Abstract: Provided are a method and apparatus for coding and decoding an amplitude of partials, in which a step phenomenon can be prevented in the result of coding the amplitude of continuation partial partials in a parametric codec, thereby improving reproduced sound quality. The method of coding the amplitude of partials includes obtaining an inversely quantized amplitude of partials of a previous frame, determining a quantization level based on a function for the inversely quantized amplitude of the partials of the previous frame, and quantizing an amplitude of partials of a current frame based on the determined quantization level.

Abstract: Provided are a method and apparatus for encoding an audio signal to efficiently encode a harmonic envelope and a method and apparatus for decoding an audio signal to decode the harmonic envelope. The method of encoding an audio signal includes performing harmonic analysis with respect to an input signal to determine harmonic parameters with respect to harmonic signals; regarding amplitudes of the harmonic signals included in the harmonic parameters as signals in the time domain so as to perform time-frequency transformation; and encoding the time-frequency transformed values. When expressing a harmonic envelope, the amplitudes of the harmonic signals are regarded as signals in the time domain so as to perform a time-frequency transformation and only a part from among the transformed values is selected to be encoded. Therefore, sound quality is not affected and coding efficiency greatly improves.

Abstract: Methods and apparatuses for encoding and decoding of an audio signal using a mixture of a time-frequency method and a parametric method according to the audio band are provided. An encoding method of an audio signal includes: dividing input audio signals into a plurality of audio bands; selecting a coding method for each audio band; encoding each audio band according to the selected coding method for each band; and generating a bit stream including all the data encoded for each audio band, wherein selecting a coding method for each band comprises selecting smaller encoded data either from a parametric coding method or a time-frequency coding method.

Abstract: A method and apparatus for encoding/decoding audio signals at a low bit rate are provided. The encoding apparatus selectively encodes one or more reference samples having the highest amplitudes among frequency samples of an audio signal, determines amplitudes of the remaining samples other than the reference sample according to a predetermined pattern, using a predetermined random function, and then encodes the remaining samples using random function input information for causing the same pattern to be generated using the same random function, thus maximizing an encoding rate for an audio signal having a large amount of noise.

Abstract: Provided is an audio encoding and decoding apparatus and method for improving a compression ratio while maintaining sound quality when sinusoidal waves of an audio signal are connected and encoded. The audio encoding method includes connecting sinusoidal waves of an input audio signal, converting a frequency of each of the connected sinusoidal waves to a psychoacoustic frequency, performing a first encoding operation for encoding the psychoacoustic frequency, performing a second encoding operation for encoding an amplitude of each of the connected sinusoidal waves, and outputting an encoded audio signal by mixing the encoding result of the first encoding operation and the encoding result of the second encoding operation.

Abstract: An audio encoding and decoding apparatus and a method thereof, capable of improving compression efficiency, by using coefficients that are stable over a period of time and in a range of frequency bands, are provided. The audio encoding method divides an input audio signal into frames having lengths different from each other; obtaining at least one magnitude in relation to each of the frames having different lengths; and encoding the magnitude. The audio decoding method separates at least one encoded magnitude in relation to each of frames having different lengths, based on the frame length; decoding each of the separated encoded magnitudes; and restoring an audio signal by using the decoded magnitude.

Abstract: A method and apparatus for decoding a parametric-encoded audio signal are provided. According to the present invention, parameters extracted from a bitstream of a parametric encoded audio signal are adjusted by a user and component signals are synthesized based on the adjusted parameters to be displayed to a user so that a user can adjust the amplitudes of the component signals to apply various sound effects according to the user's desire. In addition, since an equalizer function is embodied in a codec of an audio reproduction apparatus, additional equalizer modules are not required and thus complexity of the audio reproduction apparatus can be reduced.

Abstract: A method of implementing an equalizer in an audio signal decoder and an apparatus therefor are provided. According to the method and apparatus, a signal output from an audio signal decoder is not processed by an equalizer, but the values of frequency components are adjusted according to a user's input before subband sample data is transformed into a frequency domain signal in an audio signal decoder, thereby implementing an equalizer in a codec. In this way, the complexity of implementing an apparatus for reproducing an audio signal can be reduced and delay of an equalizer can be reduced.

Abstract: A method of and apparatus for parametric encoding and parametric decoding are provided. According to the method and apparatus, not all parameters for all component signals are generated and according to a time interval, parameters for some component signals are replaced by index information allowing similar previous time intervals to be found, thereby increasing encoding efficiency.

Abstract: Provided is a method of processing an audio signal. An apparatus for encoding an audio signal including: a reverberation signal analyzer analyzing reverberation signals included in an input audio signal and generating a filter coefficient; a reverberation signal remover removing the reverberation signals from the input audio signal using the filter coefficient; an audio encoder encoding the audio signal from which the reverberation signals are removed; and a signal combiner generating a signal that combines the encoded audio signal and the filter coefficient.

Abstract: Provided are audio encoding and decoding apparatuses capable of recovering a high-quality audio signal at a low bit rate. The audio encoding method includes: detecting at least one sinusoidal wave from an input audio signal; calculating components of additional basis vectors based on residual audio signals and the additional basis vectors of the sinusoidal wave; determining transmission of components of the additional basis vectors; and at least one of (a) encoding frequencies and (b) phases and amplitudes of the sinusoidal waves when the transmission of the components of the additional basis vectors are determined, wherein the residual audio signals are obtained by excluding the detected sinusoidal waves from the input audio signal.

Abstract: A database searching method and apparatus for searching database information for a media stored in a multimedia device or data stored in a data processing device, and providing the search result in a sound format. The method includes searching and detecting a database for a data search, transforming the detected database information into a speech signal, and outputting the speech signal as the search result.

Abstract: A method and apparatus are provided for solving a noise problem of data output from a digital audio decoder. A volume control method includes detecting errors from data; and controlling an output volume of the data based on a number of the errors. Accordingly, by controlling the output volume of audio data based on the number of errors generated from the audio data, sound that is not unpleasant for listeners can be provided.

Abstract: An apparatus and method for determining a correlation coefficient between signals and determining a signal pitch. An operation unit receives a sampled signal x[i+k] and a signal y[j+k] (k is an integer from 0 to M−1), applies those signals to a first membership function of a first fuzzy set having large values, obtains a minimum value, obtains a probability P1 that the signals have large values, applies the signals to a second membership function of a second fuzzy set having small values, obtains a minimum value, obtains a probability P2 that the signals have small values, obtains a maximum value between P1 and P2, obtains a probability P3 that the signals have large or small values, increases k, repeats the above operations for each k, and obtains M probabilities P3. An addition unit obtains a correlation coefficient indicating a degree of similarity between the signals by adding M probabilities P3.