Device and method for encoding a time-discrete audio signal and method for decoding coded audio data

Abstract

The time-discrete audio signal is processed (52) to provide a quantized block with quantized spectral values. Furthermore, an integer spectral representation is generated from the time-discrete audio signal using an integer transformation algorithm (56). The quantized blocks generated using the psychoacoustic model (54) are inverse quantized and rounded (58) to subsequently form differences between the integer spectral values ​​and the inverse quantized rounded spectral values. After decoding, the quantization block alone provides a lossy psychoacoustically encoded/decoded audio signal; while in decoding, the quantization block together with the combining module provides a lossless or nearly lossless encoded and decoded audio signal again. By generating a differential signal in the frequency domain, a simple encoder/decoder structure is formed.

Description

technical field [0001] The present invention relates to audio encoding / decoding, and in particular to scalable encoding / decoding algorithms comprising a psychoacoustic first extension layer and a second extension including auxiliary audio data for lossless decoding layer. Background technique [0002] Modern audio coding methods, like MPEG Layer3 (MP3) or MPEG ACC, use transforms like the so-called Modified Discrete Cosine Transform (MDCT) to obtain a block-wise frequency representation of the audio signal. Such audio encoders typically obtain a data stream of time-discrete audio samples. The stream of audio samples is windowed to obtain windowed blocks of eg 1024 or 2048 windowed audio samples. Various window functions are used for windowing, such as sine window and so on. [0003] Subsequently, the windowed time-discrete audio samples are converted to a spectral representation through a filter bank. In principle, the Fourier transform, or a variety of Fourier transform...

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If the encoder is implemented in software, both storage performance and processor performance

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