US 12,413,905 B2
Apparatus, methods and computer programs for reducing echo
Wouter Lanneer, Antwerp (BE); Werner Coomans, Zellik (BE); and Paschalis Tsiaflakis, Heist-op-den-Berg (BE)
Assigned to NOKIA TECHNOLOGIES OY, Espoo (FI)
Filed by NOKIA TECHNOLOGIES OY, Espoo (FI)
Filed on Dec. 21, 2022, as Appl. No. 18/069,718.
Claims priority of application No. 2118594 (GB), filed on Dec. 21, 2021.
Prior Publication US 2023/0199386 A1, Jun. 22, 2023
Int. Cl. H04R 3/02 (2006.01); G10L 21/0208 (2013.01)
CPC H04R 3/02 (2013.01) [G10L 21/0208 (2013.01); G10L 2021/02082 (2013.01)] 19 Claims
OG exemplary drawing
 
1. An apparatus comprising at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:
obtain an estimate of an echo path delay comprising an estimate of a time delay between a loudspeaker signal and an altered version of the loudspeaker signal comprised in a microphone signal;
obtain information indicative of a number of future frames used by an acoustic echo cancellation filter wherein the acoustic echo cancellation filter comprises a time-frequency filterbank configured to generate an acoustic echo cancelled signal for a current time frame;
obtain information indicative of a time shift between consecutive frames processed by the acoustic echo cancellation filter, wherein the time shift between consecutive frames processed by the acoustic echo cancellation filter comprises a hop size;
determine at least a first delay to be added to a loudspeaker signal for adjusting the echo path delay to reduce an echo in the microphone signal; and
determine at least a second delay to be added to a microphone signal for adjusting the echo path delay to reduce the echo in the microphone signal,
wherein the determination of the first delay and the second delay is based on (i) the estimate of the echo path delay, (ii) the number of future frames used by the acoustic echo cancellation filter, and (iii) the time shift between consecutive frames processed by the acoustic echo cancellation filter, and wherein the first delay and the second delay are determined so that an effective echo path delay, resulting from addition of the first delay to the loudspeaker signal and addition of the second delay to the microphone signal, is obtained that is shifted closer to an integer number of hop sizes and further from an odd integer number of half hop sizes.