristics of the audio signal such as the occurrence and location of a transient, and a control signal is generated that causes the adaptive block-encoding process to encode segments of varying length. A complementary decoder applies an adaptive block-decoding process to recover the segments of audio information from the frames of encoded information. In embodiments that apply time-domain aliasing cancellation (TDAC) transforms, window functions and transforms are applied according to one of a plurality of segment patterns that define window functions and transform parameters for each segment in a sequence of segments.

Abstract: A door hinge and a method of its use is provided which is suitable for use with glass shower screen doors. The method involves cutting a pair of circular cut-outs at a side edge of the door near the top and bottom of the door respectively. After toughening of the cut-out portions of glass, a hinge in accordance with this invention is mounted in each cut-out portion. The hinges each have a first arm which has a circular door mounting portion of substantially the same diameter as the cut-outs which are located in the cut-outs. The hinges each have two clamping parts, one part is fitted to abut with one face of the door, and the other part is fitted to abut with the other face of the door. Each part is fitted to immediately surround the respective cut-outs. The hinge then has screw holding means which holds the parts together and clamps the door. The second arm of the hinge can be mounted directly to a frame member, such as a jam member or to a further glass panel.

Abstract: Poly(ethylene oxide) (PEO) and poly[oxymethylene-oligo(oxyethylene)](PEM) disks are cross-linked by exposure to UV radiation. The rate of formation of cross-links is greatly enhanced by the presence of benzophenone, and an average cross-link density of up to 6 mol% of ethoxy units can be obtained after irradiation. The highly cross-linked polymers are insoluble in water or organic solvents and show improved physical properties for handling and the formation of free-standing films. Dynamic modulus measurements and polymer swelling are employed to characterize the polymers. Dynamic modulus measurements show that, upon irradiation, PEO and PEM become cross-linked elastomeric solids.