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US 12,218,643 B2Granted
Low latency audio filterbank having improved frequency resolution
AssigneeDolby Laboratories Licensing Corporation
InventorDavid S. McGrath
Life of this patent
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Abstract
A filterbank, suitable for modifying audio signals with dynamic gains in each band, is constructed so that the perceived latency is small, while a larger group delay is applied at low frequencies to enable higher frequency resolution in the lower frequency bands. The higher group delay at low frequencies is achieved by inserting an all-pass filter into the reconstructed filter response.
Claims19
A method of audio processing, the method comprising:
- generating a plurality of modified impulse responses from a plurality of original impulse responses, wherein the plurality of original impulse responses respectively correspond to a plurality of frequencies, wherein generating the plurality of modified impulse responses includes:
- performing a fade operation and a time reverse operation on at least one of the plurality of original impulse responses;
- generating a pre-ripple response based on a first original impulse response;
- generating a post-ripple response based on the pre-ripple response;
- and
- adding the post-ripple response to the first original impulse response, and subtracting the pre-ripple response from the first original impulse response, to generate a first modified impulse response;
- and
- filtering an input signal with the plurality of modified impulse responses to generate an output signal.
5 more elements
An apparatus for audio processing, the apparatus comprising:
- a processor;
- and
- a memory,
- wherein the processor is configured to control the apparatus to generate a plurality of modified impulse responses from a plurality of original impulse responses, wherein the plurality of original impulse responses respectively correspond to a plurality of frequencies, wherein generating the plurality of modified impulse responses includes:
- performing a fade operation and a time reverse operation on at least one of the plurality of original impulse responses;
- generating a pre-ripple response based on a first original impulse response;
- generating a post-ripple response based on the pre-ripple response;
- and
- adding the post-ripple response to the first original impulse response, and subtracting the pre-ripple response from the first original impulse response, to generate a first modified impulse response;
- and
- wherein the processor is configured to control the apparatus to filter an input signal with the plurality of modified impulse responses to generate an output signal.
8 more elements
Dependencies are inferred from the claim text.