Methods for surround sound simulation and circuits and systems using the same
AssigneeCirrus Logic, Inc.
InventorRaghunath K. Rao
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Abstract
A method of producing reverberation effects is disclosed. A filter is implemented for modeling early acoustic reflections in response to an input signal using a first processor, the filter includes a delay buffer of a selected length and having a selected number of taps for tapping samples of corresponding amounts of delay and a summer for summing the tapped samples to generate a filter output signal. A reverberator is implemented for modeling late acoustic reflections using a second processor, the reverberator receiving the filter output and generating a plurality of output signals.
Claims21
A method of producing reverberation effects comprising the steps of:
- partitioning processing tasks between a plurality of processors;
- implementing a filter for modeling early acoustic reflections in response to an input signal, the filter including a delay buffer of a selected length and having a selected number of taps for tapping samples of corresponding amounts of delay and a summer for summing the tapped samples to generate a filter output signal, the delay buffer set-up in virtual memory using areas of program and data memories associated with the first processor;
- and
- implementing a reverberator for modeling late acoustic reflections, the reverberator receiving the fitter output and generating a plurality of output signals.
A method of operating a single-chip dual-processor audio device comprising the steps of:
- with a first processor, performing the steps of:
- selectively combining digital stereo audio input signals to generate a single mono data signal;
- and
- filtering a first single mono data signal with a finite impulse response filter;
- and
- with the second processor, performing the steps of:
- filtering an output of the finite impulse response filter to obtain a plurality of filtered signals each having a selected delay and a decaying amplitude;
- and
- selectively mixing each of the plurality of filtered signals with the output of the finite impulse response filter and the input audio signals to produce a plurality of audio output signals with a reverberation component.
An audio data processing system comprising:
- a source of digitized audio data;
- a audio decoder system with surround sound support comprising:
- a memory;
- a first digital signal processor operable to simulate early acoustic reflections by filtering said digitized audio data using a delay buffer setup in said memory;
- a second digital signal processor operable to receive a stream of data from the first processor and model late acoustic reflections and output a plurality of streams of surround sound audio data signals;
- and
- inter-processor communications circuitry for transferring the stream of data from the first processor to the second processor through shared memory;
- and
- circuitry for driving a plurality of speakers using the surround sound audio data to simulate a selected environment.
Dependencies are inferred from the claim text.