Methods for parametric multi-channel encoding

Patent metadata

Field	Value
Publication number	US-10360919-B2
Application number	US-201715646482-A
Country	US
Kind code	B2
Filing date	Jul 11, 2017
Priority date	Feb 21, 2013
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

The present document relates to audio coding systems. In particular, the present document relates to efficient methods and systems for parametric multi-channel audio coding. An audio encoding system configured to generate a bitstream indicative of a downmix signal and spatial metadata for generating a multi-channel upmix signal from the downmix signal is described. The system comprises a downmix processing unit configured to generate the downmix signal from a multi-channel input signal; wherein the downmix signal comprises m channels and wherein the multi-channel input signal comprises n channels; n, m being integers with m<n. Furthermore, the system comprises a parameter processing unit configured to determine the spatial metadata from the multi-channel input signal. In addition, the system comprises a configuration unit configured to determine one or more control settings for the parameter processing unit based on one or more external settings; wherein the one or more external settings comprise a target data-rate for the bitstream and wherein the one or more control settings comprise a maximum data-rate for the spatial metadata.

First claim

The invention claimed is:

1. A method comprising:
obtaining, by an audio decoder of a playback equipment, an encoded bitstream generated by an audio encoding system;
extracting, from the encoded bitstream by the audio decoder, an audio signal;
extracting, from the encoded bitstream by the audio decoder, a first set of dynamic range control (DRC) values configured for controlling a dynamic range of the audio signal during playback by the playback equipment, wherein the first set of DRC values are generated and encoded into the encoded bitstream by the audio encoding system;
extracting, from the encoded bitstream, a second set of DRC values configured for preventing the audio signal from clipping during playback by the playback equipment, wherein the second set of DRC values are generated and encoded into the encoded bitstream by the audio encoding system, wherein each DRC value in the second set of DRC values represents a clipping protection gain indicating an attenuation to be applied to a corresponding frame of the audio signal to prevent clipping;
extracting, from the encoded bitstream, first metadata indicating how to apply the first and second sets of DRC values to the audio signal; and
applying the first and second sets of DRC values to the audio signal during playback by the playback equipment according to the first metadata;
rendering the audio signal with the playback equipment.

2. The method of claim 1 , wherein the audio signal is a m-channel downmix audio signal, the method further comprises:
applying the second set of DRC values to the m-channel downmix audio signal;
extracting, from the encoded bitstream, spatial metadata; and
upmixing the m-channel downmix audio signal into an n-channel audio signal using the spatial metadata, where m and n are positive integers and m is less than n.

3. The method of claim 1 , wherein the first set of DRC values are configured to dynamically compress the audio signal.

4. An apparatus comprising:
one or more processors;
memory storing instructions, which, when executed by the one or more processors, causes the one or more processors to perform operations comprising:
obtaining, by an audio decoder of a playback equipment, an encoded bitstream generated by an audio encoding system;
extracting, from the encoded bitstream by the audio decoder, an audio signal;
extracting, from the encoded bitstream by the audio decoder, a first set of dynamic range control (DRC) values configured for controlling a dynamic range of the audio signal during playback by the playback equipment, wherein the first set of DRC values are generated and encoded into the encoded bitstream by the audio encoding system;
extracting, from the encoded bitstream, a second set of DRC values configured for preventing the audio signal from clipping during playback by the playback equipment, wherein the second set of DRC values are generated and encoded into the encoded bitstream by the audio encoding system, wherein each DRC value in the second set of DRC values represents a clipping protection gain indicating an attenuation to be applied to a corresponding frame of the audio signal to prevent clipping;
extracting, from the encoded bitstream, first metadata indicating how to apply the first and second sets of DRC values to the audio signal; and
applying the first and second sets of DRC values to the audio signal during playback by the playback equipment according to the first metadata;
rendering the audio signal with the playback equipment.

5. The apparatus of claim 4 , wherein the audio signal is a m-channel downmix audio signal, the operations further comprising:
applying the second set of DRC values to the m-channel downmix audio signal;
extracting, from the encoded bitstream, spatial metadata; and

upmixing the m-channel downmix audio signal into an n-channel audio signal using the spatial metadata, where m and n are positive integers and m is less than n.

6. The apparatus of claim 4 , wherein the first set of DRC values are configured to dynamically compress the audio signal.

Assignees

• Dolby Int Ab

Inventors

• Friedrich Tobias
• Mueller Alexander
• Linzmeier Karsten
• Spenger Claus-Christian
• Wagenblass Tobias

Classifications

• H04S2420/03

  Application of parametric coding in stereophonic audio systems · 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

• H04S3/008

  in which the audio signals are in digital form, i.e. employing more than two discrete digital channels (data reduction aspects thereof based on psychoacoustics G10L19/02) · CPC title

• H04S2400/01

  Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved · CPC title

• H04S2400/03

  Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -> 5.1 (H04S2400/01 takes precedence) · CPC title