EP 1057292 A1 20001206 - A FAST FREQUENCY TRANSFORMATION TECHIQUE FOR TRANSFORM AUDIO CODERS
Title (en)
A FAST FREQUENCY TRANSFORMATION TECHIQUE FOR TRANSFORM AUDIO CODERS
Title (de)
SCHNELLE FREQUENZTRANSFORMATIONSTECHNIK FÜR TRANSFORM AUDIO KODER
Title (fr)
TECHNIQUE RAPIDE DE TRANSFORMATION DE FREQUENCES DESTINEE A DES CODEURS AUDIO A TRANSFORMEE
Publication
Application
Priority
SG 9800014 W 19980221
Abstract (en)
[origin: WO9943110A1] A method for coding digital audio data in which coded Fast Modified Discrete Cosine Transform (FMDCT) coefficients are computed utilising a Fast Fourier Transform (FFT) method. The described method allows a significant reduction in computations as compared to an ordinary DCT coding procedure. Also, pairs of audio channels can be combined to use a single FFT computation, where the selected transform length for the paired channels is the same. In such cases where pairing of identical transform length channels is not possible, a long transform length channel is combined with a short transform length channel and converted in two short transforms. A windowing function is also combined with a pre-processing stage to the transformation, further decreasing computational requireements.
IPC 1-7
IPC 8 full level
H04H 1/00 (2006.01); H04H 20/89 (2008.01)
IPC 8 main group level
H04H 5/00 (2006.01)
CPC (source: EP)
H04H 20/89 (2013.01)
Citation (search report)
See references of WO 9943110A1
Designated contracting state (EPC)
DE FR GB IT
DOCDB simple family (publication)
WO 9943110 A1 19990826; DE 69823557 D1 20040603; DE 69823557 T2 20050203; EP 1057292 A1 20001206; EP 1057292 B1 20040428
DOCDB simple family (application)
SG 9800014 W 19980221; DE 69823557 T 19980221; EP 98909964 A 19980221