Adaptive bit allocation for multi-channel audio encoding

Patent metadata

Field	Value
Publication number	US-9626973-B2
Application number	US-81699605-A
Country	US
Kind code	B2
Filing date	Dec 22, 2005
Priority date	Feb 23, 2005
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

The invention provides a highly efficient technique for encoding a multi-channel audio signal. The invention relies on the basic principle of encoding a first signal representation of one or more of the multiple channels in a first encoder and encoding a second signal representation of one or more of the multiple channels in a second, multi-stage, encoder. This procedure is significantly enhanced by providing a controller for adaptively allocating a number of encoding bits among the different encoding stages of the second, multi-stage, encoder in dependence on multi-channel audio signal characteristics.

First claim

The invention claimed is:

1. A decoding method to decode an encoded multi-channel audio signal, the decoding method comprising:
receiving first signal reconstruction data;
a first decoder decoding, in response to first signal reconstruction data, an encoded first signal representation of at least one channel of said multi-channel audio signal in a first signal decoding process;
a second decoder decoding, in response to second signal reconstruction data, an encoded second signal representation of at least one channel of said multi-channel audio signal in a second signal decoding process, the second signal decoding process being a multi-stage decoding process comprising first and second decoding stages;
a controller receiving bit allocation information representative of how a number of bits have been allocated among a parametric encoding stage and a non-parametric encoding stage in a second multistage hybrid parametric and non-parametric signal encoding process corresponding to the second signal decoding process; and
the controller determining, based on said bit allocation information, how to interpret said second signal reconstruction data in said multi-stage signal decoding process including interpreting which bits of the second signal reconstruction data are allocated to the parametric encoding stage and which bits are allocated to the non-parametric encoding stage;
wherein the first and second decoding stages of the multi-stage decoding processes are such that the first decoding stage receives at least one output generated from the second decoding stage,
wherein determining, based on the bit allocation information, how to interpret the second signal reconstruction data comprises
determining a second signal prediction portion of the second signal reconstruction data allocated to carry an encoded second signal prediction, the second signal prediction being a prediction of the second signal representation, and
determining a second signal prediction error portion of the second signal reconstruction data allocated to carry an encoded second signal prediction error, the second signal prediction error being an estimated error of the second signal prediction,

wherein the second decoding stage comprises decoding the second signal prediction error portion to determine the second signal prediction error, and
wherein the first decoding stage comprises
decoding the second signal prediction portion;
determining the second signal representation based on the decoded second signal prediction portion and based on the first signal representation decoded by the first decoder; and
applying the second signal prediction error received from the second decoding stage to the determined second signal representation.

2. A decoding apparatus configured to decode an encoded multi-channel audio signal, the decoding apparatus comprising:
a receiver configured to receive first signal reconstruction data;
a first decoder configured to decode, in response to first signal reconstruction data, an encoded first signal representation of at least one channel of said multi-channel audio signal;
a second decoder configured to decode, in response to second signal reconstruction data, an encoded second signal representation of at least one of said multiple channels, the second decoder being a multi-stage decoder comprising second and first decoding stages; and
a controller configured to
receive bit allocation information representative of how a number of bits have been allocated among a parametric encoding stage and a non-parametric encoding stage in a multi-stage hybrid parametric and non-parametric encoder corresponding to the second decoder, and
determine, based on said bit allocation information, how to interpret said second signal reconstruction data in said second decoder for the purpose of decoding the second signal representation including interpreting which bits of the second signal reconstruction data are allocated to the parametric encoding stage and which bits are allocated to the non-parametric encoding stage;

wherein the first and second decoding stages of the multi-stage decoder are in series such that the first decoding stage receives at least one output from the second decoding stage,
wherein the controller is configured determine, based on the bit allocation information,
a second signal prediction portion of the second signal reconstruction data allocated to carry an encoded second signal prediction, the second signal prediction being a prediction of the second signal representation, and
a second signal prediction error portion of the second signal reconstruction data allocated to carry an encoded second signal prediction error, the second signal prediction error being an estimated error of the second signal prediction,

wherein the second decoding stage is configured to decode the second signal prediction error portion to determine the second signal prediction error, and
wherein the first decoding stage is configured to
decode the second signal prediction portion,
determine the second signal representation based on the decoded second signal prediction portion and based on the first signal representation decoded by the first decoder, and
apply the second signal prediction error received from the second decoding stage to the determined second signal representation.

3. An audio transmission system, characterized in that said system comprises a decoding apparatus of claim 2 .

4. An encoding method to encode a multi-channel audio signal, the encoding method comprising:
receive the multi-channel audio signal over input channels;
a first encoder encoding a first signal representation of at least one channel of said multi-channel audio signal in a first signal encoding process;
a second encoder encoding a second signal representation of at least one channel of said multi-channel audio signal in a second signal encoding process, said second signal encoding process being a multi-stage encoding process comprising first and second encoding stages; and
a controller adaptively allocating a number of encoding bits among the first and second encoding stages of the multi-stage signal encoding process based on inter-channel correlation characteristics of the multi-channel audio signal,
wherein said adaptively allocating the number of encoding bits among the first and second encoding stages is performed based on an estimated performance of the first and/or the second encoding stage;
wherein said first and second encoding stages of the multi-stage signal encoding process comprise a hybrid parametric and non-parametric encoding stages, and
wherein the encoding bits are allocated between the parametric encoding stage and the non-parametric encoding stage based on the inter-channel correlation characteristics;
wherein said adaptively allocating the number of encoding bits comprises allocating more bits to the non-parametric encoding stage when a performance of the parametric encoding stage is saturating.

5. The encoding method of claim 4 , wherein said adaptively allocating the number of bits among the first and second encoding stages is performed on a frame-by-frame basis.

6. The encoding method of claim 4 ,
wherein said multi-stage signal encoding process includes an adaptive inter-channel prediction in the first encoding stage for a prediction of said second signal representation based on the first signal representation and the second signal representation, and
wherein said performance is estimated at least partly based on a signal prediction error, the signal prediction error being an estimated error of the prediction of the second signal representation.

7. The encoding method of claim 6 , wherein said performance is estimated also based on an estimation of a quantizati

Assignees

• Taleb Anisse
• Andersson Stefan
• Ericsson Telefon Ab L M

Inventors

• Taleb Anisse
• Andersson Stefan

Classifications

• G10L19/24

  Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding · CPC title

• G10L19/008 Primary

  Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing · CPC title