Abstract: Provided are a method and apparatus for encoding and decoding a stereo signal or a multi-channel signal. According to the method and apparatus, a stereo signal or a multi-channel signal can be encoded and/or decoded by generating parameters based on a mono signal.

Abstract: A method and apparatus of effectively encoding and decoding a high-frequency signal of a multi-channel audio are provided. A multi-channel audio decoding apparatus may down-mix a multi-channel audio input signal, expand a number of channels of the down-mixed signal, select at least one of the expanded channel signal, extract a parameter indicating a characteristic relation between the selected signal and the multi-channel audio input signal, and encode the down-mixed signal and the extracted parameter.

Abstract: Methods and systems may provide for using an adaptive entropy encoder to generate a compressed video signal based on an input video signal. Additionally, a compressed state signal can he generated based on the internal state of the adaptive entropy encoder. In one example, the compressed state signal is selectively incorporated into a data stream containing the compressed video signal.

Abstract: Provided are a method and apparatus for encoding and decoding a stereo signal or a multi-channel signal. According to the method and apparatus, a stereo signal or a multi-channel signal can be encoded and/or decoded by generating parameters based on a mono signal.

Abstract: Provided are a method and apparatus for encoding and decoding a stereo signal or a multi-channel signal. According to the method and apparatus, a stereo signal or a multi-channel signal can be encoded and/or decoded by generating parameters based on a mono signal.

Abstract: An method and apparatus to extract an audio signal having an important spectral component (ISC) and a low bit-rate audio signal coding/decoding method using the method and apparatus to extract the ISC. The method of extracting the ISC includes calculating perceptual importance including an SMR (signal-to-mask ratio) value of transformed spectral audio signals by using a psychoacoustic model, selecting spectral signals having a masking threshold value smaller than that of the spectral audio signals using the SMR value as first ISCs, and extracting a spectral peak from the audio signals selected as the ISCs according to a predetermined weighting factor to select second ISCs. Accordingly, the perceptual important spectral components can be efficiently coded so as to obtain high sound quality at a low bit-rate.

Abstract: A method of encoding a low bit-rate audio signal includes quantizing and encoding a plurality of low frequency sub-bands of an audio signal in a frequency domain, generating a codebook of codevectors using sub-bands of the audio signal spectrum, detecting an envelope of another frequency sub-band of the audio signal and quantizing and losslessly-encoding the detected envelope, selecting a codevector most similar to the higher frequency sub-band spectrum from the generated codebook's codevectors and determining its codebook codevector index, and generating a bit stream.

Abstract: Provided are a method and apparatus for encoding and decoding a stereo signal or a multi-channel signal. According to the method and apparatus, a stereo signal or a multi-channel signal can be encoded and/or decoded by generating parameters based on a mono signal.

Abstract: A method and apparatus of effectively encoding and decoding a high-frequency signal of a multi-channel audio are provided. A multi-channel audio decoding apparatus may down-mix a multi-channel audio input signal, expand a number of channels of the down-mixed signal, select at least one of the expanded channel signal, extract a parameter indicating a characteristic relation between the selected signal and the multi-channel audio input signal, and encode the down-mixed signal and the extracted parameter.

Abstract: Provided are a method and apparatus for encoding and decoding a stereo signal or a multi-channel signal. According to the method and apparatus, a stereo signal or a multi-channel signal can be encoded and/or decoded by generating parameters based on a mono signal.

Abstract: A method and apparatus for transforming an audio signal, a method and apparatus for adaptively encoding an audio signal, a method and apparatus for inversely transforming an audio signal, and a method and apparatus for adaptively decoding an audio signal. The method of transforming an audio signal includes determining a transform unit into which the audio signal in a time domain is to be transformed into an audio signal in a frequency domain, and transforming the audio signal into an audio signal in the frequency domain according to the determined transform units using a window coefficient other than 0. Accordingly, it is possible to minimize distortion of the audio signal when encoding the audio signal even at a high bit rate while increasing efficiency of compression.

Abstract: An apparatus and a method of lossless coding and decoding are provided. The apparatus to perform lossless coding may selectively perform an arithmetic coding scheme or a Huffman coding scheme with respect to a symbol. The apparatus to perform lossless coding may generate a bitstream including a first coding bit, generated according to the Huffman coding scheme. Such bitstream may include a reserved bit for the arithmetic coding scheme.

Abstract: An apparatus and method of low bit rate encoding and reproducing. The method includes transforming input audio signals in a time domain into spectral signals in a frequency domain, extracting important-spectrum components from the spectral signals in the frequency domain, and quantizing the important-spectrum components, extracting residual-spectrum components other than the important-spectrum components from the spectral signals in the frequency domain, and calculating and quantizing a noise level of the residual-spectrum components, and encoding the quantized important-spectrum components and the quantized noise level losslessly, and outputting encoded bitstreams.

Abstract: A method and apparatus to scalably encode or decode an audio signal or a video signal. A signal distribution is considered after binarization is performed based on a tree structure. Thus, a decoding end can minimize generation of quantization errors and restore an original signal. In addition, only frequency components perceptually important in terms of human hearing are set to an upper layer and encoded without decreasing a bandwidth which is restored from an upper layer. Therefore, sound quality can be increased by decreasing quantization noise while maintaining a relatively large frequency bandwidth, and the degradation of a compression performance is prevented.

Abstract: An apparatus and a method of lossless coding and decoding are provided. The apparatus to perform lossless coding may selectively perform an arithmetic coding scheme or a Huffman coding scheme with respect to a symbol. The apparatus to perform lossless coding may generate a bitstream including a first coding bit, generated according to the Huffman coding scheme. Such bitstream may include a reserved bit for the arithmetic coding scheme.

Abstract: Provided are a multi-channel encoding and decoding method and apparatus capable of encoding and decoding residual signal by removing redundant information between a plurality of channels without a downmixed signal. In the method and apparatus, a reference signal which is to be used for encoding from a plurality of channel signals, the phase differences between the respective channel signals and the reference signal, gains which are the ratios of the amplitudes of the respective channel signals to the amplitude of the reference signal, and residual signals which correspond to differences between predicted signals and the actual channel signals, are encoded or decoded. The predicted signals are obtained by applying the phase differences and gains to the reference signal.

Abstract: A method and apparatus to scalably encode or decode an audio signal or a video signal. A signal distribution is considered after binarization is performed based on a tree structure. Thus, a decoding end can minimize generation of quantization errors and restore an original signal. In addition, only frequency components perceptually important in terms of human hearing are set to an upper layer and encoded without decreasing a bandwidth which is restored from an upper layer. Therefore, sound quality can be increased by decreasing quantization noise while maintaining a relatively large frequency bandwidth, and the degradation of a compression performance is prevented.

Abstract: Provided are a method and apparatus for encoding and decoding a stereo signal or a multi-channel signal. According to the method and apparatus, a stereo signal or a multi-channel signal can be encoded and/or decoded by generating parameters based on a mono signal.

Abstract: An method and apparatus to extract an audio signal having an important spectral component (ISC) and a low bit-rate audio signal coding/decoding method using the method and apparatus to extract the ISC. The method of extracting the ISC includes calculating perceptual importance including an SMR (signal-to-mark ratio) value of transformed spectral audio signals by using a psychoacoustic model, selecting spectral signals having a masking threshold value smaller than that of the spectral audio signals using the SMR value as first ISCs, and extracting a spectral peak from the audio signals selected as the ISCs according to a predetermined weighting factor to select second ISCs. Accordingly, the perceptual important spectral components can be efficiently coded so as to obtain high sound quality at a low bit-rate.

Abstract: An apparatus and method of low bit rate encoding and reproducing. The method includes transforming input audio signals in a time domain into spectral signals in a frequency domain, extracting important-spectrum components from the spectral signals in the frequency domain, and quantizing the important-spectrum components, extracting residual-spectrum components other than the important-spectrum components from the spectral signals in the frequency domain, and calculating and quantizing a noise level of the residual-spectrum components, and encoding the quantized important-spectrum components and the quantized noise level losslessly, and outputting encoded bitstreams.