Apparatus and method for decoding an encoded audio signal with low computational resources

Patent metadata

Field	Value
Publication number	US-9799345-B2
Application number	US-201615177265-A
Country	US
Kind code	B2
Filing date	Jun 8, 2016
Priority date	Dec 9, 2013
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

An apparatus for decoding an encoded audio signal including bandwidth extension control data indicating either a first harmonic bandwidth extension mode or a second non-harmonic bandwidth extension mode, includes: an input interface for receiving the encoded audio signal including the bandwidth extension control data indicating either the first harmonic bandwidth extension mode or the second non-harmonic bandwidth extension mode; a processor for decoding the audio signal using the second non-harmonic bandwidth extension mode; and a controller for controlling the processor to decode the audio signal using the second non-harmonic bandwidth extension mode, even when the bandwidth extension control data indicates the first harmonic bandwidth extension mode for the encoded signal.

First claim

The invention claimed is:

1. An apparatus for decoding an encoded audio signal comprising bandwidth extension control data indicating either a first harmonic bandwidth extension mode or a second non-harmonic bandwidth extension mode, comprising:
an input interface for receiving the encoded audio signal comprising the bandwidth extension control data indicating either the first harmonic bandwidth extension mode or the second non-harmonic bandwidth extension mode;
a processor for decoding the audio signal using the second non-harmonic bandwidth extension mode; and
a controller for controlling the processor to decode the audio signal using the second non-harmonic bandwidth extension mode, even when the bandwidth extension control data indicates the first harmonic bandwidth extension mode for the encoded signal,
wherein the encoded audio signal comprises common bandwidth extension payload data for the first harmonic bandwidth extension mode and the second non-harmonic bandwidth extension mode and additional payload data for the first harmonic bandwidth extension mode only, and
wherein the controller is configured to use the additional payload data for controlling the processor to modify a patching operation performed by the processor compared to a patching operation in the second non-harmonic bandwidth extension mode, wherein the modified patching operation is a non-harmonic patching operation,
wherein the processor comprises a patching buffer,
wherein the processor is configured to load the patching buffer using the common bandwidth extension payload data,
wherein the controller is configured to calculate a buffer shift value using the additional bandwidth extension data indicating a harmonic grid of the encoded audio signal using a patch source band information and a patch destination band information,
wherein the controller is configured to cause a buffer shift operation to the buffer content; and
wherein the processor is configured to generate patched data using the buffer content shifted by the buffer shift value.

2. The apparatus of claim 1 , wherein the processor comprises memory and processing resources being sufficient for decoding the encoded audio signal using the second non-harmonic bandwidth extension mode, wherein the memory or processing resources are not sufficient for decoding the encoded audio signal using the first harmonic bandwidth extension mode.

3. The apparatus of claim 1 ,
wherein the input interface is configured for reading the bandwidth extension control data to determine, whether the encoded audio signal is to be decoded using either the first harmonic bandwidth extension mode or the second non-harmonic bandwidth extension mode and to store the bandwidth extension control data in a processor control register, and
wherein the controller is configured to access the processor control register and to overwrite a value in the processor control register by a value indicating the second non-harmonic bandwidth extension mode, when the input interface has stored a value indicating the first harmonic bandwidth extension mode.

4. The apparatus in accordance with claim 1 , wherein the controller is configured to cause the buffer shift operation with a wraparound.

5. The apparatus in accordance with claim 1 ,
wherein the processor comprises:
a core decoder for decoding a core encoded audio signal;
a patcher for patching a source frequency region of the core encoded audio signal to a target frequency region using bandwidth extension data from the encoded audio signal in accordance with the non-harmonic bandwidth extension mode; and
a patch modifier for modifying a patched signal in the target frequency region using bandwidth extension data from the encoded audio signal.

6. The apparatus in accordance with claim 1 ,
wherein the encoded audio signal is a bitstream as defined by the USAC standard,
wherein the processor is configured to perform the second non-harmonic bandwidth extension mode as defined by the USAC standard, and
wherein the input interface is configured to parse the bitstream comprising the encoded audio signal in accordance with the USAC standard.

7. The apparatus in accordance with claim 1 ,
wherein the processor comprises memory and processing resources being sufficient for decoding the encoded audio signal using the second non-harmonic bandwidth extension mode, wherein the memory or processing resources are not sufficient for decoding the encoded audio signal using the first harmonic bandwidth extension mode, when the encoded audio signal is an encoded stereo or multichannel audio signal, and
wherein the processor comprises memory and processing resources being sufficient for decoding the encoded audio signal using the second non-harmonic bandwidth extension mode and using the first harmonic bandwidth extension mode, when the encoded audio signal is an encoded mono signal.

8. A method of decoding an encoded audio signal comprising bandwidth extension control data indicating either a first harmonic bandwidth extension mode or a second non-harmonic bandwidth extension mode, comprising:
receiving the encoded audio signal comprising the bandwidth extension control data indicating either the first harmonic bandwidth extension mode or the second non-harmonic bandwidth extension mode;
decoding the audio signal using the second non-harmonic bandwidth extension mode; and
controlling the decoding of the audio signal so that the second non-harmonic bandwidth extension mode is used in the decoding, even when the bandwidth extension control data indicates the first harmonic bandwidth extension mode for the encoded signal,
wherein the encoded audio signal comprises common bandwidth extension payload data for the first harmonic bandwidth extension mode and the second non-harmonic bandwidth extension mode and additional payload data for the first harmonic bandwidth extension mode only, and
wherein the controlling comprises using the additional payload data for controlling the decoding to modify a patching operation performed by the decoding compared to a patching operation in the second non-harmonic bandwidth extension mode, wherein the modified patching operation is a non-harmonic patching operation,
wherein the decoding comprises using a patching buffer,
wherein the decoding comprises loading the patching buffer using the common bandwidth extension payload data,
wherein the controlling comprises calculating a buffer shift value using the additional bandwidth extension data indicating a harmonic grid of the encoded audio signal using a patch source band information and a patch destination band information,
wherein the controlling comprises causing a buffer shift operation to the buffer content; and
wherein the decoding comprises generating patched data using the buffer content shifted by the buffer shift value.

9. A non-transitory digital storage medium having a computer program stored thereon to perform the method of decoding an encoded audio comprising bandwidth extension control data indicating either a first harmonic bandwidth extension mode or a second non-harmonic bandwidth extension mode, comprising:
receiving the encoded audio signal comprising the bandwidth extension control data indicating either the first harmonic bandwidth extension mode or the second non-harmonic bandwidth extension mode;
decoding the audio signal using the second non-harmonic bandwidth extension mode; and
controlling the decoding of the audio signal so that the second non-harmonic bandwidth extension mode is used in the decoding, even when the bandwidth extension control data indicates the first harmonic bandwidth extension mode for the encoded signal,
wherein the encoded audio signal comprises common ban

Assignees

• Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E V

Inventors

• Niedermeier Andreas
• Wilde Stephan
• Fischer Daniel
• Hildenbrand Matthias
• Gayer Marc
• Neuendorf Max

Classifications

• G10L21/038

  using band spreading techniques · CPC title

• G10L19/24 Primary

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

• G10L19/22 Primary

  Mode decision, i.e. based on audio signal content versus external parameters · CPC title

• G10L19/20 Primary

  using sound class specific coding, hybrid encoders or object based coding · CPC title

• G10L19/167

  Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes · CPC title