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US 9,431,982 B1Granted
Loudness learning and balancing system
AssigneeAmazon Technologies, Inc.
InventorsJun Yang, Philip Ryan Hilmes, Chad Georges Seguin
Life of this patent
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Abstract
A loudness learning and balancing system for one or more audio channels. The system learns user volume preferences from manual interventions, providing effective and robust loudness learning to provide a consistent and balanced sonic experience. The system also reduces and/or eliminates incorrect attenuation or over-amplification of quiet interludes in the audio material, thereby eliminating artifacts such as noise pumping or breathing. In addition, the system reduces low level noise in the audio signals while preserving a wide dynamic range at most listening levels.
Claims20
A method adaptively adjusting audio output levels in a multi-channel audio system, comprising:
- receiving a first plurality of audio signals including a first left-channel audio signal and a first right-channel audio signal;
- receiving a first gain specified by a volume control of the audio system;
- applying the first gain to the first plurality of audio signals, producing a volume-adjusted plurality of audio signals including a volume-adjusted left-channel audio signal and a volume-adjusted right-channel audio signal;
- delaying the volume-adjusted plurality of audio signals, producing a delayed volume-adjusted plurality of audio signals;
- determining a first volume change corresponding to a difference between the first gain at a first time and the first gain at a second time, wherein the second time is after the first time and the first volume change indicates a decrease in volume;
- comparing a plurality of volume changes including the first volume change and at least one past volume change to determine that a majority of the plurality of volume changes correspond to increases of the first gain;
- determining a left-channel loudness level of the volume-adjusted left-channel audio signal at the second time;
- determining a right-channel loudness level of the volume-adjusted right-channel audio signal at the second time;
- combining the left-channel loudness level and the right-channel loudness level, producing a combined loudness level;
- determining that the combined loudness level is to be boosted to expand dynamic range as a result of the majority of the plurality of volume changes corresponding to increases of the first gain;
- determining a second gain to boost the combined loudness level;
- applying the second gain to the delayed volume-adjusted plurality of audio signals to create a second plurality of audio signals;
- and
- outputting the second plurality of audio signals.
11 more elements
A computing device comprising:
- a processor;
- a memory including instruction operable to be executed by the processor to perform a set of actions to configure the at least one processor to:
- determine a first gain applied to a first audio signal;
- store first audio data representing the first audio signal for a first period of time;
- generate a delayed first audio signal based at least in part on the first audio data after the first period of time;
- determine a first loudness level of the first audio signal;
- determine a first plurality of changes between adjacent pairs of values of the first gain over a second period of time, the first plurality of changes including a first change, where changes from a larger first gain to a smaller first gain constitute a decrease to the first gain, and changes from a smaller first gain to a larger first gain constitute an increase to the first gain;
- determine that a majority of the first plurality of changes occurring over the second period of time correspond to decreases to the first gain;
- determine a second gain after the first change based at least in part on the first loudness level and based at least in part on the majority of changes to the first gain being decreases to the first gain;
- and
- determine a dynamic range of the delayed first audio signal based at least in part on the second gain.
8 more elements
A method comprising:
- determining a first gain applied to a first audio signal;
- storing first audio data representing the first audio signal for a first period of time;
- generating a delayed first audio signal based at least in part on the first audio data after the first period of time;
- determining a first loudness level of the first audio signal;
- determining a first plurality of changes between adjacent pairs of values of the first gain over a second period of time, the first plurality of changes including a first change, where changes from a larger first gain to a smaller first gain constitute a decrease to the first gain, and changes from a smaller first gain to a larger first gain constitute an increase to the first gain;
- determining that a majority of the first plurality of changes occurring over the second period of time correspond to decreases to the first gain;
- determining a second gain after the first change based at least in part on the first loudness level and based at least in part on the majority of changes to the first gain being decreases to the first gain;
- and
- determining a dynamic range of the delayed first audio signal based at least in part on the second gain.
6 more elements
Dependencies are inferred from the claim text.