Techniques for distortion reducing multi-band compressor with timbre preservation
AssigneeDolby Laboratories Licensing Corporation
InventorAlan J. Seefeldt
Life of this patent
Estimating the term…
Abstract
Distortion reducing multi-band compressor with timbre preservation is provided. Timbre preservation is achieved by determining a time-varying threshold in each of a plurality frequency bands as a function of a respective fixed threshold for the frequency band and, at least in part, an audio signal level and a fixed threshold outside such frequency band. If a particular frequency band receives significant gain reduction due to being above or approaching its fixed threshold, then a time-varying threshold of one or more other frequency bands are also decreased to receive some gain reduction. In a specific embodiment, time-varying thresholds can be computed from an average difference of the audio input signal in each frequency band and its respective fixed threshold.
Claims6
An apparatus comprising:
- a multi-band filterbank configured to split an audio signal for a plurality of frequency bands;
- compression function element dedicated to a frequency band of the plurality of frequency bands;
- a timbre preservation element coupled to the compression function element, the timbre preservation element configured to provide a time-varying threshold for the frequency band;
- and
- at least one audio transducer configured to audibly present an audio signal outputted from the compression function element,
- wherein the time-varying threshold for the frequency band is determined by levels of the audio signal from neighboring frequency bands but not all of the plurality of frequency bands.
An apparatus comprising:
- a multi-band filterbank configured to split an audio signal for a plurality of frequency bands;
- compression function element dedicated to a frequency band of the plurality of frequency bands;
- a timbre preservation element coupled to the compression function element, the timbre preservation element configured to provide a time-varying threshold for the frequency band;
- and
- at least one audio transducer configured to audibly present an audio signal outputted from the compression function element,
- wherein the time-varying threshold for the frequency band is determined by at least one level of the audio signal outside the frequency band but not all of the plurality of frequency bands.
Dependencies are inferred from the claim text.