(19)
(11) EP 0 986 047 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
26.09.2001 Bulletin 2001/39

(43) Date of publication A2:
15.03.2000 Bulletin 2000/11

(21) Application number: 99202927.2

(22) Date of filing: 08.09.1999
(51) International Patent Classification (IPC)7: G10L 19/14
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 11.09.1998 GB 9819920

(71) Applicant: Tandberg Television ASA
1326 Lysaker (NO)

(72) Inventors:
  • Duenas, David
    Bournemouth, Dorset BH4 9JN (GB)
  • Bennett, Jeremy
    Eastleigh, Hampshire SO53 4QA (GB)

(74) Representative: Molyneaux, Martyn William et al
Langner Parry 52-54 High Holborn
London WC1V 6RR
London WC1V 6RR (GB)

   


(54) Audio encoding system


(57) A method of switching between long and short block encoding of frames of audio data with improved noise reduction in relation to the number of bits required for encoding. The method comprises the steps of calculating the difference in the long block perceptual entropy of a present frame and the preceding frame and switching to short block encoding of the present frame if the difference is greater than a first threshold. The method may further comprising the steps of comparing the long block perceptual entropy of the succeeding frame with a second threshold if the difference is greater than the first threshold, and switching to short block encoding of the succeeding frame if the long block perceptual entropy of the succeeding frame is greater than the second threshold. The method may additionally or alternatively involve the study of the perceptual entropy of short blocks.






Search report