EP 1192618 B1 20040922 - AUDIO CODING WITH ADAPTIVE LIFTERING
Title (en)
AUDIO CODING WITH ADAPTIVE LIFTERING
Title (de)
AUDIOKODIERUNG MIT ADAPTIVER LIFTERUNG
Title (fr)
CODAGE AUDIO AVEC LIFTRAGE ADAPTIF
Publication
Application
Priority
- FR 0001905 W 20000704
- FR 9908637 A 19990705
Abstract (en)
[origin: WO0103117A1] The invention concerns a method wherein the encoder estimates a fundamental frequency (F0) of an audio signal, and determines a compressed higher envelope of the spectrum of the signal by interpolation of the spectral amplitudes associated with multiple frequencies of the fundamental frequency with application of a spectral compression function. It transforms the compressed higher envelope in the cepstral domain to obtain cepstral coefficients (cx_sup), and includes in a digital flow transmitted to the decoder quantization data of said cepstral coefficients. The cepstral coefficients are transformed by liftering in the cepstral domain before they are quantized. A value of the spectrum module of the audio signal is recalculated at at least multiple frequency of the fundamental frequency on the basis of the transformed cepstral coefficients (cx-sup q), and the liftering is adapted so as to minimise the module difference between the audio signal spectrum and at least a recalculated module value.
IPC 1-7
IPC 8 full level
G10L 19/02 (2013.01); G10L 19/26 (2013.01); G10L 19/10 (2013.01)
CPC (source: EP)
G10L 19/02 (2013.01); G10L 19/26 (2013.01); G10L 19/10 (2013.01)
Designated contracting state (EPC)
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
DOCDB simple family (publication)
WO 0103117 A1 20010111; AT E277402 T1 20041015; AU 6291900 A 20010122; DE 60014084 D1 20041028; EP 1192618 A1 20020403; EP 1192618 B1 20040922; FR 2796193 A1 20010112; FR 2796193 B1 20011005
DOCDB simple family (application)
FR 0001905 W 20000704; AT 00949620 T 20000704; AU 6291900 A 20000704; DE 60014084 T 20000704; EP 00949620 A 20000704; FR 9908637 A 19990705