Audio encoder with signal dependent number and accuracy control, audio decoder and related methods and computer programs

Abstract

An audio encoder for encoding audio input data (11), comprising: a preprocessor (10) for preprocessing the audio input data (11) to obtain audio data to be encoded; the encoder processor (15) is used for encoding the audio data to be encoded; and a controller (20) for controlling the encoder processor such that, depending on a first signal characteristic of a first frame of the audio data to be encoded, the number of audio data items of audio data to be encoded by the encoder processor (15) for the first frame is reduced compared to a second signal characteristic of a second frame, and a first number of information units for encoding the reduced number of audio data items for the first frame is enhanced more strongly than a second number of information units for the second frame.

Description

technical field [0001] The present invention relates to audio signal processing, and in particular to audio encoder / decoders applying signal-dependent quantity and precision control. Background technique [0002] Modern transform-based audio encoders apply a series of psychoacoustic actuation processes to the spectral representation of audio segments (frames) to obtain residual spectra. This residual spectrum is quantized and the coefficients are encoded using entropy coding. [0003] In this approach, the quantization step size, usually controlled via a global gain, has a direct impact on the bit consumption of the entropy encoder, and needs to be chosen in such a way that a usually limited and often fixed bit budget is met. Since the bit consumption of an entropy coder, and in particular an arithmetic coder, is not known exactly before encoding, computing the optimal global gain may only be done in closed-loop iterations of quantization and encoding. However, this is not...

AI Technical Summary

Problems solved by technology

While power spectrum based estimators are suitable for most audio content, they can lead to problems for high-pitched signals, where the first-order estimates are mainly based on uncorrelated sidelobes of the frequency decomposition of the filter bank, and important components due to The underestimation of bit consumption is lost

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