Method and apparatus for processing two or more initially decoded audio signals received or replayed from a bitstream

• US 20060174267A1
• Filed: 11/24/2003
• Published: 08/03/2006
• Est. Priority Date: 12/02/2002
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Schmidt, Jurgen
• Granted Patent: US 8,082,050 B2
• Time in Patent Office: Days
• US Class Current: 725/39
• CPC Class Codes: H04S 1/007 in which the audio signals are in digital form data reduction aspects thereof based on psychoacoustics G10L19/02
• CPC Class Codes: H04S 3/008 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

Abstract

In the MPEG-4 standard ISO/IEC 14496:2001 several audio objects that can be coded with different MPEG-4 format coding types can together form a composed audio system representing a single soundtrack from the several audio substreams. In a receiver the multiple audio objects are decoded separately, but not directly played back to a listener. Instead, transmitted instructions for mixdown are used to prepare a single soundtrack. Mixdown conflicts can occur in case the audio signals to be combined have different channel numbers or configurations. According to the invention an additional audio channel configuration node is used that tags the correct channel configuration information items to the decoded audio data streams to be presented. The invention enables the content provider to set the channel configuration in such a way that the presenter at receiver side can produce a correct channel presentation under all circumstances. An escape code value in the channel configuration data facilitates correct handling of not yet defined channel combinations.

Claims

1. Method for processing two or more initially decoded audio signals received or replayed from a bitstream, that each have a different number of channels and/or different channel configurations, and that are combined by mixing and/or switching before being presented in a final channel configuration, wherein to each one of said initially decoded audio signals a corresponding specific channel configuration information is attached and wherein said mixing and/or switching is controlled such that in case of non-matching number of channels and/or types of channel configurations the number and/or configuration of the channels to be output following said mixing and/or following said switching is determined by related specific mixing and/or switching information provided from a content provider or broadcaster and wherein to the combined data stream to be presented a correspondingly updated channel configuration information is attached.

2. Method according to claim 1, wherein said bitstream has MPEG-4 format.

3. Apparatus for processing two or more initially decoded audio signals received or replayed from a bitstream, that each have a different number of channels and/or different channel configurations, and that are combined by mixing and/or switching before being presented in a final channel configuration,

wherein to each one of said initially decoded audio signals a corresponding specific channel configuration information is attached, comprising:

at least two audio data decoders that decode audio data received or replayed from a bitstream;

means for processing the audio signals initially decoded by said audio data decoders, wherein at least two of said decoded audio signals each have a different number of channels and/or a different channel configuration, and wherein said processing includes combination by mixing and/or switching;

means for presenting the combined audio signals in a final channel configuration, wherein to each one of said initially decoded audio signals a corresponding specific channel configuration information is attached, wherein in said processing means said mixing and/or switching is controlled such that in case of non-matching number of channels and/or types of channel configurations the number and/or configuration of the channels to be output following said mixing and/or following said switching is determined by related specific mixing and/or switching information provided from a content provider or broadcaster;

and wherein to the combined data stream fed to said presenting means a correspondingly updated channel configuration information is attached.

4. Apparatus according to claim 3, wherein said bitstream has MPEG-4 format.