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US 2016/0240183 A1Published application
Multi-rate system for audio processing
AssigneeDTS, Inc.
InventorsDaekyoung Noh, Themis Katsianos
Life of this patent
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Abstract
A multi-rate audio processing system and method provides real-time measurement and processing of amplitude/phase changes in the transition band of the lowest frequency subband caused by the audio processing that can be used to apply amplitude/phase compensation to the higher subband(s). Tone signals may be injected into the transition band to provide strong tonal content for measurement and processing. The real-time measurement and compensation adapts to time-varying amplitude/phase changes regardless of the source of the change (e.g. non-linear time-varying linear or user control parameters) and provides universal applicability for any linear audio processing.
Claims26
A method of audio reproduction, comprising:
- splitting a first digital audio signal into at least a first and a second frequency subbands to generate at least a first and a second subband signal, said first and second frequency subbands separated by a transition frequency band;
- generating a first downsampled subband signal by downsampling or decimating the first subband signal;
- injecting at least one tone signal that lies within the transition frequency band into the first downsampled subband signal;
- generating a first processed subband signal by performing an audio processing on the first downsampled subband signal;
- measuring in real-time amplitude and phase in the transition frequency band of the first downsampled subband signal and the first processed subband signal;
- processing in real-time the measurements to calculate a change in amplitude and phase in the transition frequency band;
- calculating in real-time both an amplitude compensation and a phase compensation for the second frequency subband to approximately match the measured change in amplitude and phase in the first frequency subband;
- generating in real-time a second processed subband signal by applying said amplitude and phase compensation to the transition band of the second subband signal;
- removing said at least one tone signal from the first processed subband signal;
- and
- combining the first and second processed subband signals to reconstruct an output audio signal.
8 more elements
A method of audio reproduction, comprising:
- splitting a first digital audio signal into at least a first and a second frequency subbands to generate at least a first and a second subband signal, said first and second frequency subbands separated by a transition frequency band;
- generating a first downsampled subband signal by downsampling or decimating the first subband signal;
- generating a first processed subband signal by performing an audio processing on the first downsampled subband signal;
- measuring in real-time amplitude and phase in the transition frequency band of the first downsampled subband signal and the first processed subband signal;
- processing in real-time the measurements to calculate a change in amplitude and phase in the transition frequency band;
- calculating in real-time both an amplitude compensation and a phase compensation for the second frequency subband to approximately match the measured change in amplitude and phase in the first frequency subband;
- generating in real-time a second processed subband signal by applying said amplitude and phase compensation to the transition band of the second subband signal;
- and
- combining the first and second processed subband signals to reconstruct an output audio signal.
6 more elements
An audio reproduction system, comprising:
- a quadrature mirror filter (QMF) bank configured to split a digital audio signal into at least a lowest and a highest frequency subbands to generate at least a first and a second subband signal, said lowest and highest frequency subbands separated by a transition frequency band, and to decimate at least the first subband signal to generate a first downsampled subband signal;
- an audio processor configured to perform audio processing on the first downsampled subband signal to generate a first processed subband signal;
- amplitude and phase compensators configured to apply amplitude and phase compensation to the second subband signal to generate a second processed subband signal;
- and
- a compensation unit configured to in real-time measure amplitude and phase in the transition frequency band of the first downsampled subband signal and the first processed subband signal before and after the audio processor, respectively, calculate a change in amplitude and phase in the transition frequency band, and calculate updates for the amplitude and phase compensation to approximately match the calculated change,
- wherein said QMF filter is configured to expand at least the first processed subband signal and to combine the first and second processed subband signals to reconstruct an audio output.
3 more elements
Dependencies are inferred from the claim text.