Audio signal encoder

Patent metadata

Field	Value
Publication number	US-2016111100-A1
Application number	US-201314893604-A
Country	US
Kind code	A1
Filing date	May 28, 2013
Priority date	May 28, 2013
Publication date	Apr 21, 2016
Grant date	—

Abstract

An apparatus comprising: a parameter determiner configured to determine for a frame of at least one audio signal a set of frame audio signal multi-channel parameters; a parameter selector configured to select for the frame a sub-set of the set of frame audio signal multi-channel parameters based on an error value associated with the sub-set of the set of frame audio signal multi-channel parameters; and parameter encoder configured to generate an encoded frame audio signal multi-channel parameter based on the selected sub-set of the set of frame audio signal multi-channel parameters.

First claim

1 - 23 . (canceled)

24 . A method comprising:
determining for a frame of at least one audio signal a set of frame audio signal multi-channel parameters; selecting for the frame of the at least one audio signal a sub-set of the set of frame audio signal multi-channel parameters based on an error value associated with the sub-set of the set of frame audio signal multi-channel parameters; and generating an encoded frame audio signal multi-channel parameter based on the selected sub-set of the set of frame audio signal multi-channel parameters.

25 . The method as claimed in claim 24 further comprising determining a coding bitrate for the frame of the at least one audio signal; and wherein selecting for the frame of the at least one audio signal the sub-set of the set of frame audio signal multi-channel parameters based on the error value associated with the sub-set of the set of frame audio signal multi-channel parameters comprises selecting the sub-set of the set of frame audio signal multi-channel parameters further based on the coding bitrate for the frame of the at least one audio signal.

26 . The method as claimed in claim 24 , wherein determining for the frame of the at least one audio signal the set of frame audio signal multi-channel parameters comprises determining a set of differences between at least two channels of the at least one audio signal, wherein the set of differences comprises two or more difference values, where each difference value is associated with a sub-division of resources defining the frame of the at least one audio signal.

27 . The method as claimed in claim 26 , wherein determining the set of differences between the at least two channels of the at least one audio signal comprises determining at least one of: at least one interaural time difference; and at least one interaural level difference, and wherein the sub-division of resources defining the frame of the at least one audio signal comprises at least one of: sub-band frequencies; and time periods.

28 . The method as claimed in claim 24 , wherein selecting for the frame of the at least one audio signal the sub-set of the set of the frame audio signal multi-channel parameters based on the error value associated with the sub-set of the set of the frame audio signal multi-channel parameters comprises:
determining at least one previous frame selected sub-set; determining a number of elements to be selected; generating at least two candidate sub-sets; generating a reconstructed set from a combination of the candidate sub-set and the at least one previous frame selected sub-set; generating an error value based on the reconstructed set and the set of frame audio signal multi-channel parameters; and selecting one of the at least two candidate sub-sets with the smallest absolute error value.

29 . The method as claimed in claim 24 , further comprising:
generating for the selected sub-set at least one parameter representing the selected sub-set by at least one of generating a first parameter representing a first selected element in the selected sub-set, generating a distribution parameter representing a selection distribution of successive elements in the selected sub-set, and generating a length parameter representing the number of elements in the selected sub-set; and generating an encoded at least one parameter representing the selected sub-set.

30 . The method as claimed in claim 24 , wherein generating the encoded frame audio signal multi-channel parameter based on the selected sub-set of the set of frame audio signal multi-channel parameters comprises generating codebook indices for groups of the at least one frame audio signal multi-channel parameter using vector or scalar quantization codebooks.

31 . The method as claimed in claim 30 , wherein generating codebook indices for the groups of the at least one frame audio signal multi-channel parameter using vector or scalar quantization codebooks comprises:
generating an encoding mapping with an associated index for the at least one frame audio signal multi-channel parameter dependent on a frequency distribution of mapping instances of the at least one frame audio signal multi-channel parameter; and encoding the encoding mapping dependent on the associated index.

32 . The method as claimed in claim 24 , further comprising:
receiving at least two audio signal channels; determining a fewer number of channels audio signal from the at least two audio signal channels and the at least one frame audio signal multi-channel parameter; generating an encoded audio signal comprising the fewer number of channels; and combining the encoded audio signal and the encoded at least one frame audio signal multi-channel parameter.

33 . A method comprising:
receiving within a period an encoded audio signal comprising at least one frame downmix audio signal and at least one multi-channel audio signal parameter signal comprising a sub-set of a set of frame audio signal multi-channel parameters; recovering any elements of the set of frame audio signal multi-channel parameters not present in the sub-set of the set of frame audio signal multi-channel parameters; and generating a frame of at least two audio channels of at least one audio signal from the at least one frame downmix audio signal, and a combination of the sub-set of the set of frame audio signal multi-channel parameters and recovered elements of the set of frame audio signal multi-channel parameters not present in the sub-set of the set of frame audio signal multi-channel parameters.

34 . The method as claimed in claim 33 , wherein the set of frame audio signal multi-channel parameters comprises a set of differences between the at least two channels of at the least one audio signal, wherein the set of differences comprises two or more difference values, where each difference value is associated with a sub-division of resources defining the frame of the at least two channels of the at least one audio signal.

35 . The method as claimed in claim 34 , wherein the set of differences between the at least two channels of the at least one audio signal comprises at least one of: at least one interaural time difference; and at least one interaural level difference, and wherein the sub-division of resources defining the frame of the at least two channels of the at least one audio signal comprises at least one of: sub-band frequencies; and time periods.

36 . The method as claimed in claim 33 , wherein the encoded audio signal further comprises at least one parameter defining the sub-set of the set of frame audio signal multi-channel parameters; wherein recovering any elements of the set of frame audio signal multi-channel parameters not present in the sub-set of the set of frame audio signal multi-channel parameters comprises decoding the at least one parameter defining the sub-set of the set of frame audio signal multi-channel parameters to determine the sub-set elements to be recovered.

37 . An apparatus comprising at least one processor and at least one memory including computer program code for one or more programs, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:
determine for a frame of at least one audio signal a set of frame audio signal multi-channel parameters; select for the frame of the at least one audio signal a sub-set of the set of frame audio signal multi-channel parameters based on an error value associated with the sub-set of the set of frame audio signal multi-channel parameters; and generate an encoded frame audio signal multi-chann

Assignees

• Nokia Technologies Oy
• Nokia Technologies Oy

Inventors

• Ramo Anssi Sakari
• Vasilache Adriana
• Laaksonen Lasse Juhani

Classifications

• G10L19/032

  Quantisation or dequantisation of spectral components · CPC title

• H04S2420/03

  Application of parametric coding in stereophonic audio systems · CPC title

• G10L19/0017

  Lossless audio signal coding; Perfect reconstruction of coded audio signal by transmission of coding error (G10L19/24 takes precedence) · CPC title

• G10L19/005

  Correction of errors induced by the transmission channel, if related to the coding algorithm · CPC title

• H04S1/007

  in which the audio signals are in digital form (data reduction aspects thereof based on psychoacoustics G10L19/02) · CPC title