Scalable encoding/decoding of audio signals

Abstract

An audio signal is encoded by a first waveform encoder (103) to generate a first waveform based bit-stream component. A second encoder (105) encodes the audio signal to generate a second bit-stream component comprising first enhancement data and a third encoder (107) encodes the audio signal to generate a third bit-stream component comprising second enhancement data for the first waveform based bit-stream component. The first and second bit-stream components correspond to a first representation of the audio signal and the first and third bit-stream components correspond to a second representation of the audio signal. A scalable audio bit-stream is generated by a bit-stream generator (109). The different representations may be selected between by a decoder thereby allowing a flexible and scalable bit-stream to be communicated. The second encoder (105) may specifically be a waveform encoder and the third encoder (107) may specifically be a parametric encoder.

Description

technical field [0001] The present invention relates to encoding and / or decoding of audio signals, in particular to scalable representations of audio signals. Background technique [0002] Digital encoding of various source signals has become increasingly important over the past decade as digital signal representation and communication has gradually replaced analog representation and communication. For example, mobile telephone systems such as Global System for Mobile Communications are based on digital speech coding. The distribution of media content such as video and music is also increasingly based on digital content encoding. [0003] In the context of audio and video coding, scalability of the encoded signal is advantageous and provides flexible distribution and processing of the encoded signal. For example, encoded signals can be scaled in terms of quality, bit rate, and complexity. A specific example of video coding is the progressive quality of JPEG (Joint Photogr...

AI Technical Summary

Problems solved by technology

Furthermore, the described method is impractical for recently introduced coding devices employing parametric coding techniques such as SBR and parametric stereo, since in such cases the residual signal still prohibits high entropy value and therefore require a high bit rate for encoding

Furthermore, the system is relatively inflexible and tends to provide only limited scalability

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