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

Abstract

According to the invention, a time-discrete audio signal is processed (52) in order to provide a quantization block with quantized spectral values (52). In addition, a whole-number spectral representation is generated from a time-discrete audio signal, using a whole-number transformation algorithm (56). The quantization block, which has been generated using a psychoacoustic model (54), is inverse quantized and rounded (58) to form a differential between the whole-number spectral values and the inverse quantized rounded spectral values. The quantization block alone produces a psychoacoustic encoded / decoded audio signal affected by loss after the decoding process, whereas the quantization block together with the combination block provides a loss-free, or practically loss-free encoded and decoded audio signal during said decoding process. The generation of the differential signal in the frequency range allows a simpler encoder / decoder structure to be produced.

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...

AI Technical Summary

Problems solved by technology

If the encoder is implemented in software, both storage performance and processor performance are required for this, resulting in increased overhead for the implementation of the encoder

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